Robert has belt drive kits now

[CrazyDan]

Maybe this will help, just about anything you want.............Curt http://www.sdp-si.com/products/Timing-Belt-Pulleys/index.php

Was looking at this. Only problem is I would need a much larger pulley for the chainring input, probably that expensive Gates chainring, not looking too appealing anymore unless it can be done cheaper. I guess properly tensioned v belts would be the cheaper alternative.

 

[curtisfox]

Unless you go with serpentine the V-belt drive pulley has to be about 3" other wise you get slippage. Like Whizzer they have around 2.5 to 6 then 2.5 or 3 to rim 15". 5 grove serpentine is 3/4" wide, and is the same as 5 V-belts, so almost impossible to slip. What is sad the only pulleys you can get are car size. I am doing a alternator pulley on jack shaft, with a 24" bike rim on rear wheel.

used tapered strap hinges bent to attach pulley to rim............Curt

 

[JerboaJohn]

so with belts, pulley diameter to figure ratio but is it outer diam or at bottom of the groove?

 

[JerboaJohn]

v belt pulleys are cheap,, you know riding lawn mowers have em. yeah some slippage tho

 

[curtisfox]

so with belts, pulley diameter to figure ratio but is it outer diam or at bottom of the groove?

Outside diameter, like 3" divided into 6" = 2 to 1..........Curt

 

[zean]

With V-belts to figure ratio I think you measure somewhere in between the outer diameter and the bottom of the groove because it's the sides of the belt that come into contact with the pulley. I believe if you have a 2 inch pulley driving a 5 inch pulley the reduction ratio will be about 2.6 or 2.7 to 1. Am I right about this?

 

[JerboaJohn]

might be splitting hairs the more I think abt it. +/- .1 or .2 won't be a big difference?

 

[curtisfox]

With V-belts to figure ratio I think you measure somewhere in between the outer diameter and the bottom of the groove because it's the sides of the belt that come into contact with the pulley. I believe if you have a 2 and a half inch pulley driving a 5 inch pulley the reduction ratio will be about 2.6 or 2.7 to 1. Am I right about this?

Depends on the pulleys new A pulley 1/2" and new A belt the belt will actually stick up above the pulley a tad. ..........Curt

 

[zean]

Yes I think I'm going into too much detail. Not a big difference: If someone has a top speed of 30 mph with a 2 and a half to 1 reduction ratio then with a 2.6 or 2.7 to 1 ratio the top speed would be 29 or 28 mph respectively. If there was more difference between the size of the pulleys say a 10:1 reduction ratio then there would be a greater difference in figuring out the speed. Although I think you're right I might be splitting hairs.

 

[Herman Klutz]

Google pulley ratio calculator and you find a plenty of info.