Commando stainless steel wheel spindles

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J. M. Leadbeater said:
thus posssibly endangering lives?
Click to expand...

So where are all these dead or injured riders to prove your case ??
Without these, this is just a storm in a tea cup.

Stainless would seem to be fairly widely used in the Commando world, and reports of actual problems seem to be quite limited.
Notons used big chunky fasteners, pretty much everywhere, which being quite understressed may have opened the door for stainless replacements with minimal problems.
I certainly don't anticipate any problems with any that I have used.

And, bearing in mind we don't know what standard the oem parts were done to, and that I have seen several oem axles that were involved in shunts and deformed (considerably) as a result, I'd suggest they were not very hi-tensile grades of steel anyway. ??
 
There is a BIG difference in forces and stresses on a single axle vs the standard two piece axle. The simple shear on a single axle is so much less that suggesting that it should be the same strength as the oem axle is double overkill.
Jaydee
 
jaydee75 said:
There is a BIG difference in forces and stresses on a single axle vs the standard two piece axle. The simple shear on a single axle is so much less that suggesting that it should be the same as the oem axle is double overkill.
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There is ZERO difference in forces. Shaft loads are introduced through wheel and bearings, and loads are taken up by the swinging arm (or vice versa). If the bike's geometry and weight as well as rider weight remains the same, how can the loads change? As for shear stresses, going from a two piece to a one-piece rear axle won't change stresses much either.

Yes, the threads will reduce the load-bearing area somewhat but the reduction isn't significant. Please read page 2 of this thread and you will see that the axle fails in bending, not shear. The additional flexibility introduced with a two piece axle will increase bending stresses; reduced load-bearing section further increases bending stresses. Finally, threads are themselves stress risers and high stresses combined with fatigue (although at low amplitudes) leads to tensile stress failure at a certain number of cycles. Considering the stress levels shown to exist this is a matter of course.

This reminds me why AMC optionally offered quick-detachable rear wheels (w/two piece axles) to their roadsters - the motocross models always had a one-piece axle, for good reasons.

-Knut
 
Rohan said:
So where are all these dead or injured riders to prove your case ??
Without these, this is just a storm in a tea cup.

Stainless would seem to be fairly widely used in the Commando world, and reports of actual problems seem to be quite limited.
Notons used big chunky fasteners, pretty much everywhere, which being quite understressed may have opened the door for stainless replacements with minimal problems.
I certainly don't anticipate any problems with any that I have used.

And, bearing in mind we don't know what standard the oem parts were done to, and that I have seen several oem axles that were involved in shunts and deformed (considerably) as a result, I'd suggest they were not very hi-tensile grades of steel anyway. ??
Click to expand...

Rohan, this kind of argument is of little value. Firstly, there is a difference between an engine bolt (which has redundancy) and a rear axle, which has no redundancy. Secondly, the rear axle certainly isn't chunky. in fact, at 9/16in it seems too slender to me. Third, without knowing the material specification used by the factory, how can you claim the item to be understressed?

Asking for proof of a problem in terms of fatal accidents is unneccessary, unreasonable and provocative. Knowing that the rear axle is a critical component and hearing of axle breakages (albeit the factory item, it seems) is reason enough to be extremely cautious when fitting non-factory items.
Legally, for safety critical parts, fitting such parts voids the type approval of the vehicle and this should be a concern of every maker of such parts, as well as the consumer buying them.

-Knut
 
Perhaps it should be pointed out here that Jimmy Guthrie, star Norton Factory GP Racer was killed in the German GP in the late 1930s
- when it was thought that the rear 2 piece axle in his plunger factory 'manx' broke, and steered him off into the trees.

Nortons fitted one piece axles to ALL plunger framed bikes thereafter.
All plunger framed road bikes too, all into the 1950s.

Sadly, this is the evidence that plunger frames axles needed to be one piece.

Suggesting there might be a problem, and finding there is a problem are two slightly different things.
One is armchair navel gazing, and the other is real world.

??

Meanwhile, has anyone tested oem axles to see what spec they meet.
Or seen this written someplace.
They seem rather soft, based on bent ones I've seen.
 
Plunger bike axles DID have a problem.
Where is the evidence that Commando's do ?

If no-one has analysed what the spec is for Commando axles, all this is armchair navel gazing, and old woman syndrome....
 
You have some of this syndrome yourself, that you can speak with authority ?!

I'll regret this....
 
dennisgb said:
Lots of words in this post without any substance. No actual material specifications after talking to several (name dropping) experts.

No link to what product is suspect on Ebay.

Is this of any value to anyone other than to suggest there are inferior products out there?
Click to expand...

I commented on how this post had no value on the very first page...
 
And folks have been reinforcing that message ever since,
since knowledge can never come from one source alone.

Perhaps we should ask JM what HE uses for a back axle in HIS Commando/Norton.
That could be interesting.

Nortons have been using 2 piece axles in various models since the 1930s.
And Commandos have been out of production for nigh on 40 years,
so if there was a real problem someone would have noticed....
 
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