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-   -   3 speed trany on the cheap (http://www.chiefdelphi.com/forums/showthread.php?t=69900)

colin340 05-11-2008 14:20

3 speed trany on the cheap
 
link

Sturmey Archer's S3X fixed-wheel three-speed hub will be available in January, Sturmey's US marketing manager told BikeRadar at Interbike today. Retail price for the hub is expected to be in the US$140-160 range.

The S3X will probably come with a multi-location shifter that can be used as a bar end or mounted on the down tube. Unfortunately, said Prosser, it's not possible to make it work with current brake/shift levers, so drop-in compatibility with, say, Shimano STI units, won't happen.

"Prosser said that the final production version of the hub will be lighter than the current prototype. It's hard to see where you save weight in a hub gear as there's an unavoidable amount of metal needed in the internals, and it's not like possible buyers of a three-speed fixie hub can go buy someone else's lighter alternative.

Or can they? We haven't seen it yet, but SRAM apparently has a hub that can be switched between fixed-wheel and freewheel operation and is rumoured to be working on its own three-speed fixed hub.

Prosser explained some of the background to the S3X project, which was basically by a steady stream of inquiries to Sturmey from various places around the ‘net (including, this writer, who stopped bothering Prosser about it when he told me that to resurrect the old ASC hub, Sturmey would need an order of 10,000 units.)

Various people, including the late great Sheldon Brown, helped gauge the level of interest, and Prosser hinted that if the S3X is successful, then Sturmey will consider widening the range with, for example, a closer-ratio version akin to the original ASC."-from http://www.cyclingnews.com

this came up on the unicyclist forums i know some teams talked about useing this kind of hub but it was going to be really hard to get them not to freewheel but this one are made for fixed gear bikes one thing to think about is that you would prol want to back drive them (ie motor powering the outside hub and the out put being the "input" collar) so you so you would not be gear up the output

cool but 340 and 424 will stick will AMs

Madison 05-11-2008 14:24

Re: 3 speed trany on the cheap
 
Quote:

Originally Posted by colin340 (Post 774009)
link

this came up on the unicyclist forums i know some team talk about use this kind of hubs but it was going to be really had to get them not to free wheel but this one are made for fixed gear bike were you do not have the free wheel one thing to think about is that you would prol want to back drive them ie motor powering the outside hub and the out put being the "input" collar

cool but 340 and 424 will stick will AMs

The ratios range only from .77:1 to 1.33:1, so they're probably not varied enough for most FRC applications.

Dick Linn 05-11-2008 16:29

Re: 3 speed trany on the cheap
 
Unless the specs on the hub have changed:

The hub will be made using a much stronger aluminum hub shell. Overall gear range will be 160%.

* 1st Gear -37.5%

* 2nd Gear - -25%

* 3rd Gear - Direct Drive

* Gear step gear 1 to gear 2: 20%

* Gear step gear two to gear 3: 33%

MrForbes 05-11-2008 17:08

Re: 3 speed trany on the cheap
 
Interesting hub....I ride a really old Schwinn with a normal 3 speed AW hub, and my kids ride fixies and unicycles.

Thanks for sneaking it in here :)

Dick Linn 06-11-2008 08:14

Re: 3 speed trany on the cheap
 
I looked into these quite a while back. As Madison says, the range of ratios is fairly narrow.


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