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

On Feb 18, 12:18 pm, "Drink" <jdrinkwa... (AT) satx (DOT) rr.com> wrote:
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.

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
"The Reverend Natural Light" <reverend (AT) fourthgen (DOT) org> wrote

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.



"Drink" <jdrinkwater (AT) satx (DOT) rr.com> wrote