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Title: Have you checked your tire pressure lately??
Post by: John Roberts {JR} on December 01, 2011, 04:25:08 PM
that time of the year....

I lose several # over the course of a year...

The low profile tires are hard to eyeball...

JR
Title: Re: Have you checked your tire pressure lately??
Post by: Tim McCulloch on December 01, 2011, 04:33:45 PM
that time of the year....

I lose several # over the course of a year...

The low profile tires are hard to eyeball...

JR

Indeed.  I added about 10# to my mom's tires, 5# to mine.
Title: Re: Have you checked your tire pressure lately??
Post by: Bob Leonard on December 01, 2011, 05:05:14 PM
10# to mine last week.
Title: Re: Have you checked your tire pressure lately??
Post by: Doug Fowler on December 01, 2011, 05:09:42 PM
10# to mine last week.

I have a dodgy rim on my '96 Accord, need to add every couple of weeks.
Title: Re: Have you checked your tire pressure lately??
Post by: Bob Charest on December 01, 2011, 05:22:49 PM
I have a dodgy rim on my '96 Accord, need to add every couple of weeks.
My wife's car had a flat front this morning... re-inflated & when I got to the shop they said the bead was dirty/corroded. They cleaned it and all set now. Loss of pressure finally let a slow leak happen overnight.

Wish this post had happened yesterday...  :)
Title: Re: Have you checked your tire pressure lately??
Post by: Rob Spence on December 01, 2011, 07:26:10 PM
My girlfriend's mom had new tires put on at the Honda dealer and they all went flat over the next several days. I guess they didn't clean up the rim.

I took out my trailer for a gig a few weeks ago after reading this thread. Before I left I checked the tires and they all wanted about 20#. Thanks for the reminder.
Title: Re: Have you checked your tire pressure lately??
Post by: Kemper Watson on December 01, 2011, 08:30:57 PM
that time of the year....

I lose several # over the course of a year...

The low profile tires are hard to eyeball...

JR


Everyone should have one of these:

http://www.homedepot.com/h_d1/N-5yc1v/R-100348465/h_d2/ProductDisplay?langId=-1&storeId=10051&catalogId=10053
Title: Re: Have you checked your tire pressure lately??
Post by: John Halliburton on December 01, 2011, 09:24:30 PM

Everyone should have one of these:

http://www.homedepot.com/h_d1/N-5yc1v/R-100348465/h_d2/ProductDisplay?langId=-1&storeId=10051&catalogId=10053

The heck with it, I just bought a new vehicle.

Okay, the old Honda Odyssey finally ran true to form and developed transmission problems, but it had 154k on it, so I had real reservations about dumping large amounts of money into repairing it(needed a timing belt too, and would have needed new struts and rear brakes next year).

I decided to go back to a pickup truck.  Looking into caps and/or Line-X right now.

Tire pressure is good though.  ;)

Best regards,

John

Title: Re: Have you checked your tire pressure lately??
Post by: Hayden J. Nebus on December 01, 2011, 09:46:11 PM
that time of the year....

I lose several # over the course of a year...

The low profile tires are hard to eyeball...

JR

A few weeks back I lost all pressure in a leaky rear tire of a 26' enterprise, fully loaded with PA, at highway speed. The load (arguably overload) then blewout the inner tire and we damn near spilled vertec and my A2 all over the road in a rollover.
 
It would have been a shame to lose the vertec  :)

Title: Re: Have you checked your tire pressure lately??
Post by: Tim McCulloch on December 01, 2011, 10:01:17 PM
A few weeks back I lost all pressure in a leaky rear tire of a 26' enterprise, fully loaded with PA, at highway speed. The load (arguably overload) then blewout the inner tire and we damn near spilled vertec and my A2 all over the road in a rollover.
 
It would have been a shame to lose the vertec  :)

We lost both passenger side duals on a 24'.  We weren't over weight for either the truck or tires, but it was 112° out.

My observation has been that we lose the inside dual most of the time because it's the most difficult to check or inflate... damn near impossible to get a tire chuck on the stem.
Title: Re: Have you checked your tire pressure lately??
Post by: Jay Barracato on December 02, 2011, 08:04:01 AM
The heck with it, I just bought a new vehicle.

Okay, the old Honda Odyssey finally ran true to form and developed transmission problems, but it had 154k on it, so I had real reservations about dumping large amounts of money into repairing it(needed a timing belt too, and would have needed new struts and rear brakes next year).

I decided to go back to a pickup truck.  Looking into caps and/or Line-X right now.

Tire pressure is good though.  ;)

Best regards,

John

Hi John,

Years ago I got a Bedrug http://www.bedrug.com/ (http://www.bedrug.com/) for my F250. It is a lot easier on the equipment and keeps stuff from sliding around. It is also easier on the body when climbing around back there.

It is also comfortable enough that I still sleep on it a number of times a year when I don't feel like hauling my travel trailer.

If I am not hauling gravel or sand or the like on a regular basis, I would never have Line X instead. If the rug gets dirty it hoses off fine.
Title: Re: Have you checked your tire pressure lately??
Post by: John Halliburton on December 02, 2011, 09:10:26 AM
Years ago I got a Bedrug http://www.bedrug.com/ (http://www.bedrug.com/) for my F250. It is a lot easier on the equipment and keeps stuff from sliding around. It is also easier on the body when climbing around back there.

Jay,

Thanks for the link-I was also looking into some type of liner pad on the bottom of the truck bed, especially if I get a cap.  While I love the Line-X product, it is tough to slide things on it, doubly so if it is a speaker cabinet with the same type of finish. 

A plastic or vinyl liner seems to make more sense, but this Bedrug product should do the same job.  I suspect it originally came only in green, and with stripes and numbers painted on it. ;>)

Best regards,

John
Title: Re: Have you checked your tire pressure lately??
Post by: Jonathan Johnson on December 02, 2011, 05:26:46 PM
My observation has been that we lose the inside dual most of the time because it's the most difficult to check or inflate... damn near impossible to get a tire chuck on the stem.

Don't know if this is the case for you, but driving on narrow roads with a pronounced crown can cause rapid wear of inner duals because there is more pressure on the inside than on the outside. Or so I've heard; I've never driven a rig with duals.

I've heard this is a common problem on farm trucks in the midwest.
Title: Re: Have you checked your tire pressure lately??
Post by: Jeff Bankston on December 02, 2011, 07:34:11 PM
Don't know if this is the case for you, but driving on narrow roads with a pronounced crown can cause rapid wear of inner duals because there is more pressure on the inside than on the outside. Or so I've heard; I've never driven a rig with duals.

I've heard this is a common problem on farm trucks in the midwest.
had this dually since 2006 and never had a tire wear unevenly. driven on some uneven roads. got about 85,000 miles out of the first setta bfg tires. got about 37,000 on the 2nd set of the same kinda bfg tires and all are wearing evenly. older ford pickups from the 60's,70's,80's have short front I-beams and wear out front tires fast due to side to side scrub. always check your trailer tires b 4 each trip. some ST type tires are thin and tend to seep air like a road race tire.
Title: Re: Have you checked your tire pressure lately??
Post by: John Roberts {JR} on December 13, 2012, 02:27:10 PM
Bump... it's that time of the year... Just topped mine off... one was down to 25# but with the low profile tires it was almost impossible to see any difference.

Proper tire inflation is a good thing.

JR
Title: Re: Have you checked your tire pressure lately??
Post by: Tim McCulloch on December 13, 2012, 03:02:37 PM
Yep, put 8# in each of my tires the other day.  Tis the season.
Title: Re: Have you checked your tire pressure lately??
Post by: Geoff Doane on December 13, 2012, 05:02:32 PM
Bump... it's that time of the year... Just topped mine off... one was down to 25# but with the low profile tires it was almost impossible to see any difference.

Proper tire inflation is a good thing.

JR

It's easy to remember to check tire pressure where I live, because in November, it's time to put the snow tires on.  My snow tires have their own rims, but it's also a good time to get them re-balanced and the alignment checked.  I don't even bother to change them myself any more (unless I can't get to the garage for some reason).  It costs the same to get four wheels balanced, as it does to swap the summers for winters (assuming they're already on rims).

So I've been all set for over a month now, but we haven't seen any snow.  :)

GTD
Title: Re: Have you checked your tire pressure lately??
Post by: John Roberts {JR} on December 13, 2012, 05:07:27 PM
It hasn't snowed here yet either...

I didn't own snow tires even when I lived up in New England, but I probably should have... my current ride is not snow friendly, not even rain friendly...

JR
Title: Re: Have you checked your tire pressure lately??
Post by: Jonathan Johnson on December 14, 2012, 01:44:43 AM
Check the spare, too. You don't want to discover that it's flat, too.

If you've got a pickup that has the underbed spare, position it so the stem is pointing down. That way you can check & fill without having to crank it down.
Title: Re: Have you checked your tire pressure lately??
Post by: Chris Hindle on December 14, 2012, 08:23:57 AM
Check the spare, too. You don't want to discover that it's flat, too.

If you've got a pickup that has the underbed spare, position it so the stem is pointing down. That way you can check & fill without having to crank it down.
While you're at it, grease the frickin chain.
Title: Re: Have you checked your tire pressure lately??
Post by: Bob Leonard on December 14, 2012, 08:52:46 AM
My truck checks the tires electronically within 5psi. Good enough for me. Do yourself a favor though and stay away from SLU-trac tires. They tend to keep going down on you.
Title: Re: Have you checked your tire pressure lately??
Post by: John Roberts {JR} on November 11, 2013, 05:17:02 PM
Bump .... just topped off my tires for another winter.

JR
Title: Re: Have you checked your tire pressure lately??
Post by: Craig Hauber on November 11, 2013, 08:00:45 PM
We lost both passenger side duals on a 24'.  We weren't over weight for either the truck or tires, but it was 112° out.

My observation has been that we lose the inside dual most of the time because it's the most difficult to check or inflate... damn near impossible to get a tire chuck on the stem.

My tire shop said that many make the mistake of thinking that the outer tires in a set of duals are the more important ones and if they can save a few $$ by moving the better 2 used tires to the inside and putting new ones on the outers.

They recommend that you make sure the inner ones are in the best shape before the outers and ideally just replace all 4 simultaneously. -However since they wear un-evenly, just leave the outers where they are and replace the inners new

(I of course learned this the hard way sitting beside I-15 waiting for a tire service in the middle of the desert at 125deg!)

You can also get longer stems installed that reach through the outer rim for easier access to check and fill.

Also as far as pressure is concerned, I'm sure a properly inflated and non-leaking set of tires will read a large difference between summer and winter temperatures -it may not be leaky tires when they checked out fine at 80deg, and now it's sitting at 5deg!
Title: Re: Have you checked your tire pressure lately??
Post by: John Roberts {JR} on November 11, 2013, 09:12:08 PM


Also as far as pressure is concerned, I'm sure a properly inflated and non-leaking set of tires will read a large difference between summer and winter temperatures -it may not be leaky tires when they checked out fine at 80deg, and now it's sitting at 5deg!

pV=nRT or something like that. It's been a while but I recall studying the ideal gas laws back in school.

It was 70' this afternoon when i re-filled them to high nominal pressure.  I have been doing this for the last several years and I seem to lose about 5 psi per year.

I miss the good old days when I could just look at the tires and tell if they needed air. The low profile tires always look a little flat.

JR
Title: Re: Have you checked your tire pressure lately??
Post by: Tom Bourke on November 12, 2013, 12:59:35 AM
pV=nRT or something like that. It's been a while but I recall studying the ideal gas laws back in school.

It was 70' this afternoon when i re-filled them to high nominal pressure.  I have been doing this for the last several years and I seem to lose about 5 psi per year.

I miss the good old days when I could just look at the tires and tell if they needed air. The low profile tires always look a little flat.

JR
That is the same equation I remember.  The simple version is PV/T=PV/T
T in both equations is in Deg Kelvin.  As I recall the %difference between summer/winter temps and cold/driven temp was so low when using deg K that temp was almost insignificant in PSI changes.  The real problems are leaks and under-inflation that lead to excessive flexing and friction.  This generates heat high enough to damage the tire, but not enough to cause the pressure to rise to explosive levels.  The tire material fails at a lower pressure.
Title: Re: Have you checked your tire pressure lately??
Post by: Jeff Bankston on November 12, 2013, 02:14:47 AM
My tire shop said that many make the mistake of thinking that the outer tires in a set of duals are the more important ones and if they can save a few $$ by moving the better 2 used tires to the inside and putting new ones on the outers.

They recommend that you make sure the inner ones are in the best shape before the outers and ideally just replace all 4 simultaneously. -However since they wear un-evenly, just leave the outers where they are and replace the inners new

(I of course learned this the hard way sitting beside I-15 waiting for a tire service in the middle of the desert at 125deg!)

You can also get longer stems installed that reach through the outer rim for easier access to check and fill.

Also as far as pressure is concerned, I'm sure a properly inflated and non-leaking set of tires will read a large difference between summer and winter temperatures -it may not be leaky tires when they checked out fine at 80deg, and now it's sitting at 5deg!
about  2 months ago i put the 3rd set of tires on my f350 dually. i always rotate. all the tires wear out evenly. i'v never heard of inside dually tires wearing out faster unless the floater housing is bent. i would never mix new and used tires on the rear of a duslly on the same side. the new tire is going to be taller and will have to compress before the load is also carried by the older shorter tire. the new tire will have more weight on it and thats not good when carrying maximum gvwr. its a really cheap and cheesy thing to do. also the shorter diameter old tire is going to scrub along the pavement and wear out quicker. i would never do that if i were a tire salesman. if 2 rear dually tires were still good i would put them on one side and new ones on the other providing they were the same brand and model tire and it was not a posi rear end. the tires need to be the same size on an axle with a posi otherwise one side will turn faster and wear the posi clutches out. heres a foto of my redneck hauler.
Title: Re: Have you checked your tire pressure lately??
Post by: Steve M Smith on November 12, 2013, 05:04:19 AM
10# to mine last week.

As an Englishman, I'm aware that Americans use the # symbol to show numbers where we would use No. (No. 1 instead of #1) but what does it mean when placed after a number as a few of you have done here?


Steve.
Title: Re: Have you checked your tire pressure lately??
Post by: Jeff Bankston on November 12, 2013, 05:32:35 AM
As an Englishman, I'm aware that Americans use the # symbol to show numbers where we would use No. (No. 1 instead of #1) but what does it mean when placed after a number as a few of you have done here?


Steve.
i havent a bloody clue mate ! i use this # in front of a number for numbers. i use lbs after a number for pounds as we did in construction and automotiva mechanics. i'v ben a bloody hooligan(Peter Chriss) type hot rodder since 1973. yeah mate i have had a lot of bloody knuckles. Molly Hatchet had a Bloody Reunion.
Title: Re: Have you checked your tire pressure lately??
Post by: Tim McCulloch on November 12, 2013, 08:44:49 AM
As an Englishman, I'm aware that Americans use the # symbol to show numbers where we would use No. (No. 1 instead of #1) but what does it mean when placed after a number as a few of you have done here?


Steve.

Pounds, as a measure of weight or pressure.
Title: Re: Have you checked your tire pressure lately??
Post by: John Roberts {JR} on November 12, 2013, 09:45:19 AM
Yup, here #=pounds  "and" number "and" sharp (while musical sharp may be tilted some. In UK you have currency pounds and probably weigh things in kilograms. 

JR
Title: Re: Have you checked your tire pressure lately??
Post by: Jim McKeveny on November 12, 2013, 10:51:38 AM
Geezer Alert: This is an old-school issue.

My family fleet all have TPMS. The GMs go to 1 psi resolution. It is fun to monitor the sun side v. shade on trips. Some of this stuff is out of our hands presently, but I imagine on-the-go reinflation will come to the consumer side soon.

Worst we have TMPS on is 2012 528ix (!), which only alerts when situation is dire (and will cook expensive run-flats)..

All trucks should have this as a real money-saver/safety item.
Title: Re: Have you checked your tire pressure lately??
Post by: John Roberts {JR} on November 12, 2013, 11:38:17 AM
Yup my car is getting a little long in the tooth, but it has air bags and ABS brakes so not completely low tech.

In fact the ABS brakes could probably count rotations and identify an outlier tire that is dangerously under inflated. With GPS location awareness it could even know how many rotations per unit distance are correct.

I have speculated that it should be possible to design a tire that captures air and pumps itself up as the sidewalls flex with every rotation. Just imagine an air pocket that is closed to the inside tire cavity, open to outside atmosphere, and not squeezed when near the top of the tire rotation. As the tire rotates to the bottom where the side wall flexes the cavity closes to the outside, opens to the inside, and gets squeezed. Since this is like a one direction air diode, constantly pumping up the tire, the valve stem needs to have an automatic over pressure release.

This would be enough to deal with normal leakage, but not an actual puncture.

Caveat, I haven't checked so some or all of this may already be in process, but there seems to be energy available from normal driving on a tire to keep it inflated fully. Just takes some clever sidewall design.   

JR

PS: Too much technology adds more points of failure. I already can't lock my car because the built in burglar alarm goes off spontaneously because some wire or sensor is faulty.
Title: Re: Have you checked your tire pressure lately??
Post by: Jonathan Johnson on November 12, 2013, 01:39:22 PM
Yup, here #=pounds  "and" number "and" sharp (while musical sharp may be tilted some. In UK you have currency pounds and probably weigh things in kilograms. 

JR

You forgot the new use: "hash." I think they use it on Twitter. Birds probably like hash; at least my chickens do. When they're settled in for the night you can hear them twittering contentedly.

My dad taught me that in England the inflation is so bad they have to measure their currency in pounds. ("That's pounds sterling to you, buddy.")
Title: Re: Have you checked your tire pressure lately??
Post by: John Roberts {JR} on November 12, 2013, 02:07:58 PM
You forgot the new use: "hash." I think they use it on Twitter. Birds probably like hash; at least my chickens do. When they're settled in for the night you can hear them twittering contentedly.

My dad taught me that in England the inflation is so bad they have to measure their currency in pounds. ("That's pounds sterling to you, buddy.")
The pound Sterling used to be worth 240 silver pennies equal to one pound weight of silver... These days 1 lbs of silver is more like $300 USD.  But the dollar isn't what it used to be before we went off the gold standard. Common US silver dollar coins are worth $15-20 just for their silver content.

"The wealth of nations" written by Adam Smith while not an easy read shares some interesting insights into money, commodities, trade, credit, taxes, and precious metals, etc.

JR

PS: I ignored hash tags, because I try to ignore twitter.
Title: Re: Have you checked your tire pressure lately??
Post by: Steve M Smith on November 12, 2013, 02:22:37 PM
Yup, here #=pounds  "and" number "and" sharp (while musical sharp may be tilted some. In UK you have currency pounds and probably weigh things in kilograms.

How dare you suggest such a thing?!!!!   We use proper, English pounds and ounces!

# is not sharp, ♯ is.  It has to be slanted so it shows up on a music score better than a straight version.


Steve.
Title: Re: Have you checked your tire pressure lately??
Post by: John Roberts {JR} on November 12, 2013, 02:26:43 PM
How dare you suggest such a thing?!!!!   We use proper, English pounds and ounces!

# is not sharp, ♯ is.  It has to be slanted so it shows up on a music score better than a straight version.


Steve.

My bad, when in GB the unit of measure I am most familiar with is pints.  8)

JR
Title: Re: Have you checked your tire pressure lately??
Post by: Steve M Smith on November 12, 2013, 03:40:52 PM
We haven't been as quick to adopt the metric system as the rest of Europe has.  When I was at school in about 1971, there was a metrication board set up with the intent to convert the UK to metric within five years.  Fourteen years later it was disbanded having failed.

People of my age tend to use metric for precision engineering and imperial for building/construction/carpentry type of things.

By law, our road signs must be imperial and car speedometers are in miles per hour.

The pint is a great measurement!


Steve.
Title: Re: Have you checked your tire pressure lately??
Post by: Jeff Bankston on November 12, 2013, 09:47:20 PM
Yup, here #=pounds  "and" number "and" sharp (while musical sharp may be tilted some. In UK you have currency pounds and probably weigh things in kilograms. 

JR
i'v never seen anyone use # for pounds. # is used for numbers only. in the electrical construction field and in the automotive field which as a hot rodder i'm still involved. lbs or pounds is used for wight. on my last custon crank i had made the form i filled out was 54 "pounds" not 54#. i weigh 325 "pounds" and that what the doc wrote on my last med exam for my class a commercial driver license med certificate.
Title: Re: Have you checked your tire pressure lately??
Post by: Jim McKeveny on November 13, 2013, 07:09:37 AM
USA's abandonment of metric measurement now aligns us with only Liberia as final users of ye olde inch/pounds/feet.



Title: Re: Have you checked your tire pressure lately??
Post by: Steve M Smith on November 13, 2013, 07:47:34 AM
USA's abandonment of metric measurement now aligns us with only Liberia as final users of ye olde inch/pounds/feet.

The US hasn't abandoned metric, you just haven't started using it properly yet!

You can include the UK as final users of imperial too as many of us will not let it go that easily.


Steve.
Title: Re: Have you checked your tire pressure lately??
Post by: John Roberts {JR} on November 13, 2013, 08:58:27 AM
i'v never seen anyone use # for pounds. # is used for numbers only. in the electrical construction field and in the automotive field which as a hot rodder i'm still involved. lbs or pounds is used for wight. on my last custon crank i had made the form i filled out was 54 "pounds" not 54#. i weigh 325 "pounds" and that what the doc wrote on my last med exam for my class a commercial driver license med certificate.
Thanks for clearing that up...  :o

I guess you never saw me use # for pounds. (There I did it again.) 8) Apparently it came from an early type-setting/printing contraction of lb into a single print character where they added a cross hatch to the l so it wouldn't be confused with numeral 1. Eventually they simplified it to #. 

I recall having racing engine crankshafts balanced, not weighed. Maybe they weigh it for shipping cost purposes. 

JR
Title: Re: Have you checked your tire pressure lately??
Post by: Steve M Smith on November 13, 2013, 12:31:26 PM
Thanks for clearing that up...  :o

I guess you never saw me use # for pounds. (There I did it again.) 8) Apparently it came from an early type-setting/printing contraction of lb into a single print character where they added a cross hatch to the l so it wouldn't be confused with numeral 1. Eventually they simplified it to #.

That's that one explained.  Any idea why # is used for number (or No.) ?


Steve.
Title: Re: Have you checked your tire pressure lately??
Post by: John Roberts {JR} on November 13, 2013, 12:48:55 PM
That's that one explained.  Any idea why # is used for number *or No.) ?


Steve.
No.. according to wiki it's called number sign in Canada, Pound sign in US, and Hash sign in UK.

Even the # button on telephone is called different things in different countries. More evidence of peoples divided by a common language.

JR
Title: Re: Have you checked your tire pressure lately??
Post by: Jeff Bankston on November 13, 2013, 04:45:31 PM
Thanks for clearing that up...  :o

I guess you never saw me use # for pounds. (There I did it again.) 8) Apparently it came from an early type-setting/printing contraction of lb into a single print character where they added a cross hatch to the l so it wouldn't be confused with numeral 1. Eventually they simplified it to #. 

I recall having racing engine crankshafts balanced, not weighed. Maybe they weigh it for shipping cost purposes. 

JR
when you have a custom crank made like the 2 Brayant Racing made for me they wanted to know how much did i want them to weigh. it has to do with rotating mass. the same as a 30 pound flywheel vs a 20 pound flywheel. the nascar guys like a heavier crank because they are not trying to come off the line fast and spin up fast like a drag racer. the nascar guys also use heavier rods to keep the momenton going and that also is said to save a fuel stops. i told them to grind the forged blank as light as they could. both cranks went inti my 392 cubic inch Windsor strokers. 3.9" stroke 4" bore. Oliver rods have several 6.2" rod weight choices. the super speedway rod is the heaviest and the standard light is lighter. i bought the standard light rods. there were rods that were lighter but as you go lighter they also are not as strong. i chose the standard light for strength. i use a Mcleod aluminum flywheel because i dont want all the inertia for roadracing. 
Title: Re: Have you checked your tire pressure lately??
Post by: Jeff Bankston on November 13, 2013, 04:54:19 PM
That's that one explained.  Any idea why # is used for number (or No.) ?


Steve.
when i was in school we were taught # stands for numbers. LBS is short for pounds. last night at the grocery store i was looking at meat(the kind that comes from chickens and cows) and all the packages had LBS after the weight #. also "no." also stands for number. i have never seen or heard of # standing for pounds until this thread. maybe its part of that fuzzy math garbage thats ben taught in schools for a while. i had problems on my electrical crews with young guys and the fuzzy math crap. i had to fire a guy because he kept isisting that #8 wire would work just fine even though the blue prints called for #6 wire. i tried to explain to him about circut breaker sizes and he would just argue that its what you decide to make it. i'm not joking , i had to deal with this fuzzy math stuff. that explains why companies want foreign workers to do tech jobs. its really sad when a BS eduication says it o.k. to teach kids that 2+2 can also = 5. the kids are the ones getting F'd !
Title: Re: Have you checked your tire pressure lately??
Post by: Jonathan Johnson on November 13, 2013, 05:31:14 PM
when i was in school we were taught # stands for numbers. LBS is short for pounds.

Always wondered why the abbreviation for pound is 'lb' and the abbreviation for ounce is 'oz.'

While we're at it, why is the second hand third?
Title: Re: Have you checked your tire pressure lately??
Post by: Jay Barracato on November 13, 2013, 05:55:20 PM
Always wondered why the abbreviation for pound is 'lb' and the abbreviation for ounce is 'oz.'

While we're at it, why is the second hand third?

At this point I feel inclined to introduce the unit "slug" into the conversation.

Of course to give equal credence to the metric system I can tell you about the days of my youth wandering the world and having battles with my friends. I did well since I had a nanochou which is 1000 times stronger than a picachou.

Sent from my DROID RAZR HD using Tapatalk

Title: Re: Have you checked your tire pressure lately??
Post by: John Roberts {JR} on November 13, 2013, 06:29:06 PM
when you have a custom crank made like the 2 Brayant Racing made for me they wanted to know how much did i want them to weigh. it has to do with rotating mass. the same as a 30 pound flywheel vs a 20 pound flywheel. the nascar guys like a heavier crank because they are not trying to come off the line fast and spin up fast like a drag racer. the nascar guys also use heavier rods to keep the momenton going and that also is said to save a fuel stops.
I'm going to need to think about this. You don't want more momentum in connecting rods because they are alternately moving up then down then up then down. So more mass is more that needs to get accelerated and decelerated every cycle. I suspect they need heavier rods, because they are making big horse power and they don't want the rods failing half way through a 500 mile race. Increasing the weight of the crankshaft counter weights may help smooth out the vibration caused by heavier connecting rods.

If they actually wanted to increase momentum (kinetic energy)  they could get more bang for the for the same dead weight by adding extra mass to the flywheel further away from the center to get the benefit of the moment arm. 

I suspect the simple answer is best, namely heavier rods to handle more power need a heavier crank to balance out.

OK I stand corrected, back in my misspent youth, just getting a stock crankshaft balanced was a high tech splurge we had to go all the way to Patterson NJ for. An extra expense I never bothered with. 
Quote


 i told them to grind the forged blank as light as they could. both cranks went inti my 392 cubic inch Windsor strokers. 3.9" stroke 4" bore. Oliver rods have several 6.2" rod weight choices. the super speedway rod is the heaviest and the standard light is lighter. i bought the standard light rods. there were rods that were lighter but as you go lighter they also are not as strong. i chose the standard light for strength. i use a Mcleod aluminum flywheel because i dont want all the inertia for roadracing.

It's been several years since I last threw a connecting rod, but I once had a dragstrip refuse to let me race without a scatter-shield because they didn't believe me when I told them I was stock.  ;D ;D (I wasn't). Here is a picture of me under the old hanging tree after swapping out one of my broken motors. About 50 years ago give or take. I probably didn't even have my license yet.  8)

JR


Title: Re: Have you checked your tire pressure lately??
Post by: Bill McIntosh on November 13, 2013, 08:36:35 PM
That's that one explained.  Any idea why # is used for number (or No.) ?


Steve.

It is really the octothorpe (a fun word to use in casual conversation).

http://en.wiktionary.org/wiki/octothorpe
 ;D :o 8)
Title: Re: Have you checked your tire pressure lately??
Post by: Jeff Bankston on November 13, 2013, 09:32:04 PM
I'm going to need to think about this. You don't want more momentum in connecting rods because they are alternately moving up then down then up then down. So more mass is more that needs to get accelerated and decelerated every cycle. I suspect they need heavier rods, because they are making big horse power and they don't want the rods failing half way through a 500 mile race. Increasing the weight of the crankshaft counter weights may help smooth out the vibration caused by heavier connecting rods.

If they actually wanted to increase momentum (kinetic energy)  they could get more bang for the for the same dead weight by adding extra mass to the flywheel further away from the center to get the benefit of the moment arm. 

I suspect the simple answer is best, namely heavier rods to handle more power need a heavier crank to balance out.

OK I stand corrected, back in my misspent youth, just getting a stock crankshaft balanced was a high tech splurge we had to go all the way to Patterson NJ for. An extra expense I never bothered with. 
It's been several years since I last threw a connecting rod, but I once had a dragstrip refuse to let me race without a scatter-shield because they didn't believe me when I told them I was stock.  ;D ;D (I wasn't). Here is a picture of me under the old hanging tree after swapping out one of my broken motors. About 50 years ago give or take. I probably didn't even have my license yet.  8)

JR
i have ben a roadracer since 1974. over the years i learned from Jack Roush when i wrenched on charlie Kemps cobra II imsa roadracer , Jim Grubbs a race car engine builder , www.maecomotorsport.com , Oliver rods , etc. one thing i learned about was moving mass. top fuel draengines use aluminum connecting rods because they are super light and that helps the engine spin up real fast. that also causes the engine to spin dowon faster. every moving part in the engine produces momentum. the standard light rods i have can easily handle 1500 hp. a nascar engine makes less than 700. in road racing your are speeding up and slowing down. i hit 155 mph on the front straight a willowsprings roadrace track. atg the halfway mark i start braking and downshifting so i can make it through turn 1 at about 80 mph. then i accelerate coming out of turn 3....nascar racing is quite different. once you get up to speed you normally dont downshift unless your on a short track and the engines are different for short track and tracks like talladega. the heavier rotating mass comes into play on those long tracks. i did a little racing at JIS back in the day and got board going around in circles like Billy Preston sings about. one of the 392W i have made 620 HP on the dyno. i could have used cheaper and weaker Eagle brand connecting rods but i decided to go overkill on the bottom end. as for pistons you definitly want them as light as possible. less stress on the bearings when they are yanked back down in the cylinder.
Title: Re: Have you checked your tire pressure lately??
Post by: Steve M Smith on November 14, 2013, 02:46:09 AM
It is really the octothorpe (a fun word to use in casual conversation).

That is a great word.  Up there with interrobang:  http://en.wikipedia.org/wiki/Interrobang


Steve.
Title: Re: Have you checked your tire pressure lately??
Post by: Chris Hindle on November 14, 2013, 08:06:24 AM
Jeff / John,
as a retired engine builder / mechanic, the COUNTERWEIGHTS on the crank are there to offset the weight of the connecting rods and pistons. Period.
A "heavier" crank with "lighter con rods is just going to shake the fillings out of your teeth, and rip up the main bearings.
Been there, seen that.
Same with a lighter crank and heavier rods, except that this combo shakes more. (because the heavier part is further from the centerline of the crank).
I don't grok the math, but I have seen the results.
Chris.
Title: Re: Have you checked your tire pressure lately??
Post by: John Roberts {JR} on November 14, 2013, 09:41:00 AM
Jeff / John,
as a retired engine builder / mechanic, the COUNTERWEIGHTS on the crank are there to offset the weight of the connecting rods and pistons. Period.
A "heavier" crank with "lighter con rods is just going to shake the fillings out of your teeth, and rip up the main bearings.
Been there, seen that.
Same with a lighter crank and heavier rods, except that this combo shakes more. (because the heavier part is further from the centerline of the crank).
I don't grok the math, but I have seen the results.
Chris.
Thanx... That's probably why they call them "counter" weights.  8)

There could be some extra gamesmanship in NASCAR where they may not be allowed to add mass to the flywheel (because flywheels can become grenades if they fail at high RPM). So some extra mass gets added where they can. I don't expect much advantage from increasing the rotating mass but competitive racing is a matter of inches and feet over hundreds of miles.

Back in my day we would (pay a shop to) balance stock crankshafts, adding or grinding off metal to match the connecting rod, piston, counter weight precisely, especially when planning to take an old motor up to higher RPM range.  My sense was that less was better for connecting rod weight (and any reciprocating mass) inside the motor. For me even aluminum rods were too exotic (expensive). While of course the rods and pistons and crank work together as a system so need to match. I never got that fancy in my messing around. While I did break my share of Y block bottom ends by turning a 4,500 RPM design motor up to 7,000 RPM...   

JR
Title: Re: Have you checked your tire pressure lately??
Post by: Chris Hindle on November 14, 2013, 12:06:06 PM
but competitive racing is a matter of inches and feet over hundreds of miles.

I think you'll find it's more of ounces and inches.....

and yes, when balancing a crank, it was always as a short block, with a pumped in oil supply.

Back in the olden days, after a "little work", I was able to get my 71 455HO to 7300 RPM regularly, with an occasional missed shift hitting 8000, where my rev limiter kicked in.
Did I mention I did a "little" work to that engine ?
(his was a street build, not a competitive racer)
Chris.
Title: Re: Have you checked your tire pressure lately??
Post by: John Roberts {JR} on November 14, 2013, 12:46:44 PM
I think you'll find it's more of ounces and inches.....

and yes, when balancing a crank, it was always as a short block, with a pumped in oil supply.

Back in the olden days, after a "little work", I was able to get my 71 455HO to 7300 RPM regularly, with an occasional missed shift hitting 8000, where my rev limiter kicked in.
Did I mention I did a "little" work to that engine ?
;D ;D  "71 455 is old days???  I was working with mid '50s technology, where OHV was a relatively new technology.  I managed to put enough carb, intake valve size, and cam shaft  lift/duration (with dual springs on the valves to prevent float)  with  <300 ci displacement. So I had a motor more than willing to rev thousands of RPM past it's design target. I honestly don't know how high. One motor that I blew was after my tachometer was stolen, so I was shifting when it ran out of accleration... It was pulling especially good that night, until a connecting rod let loose, cut my pan in half, and punched holes in my block.  :'(

A rev limiter would be nice but a relatively advanced technology for street racers back then. I had to put a special ignition in my supercharged mustang to prevent detonation as pressure built up with increasing RPM. It had a rev limiter too and I rather enjoyed putting the 2000 RPM chip in it, whenever I had to leave it somewhere for service.  ;D ;D  [edit forgot to mention the special ignition retarded timing based on # of boost in the intake, [/edit]
Quote
(his was a street build, not a competitive racer)
Chris.
My only taste of organized competition was running an actual extremely stock vehicle at the drags, one time when I went as a visitor but paid for a pit pass so was allowed to race. I only found out afterwards that I could have gotten $25 cash instead of the plastic trophy.
(http://www.johnhroberts.com/clipping.jpg)

Irony is that my current daily driver is a 32 valve DOHC, fuel injected, 5 speed, with posi-traction. 50 years ago that much automotive technology wasn't even on my dream list.

 
JR
Title: Re: Have you checked your tire pressure lately??
Post by: Chris Hindle on November 14, 2013, 02:07:43 PM
Irony is that my current daily driver is a 32 valve DOHC, fuel injected, 5 speed, with posi-traction. 50 years ago that much automotive technology wasn't even on my dream list.

Ain't dat da truth.
When I was working at a GM dealership through the 90's, the Quad-4 (DOHC, 4 valves per), Turbo'ed and inter-cooled Grand National, and Supercharged Bonnie were all street versions of technology I wished was (reasonably) available when I was "fixin up" my Trans-Am.
Not so much the fuel injection. I had a pretty good handle on jetting the carb. The Accel super-coil and a double point distributor driving an Accel electronic ignition box kept the spark happy at 7000+ RPM Try that with the box-stock delco or ford......

Kids today have no idea where this stuff really came from.........
That Grand National was a real bitch in the rain. Shoulda had wipers on the back glass, considering how easy it was to swap ends.......
Title: Re: Have you checked your tire pressure lately??
Post by: John Roberts {JR} on November 14, 2013, 03:20:53 PM
IIRC Chevy offered limited production fuel injection in '57, and ford countered with Paxton superchargers to win at the race track and show rooms.  Somebody from the government probably put their foot down to nip that in the bud... but it keeps coming around.  Silly now we can buy 1000 HP mercedes stock.

=====
 
Don't mention rain... I totaled my supercharged '93 mustang Cobra into a guardrail on the interstate in the rain with only 22k miles on it. I was still dialing it in. It left us much too soon. RIP  :'(

===
I used to have a Mallory dual point distributor back in the day, and the extra dwell time helped squeak a little more spark out of the old school Kettering ignition system for higher RPM (the hard part was keeping the points closed a longer percentage of the time.). My older brother built a very early capacitor discharge ignition kit while I never saw him wind his 392 hemi above 5,000 rpm.   

JR

PS: Funny how there are parallels between big iron in cars and power amps...
Title: Re: Have you checked your tire pressure lately??
Post by: Bob Leonard on November 14, 2013, 04:36:19 PM
Big iron good.

Those were days John when a shade tree and a winch were all you needed. Back in the 60's everything ran fast and a good cam, high rise manifold, dumps, traction bars, and a Holly were all you needed. We raced every Saturday night either in Lowell, MA or behind the Watertown Arsenal, literally blocking off the street. I still remember my BOSS 302 and the absolute piss my pants thrill I got the first time I opened it up. Not as powerful as, but way faster than my 64 Galaxie 500 with the 429 in it. Please god, make me young again.
Title: Re: Have you checked your tire pressure lately??
Post by: Bob Leonard on November 15, 2013, 04:45:19 PM
This past weekend I let my garage talk me into using a new brand of tire for the winter. 20" "Tractionwhore 5000" was the name. I had to bring them back because they kept going down on me.
Title: Re: Have you checked your tire pressure lately??
Post by: g'bye, Dick Rees on November 15, 2013, 05:13:44 PM
https://www.youtube.com/watch?v=5bJW-Vth9xQ
Title: Re: Have you checked your tire pressure lately??
Post by: John Roberts {JR} on December 11, 2014, 02:03:09 PM
It has been over a year so time for a reminder... I just checked my car and found two tires down around 25#. With the low profile tires I can't just eyeball them for inflation status so I have to actually measure them.

JR
Title: Re: Have you checked your tire pressure lately??
Post by: Ivan Beaver on December 11, 2014, 02:47:14 PM
It has been over a year so time for a reminder... I just checked my car and found two tires down around 25#. With the low profile tires I can't just eyeball them for inflation status so I have to actually measure them.

JR
A few weeks ago I check mine and they were low.

Thanks for the constant reminders----------
Title: Re: Have you checked your tire pressure lately??
Post by: Jonathan Johnson on December 11, 2014, 03:24:39 PM
It has been over a year so time for a reminder... I just checked my car and found two tires down around 25#. With the low profile tires I can't just eyeball them for inflation status so I have to actually measure them.

JR

The proper inflation is usually listed on the driver's side door or latch pillar.

Remember to check the spare, too! Those dinky donuts usually require 60 PSI.
Title: Re: Have you checked your tire pressure lately??
Post by: Bob Leonard on December 11, 2014, 06:16:43 PM
Back in the 60's I had a set of tires on my 64' Galaxie aptly named sluts. They kept going down on me.
Title: Re: Have you checked your tire pressure lately??
Post by: Tommy Peel on December 12, 2014, 11:59:48 AM
Thanks for the reminder JR. I need to check my car; it doesn't have one of those fancy TPMS systems like newer cars.
Title: Re: Have you checked your tire pressure lately??
Post by: Jonathan Johnson on December 12, 2014, 01:21:10 PM
Thanks for the reminder JR. I need to check my car; it doesn't have one of those fancy TPMS systems like newer cars.

How do you know the TPMS is working? Nobody hears the dog that doesn't bark.

Always a good idea to check with a gauge, even if you have TPMS.
Title: Re: Have you checked your tire pressure lately??
Post by: Tommy Peel on December 12, 2014, 02:10:52 PM
How do you know the TPMS is working? Nobody hears the dog that doesn't bark.

Always a good idea to check with a gauge, even if you have TPMS.

True enough.
Title: Re: Have you checked your tire pressure lately??
Post by: John Rutirasiri on December 16, 2014, 10:58:13 PM
How do you know the TPMS is working? Nobody hears the dog that doesn't bark.

Always a good idea to check with a gauge, even if you have TPMS.
Government regulation (in the US anyway) mandates that all TPMS system lights up a TPMS-specific MIL (malfunction indicator lamp, separate from check engine light) upon system failure.  It has been this way since MY2006 cars.  So you should know whether the TPMS is working or not.

But yes, totally agree that one needs to check tire pressure with a gauge, and not wait until TPMS lights up.

-JR
Title: Re: Have you checked your tire pressure lately??
Post by: Mark Cadwallader on December 17, 2014, 12:13:17 AM
Just asking, but how often do you check the calibration of your tire presure guages?  If you do (and don't live in Colorado Springs near NIST), what do you do to check the calibration?  (My non-NIST traceble solution is to use a 6" 1.5% accuracy guage manifold set up, in the middle of the range.)  Not withstanding the foregoing, an inaccurate guage is probably better than not checking at all. Mark C.
Title: Re: Have you checked your tire pressure lately??
Post by: John Roberts {JR} on October 03, 2015, 01:34:22 PM
Time for a reminder...

Yesterday I checked my car tires and they were down to 30#... Now that I have a good bicycle tire pump I top off my tires by hand. Putting 5# more into 4 tires was actually like work.  ;D

I counted pumps, and it took around 80 pumps per tire to hit 35#. I was no longer tempted to inflate any higher.

JR
Title: Re: Have you checked your tire pressure lately??
Post by: Ivan Beaver on October 03, 2015, 02:13:41 PM
Time for a reminder...

Yesterday I checked my car tires and they were down to 30#... Now that I have a good bicycle tire pump I top off my tires by hand. Putting 5# more into 4 tires was actually like work.  ;D

I counted pumps, and it took around 80 pumps per tire to hit 35#. I was no longer tempted to inflate any higher.

JR

Mine were low a couple of weeks ago.

Every time I think about air pressure in tires-I think of your reminders.

Thanks :)
Title: Re: Have you checked your tire pressure lately??
Post by: Scott Wagner on October 03, 2015, 02:26:07 PM
Not only are tires porous, pressure is affected by temperature. I check my tire pressures with every fill-up, if not more often. As for gauge accuracy, a 1-2 PSI difference (+/- 6%) is hardly critical in normal street-driven usage. Racing is a different story. You don't want to know how much my gauges cost.

How often do you all test the torque of the wheel lugs?
Title: Re: Have you checked your tire pressure lately??
Post by: Ivan Beaver on October 03, 2015, 03:40:30 PM


How often do you all test the torque of the wheel lugs?
I use the "feels about right" when changing tires.

So far I have not lost a wheel :)
Title: Re: Have you checked your tire pressure lately??
Post by: Keith Broughton on October 03, 2015, 04:03:30 PM
I use the "feels about right" when changing tires.

So far I have not lost a wheel :)
No Ivan, it's not a wheel that you have lost  ;)
Title: Re: Have you checked your tire pressure lately??
Post by: John Roberts {JR} on October 03, 2015, 05:24:45 PM
I use the "feels about right" when changing tires.

So far I have not lost a wheel :)
I had one get loose once (didn't fall off) but friends don't let friends prep for the drags when drunk... :o

Back in the '60s when I was a car-less college freshman in Boston with my car parked in NJ, I was home one weekend and after closing down the bars in NY (still too young to drink in NJ), me and a few friends decided to pull an all nighter and hit the drag strip the next day.. Actually it was already the next day and dawn was only a couple hours away. Long story short, one loose cheater slick was only one on the list of several new experiences. After reaching the drag strip I was unsuccessful convincing the pit inspection officials that my car was stock.  ::) I think the loping idle from my full race Isky cam gave me away. ;D Since I didn't have a scatter shield I didn't get to race that day.  :'(

JR
Title: Re: Have you checked your tire pressure lately??
Post by: Scott Wagner on October 03, 2015, 06:00:25 PM
I use the "feels about right" when changing tires.

So far I have not lost a wheel :)
Losing a wheel is certainly a problem, but not the only one caused by improperly (or unevenly) torqued lug nuts. Warped brake rotors, wheel bearing issues, etc. can all be caused by that. Snug is good enough for not losing a wheel, but even torque (within spec) is very important for the rest of the rotating mass at the end of your axle.
Title: Re: Have you checked your tire pressure lately??
Post by: Stephen Kirby on October 05, 2015, 06:50:35 PM
"You picked a fine time to leave me, loose wheel"
Title: Re: Have you checked your tire pressure lately??
Post by: Tom Roche on October 05, 2015, 08:21:00 PM
Just asking, but how often do you check the calibration of your tire presure guages?  If you do (and don't live in Colorado Springs near NIST), what do you do to check the calibration?  (My non-NIST traceble solution is to use a 6" 1.5% accuracy guage manifold set up, in the middle of the range.)  Not withstanding the foregoing, an inaccurate guage is probably better than not checking at all. Mark C.

I use an Accutire digital tire pressure gauge that claims an accuracy of within 0.05 PSI, which is plenty good for my daily commuter.  Consumer Reports reported the Accutire best in accuracy.  I've owned it for about 20 years and the battery is still good.

By the way, the TPMS in my car never fails to activate as soon as pressure drops below 32 PSI on any one tire.
Title: Re: Have you checked your tire pressure lately??
Post by: Jonathan Johnson on October 06, 2015, 01:46:54 AM
I use an Accutire digital tire pressure gauge that claims an accuracy of within 0.05 PSI, which is plenty good for my daily commuter.

Is that accuracy or precision? There is a difference between the two terms, and they are often confused.

I have a digital indoor/outdoor thermometer with a precision of +/-0.05 degrees (meaning that the display shows tenths of a degree), but it is inaccurate by several degrees.
Title: Re: Have you checked your tire pressure lately??
Post by: Tom Roche on October 06, 2015, 06:27:01 AM
Is that accuracy or precision? There is a difference between the two terms, and they are often confused.

I have a digital indoor/outdoor thermometer with a precision of +/-0.05 degrees (meaning that the display shows tenths of a degree), but it is inaccurate by several degrees.

As I mentioned, 0.05 is the claimed accuracy.  The display reads in 0.5 PSI increments.
Title: Re: Have you checked your tire pressure lately??
Post by: Scott Wagner on October 06, 2015, 12:05:24 PM
Is that accuracy or precision? There is a difference between the two terms, and they are often confused.

I have a digital indoor/outdoor thermometer with a precision of +/-0.05 degrees (meaning that the display shows tenths of a degree), but it is inaccurate by several degrees.
The tool has inherent precision. Accuracy comes from calibration.
Title: Re: Have you checked your tire pressure lately??
Post by: John Roberts {JR} on October 06, 2015, 12:34:30 PM
I like to joke that human hearing has couple digits more resolution than accuracy. :-)

JR
Title: Re: Have you checked your tire pressure lately??
Post by: John Roberts {JR} on March 07, 2018, 01:51:12 PM
bump... just checked my car tires and puny 25-26 psi....

low profile tires are hard to eyeball.

JR
Title: Re: Have you checked your tire pressure lately??
Post by: Mac Kerr on March 07, 2018, 03:39:28 PM
bump... just checked my car tires and puny 25-26 psi....

low profile tires are hard to eyeball.

JR

I don't know about yours, but my low profile tires take a lot of pressure. The recommended pressure is 41psi.

Mac
Title: Re: Have you checked your tire pressure lately??
Post by: Nathan Riddle on March 07, 2018, 03:42:47 PM
This is timely, my day job just sent out a memo to check all the company vehicles...

Apparently someone was on low tread tires and flipped his car via hydroplaning. Guy was okay.
Title: Re: Have you checked your tire pressure lately??
Post by: Bob Leonard on March 07, 2018, 04:23:13 PM
Replaced all my tires with new Michelins just before the start of the winter. Got 65,000 out of the originals and have only had 6 or so flat tires during that period of time.
Title: Re: Have you checked your tire pressure lately??
Post by: Don T. Williams on March 07, 2018, 04:49:35 PM
Since we are mostly on the subject of tire pressure, remember that many trailer tires use much, much higher tire pressures.  75 - 80 psi is common.  I lost a trailer tire because a tire shop used a standard valve stem on my stage trailer.  Trailer rims need higher pressure valve stems.

Werner Stagemobiles need 100 -110 psi if I remember correctly.  Those tires are rated for more weight and require special wheels and valve stems to handle the tire pressure!  Carefully check what the tire requires.  I see lots of "passenger car" tires and rims swapped onto trailers.  It could be dangerous or even deadly putting 80 psi into a questionable "used passenger car tire" used to quickly (or cheaply) get your trailer going !!!
Title: Re: Have you checked your tire pressure lately??
Post by: John Roberts {JR} on March 07, 2018, 05:16:33 PM
I don't know about yours, but my low profile tires take a lot of pressure. The recommended pressure is 41psi.

Mac
Over the decades when I was driving more miles a day (each way), than I now drive a full week, I experimented with (too) high inflation (45-50#), but these days I am running modest 32#.  25# was too low but would probably survive my short shopping trips.

Back in the day when I had a longer commute I had one tire fail on the highway (at speed) due to overheating from under inflation, but it did fail gracefully, mainly causing an extra PIA driving home that night. Did I mention low profile tires are hard to eyeball..? Especially if you don't look at them every time..  :o  Now I try to be more regular about  topping them up, and use a tire gauge to determine status.

I do like to pump my bike tires as hot as they can stand 50-60# because I can feel the difference in rolling resistance.

JR
Title: Re: Have you checked your tire pressure lately??
Post by: Mac Kerr on March 07, 2018, 06:31:03 PM
Over the decades when I was driving more miles a day (each way), than I now drive a full week, I experimented with (too) high inflation (45-50#), but these days I am running modest 32#.  25# was too low but would probably survive my short shopping trips.

Back in the day when I had a longer commute I had one tire fail on the highway (at speed) due to overheating from under inflation, but it did fail gracefully, mainly causing an extra PIA driving home that night. Did I mention low profile tires are hard to eyeball..? Especially if you don't look at them every time..  :o  Now I try to be more regular about  topping them up, and use a tire gauge to determine status.

I do like to pump my bike tires as hot as they can stand 50-60# because I can feel the difference in rolling resistance.

JR

If I don't keep my tires at 41psi they get cut when I hit a pothole. The northeast in winter is a pothole wonderland.

Mac
Title: Re: Have you checked your tire pressure lately??
Post by: John Roberts {JR} on March 07, 2018, 08:14:08 PM
If I don't keep my tires at 41psi they get cut when I hit a pothole. The northeast in winter is a pothole wonderland.

Mac
:o  ::)  :(  I used to live up there....    no frost heaves in MS.... ;D  Not that they take better care of the roads down here, but nature is just less of a biotch.

I figured out in the '80s I could move south, and nobody would stop me.  8)

JR
Title: Re: Have you checked your tire pressure lately??
Post by: Bob Leonard on March 07, 2018, 09:33:21 PM
If I don't keep my tires at 41psi they get cut when I hit a pothole. The northeast in winter is a pothole wonderland.

Mac


Yea, like in "wonder" where the car in front of me went. Or "wonder" if the town will ever fill this hole.
Title: Re: Have you checked your tire pressure lately??
Post by: GenePink on March 08, 2018, 03:11:28 AM
... Or "wonder" if the town will ever fill this hole.

It could be worse, there are four thousand in Blackburn, Lancashire.
Title: Re: Have you checked your tire pressure lately??
Post by: Kevin Graf on March 08, 2018, 08:34:33 AM
The 'Tire Pressure Monitor System' on newer cars, makes checking tire pressure easy.  But on all our past cars, we had a set of snow tires mounted on winter wheels and I would switch in the Spring and Fall.  But with a TPMS you need to go to a car dealer each time you switch, to have the car re-programed.
Title: Re: Have you checked your tire pressure lately??
Post by: Mac Kerr on March 08, 2018, 10:16:25 AM
The 'Tire Pressure Monitor System' on newer cars, makes checking tire pressure easy.  But on all our past cars, we had a set of snow tires mounted on winter wheels and I would switch in the Spring and Fall.  But with a TPMS you need to go to a car dealer each time you switch, to have the car re-programed.

In my car you do it yourself. After you fill your tires to the proper pressure you just reset the TPMS.

Mac
Title: Re: Have you checked your tire pressure lately??
Post by: John Roberts {JR} on March 08, 2018, 10:47:42 AM
My car is even more DIY... I have a pressure gauge in my glove box.

JR
Title: Re: Have you checked your tire pressure lately??
Post by: Dave Garoutte on March 08, 2018, 12:14:01 PM
Except when the stupid (expensive) sensors keep sending false warnings (girlfriend's Cherokee).
Title: Re: Have you checked your tire pressure lately??
Post by: Mac Kerr on March 08, 2018, 12:31:40 PM
Except when the stupid (expensive) sensors keep sending false warnings (girlfriend's Cherokee).
No expensive sensors, my TPNS is based on tire rotation speed.
My car is even more DIY... I have a pressure gauge in my glove box.

JR
My car's TPMS does not read out pressure, only pressure change, so I too have a dial gauge in in the glove compartment.
Title: Re: Have you checked your tire pressure lately??
Post by: John Roberts {JR} on March 08, 2018, 12:51:19 PM
No expensive sensors, my TPNS is based on tire rotation speed.My car's TPMS does not read out pressure, only pressure change, so I too have a dial gauge in in the glove compartment.
Sometimes too much technology exceeds the benefit... I am an old fan of KISS.

I haven't shared this lately but there is merit (imo) to running higher tire pressure on the interstate where you would like lower rolling resistance and would be willing to trade off a little traction. However for lower speed driving off the interstate you want the softer ride, and full traction.

my low tech solution is a pump mechanism built into the flexing tire sidewall, so every tire rotation could capture a tiny bit of air to keep the tires filled. Of course too much pressure is dangerous so a pressure release valve would be built in too. Ideally there could be a centrifugal component to the pressure relief valve so it holds higher pressure at highway speeds than it holds at lower secondary road speed.

Ideally this would be invisible to the driver and just work.

JR

PS: This is probably difficult because I am sure I am not the only person to have this idea.  8)