Chainring, 5 arms, 58 mm BCD?

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Brucey
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Joined: 4 Jan 2012, 6:25pm

Re: Chainring, 5 arms, 58 mm BCD?

Postby Brucey » 21 Oct 2018, 11:37am

brynpoeth wrote:
Tigerbiten wrote:The risk with a very low first gear is that if you suddenly jump on a pedal with full force then you'll over torque it and bend something internal.
But there's normally a bit of leeway in the recommendations.
I've been running the Rohloff on my bent trike around 10% below their recommendations for around 7 years now.

But it is done at your own risk ....... :D

You are straining it a bit more, but I understand Rohloff hubs are exceedingly robust, reliable and long-lived


FWIW the rohloff hub has shear pins in it so that under a single overload, the idea is that the pins fail and you lose drive. The pins are (relatively) cheaply and easily replaced. I have not heard of the shear pins actually failing in this way.

Obviously the gearing recommendation is made with some 'standard peak torque' being applied, and people vary enormously; some are capable of exerting several hundred lbs on the pedals and others are not.

Also it isn't clear that the recommendation isn't made with something else in mind rather than just simple overload; it might be that at persistently high input torque values, there may be parts that wear or are susceptible to fatigue damage.

cheers
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