Hyperinflating tires

[oldtamiyaphile]

Originally Posted by CapriRacer

To my knowledge, there has NEVER been a pressure recommendation on the sidewall of any tire. For as long as I can remember, what has been on the sidewall have been maximums, not recommendations.

Well, I meant maximum, though even that is a recommendation rather than an absolute value. Either way there's nothing written on some sidewalls these days.

[gumby79]

Originally Posted by oldtamiyaphile

Well, I meant maximum, though even that is a recommendation rather than an absolute value. Either way there's nothing written on some sidewalls these days.

Picture nesasary or At least a sorce. The law suits would make the cup run over from idiots putting 100+ psi just becuas they don't know any better and the air kept going in if you don't think so look at the coffee cup at McDonalds
The other part of that safety notice on your sidewall is the rated load @psi. This is required for proper tire selection
eg. My LT 235/85R16 has 2 ratings
1 for single. "Max load single 1380kg(3042lbs)at 550 kpa(80psi) cold" 6084lbs per axel max
1for Dual. "Max load dual 1260kg ( 2774 lbs) at 550 Kpa (80psi ) cold" 11094lbs per axel
this is off of a set of snow tires purchased in Jan2016
The reason for reducing load rating on dual is because less sidewall deflation is allowed for dual or the sidewalls will rub holes in each other causing both to fail
I have seen this during harvest season in California
Especially if there is not a scale between the field and the canary, we are talking semi trailers overloaded with ,tomatoes ,grapes ,and all kinds of fruits and nuts. Their is only 1 northbound and no southbound scale between Modesto, California and Fresno ,California I worked for Big Jim's Tire Service out of Atwater , California in the middle

[oldtamiyaphile]

Originally Posted by gumby79

Picture nesasary or At least a sorce. The law suits would make the cup run over from idiots putting 100+ psi just becuas they don't know any better and the air kept going in if you don't think so look at the coffee cup at McDonalds

I just bought a pair of Conti PremiumContact2's that only state 'see vehicle placard' no mention of maximum pressure. It's something I'd read about on forums, but never seen for myself prior. So no law suits, besides, other than truck stops you'll struggle to find air that goes over 60PSI (annoying if you need 65 for your light truck tyres). Might be different in the US, but here all you'll get is 60PSI especially from the new digital gauges.

Light truck tyres are different and will typically have more pressure info to cover various situations.

[Frank Lee]

if you don't think so look at the coffee cup at McDonalds

Speaking of lawsuits, that one was justified. McDs found out the hard way that it's a bad idea to sell a scalding hot beverage.

[CapriRacer]

To my knowledge, the regulations covering tires REQUIRES the maximum inflation AND the maximum load be printed on the sidewall of EVERY street tire. The printing is allowed to be pretty small and sometimes wheel covers will cover it up, but I think it has to be normally visible even on a mounted tire.

Having said that, there are a number of different interpretations of those regulations and 2 different versions for load/inflation are used

a) Max Load XXXX, Max Inflation YY This is NOT a recommendation, and its does NOT state a relationship.

b) Max Load XXXX at YY pressure. This is also not a recommendation, and it does state a relationship.

Now to prove this, go out to your car or truck and look. The printing is frequently near the rim and pretty small. Do NOT look at your riding mower or your tractor. The regulations do NOT cover those types of tires. However, it does cover motorcycles!

[user removed]

I bought a 2006 Scion XB new. The dealership had replaced the tires and wheels with an $1800 option which I declined so they put the stock steel wheels back on the car.

When I drove home (25 miles) I knew something was wrong. I checked the pressure and it was at 65 psi!!!!! That was the pressure of the 50 series tires they had put on the car not the 44 max pressure of the stock tires. I ran 44 until I got rid of the car.

I tried higher pressures on a 92 F150 and that truck beat me to death of those tires.

I've run 42 to 45 on the wife's Sorento and she has right at 50 k miles on the OE Continentals with just under 5/32nds of the tread left. One tire is a little noisy and there is a nail in that tire, but no leakage. Since the nail is right where most shops tell you it can't be repaired, it can stay there until she decides to replace the tires which will probably be close to 50k miles and before the winter of 2016.

I've run higher pressures for over 100 k miles, WITHOUT ANY FAILURE I COULD ATTRIBUTE TO RUNNING SIDEWALL MAX PRESSURE.

I will not run pressures significantly higher than sidewall max, 44-50 on my Mirage and at least 5 psi lower on the wife's vehicle.

How much has it saved me in 100k miles. Enough to buy the tires when they need replacing. I have a set waiting for the tires to wear out on the Mirage, at about the same 50k as the Sorento.

regards
mech

[gumby79]

Originally Posted by oldtamiyaphile

Might be different in the US, but here all you'll get is 60PSI especially from the new digital gauges.

Light truck tyres are different and will typically have more pressure info to cover various situations.

Yes the U.S. is different the other day I bumped my tires up to 80 pounds for Towing my friends F-250 on a car trailer and I got pictures of what happens with running excessive air pressure( sidewall Max) and not enough weight to compensate for the excess pressure this was at a gas station
As for LT's agreed situational awareness is required no matter what kind of tire is being used. Just got to know what to look for.
on my truck I'm running 65 PSI in the front to accommodate 3500 pounds I'm running 50 in the rear to accommodate 2500 pounds the tires are rated for 6000 + pounds per axel at 80psi . I only have 5520 pounds of weight total so I have to compensate otherwise I have too narrow of a contact patch. This reduced contact patch compromises abilitie to drive safely on icy roads.
During the said experiment I had a deer jump out on me hit the brakes and rear locked up. And the rear tried to come around on me got pictures of the skidmark only 4.5"wide with a tread surface of 7.5".Running 80 pounds of air these studs in my winter snow tires were not even touching the road not even picking up dust.
Gotta figure out how to get my pictures reduced on my new phone. I haven't figured out yet how to crop them down small enough to get them to upload here. Expect pictures of contact patch and as before referenced temperature references for what is actually touching the roadway and developing heat 30°f variation between Center 45f and age of tread 20f ground 10f measured with a Ir temp gun. My point is that just because the tire can hold more air doesn't mean it's necessarily a good thing if your weight rating of your tires is properly matched to the weight of the vehicle yes you can run 100 PSI provided the tires/wheels/valvestems can handle it and they are narrow enough and were constructed correctly for the amount of weight/pressure you are running. This would also require a completely engineering of the suspension system so that it didn't beat you to death before you got out of driveway.
Eg the new Tall Skinny high pressure prototype tires found hear

http://ecomodder.com/forum/showthrea...s-25208-4.html

On my bicycle back in High School, my mountain bike tires were rated for 60 PSI Max I ran a 85 - 90 PSI for lower rrc never had a failure 3000+loged miles. however some racing tires for bicycles are rated 200 PSI with 10 pound bicycle and 150 pound individual you can do the math and figure out how many square inches of contact patches available for traction, steering , and breaking, less than 1sq in

[gumby79]

4.5" skid mark left by a 7 .5" wide tread 235mm section ÷ 25.4 =9.25" tire inflated to 80 psi with only 2500 pound on the axel.
Notice there are three primary stripes Center and on the edges there are two 1/4-0"wide strips. These two 1/4-0" wide strips are the portion of the tire which contains studs which gave me traction on ice
Also notice, section width does not equal tread width. Section width is the widest point of the sidewall measured on the specified test wheel for that tire size. And this amount of variance varies with tire size make model manufacturer wheel that is mounted on ECT ECT...

[Galvatron1]

Originally Posted by elhigh

Working for several years as the lot boy at a Toyota dealer, I noticed that the cars all came with the tires overinflated. Not just a few pounds, they were typically all jacked up to 60psi. I wouldn't want to leave them like that for driving around, but it gives me a feeling of some confidence that maintaining the max sidewall rating of 44 won't overstress the tire.

If they came in from the Toyota manufacturing at 60 psi & the max sidewall pressure is 44 psi, wouldn't that make it hyperinflated, not just overinflated?

[JSH]

Originally Posted by Galvatron1

If they came in from the Toyota manufacturing at 60 psi & the max sidewall pressure is 44 psi, wouldn't that make it hyperinflated, not just overinflated?

My guess is the transporter is pumping up the tires to reduce the amount of movement during transportation.