Alternatives to shorter cranks for knee pain I've recently developed pain at the front of my knees when cycling. I suspect this is caused by, or at least made worse by, my bike having cranks that are too long for my leg length (172.5mm cranks for 77cm inseam).

Assuming crank length is a factor, a long term solution would obviously be to get shorter cranks. However, I can't afford that right now.

Are there any bike fit adjustments that I could make to open the angle of/reduce the strain on my knees at the top of the pedal stroke? I've already experimented with various seat height and setback changes without much success. I'm prepared to temporarily compromise other aspects of my bike fit, if it would allow my knees to recover.
Product options

You can purchase a bolt-on plate for either side that will give more pedal positions.



Any competent machine shop should be able to make you something like this, given the cranks to work from and test-fit.

Downside, this will increase your Q-factor by at least 10 mm, which could be uncomfortable.  Adds weight and surface area,and leaves end of crank arm poking well below your pedal.

On the positive side, it doesn't change your bike and can be removed in the future.  Can be fitted to hollow crank arms that can't be drilled.

Link: https://tadpolerider2.wordpress.com/2015/05/11/short-cranksetscrankarms/



Another similar option is a swing-arm pedal.  Its very similar to the plate above but includes a hinge/swivel.



Perhaps best-explained by an animation:



From https://highpath.co.uk/pulse-swing-cranks/ 

Downsides, they add double the Q factor change of the plain bolt-on plate.   Significant cost, and there's now another moving part in your transmisison.

Upsides, you can shrink your pedal circle, and you can also lower your pedalling circle if that's what you need.