Classic & Vintage - Cotterless Conundrum - No Pin Intended
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01-26-09, 09:07 PM
I thought I'd start fresh here and get some feedback on what my options are so I can move fwd with a clear head. I have a 76 Raleigh Grand Prix frame that was primered and a cotterless square tapered bb installed. I normally deal with cottered cranks so I'm not sure how to move forward. I've read Sheldon's article (http://sheldonbrown.com/raleigh26.html) on cottered to cotterless to learn more. But I don't know what type of crankarms or crankset I need.
Here's what I know. I measured the full spindle length from end to end and it measure 113mm. I pulled out the spindle and it's stamped SUGINO MW70. I'd like to run a double crank (your basic 52-42) but don't have any square tapered cranks lying around. What will work with a 113mm overall length?
Not exactly vintage, but I did find this SHIMANO crankset (http://cgi.ebay.com/Shimano-105-crankset-square-taper-52-42_W0QQitemZ120366142498QQcmdZViewItemQQptZCycling_Parts_Accessories?_trksid=p3286.m20.l1116). Would it work given what I've mentioned above? As you can tell, I'm new to this and have digested quite a bit of info today. So forgive me if I've left anything out.
01-26-09, 09:43 PM
I'm not sure about this but I feel I should warn you of one possible problem. The spindle taper may be incorrect for those cranks.....It would be best to figure out what that BB was spec'ed for and go from there to find a suitable crankset. Sugino used both ISO and JIS tapers which will affect your final decision for suitable cranks....
Anyone have a Sutherlands handy?
This should help to confuse matters:
My gut feeling is that a 113mm BB spindle is too short for a Raleigh GP to give the correct chainline. The GP has a pretty large offset on the chain ring side. As I mentioned, I used 122 and 127 mm Shimano BBs with Suntour cranks. So, I think you are faced with the following possibilities:
Trial and Error- If you want to use the current BB, you will just have to experiment. Pick a crankset and see what kind of chainline you get. See if it is close to where it needs to be. If it's close then based on whether you need a larger or smaller chainline, you can make a choice of ISO vs. JIS, or the various manufacturers. Sutherlands has a diagram that shows in a relative way where the various cranks line up on the tapered axle. But it won't vary by much. If not so close you will need a different size spindle. My suspicion is this BB is too short, but you won't know till you actually try it.
Known combination- Scrap the BB and use a BB and crankset known to work or known to be close.
Retro fit- Scrap the cotterless BB and go back to the Raleigh cottered cup/spindle/crankset. They are cheap, easy to find (I've got several lying around). On the downside, they are heavy and they have cotters. This is your low cost solution.
01-27-09, 05:00 AM
I'm not sure about this but I feel I should warn you of one possible problem. The spindle taper may be incorrect for those cranks.....
No no, this is exactly what I want otherwise I'll never learn. It just so happens that to deal with a bb, it seems there are lots of specs involved:
# of tpi
if square taper: JIS or ISO
bb shell (68 seems most common)
crank arm length (170 seems most common)
I'm closer than before but wow, you really have to know yours tuff in order to ensure proper parts. I think for $25 that's not steep for that SHIMANO 105 crankset. Or like you say, I pick up an original Raleigh bb and go back to cottered (I prefer that anyway).
01-27-09, 05:16 AM
Matching BB spindles to cranks is just too trial and error for internet buying unless you are good or lucky. You may get stuck with some cranks that don't fit and then you need to get a new spindle. Is there a LBS in your area that caters to FG/SS bikes? They will have tons of used stuff & you could buy/try out various combinations until you find something that fits.
I've got some of the same cranks that you are considering that I tried on a 113 spindle on my super course that I just built up. I built it up as a FG so I was looking for a 42 mm chainline. The chainline I got was a 39 inner to 44 outer which would have been 2 mm off of ideal. I was able to use a different crank on the 113 to give me the chainline I sought.
If you want to try the 105 cranks that I've got on your spindle, shoot me a PM & I will send them to you to if you pay for postage. If they fit & you want to keep them send me a few bucks, otherwise just send them back to me. I don't have a bike for them so they are just laying around.
01-27-09, 09:05 AM
Thanks for offering MPARKER - let me wait before I take you up on that. I think I have an in road on an original Raleigh bb, so I'll be going back to cottered. You mention FG (fixed gear?) and SS (singlespeed) various times above. That's not my intention here just in case you assumed that.
But I read you loud and clear regarding the trial and error - I never knew that.
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