Bicycle Mechanics - Does JIS taper work w/ older Stronglight cranks?
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01-19-07, 06:52 PM
I've searched for the answer here but couldn't find it...
I'd like to try using a Shimano UN72 bottom bracket and Phil Wood French mounting rings in my PX-10. I've found lots of information about this on the forums but in these threads noone ever mentions the cranks they plan to mount on the UN72 spindle. I'd like to use an older Stronglight 99 crankset. Will this work?
I just don't want to ruin a good old crankset (again!). Thanks for your help.
01-19-07, 07:16 PM
Did you get that PX10 back from Ed Litton yet? I want to see pictures!
I don't have the answer to your question, but I hope somebody else does. We'll both learn something.
01-19-07, 09:03 PM
Hi Dirtdrop! No, I haven't even taken it over there yet. Ed still has the Spitz cross frame I dropped off for repairs back in July '06! I stripped the PX-10 down to the frame back in October because I wanted to be ready to drop it off when I picked up the other one. I'm still waiting...
I heard he had a slow turnaround and it's okay because I have another bike I can ride. And in all fairness he has had some family issues (I can empathize). On top of that he's an artist and I'm willing to give someone like that a bit of leeway to do the job right. But...I can't wait too much longer. It makes me hesitate to drop off the PX-10 because, considering it's a complete restore, it will be a much bigger job and will probably take even longer.
Just test mount the cranks and have a look. It probably won't match up (ISO crank/ JIS BB) but it might. My ISO cranks mounted fine on a JIS BB, manufacturing tolerances I guess.
Stronglight is ISO taper. Usually mixing ISO and JIS results in a bad chainline and a crank that can't go back to it's original BB when you find one. Try Harris Cyclery, Sheldon has a line on anything French. He is always willing to help.
01-21-07, 04:23 PM
I found some more information ala Google:
At that URL search for these two articles:
Bottom-bracket confusion – 2004.07
Axles and Cranks – 2000.03
Basically the spindle ends on JIS spindles (like Shimano) are a tiny bit fatter than ISO (like Stronglight). If you put an ISO crank on a JIS bb it won't slide all the way on. This means that you probably can't use the same spindle length as before because the cranks stick out a bit further...so predicting spindle length can be a bit tricky.
There might be a risk of ruining the cranks; because the crank can't completely seat onto the spindle there can be room for a bit of play if they're not tightened enough. And if they ARE tightened down with a lot of torque you risk permanently deforming the crank's spindle interface. Once you do that it sounds as if you can not install that crank on an ISO spindle again (although the author of the question in second article counters this).
The first article points to Sheldon Brown's comments on the matter at
"ISO cranks (Campagnolo, Stronglight, others) won't go as far onto J.I.S. spindles as they ideally should.
J.I.S. cranks (most Japanese models) may bottom out if installed on ISO spindles.
In practice, you can very often get away with mixing these sizes, as long as you select an axle length that gives the desired chainline."
At one point I posted a question on this forum about which Phil Wood spindle tapers would work for old Stronglight cranks ("standard" taper is the answer from Brent at Phil by the way). In his reply to my question, unworthy1 wrote
"Phil Wood, in their wisdom, chose to make a 3rd option (the "Standard") that splits the difference between the ISO and JIS SPINDLE SIZES and creates one spindle end that is "universal" as far as it applies to regular JIS and older European cranks (which is all that used to be on the planet, square-taper wise). But because their "universal standard" was by definition going to be slightly different from the spindle length you are replacing, you have to check with Phil, either look up on the Phil chart or call them, to insure you buy the right length for your application."
I guess I'll just have to try it and see. Once the bike is built up again (pending frame restoration) I'll post my findings...might be several months. Thanks everyone.
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