"It is strange for you to ride a bicycle" (or "for you, it is strange to ride a bicycle") means you don't think it is normal to ride a bicycle, you find it is strange.
Example: ME: Is it strange for you to ride a bicycle?
YOU: Yes, I think it is really strange... I don't like bicycles...
"It is strange of you to ride a bicycle" means "it is unexpected" that you would ride a bicycle. it means "I" find you riding a bicycle is strange.
Example: If you normally don't ride a bicycle and I see you riding one, I would say "It is strange of you to ride a bicycle"