what is the widest back tire i can fit on a 90 gt, i would like to get a 12 if possible and does anyone know where to get the rim for that?
thanks

 

I have always been told a 10.5" wide in a 28" tall with a wheel spacer.
It is going to stick out a bit though.

To me it looks better if you can get a rear-end shortened about a 1.5" on each side and run a 10" tire.

If you do use the spacers, make sure to get longer studs to compensate for the wheel spacers.

 

double post

 

I have 275/45/17 on the rear of my 87 GT. That is the widest I could fit without messing with the quad shocks. They are 10.83" wide. The rims are 17X9. Here is a picture from the rear.

 

a 10 1/2" will fit if you reverse the quads

if you use a spacer they will rub and cut on turns