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Old 10-27-22, 11:11 PM
  #16  
dddd
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Originally Posted by oneclick
Shims won't work; or if they do, not well or for long. The essence of the fit of a taper is that that there is a large surface area. If you get the small end of a tapered axle to fit - with shim - into the un-tapered crank, the whole of the fit is a line of contact at the end of the shim. The only way you get any area is by distorting that end into a wedge, but you still have only a small fraction of the area of a matching-taper fit. The crank will squirm; if you only have one flat shimmed it will also wobble; and that end of the shim will quickly be permanently deformed and the fit is then loose.
I didn't read anyone here suggesting using a tapered spindle in the un-tapered crankarm.

The suggestion of using a shim(s) is to create some degree of needed interference fit with the straight bore and spindle, versus a tapered setup.

Obviously, only a very thin shim can be made to fit in a straight square spindle interface, cut long enough so it can't get pushed out of the way as the crankarm slides onto the spindle, then trimmed away after tightening.

But basically, using a straight square spindle and bore made of aluminum is kind of a nightmare, both in use and in manufacturing.
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