Correct Tire Pressure ?

Hello,

Have a 2009 Buick LaCrosse. Tires on it are Nokian WRG2 225/60R16 98H

Folks at the dealership checked tire pressures during an oil change, and have now made them all 35 psi (when cold).

Have to admit that the car seems to handle a bit better with the higher pressures.

Used to be around 31 psi when cold and just starting out.

Tech Support at Nokian says to use what is on the car door sticker. They would not suggest any p which is a bit surprising as I thought the 'correct' pressure was probably more specific tire type determined, than what Buick would suggest.

Anyway, it's now 35 psi when cold. Goes up to about 38 after driving.

Car sticker says to set at 30 psi

Think what I have now (35/38 psi) is "safe" for summer driving ? Would hate to have a blowout due to higher pressures. 38 psi sounds quite high (to me). Is it ? Safety aspects are really important to me.

Any thoughts would be most appreciated.

Thanks, Bob

Reply to
Robert11
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If the tires are wearing fine with 31 lbs, put them back to 31. The oppisite is true, air pressure to low, (25 or under), will cause a blow out. You would be surprised at the how much air you can put in a tire before it blows. Air pressure to high will cause the center of the tire tread to wear faster. Air pressure to low will cause both outer edges of a tire tread to wear faster.

Reply to
no way

The question is what is the contact surface area of the tire when you make a turn? How much tread is contacting the road?

Mark on the tire with a thick white china marker, then drive on the road and make a few tight turns. Do you get nice even wear across the surface of the tire? If so the pressure is good.

You won't have a blowout because the pressure is too high... it's still probably way below the maximum rating on the side of the tire.

But you MIGHT have an accident because your handling is poorer than it should be, or because you skid when you wouldn't have skidded if you'd had more tire grip.

Then again, you might ALSO have far better handling and more contact area than you would with the lower pressure.

Don't guess, measure.

--scott

Reply to
Scott Dorsey

Chalk 'em and find out.

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nate

Reply to
N8N

The "correct" tire pressure according to almost all tire companies and car companies is the one provided by the vehicle manufacturer, assuming you are using the OE tire size. If you have changed the tire size to one that was not an option for your car, then you'll need to experiment. I'd never go lower than the pressure recommended by the car manufacurer. The pressure listed on the tire sidewall is the maximum pressure allowed for that tire, not the correct one for the car. Idiots at tire stores often inflate tires to the max pressure listed on the side walls. This is not really a big deal with regualr P series tires since they mostly have a 35 or 36 psi maximum pressure listed on the sidewalls and most cars these days recommend something in the 27 to 35 psi range. You can get in trouble if you ahve LT tires or P series extra load tires. These can have maximum pressures listed on the sidewalls of 45 psi or greater. Try driving something that was intended to use 35 psi with the tires inflated to 45....not fun.

I see others mention the chalk test. I suppose if you rub the chalk all over the tire and drive it like you normally do, it might show you something. A better modern test would be to use a contact thermometer to check the temperature across the width of the tires after a "normal" period of driving. You'd like to see a consitent temperature from one edge to the other. But if you only do short trips, seems like you might never actually reach steady state on the tire temperature.

Best bet is to go with the vehcile manufactuer's recommendation, and if you like the firmer feel, an extra pound or three won't hurt anything (just monitor the tires for excessive wear in the center).

Ed

Reply to
C. E. White

If tirerack tech articles are to be trusted at 35 the hydroplaning resistance is typically better than at 30psi. Not an issue if you crawl in torrential rain but is probably more important with asymmetric tread pattern tire such as WRG2 than with symmetrical tires that are often quite good at getting water and slush out at freeway speeds.

Reply to
AD

Tire size and recommended pressures are spec'd by vehicle manufacturers.

No, it's a little on the high side, shouldn't be a problem for a reasonable motorist. -----

- gpsman

Reply to
gpsman

My 2004 Buick Century (bought new) also says to set it at 30 psi all around. That seemed a little low to me too. I have compromised at 32 psi all these years. Probably my imagination but it seems to make the ride a bit harder. Perhaps Buick specifies 30 psi to give this low end Buick a softer ride? It currently has 22K miles on it (don't use it much) and the tires still look new, no noticeable wear patterns. Now I have to decide when to replace them because of old age (now 8 years old). I've read different opinions on the matter but the consensus seems to be 10 years. Opinions here?

Reply to
AJL

I never got that much milage from tires. If kept indoors, they should be good. I had one set on a car for longer, but you could start to feel the dryness, and some cracking. Cracking occurred with me on a set of performance michelins in less than two years. Did a lot of armor all, which I suspect was the major reason, aside from being in the outdoors, in the desert. I think you have to worry about the inner layers which you can't see.

Greg

Reply to
gregz

I see those same michelins on ferraris, resurrected from storage, they look fine on tv. Michelin XWX. I think I got maybe 10k at most. Very sticky tire, but not linear breakaway.

Greg

Reply to
gregz

tire replacement due to "old age" is just bullshit blown up congressional [and public] skirts by frod to help them wriggle out of multiple corporate manslaughter lawsuits for killing thousands of americans selling a vehicle [the exploder] they /knew/ to be fundamentally unstable and that would roll just because of a flat tire.

tire rubber doesn't rot on its own. and if the vehicle has been garaged in a reasonably ventilated area, you're absolutely not going to have any problems. as you may know, aerospace rules and regs are orders of magnitude stiffer than for ordinary passenger vehicles, and this is what michelin have to say about storage life of aero tires:

"Michelin aircraft tires or tubes have no age limit and may be placed in service, regardless of their age, provided all inspection criteria for service/storage/mounting ... are met."

Reply to
jim beam

open the owners manual, and inflate to the maximum pressure recommended for sustained high speed freeway driving. i guarantee it's less than the maximum pressure the manufacturer says the tire can tolerate per on the side wall of the tire.

Reply to
jim beam

This car has been garaged its whole life.

No noticeable cracks or drying in my tires.

This car only gets washed 3 or 4 times a year so no excess Armor All... :) Though I was under the impression that Armor All protected the tires from sun damage.

I also live in a desert climate (Phoenix) and the summer is especially hard on tires.

Yup. That's what I wonder about. There seems to be a wide range of opinion on the matter.

Reply to
AJL

The 'old tire' defense may be used in litigation, but I don't think that makes the old tire replacement concern 'bullshit'. There are too many articles on the subject by authors that have no reason to fabricate. But the problem for me is that while all the articles I've read agree that old tires should be replaced eventually, there seems to be no consensus of when. Most seem to be at 10 years, but many are also earlier.

Here is a sample article:

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It's not so much the rubber rot (though rubber also deteriorates with age) that's my concern but more what I can't see which could cause the increased chance of tread separation at high speeds. Especially here in the desert where freeway road temperatures can be brutal.

I would imagine that an aircraft tire is considerably better built than my car tire. I'm not sure that's a good comparison.

But according to my above posted link Michelin has a slightly different age limit for its car tires, 10 years:

"Tire manufacturers such as... Michelin say a tire can last up to 10 years, provided you get annual tire inspections after the fifth year."

But then the very next sentence says there's no way to date a tire:

"Manufacturers Association says there is no way to put a date on when a tire "expires," because such factors as heat, storage and conditions of use can dramatically reduce the life of a tire."

And this is typical of all the articles I've read on the matter. No consensus on the matter. Which is why I was curious what those here thought. Anyway I think I'll keep the tires for at least for another 2 years.

Thanks to all for your opinions.

Reply to
AJL

I heard of more horror stories with the stuff I used in the 70s. At least the newer stuff has uv protector. Tires cracked, dash cracked also. You will have less performance once the rubber gets dry. I like to take it out and do some hard driving to expose fresher rubber. Not sure how old the tires are on my datsun. They look fresh. 66 roadster. I previously was a one owner 77 z. 32 years. Went through 4 sets of tires, at 67k miles.

Greg

Greg

Reply to
gregz

Some of the data from insurance claims indicates that 82% of the age failures occur after 6 years. They extrapolate that tires over 10 years of age should not be put in service at all.

Companies like Ford, GM, and VW have agreed with this, according to what I can find.

Reply to
hls

This is the best option on here I would recommend, and I do it myself - run ning 1-2psi over the door sticker. Depends on the profile though, and even just a pound over on lower profiles(55 or 50 or 45 series tires) might ro ughen up the ride undesirably. With 60series and up you have have more side wall compliance, hence more room for experimentation. The chalk method doe s not work for me; I draw two lines across each tire - from the sidewall ac ross the tread. By the time I've gone up & down my driveway it is ALL gone. smh!!!

Reply to
ckozicki

are you guys for real??? you'll /really/ believe the guys with a vested interest in ass-covering and protecting their biggest advertisers over the guys that actually make the freakin things? and in this case, the guys who are not only the most advanced technologists in the field, but who have to satisfy the f.a.a?

you guys go ahead and waste you money and ignorantly keep on propagating the propaganda that gives manslaughterers a free pass. i won't. and i'm disgusted that you will.

Reply to
jim beam

- from the sidewall across the tread. By the time I've gone up & down my dr iveway it is ALL gone.

You don't need chalk, you can tell by the wear pattern.

Tires have a range of pressures. If the pattern is rolling over the edge even ever so slightly to the sidewall, it's under-inflated. If it doesn't reach the edge, it's overinflated. -----

- gpsman

Reply to
gpsman

for normal "pedestrian" applications, this is largely true. but for more sporting applications, or at least, driving that doesn't involve going in a straight line, some of the performance tires have sloped tread shoulders which don't normally touch the road, but which are designed to gradually lay more rubber as lateral force increases. "pedestrian" tires don't have this of course, and their edges are quite sharp so the tire type is easy to distinguish. so, with regard to pressure, not reaching the edge doesn't mean it's over-inflated if it's a tire whose edge is rolled.

Reply to
jim beam

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