Thread: Model A Wheel/Tire Clearance?

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Hi guys,

I'm ordering wheels and tires for the 1930 Ford and am trying to fill the wheel well with the fattest tire I can get in the back and with the deepest dish. I cannot tub the wheel well so I have stock fenders. I will be cutting down the ford 9" so the only thing I have to worry about is fitting the tire in the wheel well without it rubbing.

From the inside wheel well to the outer lip of the fender, I have 12". I purchased a 17" cagar wheel 9" deep with a nice dish, well it arrived and apparently 9" is measured between the rims edges as the overall wheel width is 10". So I have 2" clearance to the inside wheel well.

Tire selection was planned for a 265/70 R17. The wheel cross section of this tire is 10.7" which will leave me with 1.3" clearance for the tire between fender and inside wheel well..


I looked into dropping down to an 8" wheel with a 255/70 R17 tire but that will only give me .5" more clearance at the tire cross section. Not sure if it's worth it?

Any way I guess I'm wondering how tight can I set this up? How much travel do I need to plan for? I wish I could mount the tire and wheel and have the ability to exchange, but you know the return policy on wheels.

What do you guys think?

You can cut a tire profile cross section from a piece of plywood and use it by sliding around wheel at point of travel that is most restrictive--------

6696, with a fender width of 12" and a tire cross section of 10.7" you have 1.3" total clearance, but that's only 0.65" on each side. That's likely OK, but you're going to have to measure carefully to cut down the rear end to make everything work. Since you already have the wheels your backspace is set, so center both wheels in the fenders and measure between the inside mounting flanges on the wheels, side to side. That's your differential flange to flange outside measure, and if you compare that to what the differential measures now the difference is what you'll be cutting out of the axle tubes, either taking it all out of one side or splitting it equally between the two sides if you want the pinion to remain in the same relative position it is now.
It's all going to be a matter of careful measuring, careful fabrication to cut the differential just right, and then careful mounting of the suspension. With clearances that tight you're going to want to limit suspension travel, and a panhard bar may not be your friend. A watt's linkage will keep that differential moving straight up & down as the springs work.
Sorry if this is not the type of info you're looking for.

Thanks for the responses guys,

I've never heard of a Watts Linkage before,....pretty cool bit I don't think it will fly with my setup. I am going to go down to the store and see if I can "borrow" a 265/70 R17 and set it in my wheel well. I know it will be slightly different given that it wont be mounted but it may give some insight.

The more I think about it, I think the rim will be okay, my problem will be the tire cross section of 10.7".

Well see, I'll report back.

Dust

I have a 1925 model T Tudor it had a model A rear in it I got a 68 mustang 8" 1/4" wider than the
Model A I have 20" wheels on it from an 07 mustang GT had to use spacers rear tires are 11" wide
Jim. You ma not have to cut down a mustang rear