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following my recent post about the problem with FSA Omega BB30, I was advised to throw it away and go for a new one.

I've done some research and decided to upgrade with SRAM Force 22 BB30, already ordered it. Now, my FSA had 50/34 teeth and the new SRAM will have 53/39. Obviously, I will be looking for a new chain but my main concern is whether it is compatible with the Shimano CS-HG500 cassette that I currently have.

Also, since I have FSA's BB30 bottom bracket already installed, I assume that the Force 22 should be compatible, or am I wrong?

If you know any other problem that this upgrade might cause or anything that I should look out for, please let me know.

snejus
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1 Answers1

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Cassette compatibility is not a concern, cassette sprockets don't care what's on the other end of the chain. BB30 crank will fit right into the BB30 bottom bracket. Front and rear derailleur capacity will be fine because you have less difference between chainrings (53-39=14, rather than 50-34=16).

You currently have a 10 speed drivetrain, and the Force 22 crank is for 11 speed. Chainring spacing is slightly narrower for 11 speed cranks as 11 speed chains are narrower than 10 speed chains. The opinion on this site seems to be that you can mix 11 speed cranks into 10 speed systems and vice versa.

As you say you will need a new chain because the length will need to be longer. You might consider a new cassette as well so you have a full new drivetrain. Front derailleur will need to be be moved up to accommodate larger rings, check this is possible on your bike. You should also check that your chainstays have enough clearance for the larger rings. A 53 tooth ring is about 6mm greater in radius than a 50, a 39 tooth about 10mm greater than a 34 (see this question).

My main concern would be compatibility with legs, as you will have a substantially (15%) higher spread of gear ratios. If you live in a flat area and never use your lowest gears you are probably OK, but if you are using your full gear range you may want to reconsider and stick with a 50/34 crank.

Argenti Apparatus
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  • Thanks for a timely answer again, Argenti. I live in London, so the gear ratio is not a big concern for me. Now in terms of upgrading to 11 speed crank, I reckon that it shouldn't pose any problems with my current setup since the front dérailleur can be easily moved up and the ring spacing on my cassette should be to accommodate a slightly narrower chain. Though would it actually work the other way around? If I wanted to accommodate a 10-speed chain on a 11-speed cassette? Would the spacing not be too narrow? – snejus Dec 22 '18 at 18:40
  • I'd run a 10 speed chain with a 10 speed cassette, 11 chain with 11 cassette. The cassette and rear derailleur are more sensitive to chain width, and you change in the rear far more often then the front – Argenti Apparatus Dec 22 '18 at 18:59
  • This makes sense. Though upgrading the entire drivetrain will get very expensive very quickly, since I'd have to upgrade my Shimano Tiagra shifters as well. I guess my best bet would be to look for a 10-speed crankset instead. – snejus Dec 22 '18 at 19:11
  • I think you misunderstand: you can run a 10 speed cassette, derailleur, chain etc with 11 speed cranks. The chainring spacing is slightly different, but it works. Opinion on this site seems to be you can get away with a crank 1 speed different from the rest of the drivetrain. – Argenti Apparatus Dec 22 '18 at 19:14
  • FYI see my edit about chainstay clearance for larger rings. – Argenti Apparatus Dec 22 '18 at 19:17
  • Okay, I see. In terms of the chainstay, it seems as though it should accommodate the difference. It's a CAAD Optimo frame (from 2017) so I reckon they should have thought about larger chainrings when they designed it. – snejus Dec 22 '18 at 20:01
  • Not necessarily. 50/34 'compacts' are pretty standard these days, 52/36 is considered higher gearing. 53/39 cranks are really an older standard used before 11 tooth sprockets became available. – Argenti Apparatus Dec 22 '18 at 20:05