[GoatRider]

For owners/racers of 69 GTO's. I would like to know what is the biggest (Diameter) rear tire anyone has been able to run without having to modify the quarterpanel to "stretch" the opening from back to front???

I am confident enough in my welding skills to narrow the frame rails and install tubs, but would really like to avoid doing any sheet metal work on the painted portions if say a 30" tall tire will fit in the opening... Not to mention doing so would mean the bright trim pieces would not fit afterward.

Thanks for any advice.

"Nothing Beats an Ol' Goat..."

[GoatRider]

For owners/racers of 69 GTO's. I would like to know what is the biggest (Diameter) rear tire anyone has been able to run without having to modify the quarterpanel to "stretch" the opening from back to front???

I am confident enough in my welding skills to narrow the frame rails and install tubs, but would really like to avoid doing any sheet metal work on the painted portions if say a 30" tall tire will fit in the opening... Not to mention doing so would mean the bright trim pieces would not fit afterward.

Thanks for any advice.

"Nothing Beats an Ol' Goat..."

[Marty Phipps]

Tire diameter isn't an issue as much as width is.
I haven't done a GTO before, but I have had to rework over a few older Mopars for racing.
Remember there's an inner wheel lip for the wheelhouse to attach to the qtr.
That accounts for a 1" reduction of the tire width.
For tire diameter, try this after you've established how wide you're going to run.
With the car sitting level side to side.

At the center of your quarter wheel opening,and rear axle center line string a plum bob inside the quarter at the highest possible contact spot for the outer tire edge.
Probably about midway between the crown of the qtr. and the edge of the wheel opening top.
Now run a string from the inner front w/o edge to the rear w/o edge.
Slide the string down the wheel lip until it comes in contact with the plum bob string.
Measure from the intersection of the string to the wheel lip edges.
That measurement will tell the maximum tire diamater you can run, with out cutting the wheel lip or outer qtr..

[GoatRider]

Thanks for the Reply Marty, but I should have been more specific...

The car has a "back half" job about 75% done including the entire wheel wells, outer and inner, are cut out to install sheet metal 24" wide by 40" diameter tubs. The wheel tubs are designed to be welded to the frame rails and/or trunk floor and can be glued to the (insides) of the quarter panel with adhesive so you don't have to weld onto the quarter and ruin the paint.

What I am worried about is the actual size of the wheel well OPENING in the quarterpanel. I have seen some race car projects where the outer skin (which is all that is still there right now) has to be cut with a "C" shaped section taken out and the wheel opening "stretched" front to back to allow for bigger tires to be taken on and off; and also leave at least a couple inches clearance down along the bottom of the body line when sitting at ride height.

Hope that is more clear. I would really love to hear that someone has put a set of Mickey Thompson ET Streets 30 x 13.5 x 15 or larger on a 69 GTO without having to do that procedure!!! (I do not have a set to use as scale models during fab.)

"Nothing Beats an Ol' Goat..."

[J.C.you]

I would try to borrow a tire and wheel the size you are wanting to install. Trial fit, the best way.

wanna race? gimmie the move--