Bicycle Mechanics - JIS taper crank on ISO taper spindle -- safe?

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mediccody
10-16-07, 11:23 AM
The forum search function is not even letting me search using "jis" and "iso" as words, and I can't turn anything up on google or by adding other words on the forum search.
I've got a Sugino crankset, designed for J.I.S. taper spindles mounted on an old Stronglight I.S.O. taper spindle from the early '80's. I'm aware that Sheldon Brown suggests it is probably safe to do, but I have also heard of people eventually stripping out the square taper. Has anyone on these forums had this issue, which they could provide details about, or has anyone around here ridden a similar setup for at least a year or two without issues?
I'm just going to tighten the crank set on there as tight as I possibly can, make sure my chainline is straight as hell, and pray that the cranks don't fall off until I can find a nice set of 165mm length ISO arms.
mediccody
10-16-07, 11:43 AM
Is this one of those topics that no one wants to touch with a 10 foot spear?
MichaelW
10-16-07, 11:48 AM
I think I have a mismatch with Stronglight chainset on a Shimano spindle. The cranks are perched a bit too far out for my liking but the chainline is OK and the cranks have surved for 7 years so far.
Doing it the other way you may bottom-out not be ablt to tighten the cranks (I think??). At your own risk, suck it and see.
I think you may be all right temporarily. I did the opposite mismatch (ISO cranks on a JIS spindle) and discovered it was the cause of the mysterious creak. I couldnt get them alll the way down on the spindles. Once I got the right match (in this case Suntour Superbe cranks on a Campy BB), all was silent and right.
Sheldon Brown
10-16-07, 12:37 PM
The forum search function is not even letting me search using "jis" and "iso" as words, and I can't turn anything up on google or by adding other words on the forum search.
I've got a Sugino crankset, designed for J.I.S. taper spindles mounted on an old Stronglight I.S.O. taper spindle from the early '80's. I'm aware that Sheldon Brown suggests it is probably safe to do, but I have also heard of people eventually stripping out the square taper. Has anyone on these forums had this issue, which they could provide details about, or has anyone around here ridden a similar setup for at least a year or two without issues?
I'm just going to tighten the crank set on there as tight as I possibly can, make sure my chainline is straight as hell, and pray that the cranks don't fall off until I can find a nice set of 165mm length ISO arms.
http://sheldonbrown.com/bbtapers
Sheldon "Works For Me" Brown
mediccody
10-16-07, 02:14 PM
The link is actually sheldonbrown.com/bbtaper, no offense to the eminent Sheldon Brown meant, of course....
Reading that link for about the fourth time in the past week, I actually did gain some further understanding. I'm using a French threaded Stronglight cup setup, and hadn't really considered that the most damage would result from removal/replacement of the cranks while overhauling the BB.
I started a thread about this last week, and as far as I understand I believe that my only solution for less than $150 (The price for 165mm ISO cranks or a custom sealed French threaded bottom bracket) is a Stronglight or other older 170mm crank for an ISO spindle.
Thanks guys
HillRider
10-16-07, 04:22 PM
JIS cranks may ( and it really is "may") go too far up the taper of an ISO crank if the tolerances add up the wrong way. I'd try it first and if the crank arms don't slide so far up that they bottom out on the spindle shaft, you should be ok.
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