My chain has just started catching the cassette for no reason. After further investigation I’ve found the front outer chain ring is moving left to right about 3or4mm when you turn the crank arms around. I’m 6ft 4inches tall and about 95kg. When I ride i occasionally stand up to get some circulation back in my rear end. I’ve also noticed that I bare all the weight on one leg. I think this has caused the problem. I really do look after my bikes so there is no way it could of happened any other way. Or maybe too much power in my legs (I wish) can it be straightened?

Anyone?

Is the drive side crank on nice and tight?

Are the chainring bolts on nice and tight?

Can you take the DS crank off and check its straight?

Standing on one pedal would not bend a chainring. Something odd going on there.

Take the chainring off and rotate 180 degrees to see if it’s the spider or the ring.

Very rare to see a bent spider these days.

Take it off out in glass coffee table that should tell you if it is bent or not

I bet your bottom bracket is knackered

Had this once, turned out to be loose chainring bolts.

Very rare to see a bent spider these days.

Pretty rare to see a bent Shimano ring too!