any sheave that can accommodate two belts?

[butterbean]

I'm planning a two speed drive with a stepped pulley, two belts and an idler clutch. Anyone know of a rear wheel sheave that can accommodate two BX type v-belts? GEBE? Whizzer? Whizzer clone? I know the gebe sheave is for toothed belts, but if the teeth can be ground off and I can throw two v belts on it, that would work. Or do I need two separate sheaves?

 

[butterbean]

Bump, anyone?

 

[butterbean]

Bump again

 

[keatonx]

Two belts? Are you going to have a belt for each pulley and have 2 independent belt tensioners?

 

[butterbean]

Sort of. Two pulleys on a pivot arm, moving the pivot arm up or down via a handlebar lever and cable will engage one belt and allow the other to slip. After looking around and researching, aside from a cvt that I'm not sure would work due to having a metric crankshaft, this is the cheapest and the simplest. A cvt might be cheaper, but I can order parts for a two belt setup one at a time. Besides that, I can control this setup manually and shift gears on the fly (no need to go into neutral).

 

[butterbean]

So does anyone have an answer for me?

 

[keatonx]

Oh, that would work nice; make sure whatever belt that's disengaged has tons of slack, or else the gear ratios will be fighting each other and you'll lose a bit of power. More so with the ax or bx series belts, cuz they aren't wrapped; just bare rubber.

And I saw your $250-300 estimate in the chat box; what are you making it out of, gold? two drive sheaves (less than $10 each), two idlers which can be homemade or from a car's belt system, a rear sheave (which can be made with a slightly smaller bicycle rim), two belts and you're basically done

 

[keatonx]

You should be able to use any rear sheave; there's so much contact area on that massive sheave that it should get tons of grip. I saw a thread where someone converted a FD to v belt drive, using a non v-belt sheave

 

[keatonx]

Why are you going with the bx series over ax? You'll already have limited width on the rear sheave, and the ax belts are much stroger than you'll ever need. I have an ax-22 on my 140cc lawnmower bike and I abuse it with clutch starts etc. and it hasn't flinched.

 

[butterbean]

Well I was going to buy a Whizzer sheave because it comes with the clamps and the holes drilled exactly where they are supposed to be, no way I am trying to guess where to drill the holes myself. The stepped pulley I found is $50 but if you know where I can find them cheaper....do you think a Whizzer sheave can accommodate two ax belts? and I was also counting the cost of a 1955 roadmaster frame, that's $100.