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I have a Specialized Allez E5 from 2017 with Shimano Claris (8 speed) and I'm looking to replace my crankset.
I believe this is my current crank.
My specific and potentially stupid question - am I right in just looking for replacements that fit my BB or is there anything special I need to consider for the 8 speed? I'm probably going to get a like-for-like replacement in terms of teeth, ring size and so on.
Thanks
is there anything special I need to consider for the 8 speed?
Yes, you specifically need an 8 speed crank.
8, 9, 10 etc speed group sets use progressively narrower chains, and the cranks have narrower chainring spacing to suit.
Many people seem to think you can get away with one speed difference and there are special shims available that adjust chainring spacing but it’s easier to just get a explicitly compatible crank.
Be aware that FSA MegaExo road (68mm shell) is dimensionally the same as Shimano Hollowtech II road, so you can fit a Shimano crank. Personally if I were upgrading to a Shimano crank I’d upgrade the bottom bracket to a Shimano unit also.
You can get any 8-speed crankset that fits your BB, that means not just the spindle diameter, but also the axle length - that means a road one. If it is a road one, you should get the right chainline without much worrying.
You can also get many other 8-speed cranksets, provided you also buy the right BB, they are much cheaper than the cranksets. That mostly depends on the manufacturer, because the newer BB standards are proprietary. Shimano will use Hollowtech II or older Octalink, FSA will use MegaExo and so on. Only cheaper cranks will typically use the universal square taper.
