CAMPYBOB said:
...in another thread you stated:
Regardless, I think you should opt for the Campagnolo components on your next bike because I know you & your bike mechanic(s) will probably be able to exploit the minor design flaw in the Ultra Torque crank, and I want to be able to know that I was "right" about it!
Can you tell me 'what' the design flaw is? Clue me in if you would please.
Thanks,
Campybob
Others may disagree (AND, they may be right!) ... I am probably/possibly the ONE-and-ONLY PERSON in the whole wide world who can envision a potential problem with the fingers of the Hirth Coupling in the Campagnolo Ultra Torque crankset ...
In short ...
When used in OTHER applications, I think there is a more consistent (if variable) AXIAL load (from a motor) whereas on a bike, there could be uneven loads from uneven pedaling ... so, while all the other two-piece cranks have a one-piece spindle (which undoubtedly flexes an infinitesimal amount), the fingers of the joint (and, connecting bolt) must
endure the stresses in the Hirth coupling.
But, the greater problem is with what I will refer to as the the lateral load (you can refer to it any other way you choose) ...
In the worst case scenario, the bearings on the side being driven/"mashed" bear more load ... you know, potentially resulting in premature (?) bearing failure akin to what was seen in the early ISIS bottom brackets which only had a single driveside bearing cartridge ... except, that it on the Ultra Torque crank it could occur on both sides.
So, if you have a cyclist who is negligent in his/her maintenance (or, who has an LBS mechanic who is not dutiful), the coupling potentially suffers more stress ... the connecting bolt potentially suffers more stress ... the bearings potentially suffer more stress.
I reckon that if someone can manage to mangle a DA cassette & crank-or-BB in short order, then I think he-and-his-mechanic can inflict comparable injustice on the Hirth coupling.
