[James | Go-Ride]

So originally we thought the Honda bike had an internal belt-drive system, much like that used on snowmobiles (two cones that get closer together or farther apart, changing the effective diameter of the "gear" the belt is running on. Have you thought at all about doing something like that for your internal gearing? You could have a shifter with no indexing (I'm aware that friction shifters are many years behind us) and have an infinite number of gears. I suppose I'm asking because I have no engineering background (philosophy major...totally useful!). Kris suggested that if an 80 hp snowmobile engine can use a belt that is only 1.5" wide, a .3 hp human should be able to utilize a belt that is about a quarter of an inch wide, and small, lightweight cones. Thoughts?

 

[dropmachine]

IF they were snowcones, i'd be all over it.


mmmmm.

 

[MMcG]

Originally posted by dropmachine.com
IF they were snowcones, i'd be all over it.


mmmmm.

 

[buildyourown]

Lots of machine tools use the same method for changing speeds. Both my mill and lathe have one. The problem is there is a LOT of drag from the pulleys on the belts. This design also doesn't work at low speeds. When you have HP to spare and high RPM, its great.
Alot of people have been working on a CVT for bikes, including myself. When I find the holy grail, I'll sell you a piece of the action.

 

[dw]

Yo James

The thing with the belt drives is that they need really high RPM to transmit that kind of power. Belts in general are not the best for high torque applications, and when you size a belt for a certain application, they are almost always rated as a function of a horsepower at a certain RPM. The other issue associated with the belt CVTs is that there is a quantifiable amount of power loss and slippage when shifting. Thats not too noticable on a engine vehicle where you hit a lever and the thing goes, but the human body is super sensitive to that kind of thing.

Dave

 

[Espen]

I just picked up the latest MBA.
It's a pretty good explaniation on how the Honda CVT transmission works. Drawings etc.

e

 

[Rik]

Originally posted by James | Go-Ride
Have you thought at all about doing something like that for your internal gearing?

Even though DW already answered, I might as well chip in my worthless comments... the amount of force required to move those conical pulleys in and out is HUGE, plus as already said, they suit a high RPM application... bicycles have way too much torque for their RPM to use systems like that.

 

[James | Go-Ride]

Well I guess that settles that. Thanks for the answers homies.

 

[Curb Hucker]

Originally posted by James | Go-Ride
(philosophy major...totally useful

It got you a job at a bike shop