A suggestion from Allante owners and GM engineer on the Allantnet.org site suggested 38-40 front and 30-32 rear on the Allante. Ride is a bit firm, but thats how I like it. I try to stay within that range, but previously ran 34 all around. I would be currious as to what others run as well.
As soon as you change the tire size, you're on your own. Experimentation is the only way unless you have someone with the same car/tire combo that has had success.
Yes, but the size I went to is the optional for STS 235/55-17, mounted on Cadillac rims of the proper size. What does the door sticker say for STS's with this size tires??