Tire PSI

I run 34 front and 32 rear in both cars with 17" wheels and Michelin Pilot Sports all round.

I use the Michelin Pilots Sports but I have 245/40-17s in the front. For just driving around or going to work I'll run them at 28 or 30 cold. That keeps my fillings in my teeth and my internal organs in their original places. If I was going to use them in any situation where handling was important, I would start at maybe 42 in the rear and maybe 38 in the front. A lot depends on what are your priorities and what is your alignment and how long you want the tires to last.

50 sounds ridiculously high, I would certainly get some more info before running at that pressure. I expect you would be running on the center of the tire at that pressure, I am also assuming that is your hot pressure which still would be too high in my book. Of course every tire is different. Looking around the web I saw many people looking for 35-38 psi hot which might be 32-35 cold - might be too soft for your comfort but should give maximum grip without the tire getting greasy. Call someone at Michelin 1-866-866-6605 - they should have some good info.

I kept front and back at 38 today and put on 100 miles. The roads still had some dust on them, which was ok because it gave a solid indication of where the rubber hits the road. I think 38 is the magic number for me ...

Weird, but I thought for sure I started this thread in the Coach forum. Oh well ...

I have the 335/35/17 rear and 245/45/17 front. Those pressure sound way high. I had the fronts replaced this week (1999 date on the old ones)and my tire guy noticed the rears were running a bit in the centre. He suggested 28/28 for around town. Less bone jarring as well.

quote:

Originally posted by EA #3528:
Weird, but I thought for sure I started this thread in the Coach forum. Oh well ...

You did, and I moved it.

Now why would you start a thread about tires in the coach forum?

On average I move a half dozen threads to other forums each week.

By the way,

Assuming your toe in and camber are set properly, you'll want to run enough air pressure to achieve even temperatures across the face of the tire, at least as a starting point for a track setting.

On a street car, the best setting will be the pressure that achieves even wear across the tire. Too much pressue will cause the tire to wear faster in the center, too little pressure will cause the tire to wear faster on both edges.

I'm running close to the factory recommended setting, i.e. 28 psi front, 26 psi rear. One end (the rear I think) is running about a pound less pressure than the factory recommendation, due to wear.

The pressures that work best on the street will likely be inadequate on the track.

Wow, that's really hard. I have the same tire but never went above 34 on the street. And even that is hard if you want the rears to grab when you put the hammer down. In the cold or wet it is wise to stay softer. Ask Marcus.

quote:

Originally posted by Cowboy from Hell:

quote:

Originally posted by EA #3528:
Weird, but I thought for sure I started this thread in the Coach forum. Oh well ...

You did, and I moved it.

Now why would you start a thread about tires in the coach forum?

On average I move a half dozen threads to other forums each week.

Nice work, Cowboy. That's why this forum works so well, I guess. I'm just a rookie, remember!

As part of my inspection (which is a legislative requirement for all cars entering Alberta), all 4 wheels were checked for alignment. The technician mentioned that my toe in and camber were both acceptable, but that I should pop back in a few weeks for a free review once I've had some drive time as there are some minor tweaks that could be made.

The good news is that I'm riding smooth. Not a lot of bone-jaring and traction is awesome.

Have a look at this pic. The dust on the rears will show you where my rubber hits the road. The outter wall has not been in contact, which indicates that I have room to back off the 38psi I am running?

Continued thoughts?

Just came back from a short 15 mile run ... this time with the front/back at 33psi.

There was a noticeable difference in ride (a lot smoother), although I did not hammer down to test for performance.

Have a look at my tread wear ...

I have the same rubber, I run 34 psi on all 4 corners.... I run 50 psi in my truck when I'm towing heavy loads

Passenger rear ...

Driver rear ...

I only put 50 psi in the Pantera when i carry fat chicks around

Not the constructive feedback I was hoping for ...

I just put 34psi cold in my Pilot Sports on all four corners. It feels good, but I may drop them a bit and try 30psi cold.

Michael

AHHHHHHHHHH! I'm going to have nightmares tonight!!!!

Erik,

I run 30—32 in my P-Zeros of the same size. Personally, I like a bit softer ride.

EA,

Just a hunch. I am going just by your photos and I don't have all the info on your car ....

My personal opinion is that your camber is out. I know your alignment shop said its fine but I have my doubts. I had seen the same thing on my car when I took the shock spacers out and went to the wide rear rims.

If your car has had the shock spacers taken out as well (or different shocks that lower the car) and with the wide low profile tires, it could be that you need extendable upper A-arms to put the camber in spec. The wear (dust) pattern on the tires makes me suspect this. Because the cars are hand built, some cars get away with not needing this - While others do.

After I put in the extendable/adjustable upper A-arms - all was well. The downside was that I prematurely wore some tread off the inner side of the rear tires before I did this.

HTH

B.G.