I’m running a 1×9 setup and at the moment the chainline is biased slightly toward the small cassette cogs. I was wondering if it would be possible to remove one of the two drive-side spacers from the bottom bracket to improve the chainline.

Would this work, or would the crank-axle be too long? Would the plastic sleeve inside the BB still work?

I’m sure someone must know…

Thanks all.

I’m sure if you moved a spacer from drive-side to non-drive-side, you’d be fine – effectively shift the whole crank assembly 2.5mm

I’m sure somebody else will be along in a minute to back me up/discredit me….

You need to move the spacer to the non-drive side. Only possible issue then is crank clearance against the chain stay on the drive side.

Alaric.

Your crank axle would be too long.

You could move a spacer from the drive side to the non drive side to move the chain line a little bit more inboard for running 1×9

Or

You could mount your single chain ring on the back of your crank spider to achieve the same result, just check for clearance between your chainring and the chainstays

Thanks guys.

My 1×9 has the same slight offset.

Thought about making the same change with the spacer (drive to non-drive) but then I assumed that I would be offsetting my pedals finally by the same amount.
Perhaps I would never feel it but didn’t like the idea of pedalling offset.

I have taken out one of the two drive-side spacers and not moved it to the non-drive-side and it works fine. This is on a steel bike with a skinny seat tube. I say this because on an aluminium bike with a fatter seat tube i needed the two drive-side spacers so that the chainset was more outboard and the front mech had enough space to pull the chain onto the granny ring before the mech hits the frame – it wouldn’t shift easily without both spacers.