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Old 01-20-06, 01:37 AM   #1
peripatetic
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Raleigh three-speed/fixed conversion

I've got this old Raleigh three-speed frame, still in decent shape, and I'm driven by the mad gods of stupid challenges to try and convert this thing to fixed. Sheldon Brown's got a blurb on doing it: according to him, the hard part is swapping out the cottered cranks and getting a spindle or bb that'll work with cotterless. Just wondering if anyone around these parts has actually succeeded in something like this, and if so, could you share your experience? I do really like the frame, and I have a vision for the build...

I also ask here because the one time I asked at an LBS, the owner of the shop simply shook his head, told me the geometry was wrong and that it couldn't be done. On questions of whether or not it can be done, I tend to defer to Mr. Brown. So please don't tell me it can't be done unless you've really tried and failed. And if that's the case, then tell me why you're sure it can't be done.

Also, any suggestions for brakes et. al. to outfit?

thanks.
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Old 01-20-06, 08:30 AM   #2
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The geometry has nothing to do with it. The problem, as Sheldon said, is that older Raleighs used non-standard bottom bracket threading. The cup diameter is the same as "English" but Raleigh used 26 threads/inch instead of the standard 24tpi. If you can find properly threaded cups, you can use any cup and cone bb spindle of the right length.

In fact, if the cottered crank cups are in good shape, you might be able to fit a cup and cone square taper spindle using the stock cups. I did this successfully on an early '70's Raleigh road bike that we coudn't find replacement cups for.
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Old 01-20-06, 08:48 AM   #3
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Quote:
Originally Posted by HillRider
The geometry has nothing to do with it. The problem, as Sheldon said, is that older Raleighs used non-standard bottom bracket threading. The cup diameter is the same as "English" but Raleigh used 26 threads/inch instead of the standard 24tpi. If you can find properly threaded cups, you can use any cup and cone bb spindle of the right length.

In fact, if the cottered crank cups are in good shape, you might be able to fit a cup and cone square taper spindle using the stock cups. I did this successfully on an early '70's Raleigh road bike that we coudn't find replacement cups for.
Yeah, I know that the geometry had nothing to do with it; but the asinine quality of the response told me that the LBS wasn't necessarily going to have my interests in mind when answering my question. Sheldon's page described finding a specific spindle that will fit 'just about right'; unfortunately, I think that he edited that part out; maybe he felt that the whole article was too complicated. I do have the cottered crank cups from an old Raleigh Grand Prix ('72.) So I think that, either way, it should work. Should I just go ask an LBS to scrounge around for a square-tapered spindle that I can get to fit? Once I'm done with that, I assume that the rest will be smooth sailing, no?

Thanks for the info, Hillrider. I at least know that it can be done.
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Old 01-20-06, 10:17 AM   #4
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If the cranks it has are usable, why not just use those? Is it because it has different pedal threads?
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Old 01-20-06, 10:21 AM   #5
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Quote:
Originally Posted by peripatetic
I've got this old Raleigh three-speed frame, still in decent shape, and I'm driven by the mad gods of stupid challenges to try and convert this thing to fixed. Sheldon Brown's got a blurb on doing it: according to him, the hard part is swapping out the cottered cranks and getting a spindle or bb that'll work with cotterless. Just wondering if anyone around these parts has actually succeeded in something like this, and if so, could you share your experience? I do really like the frame, and I have a vision for the build...

I also ask here because the one time I asked at an LBS, the owner of the shop simply shook his head, told me the geometry was wrong and that it couldn't be done. On questions of whether or not it can be done, I tend to defer to Mr. Brown. So please don't tell me it can't be done unless you've really tried and failed. And if that's the case, then tell me why you're sure it can't be done.
The geometry of these bikes is actually excellent. There's a very simple solution to the bottom bracket "problem" that won't occur to many younger mechanics: Stick with the original Raleigh cottered crankset. These are extremely reliable, provide chainline that matches most track hubs, and are generally of very good quality.

The cottered cranksets have only two negatives:
  • They are a bit heavier than aluminum cranks...but I don't think this is going to be a weight-weenie project anyway.
  • They are harder to remove, but this is only a problem if you actually need to remove them. The quick and dirty solution is to drip some medium/heavy oil down the seat tube to fershen up the grease, and maybe adjust the bearings a bit. Don't remove the cranks unless it is absolutely necessary.

If the cranks do need service, it's somewhat difficult, but not all that hard. See: http://sheldonbrown.com/cotters

Sheldon "Cotters Work" Brown
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Old 01-20-06, 10:25 AM   #6
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My mind, it is blown! Keep the cotters!?

No, seriously, that's the most reasonable thing to do. I'm on my second bike with cottered cranks, and they don't ride any differently than cotterless. There's no difference in terms of how they work at all. I'm not saying I love them, but they work.
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Old 01-20-06, 10:42 AM   #7
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For my Raleigh-threaded bike, I bought 26tpi rings made by Phil Wood from Harris Cyclery and used a Shimano UN72 bottom bracket purchased for a song off eBay.

Of course the rings are not cheap.

To Sheldon's list of cottered crank negatives, I would add that they will rust badly after sitting in floodwater for 2 weeks.
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Old 01-20-06, 02:49 PM   #8
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Hmmm. Already removed one of the cranks. The cotter pin's shot. Guess I could just get another one. It's not really a "weight weenie" project, but since I have to get the thing up and down several flights of stairs, I don't particularly relish retaining the weight the cottered cranks represent. But the logic is undeniable for this thing. And the frame's got a fair amount of degradation (rust, paint damage.) I was actually considering a strip and repaint (or some kind of rust-finish scheme. Basically wanted to build up a very nondescript but fun fixie ride. I have most of the parts necessary, so maybe I'll just go with the cranks and see how it works out...

Thanks for the help, all, and thanks for reminding me which bb I needed, spider-man.

I also have a use for those moustache bars I've been saving...
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