Twinturbofan

I bought a 2003 tt which came with 19" Victor Equipment Zehn wheels. The car had 235 35 19 on front and 285 30 19 on rear. Ran for 2k miles no problems. Then found right front strut was bent. Replaced both front struts (Bilstiens), mounts and bearings, new front brakes including new stock rotors and replaced rear tires as inside edges worn to cord. At first, thought 305 or even 315 30 19 would be best on rear but after reading all about diameter differences and possible problems with center viscous coupling put identical Bridgestone RE050A Pilot rear tires on (285 30 19) and had a 4 wheel alignment done. Took car out for a spirited drive and in the middle of a hard left, there was a minor thump sound and the car lurched twice towards the outside of the turn. Scared the s___ out of me! After numerous drives during which this seemed to happen rarely but arbitrarily in both right and left turns (only with high lateral loads), and noticing one time the PSM light blink on and off and one time the red brake light flashed 3-4 times in rapid succession, took the car to the shop and had codes read out. Tiptronic trans was reading "inplausible wheel speeds". I believe the PSM is braking one of the front wheels at the most inopportune time. I am wondering if putting new rears on while not replacing the worn but still serviceable fronts could be causing this? Has anyone else experienced this? Any ideas or suggestions? Any input would be appreciated. Thanks.

lhsa

you should have purchased 315/25/19 rears, which are the proper diameter match to the 235/35/19 fronts.

Fikse Wheels

Double check the width and offset of the rear wheels before purchasing the 315/25 19
The PSM may also not like the wider front and narrower rear as compared to stock. The 235/35 front and 315/25 rear is a much better combination, but only if you have the correct rear wheel size.

adam_

Youve got wrong size tires on the car. 25.5" OD on the front, 26.0" on the rear.

Spec on OE tires is 0.1" difference, you are 5 times that. Your tires are revolving at different rates front and rear, this can damage the differential and cause issues with PSM intervention.

Personally I do not think the PSM can tell a damn thing about how wide the wheels are.

A

Joe Weinstein

How worn, and what brand of tires? ALso, get your dealer to recalibrate your
steering angle sensor. I have had this problem occasionally, but not recently
after having done that. It takes them 5 minutes to do.

Twinturbofan

My rear wheels are 19 x 11 (ET36). Will the 315/25s work on these? Tires are Bridgestone RE050A Pole Position, well worn in front, brand new in rear. It appears I may have to buy 4 new tires (315/25 for rears) in order to correct this problem. My research shows a diameter difference of .1" in stock 18" rim form and that I currently have a .3" diameter difference with my rim/tire sizes. I am wondering if the fact that the rears are brand new and the fronts are worn is causing the difference to exceed the PSM tolerances.

ca993twin

Perhaps you can find an appropriate sized front tire which will work on your wheels and will better match the rear size you have now?
Yes, 315x25 will work fine on a 11" wheel.

Rufus uses 255x30x19 and 315x25x19. These are very close to the original overall height that came with the car with 18" wheels.

Joe Weinstein

There doesn't seem to be a 315x25x19 in the RE050A... Just look at the actual tire specs
from the tire rack site. A difference of 0.3" is fine, but if your fronts are worn and your
rears are new there will be a bigger difference. Just buy new fronts.

Twinturbofan

Thanks everyone for the advice and suggestions. It's back to the tire shop for me. I appreciate the help.

Kevinmacd

Check this out:
http://www.europeancarweb.com/featur...est/index.html