The patient is 2019 Cannondale Synapse with FSA crankset, BB30. I have an issue with adjusting the front derailleur. The chain rubs against the derailleur cage but only during the push phase of the pedal stroke. I recorded a video to get a better look at the issue and I noticed that the crank slight moves once the pressure is put on the crank. On the video you can see that when I clip in and when I push during the pedal stroke the crank moves slightly to the outside.

Is there a way of correcting that?

1 Answer 1


I had this, Cannondale 2019 Optimo, FSA crankset was knackered and needed replacing, the crank that was attached to the axle (?) was supposed to be one solid piece but it was coming apart. FSA cranks are junk from what I've heard, at least the ones fitted by bike manufacturers, they might have some better aftermarket cranks available. Bike shop initially replaced the bottom bracket but if they'd inspected the crank properly first they would have noticed the play in the crank which got progressively worse.

If you lean over the saddle from the back wheel and hold both cranks, see how much sideways play there is, and whether you can wobble the chainrings, and whether you can move one crank independently of the other. If you're lucky it will be the bottom bracket as it's cheaper to fix but if it's disassembled make sure they check how solid the cranks are on the axle.

The bike had only a few hundred miles on it but because I'd bought it second hand it was out of warranty. :-/

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