Currently looking at some 15X7 +40 wheels to be match to some 225/45r15 tires for track duty, I readed a lot on the forum but can't seem to find a positive answer as if it will fit my GD3, anyone can confirm me if or if not it 's gonna work and if necessary what Mods could be required to be made?

I'm currently running an eibach prokit suspension drop (about 1.5 inch lower) if you have to know...

Thanks for the help!

 

it'll work... you'll likely have to trim the rear bumper to quarter panel tabs...

however, 225's on a 7" wide tire isn't ideal... are you staying 7" because of a rule? you'd be better sorted to do a 205 on a 7" or 225 on a 8"

 

Yeah! Rules says 7.5 wide max for the wheel and 225 wide max for the tire.... 7.5 being hard to find at resonable price, I'm thinking I'll have to compromise on 7 inchs....

I'm prepping the car for STF class auto x next summer.....

 

With that wheel spec, 225s will not work in the rear without modification. If I remember right, the mounting tab for the bumper itself needs to be ground down (where the bumper screws into the rear quarter) and be resecured in another location...

How to secure it... I'm not 100% sure. I do know for a fact that Blue Cell's former GD3 had this done.

As for the fronts, you should be able to clear with a bit of negative camber. I'd say -2 degrees would be a decent starting point then working from there as you check clearances during lock to lock (both static and while moving) and during full compression.

I'm rather curious to see how this setup would be in person as I am running a 225/45 on a 15x9 +35 so my tire is actually stretched. In your case, the tire is a little too wide (but safe) for the wheel... really curious to see how sidewall flex will come into play there.

 

STF (at least here anyway) is limited up to a 225 width tire and a wheel width of no wider than 7.5 inches.

http://www.good-win-racing.com/mazda/miata/process.html

949 Racing wheels are usually a darn good bang for buck and DO come in 7.5 widths. Just inquire about offsets.

 

Yeah! But like i said, budget is part of the equation, plus I'm canadian so our money is worth crap at the moment...

So far, 90$ can. For a 15x7 new wheel is what I have to beat....

 

you can secure the rear bumper with a zip tie - i have it done and super easy...

you could also get fancy with something like this: