Originally Posted by
luker
muddy waters. one of my favorites, btw. I'm looking at an original 68-ss bottom bracket axle in 115 and a 200x (early) record cartridge bottom bracket. The taper length on the newer unit is 16.55mm, while the older unit has 14.64mm useable length (measured from the inboard end of the little bevel to the end of the taper ramp. I'm trying to figure out whether I can use a newer (2004 or so) crank on the older nuovo record axle. It looks like it'll work, but I can't be sure that it'll tighten down. Anyone ever try to go this way?
Useable taper length is almost irrelevant as long as your staying within the same family ie: JIS/ISO. Whats available (useable length) and whats actually engaged are 2 different things. I dont see any reason why you couldnt mate up the newer crank which is ISO/skinny to the older spindle which is ISO/skinny. OK, maybe the spindle isnt techincaly ISO because it was never designated as such but its close enough to call it that!!
Originally Posted by
unworthy1
that post #29 has got some serious depth, thanks to you Jim for all the work...I'll be referring back to this frequently, I'll bet.
Just goes to prove (to me) that some of these "standards" allow for a pretty wide tolerance...and you often just have to test it with the good old "go/no-go" method.
The only problem I see with the 'go/no go' method is that you have to look at more than frame clearance, you have to look at spindle engagement depth as well. An JIS spindle only engages about half way into an ISO crank. Thats not alot of contact patch/surface area!!!