Ive bought a spinning bike to help in lockdown, and its ace...I want to change the pedals to a clipless set. I bought some clipless pedals, but the thread on the pedal is way smaller than the ones coming off. I read about and bought an adapter, but its on marginally larger. Is what I'm trying to do possible, there only seem to be 2 pedal sizes and each would be way to small to fit my crank. Is it possible I have a crank that only fits its own pedal size??. Any help would be appreciated as I'm a set of pedals shoes and an adapter down at the moment.