Been reading from posts and can’t find my answer. Any help would be appreciated.

Scenario: I currently have a Felt AR5 10-speed with shimano 105 rear/front derailleur, 105 levers & brakes and a FSA crank 50/34 compact. I will like to change the crankset to 105. But I believe the 105 is only a 11-speed type crank.

Question: will the shimano 105 11-speed 52/36 crank work in this scenario? And what bottom bracket would be needed (BB30 or BB60 English). I would still run with 10-speed.


  • The Shimano 5700 series is 10 speed in the 105 line. It was the standard product up to 2014. Have you checked to see if it is still available? I know they keep many of the older lines available for replacements. Commented May 30, 2020 at 20:32

1 Answer 1


The width difference of 10 and 11 speed chains is very close (5.88 vs 5.62mm) so usually this works without issue. There is always some possibility that even this difference will cause rub against the large ring in some of the small/small combos. Very short chainstayed bikes like yours increase the likelihood. Chainring micro spacers such as the 0.2mm FSA are the fix if there are issues. You'll also need to make sure your FD can be moved up a little, but that shouldn't be a problem.

You haven't said what kind of BB shell your frame has. If it's threaded you need any ISO/BSA threaded Shimano road bottom bracket. If you've got FSA cranks with a 24mm spindle now then you can use your existing BB if it's not worn out. If it's BB30 you have the option of using any of the myriad adapter systems for 24mm cranks, which consist of reducer bushings, press-in shell adapters, and screw-together adapter bottom brackets. There are many questions here about the pros and cons of these systems. Your bike's cable routing arrangement in some cases can inform which is best.

  • Thanks Nathan for your response. I don’t know what BB I have currently but the bike shop did say they would order some type of conversion for the BB. But I believe I heard that the BB is probably threaded.
    – Michael
    Commented May 30, 2020 at 0:17

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