What rear tires fit the '87 Trans Am?

Question

Hi all, I have an '87 Firebird Trans Am and I want to fit some fat tires on the rear. I don't have any narrowed axles, tubbed fenders or other such mod to affect fitment; original axles & suspension geometry. I need to lift the rear a little to raise the I.C.G. and help the suspension hook and intend to do some other mods (shortened torque arm, CA reloc. brackets, etc.) and am willing to swap rims to fit the tires. So, there it is: Does anybody have insight as to how fat a tire will fit the rear without scrubbing? Best Regards, Jim

The Reverend Natural Light · Accepted Answer

Jacking the ass-end up and stuffing in huge tires will ruin the handling of the car.

If you don't already have the honeycomb 16" wheels, I'd recommend finding two pair of matching front wheels (4 fronts, so you can rotate them and it'll be a tad wider in the back), and put on some good

245/50R16 performance tires. Lower it about an inch, bolt in a set of Koni shocks and struts, and weld on subframe connectors.

Also check the gearing. If it's anything other than a 3.73:1 rear with a limited slip diff, go get one at a boneyard. It'll make a huge difference.

Drink · Answer

Thanks for the advice.  I'm not exactly wanting to "jack it up"; just lift it up a little since the springs are either sagging or somebody lowered it to the point that the links are pointing down.  I already have the honeycomb 16" with 245/50R16's, subframe connectors, 3.73 gears in the factory posi. I'm setting it up for a bracket drag car and don't really straighten out curves:)  It's not a dedicated race car; just for weekend fun.  I'm not putting slicks on it.  I intend to shorten the torque arm and lift the back just a little to fix the geometry so it'll hook a little better.  Still, traction starts with rubber on the road and I want wider tires on the rear.  Anybody have any ideas on what fits?  Best Regards,  Jim

Badda Bing Badda Boom · Answer

10 years ago, my son bought a used 87 Trans-am WS6 that came with 275/50R16's on the rear. When we took them off you could see a small amount of rubbing on the inside wheel well in a straight vertical pattern centered on the axle. We put new stock size 245's back on it and it handled a lot better. This was a 305 TPI 5 speed with WS6 suspension.Jacking up a good handling sports car so it looks like some kind of a reject from a 60's drag strip should be a crime.

What rear tires fit the '87 Trans Am?

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