MG rear axle questions

[Michael Oritt]

I have some questions concerning MG rear axles:

1. Is the rear axle assembly the same for both disc-wheel and wire-wheel MGA's? ( I know that the axle shafts were different).

2. Is the rear axle assembly for an MGA the same as for early MGB's?

3. What final drive ratios were available for the MGA as well as for other BMC cars that used that axle.

4. Does anyone make aftermarket hardened MGA axles much as does Winner's Circle for Sprites, etc?

Thanks in advance for the help.

 

[tony barnhill]

The wire wheel rear axle assembly is narrower than the disc wheel rear axle assembly.

 

[ronzi]

1. Different half shafts and hubs, and the casing was different as well.
2. Isn't the rear track of the B wider?
3. The 1600 MkII came with a 4.10, the rest the the A line with a 4.3. Options were 3.90, 4.55, and for the cammer, a 4.88 and 5.12.

 

[Steve_S]

1. As Tony pointed out, the wire wheel axle housing is about 2" narrower than a steel wheel axle.

2. Yes. Only the brakes are different and they are still interchangable. I don't remember if the spring attachment points are in exactly the same place. if not, they are close.

3. A lot. I believe you will find anything from 4.55 to 3.7.

4. Not that I'm aware of, but MGB axles are not known for being easy to break. It sounds like you plan to race this axle, but I still doubt you will have a problem unless you're putting a big engine in the car.

 

[Deleted member 3577]

If your thinking of swapping out the Elva rear for an MGA.....

Remember that the bolt circle is 4 1/2" or something.
(The Elva is 4")

Also...You won't have to worry about snapping an MGA axle.

Keep in mind your unsprung weight will increase.

(But no more peeing /bcforum/images/%%GRAEMLIN_URL%%/grin.gif )

 

[Hap Waldrop]

Don't Elvas have Spridget rear ends? If so, there are more goodies for that rear end that you can shake a stick at.

 

[Deleted member 3577]

Yea...But Spridget rears stink....

The axles always break and they leak like crazy.

And if you want an LSD....They cost more.

 

[billspohn]

Don't Elvas have Spridget rear ends? If so, there are more goodies for that rear end that you can shake a stick at.

The MGA axle was an SCCA authorised option.

They used to break Spridget axles regularly.

 

[Hap Waldrop]

Winner Circle sells racing axle and double bearing hubs for the Spridget rear ends, in 25 years of racing Spridget the only failed axles I ever had was when I tried to shove the car into first gear going into turn one at Charlotte, it still didn't break the racing acle, just twisted the splines. If I was going to a MGA/B banjo type rear end for a race car, I would look into building a "hybrid rear end" where you use the MGA/MGB banjo center section, but the later MGB tube axles, hubs and ends of that housing, it's about as bullit proof as you can get. We recently built a "hybrid" banjo rear end for a vintage race, Tony B built one as well for his GT.

 

[tony barnhill]

Top rear end is salisbury
Middle rear end is Banjo
Bottom rear end is 'Hybrid'

We took a Salisbury differential casing and cut off the ends of the tubes. Next, we took an old banjo differential casing that was laying around and measured for wire wheel axle length and whacked its ends off. Then, we welded the Salisbury ends onto the banjo casing. However, it wasn't as simple as that. There was some machine work to do to turn the outside dimension of the banjo casing down after it was cut so the Salisbury ends would slid over it (the Salisbury inside dimension also had to be turned down so the banjo would fit properly). We also built-in a little negative camber to ensure the wheels would maintain maximum rubber on the road during hard cornering; at the factory, they were built with 0 camber. My hybrid casing now has 1/2 degree of negative camber at the axle end which works out to 1-1/2-degrees at the road.

{Oh, I realize there's no rebound strap bracket - don't use them on this car!}