Best width for fendered 31 model A

Trying to figure the best width for a rear end that will get as much tire inside the fenders and still have a fairly deep rim. I've herd everything from 53" to 56". I'm thinking 53" might be the best for a little deeper rim. Any help or advice would be great.


Register now (free) or login to remove ads

You should ALWAYS measure the rear end from the wheel mounting flange to wheel mounting flange. Backing plate to backing plate will vary because of the different offesets of the brake drums and brake drum widths.



With that being stated ... most Model A guys try to get down to the 56 inch wide mark. There are no factory 9 inch Fords that narrow so folks use a 57 to 59 Ford car rear end ( 58 inches ) if they just have to have a 9 inch. A early Maverick with the 5 lug wheel pattern is a 8 inch series rear end and most Model A guys use them because they are 56 inches wide.

There may be other rears that are the narrow width but I prefer the 8 inch/9 inch Fords for ease of parts and serviceability.

_______________________________



On my 32 Ford 3W coupe ... my engine is 430 horsepower so I was afraid to use the 8 inch Ford so I narrowed a 9 inch Ford down to 56 inches.





I wanted the 235/75/15R tires under the fenders ...

__________________


Sorry, I may have been a bit short with you...
I don't suffer fools well. I'm workin' on it

... NOT ...

My '31 has a '57 Ford 9" rear - but you do need to be cautious with wheel back spacing unless you like tires hanging outside of the fender. These wheels are 17x8 w/ 3.75 back space and a 31" tall tire





Dave W

Thanks for the reply. If you used a 57 ford rear end, would that be 52"wide, flange to flange? Great looking roadster!

It's the narrowest at 57.25. I've seen that 52" figure as well in several sources. Here's a real good write up > Then there is this one.

Another good choice or two is the 8" plus the Explorer 8.8 with the integral parking brake. Both of these are plenty strong enough for 3-400 Hp

Dave, what size tires/wheels and setback do you have on the front of your A? Do the tires rub the inner fenders or the supports? BTW, my Heidts front end (like yours), the lower arm front pivots run into the radiator splash shield. Yours seem to clear. Did you modify the shield?

You might look at the rear fenders for Model A pickup truck, they are wider than the fenders for a coupe or tudor.

These are the wheels - Billet Specialties GTX01 – Fronts are 15x6/3.5BS, tires, Yokohama AVS ‘Z’ 205-60x15(wide!!).

This happens to be a rear and are 17's, but the design is the same with 3.75 BS instead of 3.5.

Those rear fenders on mine are from an 'A' pickup. The only difference - no holes for light stands.



The chassis and front suspension are TCI, not Heidt's so it might be that the mounting points are different. The only parts that I had to modify were the front fender braces. What I did was to cut a 'U' shaped notch in them to clear the upper support. I have lots of clearance as shown in the bottom photo:





Any other ideas/questions/problems - give me a shout or PM and maybe I've figured it out for mine

Dave W

I have a 31 chevy coupe with stock rear fenders and have a 56" old 10 bolt chevy from an old nova. MY wheels stick out about 2" but there MT 12" wide on torque thrust rims. sc

For the first differential I installed under my A I used a 57 Chevy car. I believe it to be 54". If you like Ford differentials the 55-56-57 station wagon differentials are narrower than the other Ford cars and fit well. In the car I am building now I am using the differential out of a S-10 pickup.

You really don't want a '55-56 wagon differential as it is an impossible unit to source parts for, is a weakling drop out the back rather then a later, '57 up removable carrier 9" differential. There are a couple of 8" units that will work fine, but they are also getting difficult to find parts for these days. As for '57-'59 parts - not a problem, especially if you have the original pieces in hand as bearings and seals are standard parts

I checked the rearend i have in my 31 and its a 68-79 nova 10 bolt, 8.5 gear. the outside dim is 60 1/4" from the outside of the brake drum, and 53 1/2" inside backing plate to backing plate. Easy to get parts. I rebuilt all the brakes form the NAPA store.

'70s Maverick or Chevy S-10. Get out the tape measure. Stay with a 70 or 78 series tire. Go to rod runs & cruise nites to check other Model As.
Jim, School of Hot Rod Hard Knocks, 1957

Attached Thumbnails