I just picked up my RX-8 from the dealer - they did a 15k service includes tire rotation. I'm not too smart about technology but when I saw that the tires were inflated to 40.. hm.. I used to run @32.

The service writer agreed it was too high but the garage guy who had put it to 40 said something like "the tires are so big they can handle 40".

On another note.. I read here something about the tires being directional and that this has implications on how you can rotate tires (no switching left and right, correct?). I'll admit that I don't know what directional tires are but now I'm nervous that the dealer's techs may not know either.

And I didn't mark them before I brought the car in, so I cannot tell.. well, one of the rims had a small scratch next to the lug nut, I'll try to find that.

What do you guys say? 40 is ok, just less grip?

And what about improper tire rotation?

The garage guy is full of crap. Adjust the pressure to the recommended value. Too much pressure gives less grip, uneven wear (more wear in the center of the tire), and danger of blowout over sharp bumps. 40psi is the MAX rated pressure for the tire, which is NOT the correct inflation pressure. The correct inflation pressure depends the vehicle (weight, f/r balance, etc.). For the 8, the pressure should be 32 psi cold on all corners. This is measured with the car on the ground, not with the tires off the car.

You can check the tires direction yourself - the correct tire rolling direction is on the sidewall. The word "Rotation" and a little arrow is molded into the sidewall.

Watch out man. Thesamething happened to me several months ago. All 4 of my tires had 40psi instead of 32 andmy car felt like it lost its suspension. The road felt incrediblyrough and everytime I went over a bump I shuttered. I drovearound like that for 3 days before noticing that the morons had pumped toomuch air into the tires.

I guess I have to praise them that they wrote the 40 on the sheet.

Thanks for the info on the tire direction.

I have to wonder if the dolts in the garage are putting 32 psi in the tires when they're off the car and then expecting that it'll not change when they put them on the car????? Duh!

wouldn't the TPS come on if the tires were 40? seems like it would.... :confused:

No, my service writer tested that as I pointed out the 40 psi.
They only recongize too low pressure.

Okay, here's my scoop on tire pressure. I'm worried about my tires. I did my routine monthly check the other week and found my tires at 55 and 57 psi. What the? I just checked the tires in the underground garage at work here after commuting about 70Kms and letting it sit for 3 hrs. The pressure is still at 55 and 57 psi. This is how I picked up the car from the dealership. I've been wondering why I feel like I'm driving without suspension since I picked it up. Is this normal even if the tire got hot or what? I'm going to check in another hour or so and bring it down to 32 psi, which wasn't on the inside of the door either.

Originally posted by ptiemann
No, my service writer tested that as I pointed out the 40 psi.
They only recongize too low pressure.

I'm pretty sure the manual says it'll warn for high pressures as well as low.

upon delivery of my 8 in 08-2004 the car was handling very badly with BIG understeer... checked the pressure and it was at 50 on all 4... lowered that to 32 and the car started to feel perfect...

I had my car delivered with 45 PSI in each. The correct pressure is 32 LBS.

It seems they ship the cars with higher presure so they can strap them down firmly without crunching the tires. The vehicle prep guys are SUPPOSED to lower the presures down to 32 LBS.

And yes, the little inflation doo-dad did light up...the bottom of the scale is ~29 LBS and the top is ~35 based on what I have seen.

BTW, at 45 LBS the car rides like poopies!

P.S. the sticker for the tire presures is on the door - not the one on the sill. There are 2 of them.

I got my car from the dealer about 3 weeks ago. They rotated the tires and I have a noisy ride now. I am not sure why and we are looking at getting the alignment checked. Anyone else have more noise or notice any difference after rotating?

Proper pressure is 32. The tire can handle more (as per the sidewall) but the car was not designed to take more than 32 unless you are taking more than the maximum load.

Given the car's 2900 lb weight, overinflation would likely cause crowning, no? You'd get abnormal wear in center of the tread not to mention a suspension that rides like a cement truck.

Probably other adverse effects as well like irregular contact patch and lower than optimal traction.

Best to check tire pressure when tires are cold. And the noise after tire rotation has been discussed elsewhere.

The TPMS (http://www.finishlineperformance.com/rx8/docs/index.html)
(for those of us in the US) only warns you if your tire pressure is not between 26 and 49 PSI. That's 32 -6/+17 - way too wide to skip checking your tire pressure at least monthly, if not more often.

rx8cited

At 40 lbs, your tires will wear right down the middles. And, if you didn't notice, you lost some traction.

I just want to cry when I read what those dealers do.. paying no attention and an unsuspecting buyer pays the price (prize).

Doesn't comfort me that my dealer isn't the only one doing this kind of stuff. Makes me just wonder about their other work.

My tire pressure warning light came on shortly after I picked up my car. I checked the pressure and three tires were at 32 but one was at 65. After I let some air out to bring the pressure down to 32 the light went out. So the tire pressure sensor does respond to the pressure being too high. I'm just not sure how high it has to be to trigger the warning light.

Originally posted by davesaunders300
.... I'm just not sure how high it has to be to trigger the warning light.

I posted then answer to that a few posts before yours :D.
rx8cited

I came looking for the same reason. All my tires are at 40PSI precisely (took delivery yesterday) while the sticker they added for the sport package tires says 32PSI. Seemed a little rough of a ride.... makes sens the check they do with the tire off the car. The worst such thing I had was on a large Chrysler years ago, when after fixing a tire, they put 55PSI in it. That tire was rated at 45PSI max! But as the car pulled on the other side, I stopped within few feet and checked it - correct it. But those guys were Pep Boys, not a high price dealer working on their own cars! Agree about this kind of thing being an indication of the quality of their other work - and car knowledge :o)

Alex

Originally posted by RodsterinFL
I got my car from the dealer about 3 weeks ago. They rotated the tires and I have a noisy ride now. I am not sure why and we are looking at getting the alignment checked. Anyone else have more noise or notice any difference after rotating?

Similar here. I rotated tires at 13,500 miles, and now at 17,500 miles they still are noisy. This was my 1st rotation, with the rears much more wore. Never had my alignment checked tho...

BTW, which dealer is this???

For 8's directional tires that are same size all around, you'll rotate front and back tires for left and then do the same for the right. You can't rotate in a X pattern unless you get non-directional tires. The directional grooves on the tires expel water for rain driving and cuts down on noise when they rotate correctly.