Originally Posted by
RonH
I'm 72 and have never had a knee replacement but from what you're saying I'd suggest going to your local bike shop and get fitted to a new bike. Your body may have changed, your knees may want something you never thought of and the shop owner can get you on the right bike.
+1
It's not just a question of the frame and frame geometry, but of the gearing. I'm 55 and a year round commuter. In the last year or so I have "noticed" my knees more. My three bikes have different gearing and crank lengths.
I used to be a "masher" (higher gear, slow cadence) but now I find myself "spinning" more (lower gear, higher cadence). Of course YMMV.
I will also mention that I swam a mile a morning in my late 20s. TWo years after stopping I jumped in a pool and after less than three laps I had to stop and couldn't immediately raise my arms to climb out of the pool. (I was 31).
Find a bike you can ride comfortably now and work your way back up to something more sporty and aggressive, if that's something you feel like doing after getting back into some sort of cycling shape.