DIRECT DRIVE THROUGH THREE SPEED HUB?

[Hugh-Jassman]

I need some advice, are there any three speed hub gear hubs that are stong enough to run 2800 watt moter through?

I am thinking about a sturmy archer with a disc brake on the other side. or would it be better to just forget the gear hub, and drive the wheel dirctly with the proper gear reduction.

I figure I would do 350 to 400 lbs on an 8% grade.

No idea how much torque I would need but keeping it under 20mph would be just fine. even 15mph seems like a lot.

and woould those gears keep the Lightning Rods motors spinning fast enough, or would I need a heavyer motor?

 

[gogo]

I need some advice, are there any three speed hub gear hubs that are stong enough to run 2800 watt moter through?

Probably not.

Just get a suitably large motor/controller/battery that will provide the torque you want, and a chassis/drivetrain that can handle the torque. Why complicate with gears when you don't have to?

 

[cheekybloke]

The only options i know of are the Rohloff or the Nuvinci N171 for a geared hub that will take that amount of power.
Darren

 

[Hugh-Jassman]

thanks that really helps.....but miles' project used a two speed hub...shimano?

well I would rather use the more expensive hub for the lightening rods big block motor.

maybe if I were to use their two stage gear reduction the hub would not get so much torque?

 

[allinv]

With the LR big block kit you don't need any gears.
It will be plenty of power single speed, just gear it low, ask him about it.
And you won't have to deal with letting off the throttle to shift.

 

[Hugh-Jassman]

the real problem is that I do not want to build an illegal motor cycle.
I want to actually be able to sell these in a store. I think a single low gear is hte right thing to do. And if the power curve follows the gear curve, it should be fabulous. what?

With the LR big block kit you don't need any gears.
It will be plenty of power single speed, just gear it low, ask him about it.
And you won't have to deal with letting off the throttle to shift.

 

[Chalo]

Even the Rohloff and NuVinci 360 are not rated for 2800W. The NuVinci N171 is rated to do it. At that power level, even normal bicycle chain drive becomes a maintenance problem.

If you're trying to build something legal, it will be gear-bound to a top speed low enough that it won't need variable gearing. Just use a high enough pedal ratio that the rider can keep up with 20mph or whatever top speed, and leave it at that.