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-   -   High Ratio 2 Chain Design? (http://www.bikeforums.net/alt-bike-culture/892890-high-ratio-2-chain-design.html)

dfinch 05-31-13 08:26 AM

High Ratio 2 Chain Design?
 
1 Attachment(s)
Here's a random idea we had. Has anyone seen this before? The idea is to have a ridiculously high gear ratio on a fixed bike by inserting a second chain and third sprocket.

Your thoughts?

http://bikeforums.net/attachment.php...hmentid=320285

Shimagnolo 05-31-13 08:28 AM

http://www.canosoarus.com/08LSRbicycle/LSR%20Bike01.htm

Note the intermediate shaft is behind the saddle.

dfinch 05-31-13 08:41 AM

Nice! Thanks.

0.2HP 05-31-13 08:46 AM

Also used on high speed recumbent bikes:

http://www.popsci.com/diy/article/20...s-fastest-bike

http://www.popsci.com/files/imagecac...t_385xbody.jpg

bhtooefr 06-08-13 12:15 PM

And delta trikes and quads use that method a lot, too, with the IGH as a mid-drive.

Artkansas 06-13-13 07:57 AM

Quote:

Originally Posted by dfinch (Post 15688219)
Here's a random idea we had. Has anyone seen this before? The idea is to have a ridiculously high gear ratio on a fixed bike by inserting a second chain and third sprocket.

A Giant Stiletto is already set up to do that. You just change the gear.

http://choppersforlife.ru/giant/254.jpg

arex 06-13-13 05:04 PM

I wonder how much extra drag is introduced?

StephenH 06-23-13 06:20 PM

You didn't say why you'd want to do that. Take a regular road bike, put it in high gear front and rear, and you can't hardly get it started. So you have the potential to make a rather useless gearing system.

Note that if you're after maximum speed, you need to have it where your legs are spinning at the optimum speed for the most power, not doing leg-press exercises at slow speed.

Flying Merkel 06-26-13 11:00 AM

This is Alt Bike land where we are unencumbered by sense & reason. Looks cool, good enough reason for me.

Doug5150 08-14-13 09:13 AM

Another example of mid-drives is when people build velomobiles or cargo trikes, and they want a wide range of gear ratios but also want to be able to shift gears while standing still.

Using two internal-gear-hubs (the second one as a mid-drive) gives that ability, and still doesn't cost a great deal of money.


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