Is Repeated Removal of Crank Bad
07-25-11, 02:26 PM
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Is Repeated Removal of Crank Bad
Just thinking - Had to take off my crank to inspect my bottom bracket for a click - Then to check my crank bolt nut - Then to try out a new 34T ring - And now to put the ring in properly...
Does repeated removal wear out a square taper crank?
(The crank is a cheap Sunlite alloy crank (170mm 53/39) that I put on my 70s UNIVEGA till I could get a more period SHIMANO - I did not expect it to hold up so well, and with a cheap 34T inner ring I am ridding with the same comfort I used to 10 years ago)
Does repeated removal wear out a square taper crank?
(The crank is a cheap Sunlite alloy crank (170mm 53/39) that I put on my 70s UNIVEGA till I could get a more period SHIMANO - I did not expect it to hold up so well, and with a cheap 34T inner ring I am ridding with the same comfort I used to 10 years ago)
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07-25-11, 02:31 PM
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No one cares
not if you're doing it right.
I don't see how you need to remove the crank arms to put a chain ring on though.
I don't see how you need to remove the crank arms to put a chain ring on though.
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07-25-11, 04:58 PM
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I would think that as long as both your tapers and your spindle flats are clean and dry when you install, and you don't force the crank up the flats too far, it shouldn't cause any un-due wear.
07-25-11, 05:05 PM
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I wondered the same as I think a person could inflict wear on the tapered square holes on the crankset that the spindle ends up slightly deeper and deeper with each re-install and tightening?? But it might take a lot of removals and installs to do that much wear....I dunno.......So far I have not ever bottomed out my cranks on my spindles yet.
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07-25-11, 05:21 PM
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From what I've read about tapered cranks, we should all own and use torque wrenches, as it's important to get the right torque to 'pre-load' the bolt. And after torqueing to the right figure, one should not come back later and re-tighten it, because that leads to a vicious cycle wherein the crank 'climbs' up the spindle and eventually splits. The key is to tighten it right and then leave it alone.
07-25-11, 05:27 PM
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I think you're concerned about a fatigue failure at the corners of the holes in the cranks (where there's a stress riser)? Well designed cranks have fillets between the flats and should take thousands of on-off cycles to elongate micro-cracks enough to pose any danger.
I would be more concerned about the installation/ removal procedure scratching the crank which might start a macro crack. Cleaning then re-greasing or using anti seize should minimize that worry.
https://en.wikipedia.org/wiki/Fatigue_(material)
If anything, I'd think the crank threads for the remover tool would be the weak link.
I would be more concerned about the installation/ removal procedure scratching the crank which might start a macro crack. Cleaning then re-greasing or using anti seize should minimize that worry.
https://en.wikipedia.org/wiki/Fatigue_(material)
If anything, I'd think the crank threads for the remover tool would be the weak link.
07-25-11, 07:05 PM
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I definitely avoid unnecessary R&R cycles.
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Capo: 1959 Modell Campagnolo, S/N 40324; 1960 Sieger (2), S/N 42624, 42597
Carlton: 1962 Franco Suisse, S/N K7911
Peugeot: 1970 UO-8, S/N 0010468
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"Far and away the best prize that life offers is the chance to work hard at work worth doing." --Theodore Roosevelt
Capo: 1959 Modell Campagnolo, S/N 40324; 1960 Sieger (2), S/N 42624, 42597
Carlton: 1962 Franco Suisse, S/N K7911
Peugeot: 1970 UO-8, S/N 0010468
Bianchi: 1982 Campione d'Italia, S/N 1.M9914
Schwinn: 1988 Project KOM-10, S/N F804069
