Classic & Vintage - what do I need to know to get new cranks
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08-17-09, 01:05 AM
Hi, I have a 1975 Peugeot and I want to change out the cottered cranks to cotterless cranks. I am so ignorant about this stuff that I don't even know what I don't know. So, that's why I'm asking you all to help me understand what I need to complete the change. Does the axle have to be changed? Will I have to change out the chain rings? Please help a girl out!:rolleyes:
08-17-09, 01:18 AM
Whether you need to get new chainrings depends on what size chainrings the old and new cranksets would take. It's possible you could find something that uses the same size as what you have now, but that might limit the choices you would have for your crankset.
At minimum, you will need to change the crankset and the spindle (what you might be calling the axle). It is quite possible that you may need to change the bottom bracket as well. If this proves to be the case, you will need (98% certain) to locate a suitable French threaded bottom bracket.
It would be ideal if you can find a friend, or LBS that has experience doing this. Without the proper tools, removing the current configuration could prove a challenge, and acquiring what you will be replacing it with could be hit and miss - until you hit upon the right combination of sizes that you need.
There are people here who could talk you through this, but it could be quite the adventure.
A good starting point would either be good pictures, or a description of what you have on there now, and what you have in mind to replace it.
Hello I changed from cottered to non cottered on a peugeot and all I had to change over was the spindle (axle). I was able to re use the rest of the bottom bracket, bearing, cups, balls, etc. I think the donor spindle came off a raleigh. The raleigh spindle was also a little shorter in length as it did not need to cater for the cutaway on the spindle to fit the cotter pins. Perhaps you could get or you may have any rubbish bike to practice removing the bottom bearing if you have not tackled this job before. Cheers.
08-17-09, 06:49 AM
It could be as simple as replacing the spindle, but there are a lot of crank sets that would fit once you get the spindle changed, and therein lies the rub.
I've always just fixed the immediate problem first (to a spindle with square taper) and worry about the next step, because it often takes care of itself.
So that's what I'd do, either replace the spindle or the bottom bracket, and go from there. The length of spindle, etc is better handled when you can provide some info and pics.
This is where to get help, though.
Yes you will have to change out the spindle.
Yes you will have to replace the crankset.
You need to find a local dealer with a box full of old spindles to help you in this quest. Spindles are cheap, its just finding the right one to fit your bike.
You can find nice vintage cranksets on ebay all the time. I have bought several that way.
08-17-09, 07:54 AM
What crank are you changing to?
Here's what a quick Ebay search found:
08-17-09, 07:55 AM
And another, cheaper option:
Don't forget bearing cup thickness, typically either 3 or 5 mm, which dictates the required spacing between your spindle's bearing races. If you want to reuse your old cups, you will need to a new spindle with the same bearing face spacing as your current one.
I put Sugino cranks on a ca. 1974 UO-8 and ended up buying the crankset, matching cups, and spindle.
As far as I know, the only cotterless aluminum spider which can take your existing steel chainrings (why bother?) is the TA Professional, whose 3-bolt BCD matches that of most European cottered cranks.
08-17-09, 12:32 PM
Assuming that your bottom bracket is French-threaded (almost certain, but should be verified) one option might be:
Find a TA Cyclotouriste (Pro 5 vis) or Stronglight 93 or 49D crankset on eBay. The 93 may be easier to find replacement chainrings for if you need to do that (# teeth or condition).
Find a TA (aka SpecialitÚs TA) or Stronglight bottom bracket on eBay with spindle length 118 mm for double chainrings (dunno for triple) -- either one is OK.
Get a sealed-bearing bottom bracket from Velo-Orange.com with French cups. These have JIS-standard spindle ends; so:
Get a Japanese (JIS-standard spindle, not Stronglight or TA) crankset -- in much more plentiful supply. And you could go with 110 BCD (bolt-circle diameter) cranks to put smaller rings on the set, if you like.
The crap-shoot here is you need to know what length spindle you need for a given crankset. Stronglight and TA used 118 forever (and more recently, not, I think), while the various people making JIS cranksets are all over the place; plus the double or triple thing require different lengths, and then there's offset (spindle longer on driveside than non-drive side) vs symmetrical (which I believe VOs BBs are, but confirm).
To make it even more complicated, not all Japanese cranks are JIS standard -- some are Campagnolo standard (Sugino Mighty Competition, Suntour Superbe and Sprint, Dura-Ace AX for example), but these are high-end and the exception.
If you have a particular crankset in mind, then finding a bottom bracket to fit, even on a French bike, is easier than doing it the other way around. Sutherland's Manual (at least older editions) has pretty good information for spindle/bottom bracket mixing and matching with cranksets -- someone here can help you with what's going to work, at least in theory.
08-17-09, 04:21 PM
It definitely not be easier to find 122 BCD Stronglight 93 rings!
08-18-09, 01:32 AM
Here the Velo-Orange part:
I may be buying this and trying to fit a Shimano crank to a '72 Peugeot (I've got a '75 also). And I may be doing it within the next month, so if you are in no hurry, I can get back to you with my results. Send me a reminder pm, if you want.
The spindle length is the big issue for me. Although the idea of symmetrical bb's (as Charles mentioned) was news that I'll have to plan for. I'll get the crank first, then try to determine the spindle length by estimating the required clearance between crank arms and chainstays. It's all a bit foggy to me at the moment. I'm not great at visualizing mechanical things or anticipating problems.
Btw, I was very reluctant to work on the bb of my '75, but it was worth learning about, and very satisfying. I've taken both bb's apart now and both times had to pay the LBS to press, then bang out the cotters. $5 each side. After that, removing the cranks and bb wasn't too bad. The adjustable cups came out very easily on both. The fixed cups - much harder. I had stripped the frames anyway, so I could put the fixed cup into a vice and rotate the entire frame to generate torque. Worked like a charm.
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