Warranty and tire pressure

[Falcon_LS]

There's a gas station a few hundred meters from a friend's house, so on my way home I decided to stop by the station and adjust the tire pressures on my Montero.

The door sticker calls for 26 PSI front and 29 PSI rear on the 265/70-16 tires (Pirelli Scorpion STRs fitted). I haven't got an infrared thermometer just yet, but when the tires are hot I usually add adjust to pump to 2-3 PSI more (e.g. 28-29 PSI instead of 26). With an ambient temperature of 8 Celsius and about 500 meters of driving, I decided I would go with the recommended cold pressure.

When I drove into the station, there was an attendant there who wouldn't let me adjust my own tire pressure. He automatically adjusted the gauge to 35 PSI, and I stopped him saying I need 26 up front and 29 rear. His response was "You're wrong, it's 35 for this car." I kind of lost my temper and left after that. When I rotate my tires in another 400 miles, I'll do the proper adjustments with my tire inflator.

Even with my Grand Marquis, if there's an attendant there, they always want to set the gauge to 35 PSI regardless of hot or cold. The door sticker calls for 32 PSI cold, so I suppose 34-35 isn't so bad when hot.

Basically everything gets 35 PSI by default here, regardless of manufacturer's recommendation. So this got me wondering, what sort of an impact this might have on tire warranties, when you are not following the manufacturer's recommendation for a particular application? When tires are installed, the installers always go by the tire placard.

 

[CapriRacer]

Do they have mileage warranties in Kuwait?

If they do, then they will go by the kind of wear on the tire. If it isn't even, then the warranty doesn't cover the tire - even if the miles driven is pretty small. Over-inflated tires tend to wear in the center, so that would void the warranty.

 

[Falcon_LS]

Thanks for the info!

Some manufacturers (Goodyear, Hankook and Toyo to name a few) have a 1 year, open mileage warranty. Others have a 60,000 km (36,000 mile) warranty.

 

[kballowe]

I don't live where you live but I can tell you that I nearly always run 35 psi in my automobile tires.

I find that 35 psi gets me the best tire wear and traction.

Think about it this way - how many tires have you seen with the edges worn out and a lot of tread in the middle (not counting mis-aligned front-ends). Typically these tires are under inflated.

Under-inflated tires run hotter than over-inflated tires.

The reason that a manufacturer may recommend a lower tire pressure is that the car will ride smoother and the tires will be quieter. Everything is a trade-off.

 

[bigmike]

If you ask about tire PSI here, you'll get 100 different answers. I over inflate mine to 38-39 PSI. I wouldn't feel comfortable running most tires below 32PSI.

 

[flwxman]

Your tires are probably better off at 35psi... 26psi is one major thing that got Ford in trouble.

 

[Eddie]

If the set pressure does not exceed the MAXIMUM pressure for that tire on the sire sidewall then there is no problem.

 

[BigCahuna]

How about getting your own air compressor? This way you can set the pressure to whatever you want to.,,

 

[kballowe]

Yes, and a GOOD tire pressure gauge.... those el cheapo tire gauges are horribly inacurate.

 

[ARCOgraphite]

Eddie got it, and tires are an important part of the vehicle suspension - I would not overinflate grossly. Many cars today have somewhat oversize tires for the vehicle weight (like my 2200lb yaris with 185 62 15. Look at the word - over-inflate - thats means the pressure is incorrect.
To investigate correct inflation further: If you drive slowly thru some water then some sand on a flat road the sand will paint the tyre and show of any gross over- or under-inflation; you dont want to see the sand "paint" rolling over the sidewall more than say 1/8in in front, or conversely, the sand paint pattern not painting to the tread edge break. Also be sure to anticipate any increase in load. You need less air in the back when not running a full placard capacity load. Over-inflation will damage suspension components and reduce braking effectiveness. I tweek my tires to within a 1/4lb/[]".

 

[opus1]

Originally Posted By: Eddie
If the set pressure does not exceed the MAXIMUM pressure for that tire on the sire sidewall then there is no problem.
Winner!

Lower pressures are set by the car maker for a smoother ride.

 

[Y_K]

Smoother ride? Here we go: thinner oils for CAFE, and lower tire pressure for smoother ride..

 

[bigmike]

10 original responses... 90 more to go!

 

[crinkles]

Sounds like my father in law - 35 PSI for everything, and he transferred that gem of knowledge to his daughter, my darlign wife. well now our car gets 35 PSI all round

 

[CROWNVIC4LIFE]

Every tire shop since the early 80's from NYC to Miami [including Ford] told me to keep 35 PSI all aound in all my Panthers...It turns out I get the best ride,handling and the most life out of them doing it that way.

 

[UncleS2]

The door frame sticker on Mom's 2008 Crown Vic specifies 35 psi, front & rear.

 

[CapriRacer]

As a tire engineer, I enjoy all the thoughts about inflation pressure. But there are some things that strike me as odd.

- Many folks are posting what inflation pressure they are using - but never reference what the vehicle tire placard says.

- Many folks are referencing what is written on the sidewall as though that has meaning other then what it says - maximum

Let me give you an example. Falcon, our OP, says that the vehicle tire placard says his front tires are supposed to be inflated to 26 psi. So if the tires say the maximum is 51 psi, then that is double! Does this sound like the right answer?

So where does the pressure on the sidewall come from?

Here: About half way down there is a discussion about the notes on page 1-34:

http://www.barrystiretech.com/loadtables.html

The notes say that a tire manufacturer can put any of those pressures on the sidewall and doesn't give a rationale as to what to use when.

So what about the vehicle tire placard?

It's a government requirement that it be there. Clearly, any vehicle manufacturer would pay close attention because it is a government requirement. Further, all vehicle testing would be done at that pressure. I think that means that it is a VERY important reference point - whether you agree that is the right pressure to use or not.