[ponchopio]

First of all...WHOAH! That is an AMAZING GP Logan!

Going to a 15" won't necessarily throw the speedo unless you go to a different overall tire height. For example, going to a 15" rim with a slightly lower sidewall profile that matches the previous tire height will not alter the speedo operation and will actually improve handling a bit.

I have the stock 14x7 Rally IIs on my 70GP and I think another 1" of offset would really meet the outer wheel lip nicely. Check out www.wheelvintiques.com for some additional info about measuring.

In a nutshell, if you had a 14x7 Rally II spare, lay a straightedge across the back rim lip and measure the distance to the mounting surface. This will be your backspace. I think a 15x8 Rally II with the backspacing measurement from your 14x7 will give you a nice, deep looking offset allowing for more tire width without looking "tacky". Obviously there are a number of factors you need to consider so use the rim measuring tools at the wheel sites like WheelVintiques and educate yourself. They are really easy to use.

BTW, I have a few questions for you about your GP. Would you email me off the board at your leisure? Thank you!

John Piotrowski
[email protected]
www.fullsizepontiacs.com