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Old 09-27-04, 08:53 AM   #1
Mr.Weatherby
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Internal Hubs, front derailers.

I haven't done a lot of research on this yet, so I thought I would come here first.....

Is there any reason why it would be inadvisable to put a front derailer on bike with an internally geared hub? It would probably necessitate a chain tensioner, but are there other problems? I only ask because I've never seen a bike on the road set up like this.

Any advice would be helpful. Thanks!
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Old 09-27-04, 09:36 AM   #2
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Other than the need to provide some way to take up the chain slack, I don't foresee any problem.
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Old 09-27-04, 10:46 AM   #3
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I've been thinking about trying this myself, just to see how well it works. As long as the hub is freewheeling and there's a chain tensioning device, I don't think there'll be a problem. I'll just use a old set derailer as the chain tensioner. You'll also need to use one of the thinner cogs on the hub, like the ones that usually come with Shimano-type coaster brakes, since they'll accomodate 3/32" chain. Older cogs usually seem to only be 1/8" types.
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Old 09-27-04, 10:52 AM   #4
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Thinking about a Rohloff?




Pant, pant ...
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Old 09-27-04, 10:54 AM   #5
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Quote:
Originally Posted by shecky
I've been thinking about trying this myself, just to see how well it works. As long as the hub is freewheeling and there's a chain tensioning device, I don't think there'll be a problem. I'll just use a old set derailer as the chain tensioner. You'll also need to use one of the thinner cogs on the hub, like the ones that usually come with Shimano-type coaster brakes, since they'll accomodate 3/32" chain. Older cogs usually seem to only be 1/8" types.
Good to know shecky. Do new cogs fit on old models? If not, do you know if you can use a coaster brake model for a setup like this? Do chain tensioners work with coaster brakes?

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Old 09-27-04, 02:17 PM   #6
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No.
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Old 09-27-04, 02:18 PM   #7
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No.
what?
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Old 09-27-04, 02:33 PM   #8
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Most hub gears use a three-spline steel cog held on with a circlip. This would include SRAM/Sachs, Sturmey Archer, Shimano. The same cogs also work on most contemporary coaster brake hubs such as Shimano and KT. I've used new Shimano coaster brake cogs on old Sturmey Archer hubs without problem.

I know of no chain tensioner that will work with a coaster brake or fixed gear, since chain needs to be fully tensioned when back pedalling. Every chain tensioner I know of is spring loaded like a derailer and would massively de-tension the chain when backpedalling, and likely never really activate the coaster brake. So it wouldn't work.
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Old 09-27-04, 04:27 PM   #9
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Find a lbs that sells Raleigh. They market several comfort bikes with the Sram 7 speed hub and a front derailer. I saw a couple in Danville, VA recently. I didn't look closely as I was not really interested.

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Old 09-27-04, 05:14 PM   #10
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I haven't seen any Raleighs like that. I have seen a Raligh comfort bike that had a SRAM dual drive, basically a three speed hub with a 7 speed cluster, to get 21 gears without a front derailer.

The 7 speed hub with a front derailer would be unusual, I think, for a new bike.
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Old 10-05-04, 07:40 AM   #11
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Every once in a while we run into 3speed Sturmey-Archer hubs with a REAR deraileur and 2 or 3 cogs on the HUB. The derailleur is usually a Huret.

We have this setup on a Raleigh Sports in our shop right now. I'll try to take a couple photos.

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Old 10-05-04, 08:07 AM   #12
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Check out the harris cyclery website (sheldon brown). He's got an article about using a 9speed triple shimano group with a 2 speed internal hub for a total of 72 gears - or something like that...
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