internal gear multispeed hub torque stresses

[flyinmonkie]

Pretty sure Dec toasted a sram dual drive with his current RC set up while shifting under power. He may have thought it would last longer if one did not shift under power. Correct me if I'm wrong D.

Clay

 

[AussieJester]

The ones that broke were not SRAM DD .. correct ??

incorrect it was a SRAM with two broached freewheels fitted. Luke disassmbled one of these multispeed SRAM
only to find it was not very beefy at all and very similar to the sturmey archer 3 speed i blew. If you use
multi speed hubs in rc setups they will blow sooner rather than later mine started skipping on the first ride.

KiM

 

[jmygann]

Then Randy and Miles are the only ones with any serious miles on a motor driven SRAM DD ??

 

[deecanio]

hi Guys,

Sorry i missed this one.
i broke my sram DD (dual drive) within 20 mins of play, my own stupid fault as i changed under heavy throttle, had worked fine up till then, i will be looking into replacing the internal shaft and give it another chance when i get time.
Oh that was with the 3220, gearing of about 14-1, 2-1 on the single stage and then 7-1 from 11t to 80t extron, 50v around 3.5kw at the time, 1st gear mangled on the sram, can feel it in pedal only now.
I dont feel like it got a good day in court to be fair so i will re-run it dependant on cost of replacement shaft.

D

 

[amberwolf]

Mine wont' be SRAM, but I'm probably going to use a 3speed hub in a motor driven chainline:
http://endless-sphere.com/forums/viewtopic.php?p=294680#p294680
not sure if it will quite work out like that, but I think it will.

If it does I'll post up results here as I get them.

 

[jmygann]

i changed under heavy throttle, had worked fine up till then,............. 50v around 3.5kw at the time,


3.5kw and power shifting .... I also say the jury is still out

1.2 kw of power (cyclone) is reasonable.

suggestions on a 1.2-1.5 kw motor to drive SRAM DD ???