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Old 12-24-18, 04:44 AM
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seamuis
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Bikes: Raleigh Competition, Pashley Roadster Sovereign, Cielo Sportif Classic, Mercian Vincitore Speciale

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Originally Posted by 12boy View Post
Having read through this thread, I am puzzled by the bottom bracket length. I have always understood what is needed is a straight chainline. If you have a 120 OLD rear wheel, the chainline will probably be around 43mm. Then the distance from the center of the seatpost to the middle of the chainring would also be 43 mm. I would be surprised if a BB spindle greater than 107 mm would work. Stripped down as yours is I would think it would be around 22 lbs or less, hardly a porker. I think it is a very nice bike. BTW., the late great Sheldon said an ISO crank arm will work fine on a JIS spindle and I have found it so as well, although JIS on ISO spindle not so much.
we all know the taper angle is supposed to be 2 degrees, and that technically they should all mate up just fine. But we’ve also all heard about proprietary tapers used by shimano and campagnolo in the past. In my experience it works MOST of the time. But for me, I once experiemented putting a late 70s campagnolo gran sport crank on a JIS shimano spindle and it never mounted proper. Could have been that taper on the crank was off. (Tourquing down a crank can certainly damage the taper) But it ended up causing the spindle to rust because water got between the crank and the spindle. This caused the crank to get stuck and I ended up damaging the crank trying to remove it. My point here is that with vintage, pre-used cranks, you can’t guarantee that the taper on your crank isn’t damaged, which can cause fitment issues, regardless of the spindle taper you choose. It can be a real crap shoot, basically.

Anyone know if there is a tool that can check the taper on a crankarm for damage?
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