How to claim extra credit reward?

I completed the extra credit rides, and I got the message stating something was unlocked, but the message disappeared too quickly I cannot figure out how to claim the reward. I think it has to do with a colorful set of wheels if I ride a BMC frame?!?

My understanding is that it’s a custom paintjob for the BMC bike.

Which bike? I think there are two BMC frames for sale in the shop.