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Can someone please give some advice to help find a new crankset?
#1
I apologize in advance if I mix-up some lingo, I have almost no experience in fixing bicycle drivetrain.

Previously I had Comet CKM-7159 as crankset (I managed to find this datasheet that seem to describe it pretty good - datasheet)

Long story short, pedal track on the left crank got completely destroyed. Since it's two-piece crankset (or I just have not enough muscles to detach left crank from the spindle) it looks like I need new crankset <sigh>.

Based on my filters:
- crankarm lenght from 170 to 175 mm
- bottom bracket diameter - 24 mm
- crank gearing - 1
- chain gearing - 11
I get exactly 7 sets:
results

Sad

I'm trying no to spend the fortune here, so I look at the cheapest option on the list:
https://www.bike-components.de/en/Shimano/GRX-FC-RX600-1-Crankset-p72011/?o=200945-black-175-0-mm-40-tooth

It looks okay to my non-trained eye, I think it should work. However, when I look at the description of my bottom bracket - https://www.bike-discount.de/en/fsa-megaexo-bb-7100-24mm-to-mtb-bsa68/73-mtb-bottom-bracket - I see this interesting bit:

> Only for cranksets without clamping screw on the left crank arm (NBD)

And as far as I understand my main candidate for new crankset actually has this clamping screw.

Do I interpret this correctly and this set is indeed incompatible with my bottom bracket? Or it will fit after all?
Also any other constructive criticism of my though process is very welcome, as I said in the beginning, I have almost no idea what I'm doing.

Thank you in advance.
  Reply
#2
Things you actually need to check include

Bottom Bracket Size: Measure the bottom bracket shell. It is usually 68mm or 73mm on basic standard american threaded. The spindle for cranks are specific to this size. If you have a 73mm the GRX will not work. You will need to get a more mountain specific crank. In FSA standards, that will be 386EVO or the newer 392EVO.

If you have a specialty bottom bracket, such as BB30 or PF30, you will need a crank specific to that.

Then next thing you should check after this is if your frame has Boost or Super Boost. If it does, you will yet again need a specific crank for Boost or Super Boost. To do this, measure the across from dropout to dropout. A normal dropout is typically 130/135mm. Boost will be 148mm. Super Boost will be 157mm.
  Reply


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