If we could find a good jackshaft (commercially available would be a big plus...I have seen the ones for the mini bikes and go karts but I think the sprockets are for the wrong chain sizes to make an easy quick fix ) and way to fasten it to frame easily I believe we would have the multi speed problem beat)....Any ideas?
Re:" sedate use" As far as I know the Nuvinci was intended for normal bicycle use,and the transmission ratio between the front (pedaling) sprocket to the one on the is not supposed to be less than 2,presumably in order not be able to apply too much input torque.There is no max speed limit in any specs I have come across ( people can only pedal so fast).There is a friction transmitting fluid in the hub and it is conceivable that at high revs something could go awry.That is all I wanted to bring up.Torquewise i think there is not much to fear for normal motorized use.(not two 300 pounders on a tandem with gearing to match).We simply don't know if there is a speed limitation, JJ
I think that is pretty far fetched,if you had less than 2:1 the hub speed would be lower it's hard to imagine that this would adversely affect lubrication.If you take a 350 lbs heavyweight, standing in the pedals (17 cm), with a 2:1 ratio you end up with about 90 ft.pounds at the hub!.It is reasonable to have a max input torque spec.(as do the internally geared hubs),the 2:1 ratio, implies this,JJ
Quoting from the NuVinci Dealer Technical Manual:
" The NuVinci CVP (Model N170S) was designed for use in Commuter or Cruiser Bicycle Applications.
THIS MODEL IS NOT APPROVED FOR IN RACING OR OFF-ROAD BICYCLES.
If you have any questions about it you can contact them at 866-904-3630 (service dept) or visit www.atcnuvinci.com and get your info sraight from the horse's mouth.As I pointed out before the torque handling capability of the hub is rather ample,unless you are trying to get up a steep hill with a very heavy load.Wether it has inherent speed (rpm) limitations is not known.(like,say running it at 50mph).I venture to guess that the NuVinci folks will be rather conservative.They don't relish getting flak from irate customers with busted hubs, period.
I think that is pretty far fetched,if you had less than 2:1 the hub speed would be lower it's hard to imagine that this would adversely affect lubrication.If you take a 350 lbs heavyweight, standing in the pedals (17 cm), with a 2:1 ratio you end up with about 90 ft.pounds at the hub!.It is reasonable to have a max input torque spec.(as do the internally geared hubs),the 2:1 ratio, implies this,JJ
I don't recall exactly,most likely ran across this when browsing around the Sheldon Brown site www.sheldonbrown.com,there is an extensive discussion about these hubs,there is prob. a link there to a manufacturers site& spec sheet.I think it dealt with a 7 speed hub where the max input torque was reduced in the lower range,but I can't recall the numbers.You could also email Sheldon,I once asked him a question about an ancient Shimano hub I have and he answered right back.But remember he is prob. a cycling purist aghast at putting engines on bikes.Good luck,JJ
