Noob tackles belt drives

Tinkerbot

New Member

Sep 6, 2015

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Sarasota

Sep 6, 2015

• #1

I've been lurking for awhile now, and have been imagining all different types of setups that I would like to attempt.
I really would like to use a 26" sheave on the rear wheel, but the setup I'm considering is similar to a whizzer, or golden eagle which I believe uses a 20" sheave.
I was wondering if I increased the size of the driver pulley would I be able to increase the size of the rear wheel sheave?

 

C

curtisfox

Well-Known Member

Dec 29, 2008

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minesota

Sep 6, 2015

• #2

Yes increasing the drive pulley you can increase the driven pulley. A whizzer is 16" and so is a 20" bike rim. When you say 26" do you mean a 26"bike rim? actual size is around 24"..........Curt

 

Tinkerbot

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Sep 6, 2015

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Sarasota

Sep 7, 2015

• #3

Oh, right! I forgot that bicycle wheel sizes approximate the rim AND tire diameter.
That means that the drive pulley won't have to be that much bigger.

I do like the looks of a great big ol' rear wheel sheave...

Thanks, Curtis for the reply...

 

C

curtisfox

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Dec 29, 2008

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minesota

Sep 7, 2015

• #4

And if you get to big you start running into frame clearance. Whizzer sheave is about the biggest unless you want to cut the frame,witch is not to hard if you can weld..........Curt

 

Tinkerbot

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Sep 6, 2015

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Sarasota

Sep 8, 2015

• #5

Thanks for the warning, that is one of those things that maybe I wouldn't realize until pretty far into the build.
Any excuse to cut, and weld something is welcome!

 

C

curtisfox

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Dec 29, 2008

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minesota

Sep 8, 2015

• #6

Check this out how the cut and made room for the pulley,just simple flat stock welded on the ends of the cut section of tubes. And also the Z shaped brackets that hold the pulley to the rim on it and others on the page...........Curt

https://www.google.com/search?q=191...KvujBXX0M:&usg=___A9f5JENub4hoVZfFX4SLj-thlI=

 

Tinkerbot

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Sep 6, 2015

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Sarasota

Sep 9, 2015

• #7

This guy did something similar:

http://img.photobucket.com/albums/v475/beau_layman/DSCI0074.jpg

There's that 24" sheave that i like so much.

I can't find the image anymore, but I saw an early motorcycle that had a smaller sheave mounted to a larger one with a double drive pulley, and two belts with two independent tensioners that gave the bike two speeds.

I think my obsession with two speed gearing comes from playing racing games in the arcade as a kid. You had a hi gear, and a low gear : )

Thanks, Curt for taking some time and showing me around a bit.