[b-man]

Originally Posted by Supertacks

It seems lots of folks are asking about tire size and wheel combos. Perhaps we should start a reference thread. A good side shot, front shot and rear shot of our cars, with tire size listed and notes about suspension mods that would affect ride height. That way we would have a good reference point.

I am getting ready to put some new sneakers on my 69 GTO Convertible. I have a set of 15x7 rallys I would like to use but have a million questions and only one chance to get it right. What is the widest tire I can put on those rims? What will fit? etc. This would be a great way to see what I am getting into.

I'm making this thread a sticky, but it must contain useful first-hand information about your own car only. Post a picture if you can to illustrate, we all like to see pictures.

Don't post pictures that are so large that we have to scroll back and forth to read the thread.

If your pictures are too big, please ask for help reducing their size in the 'Test & Tune' forum, I will delete any giant pics.

Posts must at the very minimum contain the following 3 pieces of information:

1) Rim diameter and width, front and rear.

2) Wheel backspacing measurement, front and rear. What brand of wheel and the actual name of the wheel would be good info to include as well.

If you don't know the backspacing measurement, kindly remove one front and one rear wheel and measure them. The measurement is made from the very back edge of the rim lip to the mounting face. With the tire mounted on the rim, lay a straightedge (a yardstick will do, on it's edge) across the tire sidewall and measure down to the wheel mounting face. Then measure down to the rim lip outer edge and subtract this measurement from the first one, easy to find your backspacing. Without that backspace measurement, there's no way to help anyone with your wheel/tire information.

Link to help you measure:http://earlywheel.com/choosing.html

I know that backspacing on some wheels are measured from the actual inner tire bead mounting surface, and this is probably the proper way from an engineer's standpoint (I was reminded of this by PY member TJH, may he RIP). But it's easier for reference to measure from the back edge of the rim lip since you can actually see it with the tires mounted. Plenty of wheel makers use the method I like to use, from the back edge of the rim lip.

3) Tire sizes, front and rear.

Tire brand would be good too, especially for those who are running specialty tires like redlines.

It would also help to state if your car still has the original width rear axle still in it, as a lot of rear end swaps are done with wider or narrower OEM rear ends. Some of us run a custom-narrowed rear for better looks or tire fit.

If your car is tubbed like a drag race car or Pro-Street car, any wheel/tire info you post is useless without knowing the width of the rear axle from flange to flange. Same thing goes for Pro-Touring cars with extensive chassis work, please let us know what's holding up the wheels.

Every kind of Pontiac is welcome, restored, modified, Pro-Touring, Pro-Street, drag race cars, big luxury cars, you name it. But it must be a Pontiac, so of course any later model front-wheel drive Grand Prix, Firebird up to '02 or GTO up to '06 is welcome. We don't want to see your other non-Pontiac cars, no matter how cool you think the wheel/tire combo is.

This thread should be a good source of technical information for those who are trying to decide what will fit or what looks good. If you have any questions about someone's combo, please send them a Private Message or start a new thread referring to their post in this thread.

We want to keep this thread 'clean' so it can be a useful archive, just wheel/tire combos only. For this thread to have any sort of usefulness or longevity please do your best to post good information, don't leave anything out. Any posts not following the format above will be deleted from this thread.

Thank you.