full width hub analysis

[admin]

Paul Jameson had some analysis carried out on a broken full width hub.
The results are in:

http://www.arielownersmcc.com/members ... Papers.htm

(bottom of the page)

cheers

[Graham.Goral]

Interesting... It'd be even more interesting to see a similar analysis of a broken rod from a square four with regard to age-hardening.

[robin.parker]

Am I right in finding that report somewhat encourageing?
Mind you, I am regretting NOT purchasing a N-r--n 8" Full Width Hub Front Wheel, complete with tyre, brake-plate and spindle, for £50.00 at Wistanstow the week before last! How daft can a man get?

[keith.mettam]

As Robin suggests, the report seems encouraging up to a point. That point is the conclusion that the hub is likely to have failed due to 'rapid overload'. What we really need to know, but probably never will, is what was the 'rapid overload' applied to the drum causing the catastrophic failure ?
Keith Mettam.

[andrew.chapman]

Encouraging? Really?

What it says to me is that a perfectly good part, not suffering from any age-related weakening, made from the material that it is supposed to be made of, with no identifiable faults, is perfectly capable of failing when subject to load.

My Ariel doesn't have an alloy torque arm but, if it did, I would be seriously considering replacing (or supplementing it) it with a steel strap unless I could establish that the load that caused it to fail was exceptional by a considerable margin.

[keith.mettam]

Yes it pretty much complies with the standard according to the figures. The analysis, as mentioned, suggests no age related deterioration but it goes on to conclude that the failure was likely to have been caused by 'rapid overload', whatever that is. I am of the opinion that the Ariel design engineers would have certainly designed the hub assembly to more than cope with emergency braking etc. by a good safe margin which still begs the question ''what is rapid overload for this type of hub ?''
Keith Mettam

[andrew.chapman]

I think that "rapid overload" is a euphemism for a shock load. I.e. a sudden spike, probably caused by the instantaneous locking of the brake.

[Simon.Gardiner]

I wouldn't be surprised if there was an 'impact' in this somewhere....

[keith.hodgenia]

As there is no age related weakening, it seems to me that the only thing to have changed over the years is the brake shoe material. It wouldn't be the first time modern materials have given us trouble. Keith.