Technical Model A build, what width rear axle to use?

Hey everyone, my dad, brother and I are building a 1930 Model A 5-window coupe. Dad and I are funding the project and my brother and I are doing most the building. This is our 1st model a build. Dad hasn't had a hot rod in forever so when its all complete, I plan on handing the keys over to him.

Anyways, so Dad had a 5-window coupe body sitting in the barn for years. Last summer we decided to start a hot rod project. We bought a model A frame from Speedway. We used some parts dad had and some stuff from speedway to get the front axle, suspension and steering done. Last fall, a complete running/driving stock model a went up for sale nearby and my dad bought it. So that car's entire body will be donated to our hot rod project and then dad's barn coupe body will probably go on the new car's stock chassis. We are trying to decide what rear axle to use for the speedway framed car. The car will have full fenders and running boards. Dad wants to use 35 ford wire wheels. We are going to use a pretty mild Small block chevy and a th350 trans.

Any help is greatly appreciated. Thanks

 

56 to 57" from axle flange to axle flange. 8" Maverick is 56.5" if you can find one.

 

A first gen bronco 9inch would probably get you close as well. Be sure to factor in the width of the spaces to run those 35 wire wheels on the later drums

 

I am cutting my rear to 58" for the sedan( its currently 60 and the pinion is offset 2"). A common rear back in the old days was from a '57/8 Ford. They were approximately 58"

 

maverick. 8"... but we ... [bad knees] measure from backing plate to backing plate so we can measure them about anywhere when alone...
maverick's are 8" and are 49.??" BP. to BP, 5 on 4.5" BC.....
bronco's are 9" and are 51.??" BP. to BP, 5 on a 5.5" BC...
rock on !

 

http://www.carnut.com/specs/rear.html go here for rear end widths

 

Everybody here is right on the width 9" Early Bronco, 8" Maverick, etc. But, you can't put 35 Ford wires on a rear end with modern brake drums. 40 Ford brake drums are cone shaped and support the forces exerted on the early wire wheels.

 

You have to put a machined spacer behind the wheel.

I personally wouldn't run '35 Wires on anything that required the strength of the later model rears. But I am an odd duck, or so I have been told. LOL

 

Here is a Ford Explorer rear end with 10 inch wide wheels. 48.5 inches between the inside rubber. Nice posi track with disc brakes

 

I am not familiar with speedway frames but width would also be dependant on body channel and frame Z if it's being done in this case also rim off set and width of tyre.

 

I am aware of the machined spacer required for these wheels (if we decide to go the wire wheel route) In fact, Speedway does offer a 5x4.5 to 5x5.5 adapter that has the proper machined cone to support the 35 ford wire wheel

Not going to channel or Z it.

Thanks for the tips, it gives me something to get started

 

By the time you find a maybe good used one and going through it you can get a custom one made to fit like it should.
It will cost more but should fit exactly the way you need it to.The housings are pretty cheap considering its the rest of the stuff like the axels and brakes that add up.Im going through something similar on my 28 mopar.Found a 9 inch out of a late 50s edsel that is the right width.Doesnt have the right axles to run the 5 on 5.5 wheels so I will need to deal with that along with finding all of the brake parts as it was missing them.

 

So we ended up getting a 1966 Ford Bronco 9" rear axle. I ordered a front disc brake kit from Pete & Jake's that will fit the 35 ford wire wheels (as well as the adapter rings). Now the 35 wires do not fit over the drums of the 9". Does anybody have pics of one of these axles under a full fendered A with the correct wheel spacers? Kinda worried it may put the tires out too far and they will look dumb. We are quite a ways away from putting a body on this.

Worst case, we will run some other wires that my dad has. He has a pair of 15" painted wires with 5x5.5 bolt pattern & they clear the front & rear brakes, so we'd have to find 2 more

 

Hey. So there's a few things to consider before you get too worried and because you have it all in hand you can sort of mock it up for yourself and see.

The 35 wire wheels. They want to be meeting the drum or spacer behind the lug holes. The older brake drums are coned shaped so it reaches up in there. The newer drums are flat so as you've found they don't reach. The spacer basically fits onto the flat drum to reach the back of the wheel mounting surface and only really need to space the wheel out a fraction of an inch away from the drum.

Your just wanting to make sure when tight your wheel is bolted on with out the larger diameter back half hitting the drum like it does now.

That make since? You basically making a flat drum a coned drum. Stick the wheel up to the drum, your wheel bolts aren't going to reach but hold it up there anyways. Now add like 1/8 and that's probably more than enough space to clear.

They aren't really being used as a spacer conventionally would be they are because the wheel mounting surface isn't where they are on a normal wheel.

You do see some people running a huge spacer on 35 wires, for what reason other than liking a huge scrub radius and showing off there brake drums I have no idea.

I know some people buy the prescribed spacers and then have someone whittle them down a little on a mill until they are nice close to the drum but not touching. You'd never even know the spacer was there.

With out the parts in hand and just looking st photos online this would probably sound confusing but hopefully with everything you have in front of you it's a pretty easy thing to see how it works.

If not I can draw you a picture. Seriously, not being a dick sometimes it's just easier to see it drawn out

 

Not sure what your abilities or skill level are but you can get any size ford or Dana axle and cut it down to size and have the shafts resplined by a place like Dutchman or the like. You need to have the fixture to center the bearing caps but you can use it for shortening as many housings as you want. A good investment if you plan to build more than one. Opens up your search quite a bit this way.


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I see what you are saying (I think). It seems though that the wheel center portion of the 35 wire doesn't fit over the drum, like at all. This weekend I'm gonna try and get over to where we have the project at and try to mock up things some more to get a better handle on this

We didn't really want to get into having the axle cut down, which is why we picked up the bronco 9" since it already has factory posi. The axle is in real good shape, just needs the brakes done. This is my 1st hot rod project. Before this, my brother and I were building offroad 4x4 trucks

 

I used to build off road rigs and components as well. Weird. Anyway, if you find yourself struggling to find a perfectly fitting axle, making your own is just super easy.



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Yeah it's not supposed to fit Over the drum. Even with stock brakes it doesn't.

I'll draw a picture .

 

Ok so I tend to over complicate things but this is what the spacer is for A/B/C are all widths so you can see the cone width of a stock drum B is the same as the spacer width on the flat drum.

These wheels are 4 inches wide with two inches of back spacing. The matting surface is the very center section where the studs come threw.

NOT the back of the center of the wheel that is probably just a hair smaller than your new drum if not about the same size.

On the left you can see how the cone or spacer goes inside the wheel so you can bolt the small center section firmly. That back section that's not going over the drum doesn't go over the drum, and should not be pushing up against it when bolted on.

I know, kinda weird.

So if you've already found the wheel doesn't go over the drum you've already done half the work. Put the wheel up against the drum, add a fraction of an inch on each side to back the wheel off from touching the drum and that's your width with the "spacers" which actually only move the wheel out that fraction of an inch

 

Thanks Tim, the drawings help

 

OP,

You ask for the best size, guys tell you what to use, but you already have an axle that's too wide and you seem committed to use it. There's a reason 56" axles are used. They fit right and result in pleasing tire to body relationship with traditional type wheels and offsets.

One of the biggest mistakes guys make is using whatever stuff they happen to have, whether it's axles or camshafts or spindle nuts. Read more builds to see how others do it and get an idea what you really want your rod to look like. You'll be much happier and pleased with the result.

 

Early bronco 9" was mentioned a few times earlier in this thread. Plus it was mentioned to me a few times while talking to local rodders. That's why I went with it

 

I built a T roadster parallel to your project. I too used a Bronco 9" I to used Pete & Jakes brakes. I had my 35 wheels powder coated ordered Coker tires had them mounted and balanced front went on great then I found out they would not fit on rear. Plan ahead do your research.(what you are doing now) .
I finally put steel wheels on. The spoke wheels might be better as after market type and 5 on 4.5 bolt pattern.
Good luck with your build. My son and I build hot rods together. I'll bet your dad is proud. I would be.
Terry aka dirt t

 

Ok I know these things.

A 46 banjo is wider than a model A banjo
A bronco 9 inch is narrower than a 46 banjo

I know you can run a 40 ford 4 1/2 steel wheel with 750's on an early A with fender with the 46 rear.

So using a narrower bronco 9 inch, with a narrowered rim aught to work fine

 

And that's how it looks. A touch wide but completely acceptable so the narrower rear should be about perfect

 

Thanks Terry. Dad is 72. It's really important to me that we get him something cool to enjoy while he's still able to drive. And most importantly use some of his parts that he's been hanging on to all these years

 

When choosing a rear axle for the Model A that you see on the left, my thinking was it is a light car with skinny tires and not a lot of horsepower, even with a "built" flathead. Next; it takes horsepower to turn the axle. You can't top the strength of a Ford 9", but they are up there with the highest users of horsepower. The Dana 44 from an International Harvester Scout II has the 5 X 5-1/2 pattern and is 1/2 inch narrower than the front dropped I-beam. But they are hard to find. (Backing plate mounting flange is the same as the "old Ford big bearing" flange.)

 

Be aware; unless you machine a custom spacer, you will still need a "wire wheel support ring" to properly mount a '35 wire.

 

To give you an idea of wheel spacing; this is a 15" mid '50s F-100 wheel with a 235/15 tire on a Bronco rear. We had to fab mini-tubs to clear the tire on the sedan; a coupe would clear OK.

 

I am running a 55" Ford 9" rear end on mine, flange to flange. But I am running 8" wide rear wheels.


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