afm199
Well-known member
Spin bikes are crap. Real bikes have outboard roller-bearing bottom-brackets. Can handle 2000w output continuously without failure for decades. Get real bike and put it on trainer. Even better, rollers.
You need the natural rocking motion that offsets pedaling forces (follow someone on road, you'll see bike rocking laterally). Without rocking, all those forces go into your knees (spin-bikes do not rock).
Also most spin bikes are set up horribly and knee-damage is guaranteed with seats that are way, way too low. Seat to pedal-spindle centre should be 1.05-1.10x leg-length. Velodrome riders may use up to 1.15x for max-power. Multiple different methods agree to within 1mm. https://road.cc/content/feature/166709-how-set-your-saddle-height Problem is most people going into spin-class or getting on their own spin bike don't know how to adjust bike to within this 1mm. They just hop on and barely know if they're not fitted properly, especially on gym bike that may have been grossly adjusted out of whack by previous user.
This! Get a good road bike and ride it on rollers, either free rollers or resistance rollers. I've been riding rollers for 35 years, they are great.