Tire Pressure on 15x8 rims vs. 15X7

JimmyGold · October 22, 2004

I get a really rough tide at about 60 mph. I have had my front end inspected, everything is in good condition. I don't have vibration in the steering wheel that comes from bad steering components or poor balancing, it's the whole car that vibrates really hard. Granted these are All-terrain tires that have deep cross tread. The guys at sears think my problems are due to the tread. I'm not to sure.

I read an article that said increasing rim width on the same tire will increase sidewall stiffness? Is this true? If so, should I decrease my PSI from 32 to say 29? Thanks!

I would appreciate any feedback any of you guys and gals may have. I have a 2000 GMC Jimmy, I replaced my stock rims that were 15X7 to 15X8. At one point I had 255/70/15 Yokohama Avid ST's on, which sucked. They were out of round and the tread had cracked, after 8,000 miles. Yokohama paid for a new set of tires from Bridgestone for me. I purchased 235/70/15 Dueler APT III's, I wanted a size that could easily be replaced if I had tire failure, had a tough time before.

In any case, these tires are definitely good the only problem is the rough ride. Thanks again.