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I have a bike that I rather like, but it's geared entirely for high-speed road bike type work. It's fantastic on the flat areas of the route that I take every day, but I also have a couple of serious hills that I cannot climb with this one (I can climb them with a different bike).

So, I'm looking at the possibility of saving money to replace the entire bike, or to regear it. An option that I saw today was something like the Shimano Alfine 11-speed hubs. I've not calculated gear ratios, but it's claimed that they have a very wide range and such a thing would benefit me.

So, if I wanted to retrofit my bike to an internally geared hub, what is involved (and what are the terms I'm looking for)?

  • size of axle?
  • distance across the rear fork?
  • what to do with no-longer-used rear derailleur?
  • will my existing grip-shifter need to be replaced, and does that entail anything other than just putting the new one on and attaching the wires?
  • will my entire rear wheel need to be replaced?

I'm pretty vague on what industry terminology would be used in this case. I'm also trying to evaluate the viability of even doing this as I balance my options for adjusting or replacing the bike to better fit the city I live in. The only adjustment I haven't mentioned is for me to replace the front chainring (there's only one on this bike) with something a little smaller. I'd lose level-ground power but gain some climbing power. And that, really, might be the least expensive and easiest of all of my options.

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2 Answers

up vote 3 down vote accepted

The first thing you should be looking into is gearing to ensure that an internally geared hub will work for you! The more you pay, the more gear range you get out of a hub, but even the nicest internally geared hubs don't match the spread of standard mountain bike gearing.

If you've decided that an Alfine 11 hub is for you then to answer your questions in order:

-the axle size shouldn't be an issue.
-the hub spacing is 135mm. That's mountain bike spacing typically. Apparently it can be adapted down to 130mm but I'm not going to detail how to do that here
-sell it/keep it/ use it as a paperweight
-The hub will have a dedicated shifter. I seem to remember that there are both trigger and grip shift options. Should fit without issue, though you'll probably have to take your grips/bar tape off.
-Yes, unless you have an incredibly nice rim with the proper drilling that you want to re-use.

You will also need a chain tensioner if your bike does not have horizontal/track-style dropouts, which I doubt it does. I believe there's one that goes along with the Alfine that Shimano sells as an accessory, though I don't think you have to have that particular one.

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You could most likely leave the derailleur on as a chain tensioner. You can probably completely remove the cable to the rear derailleur, and adjust the bottom stop, so that the chain stays on the sprocket. –  Kibbee Aug 3 '12 at 1:20
    
+1, good answer! I would save the whole rear wheel and assemble a new one with geared-hub + new spokes + new rim. The spare rear wheel will surely have a use (for you or someone else), and disassemble it doesn't worth the money/handwork/time. –  heltonbiker Aug 3 '12 at 13:53
    
Thanks for the technical details. I'll put all this to use while evaluating everything else. This is actually a level of bike modification I've never even approached before. –  Savanni D'Gerinel Aug 3 '12 at 17:28
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Seems to me that replacing the crank with a double or triple would make more sense. Or just buy a new (used?) bike.

To install the multi-speed hub you'd have to have your rear wheel relaced, another $50-100 over the $600 cost of the hub. And you might have to buy a new rim, if the drilling on your current one is wrong. A lot of money to spend for something that will still be a less than ideal solution to your problem. Might make sense if you like to tinker with bikes, but it doesn't sound like that's the case.

It's unlikely that your existing shifter would work with the new hub.

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I'm looking at these options specifically because the bike can't be modified to carry a front derailleur. Also, replacing the bike is a very expensive prospect, but one that I'll consider one day. I'm just looking for ways to add versatility without doing a full replacement. –  Savanni D'Gerinel Aug 3 '12 at 11:55
    
@SavanniD'Gerinel -- For the roughly $800 it would take to make the switch you could buy a fairly decent used bike, if you shop around. –  Daniel R Hicks Aug 3 '12 at 16:31
    
Fair point. My current racer recumbent was $1000 used. –  Savanni D'Gerinel Aug 3 '12 at 17:27
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