Sprite axles

[Michael Oritt]

Last weekend at VIR I broke one axle at the diff--on inspection the other one was severely twisted, perhaps by the shock from the first one's breaking. Luckily I had spares with me and got back on the track.

In any case I found the following online and would appreciate any input or thoughts:

"A method of preventing axles from breaking is to have them `turned down' all along their length from the spline to the flange. Turn them down so that the diameter is the same as the distance between the bottoms of two opposite `valleys' of the splines. This means that instead of the twisting pressure only acting across the narrow section of the spline (and eventually causing it to break off there inside the diff), this twisting pressure will be evenly distributed along the whole length of the axle, and so it will not break inside the diff (or anywhere else)."

BTW they were Winner's Circle axles, though they are of the "old pattern" with a bolt through the end and were likely 10 years old.

 

[aeronca65t]

I guess the first question to ask is whether or not you have double-bearing hubs.
Sprite axles are "semi-floating". The stock design provides only one bearing on each side and requires the axles to share the side loads of cornering (as well as the twisting loads that all axles take).
I have had fairly good success with stock axles and double-bearing hubs. On the other hand, I have heard that running race axles on single bearing hubs will only help a little bit.

As for your idea that turning down the axle may improve it...this *may* be true, since the twist is likely to be imparted on a longer section. But only if the axles mostly see twisting loads and very little side loads (in other words, in a car with double bearing hubs). With single bearing hubs, I think it might make things worse.

We have an old race axle that has many races on it that has a deep, rounded spiral groove cut in it. I *think* it is intended to reduce oil throw to the outer ends of the axles, but we've wondered if it is also intended to reduce the axle cross-section so that it is "equally as weak" as the root diameter of the spline section (thus, sharing more of the axle twist load). Not sure but it's outlasted many other axles.

 

[Michael Oritt]

Nial--

Yes to the double bearing hubs.

I realize that with a "B" series engine I am pushing more power through the Sprite rearend than "originally intended" and indeed many racing Couriers have been converted over to MGA rear axles, then down the slippery slope to larger wheels, tires, brakes, etc. FWIW I'd like to stick with the original axle, Elva mags, etc.

It may or may not be a coincidence but this break occurred immediately after I unhitched a front antiroll bar and adjusted the upper links down one notch to give better "bite"--("The rest of the story, etc. etc").

Perhaps I got bit?

 

[Hap Waldrop]

We have an old race axle that has many races on it that has a deep, rounded spiral groove cut in it. I *think* it is intended to reduce oil throw to the outer ends of the axles, but we've wondered if it is also intended to reduce the axle cross-section so that it is "equally as weak" as the root diameter of the spline section (thus, sharing more of the axle twist load). Not sure but it's outlasted many other axles.

Those are pretty rare Nial, I have couple of those, they are done that way to pull oil back form the hubs and not let rear end oil flood the seal area.

Michael, Bob Lemke who has been racing a Elva for a long time and really a good, fast driver, who preps his car very well, he would be a good person for you to talk to about racing Elvas. I known Bob for years and he is a very smart racer. Email me at work hapwaldrop@acmespeedshop.com, and I get you in touch with Bob.

 

[JerryB]

""""""turned down' all along their length from the spline to the flange""""""

""""""""""BTW they were Winner's Circle axles, though they are of the "old pattern" with a bolt through the end and were likely 10 years old."""""""

After 10 years of use they were screaming "tired". Regular inspecton after very few races might not have cought them after years of use.

Most aftermarket axles are necked down.

The hot setup , but expensive is true floater ends. dwarfcarproducts.com ......take a look.....

Huffaker uses some of these ..and they are fairly expensive. Doing a housing from scratch they are not that x-pensive however....as figuring the cost of d.b. hubs and axles, studs, straightening the housing, etc etc. An added benefit is slide out axles and no problematic oil leakage issues.

Part of the problem is housing flex and rarely is a Spridget housing straight. Even with a grippy 205 tire you should get good service from the Spridget housing. At a minimum you should find someone with a mandrel for the housing , straigten and reinforce. There is a guy in Arizona that is real good with housings....I have his phone # somewhere ..havent talked to him in a few years tho.