NuVinci Hub + SBP Shifter KIT having BOTH is REDUNDANT!

[highlander9]

I've seen a thread where a person had both! What's the point?

One is a CVP or continually variable planetary transmission + allows for pedaling unaffected and independent from the motor drive.

The other is a rear derailleur + allows for pedaling unaffected and independent from the motor drive.

Wouldn't the benefits of having both the shift kit and CVP quickly taper off after the start-off point which requires pedaling? And if you do pedal, you're still using the CVP anyway.

Plus, you'd have to close the throttle when shifting the Nuvinci (likewise w/ the shift kit), but you don't have to worry about all those expensive parts with just a normal rear derailleur....

It also says on Staton, you need a 34t front freewheel to make it work with a NuVinci...

All these things are factually conflicting! I need help!

 

[BarelyAWake]

Um, no they're not conflicting at all when you take into account the shiftkit shares the same drive chain as the pedals (via jackshaft & freewheel ofc) so instead of a single speed engine, you've all the gear range of the NuVinci available to it as well as your pedals.

Technically you don't actually need "close the throttle" while shifting with an internally geared hub or derailleur setup - but people do anyway to reduce the "slamming" effect of speed shifting... the NuVinci however is so tough you'd prolly not need to worry about that with your typical HT - I don't recommended speed shifting BTW, I suspect it is the primary cause of premature internally shifted hub failure & the "turbine blade" twisted tooth effect on the rear cassette of a derailleur bike...

Even with only the three gears available with my Sturmey Archer internally geared hub & shiftkit, I can almost start off w/o pedaling at all - I can actually but I'd hafta burn the clutch a bit. With you're typical 21sp or the NuVinci with it's far wider gearing range no doubt you could start off from a dead stop & no pedaling, depending on your primary ratios ofc.

 

[5-7HEAVEN]

I've seen a thread where a person had both! What's the point?

One is a CVP or continually variable planetary transmission + allows for pedaling unaffected and independent from the motor drive.

The other is a rear derailleur + allows for pedaling unaffected and independent from the motor drive.

Wouldn't the benefits of having both the shift kit and CVP quickly taper off after the start-off point which requires pedaling? And if you do pedal, you're still using the CVP anyway.

Plus, you'd have to close the throttle when shifting the Nuvinci (likewise w/ the shift kit), but you don't have to worry about all those expensive parts with just a normal rear derailleur....

It also says on Staton, you need a 34t front freewheel to make it work with a NuVinci...

All these things are factually conflicting! I need help!

You need the shift kit to connect the engine to the NV orrrr the rear derailleur. Needless to see, a pedal bike with or without NV hub and no engine does not need a shift kit.

A 2:1 pedal ratio is recommended for NuVinci hubs, hence the 34t chainring/17t rear sprocket combination. However, the motor-driven gear ratio is inversely proportional to pedal ratio, so this 2:1 pedal ratio is .5:1 gear ratio for the engine. Multiply that by 3.5:1 maximum NuVinci ratio to get 1.75:1...

The shift kit allows engine connection to the rear derailleur or the NV; the chainring/engine sprocket/NV(OR rear derailleur) determines gear ratio.

Shift kit works with either rear derailleur or NuVinci hub. My present bike has frame-mounted GP460 engine, 11t/63t engine sprockets, 30-tooth chainring, shift kit and 11t-34t rear derailleur. Its gear ratio ranges from 10.5:1 to 32.46:1.....

My 29er frame-mount project will use NuVinci hub, shift kit, 2:1 pedal ratio and gear range from 7.16:1 to 50.1:1...

The shift kit is the key to rear derailleur or NuVinci hub.

One more thing...The rear derailleur's or NuVinci hub"s gear ratios alone are not enough to stimulate your engine. You WILL need at least 10.7:1 more gear ratio from jackshafts or chainring/engine sprockets.