The cause?
Mysterious Grease Marks usually have one simple cause – when the rider comes to a stop, they favour removing their right leg from the pedal, to place it on the ground. Whilst there, they rest their bike against their leg, or allow the leg to brush the bike.
How to: Master clipless pedals
The right side of the bike, also called the ‘drive side’ is where all the magic happens: the chain, cassette, chainrings are all there. And they’re also all covered in grease and oil.
The cure?
The only way to avoid the mark is to learn to avoid brushing your leg against the offending components – the chain rings, cassette, and chain.
This could be through switching the leg you clip out with. However, if this is well ingrained in your mind it might not be worth perusing this option. As a dedicated ‘right foot clipper outer’ I recently found myself forced to use the left foot, and genuinely nearly suffered my first ‘clipless crash’ in about five years…
The other option is just to hold the offending leg a little further away – it might take a little mind training, and maybe some light hypnosis, but you’ll get there.