Almost every time I go on the turbo with 5-10 minutes I get pain in my left knee, if I ignore it and ride thought it when I finish and get off the turbo I end up with a achy dull pain in my knee that seems to last a random amount of time. This has been going for say 10 weeks, I used the same bike on the turbo earlier in the year with the same bike fit without a problem, indeed nothing has changed but the knee pain.
Whats even more confusing is that if I take the bike off the turbo and ride the same bike, same pedals, same shoes etc outside in the real world then no knee pain. I've been ramping up zone 2 work on the same bike and did 12 hours outside last week with no pain, today I've just aborted a turbo session within 20 minutes due to knee pain.
Any ideas as to what's going on and how to fix it? With the weather getting worse I'd like to be able to use the turbo
I think the stock answer used to be that cheaper/older turbos didn't have enough flywheel effect so the rear wheel would slow down between pedal strokes and you were effectively re-accelerating the wheel with every pedal stroke.
Better turbos have bigger flywheels which mitigates this (any trainer that boasts 'better road feel' is effectively doing this). I can't remember how this works with rollers, I think they have pretty lousy flywheel effect.
I had that; bought rollers, never had a problem with them.
Is the bike set up like it is on the road? My trainer doesn't have the same angles as the bike does normally. Had to spend a bit of time setting it up. Could be your saddle/bars are at the wrong angle hence the pain.
To follow on from what Poah is saying - what is causing the asymmetry when you are on the turbo versus on the road.
Do you have any history of knee issues that you might be exacerbating?
I find i have to tweak my saddle position on the turbo as otherwise I get very uncomfortable in the nethers. You might be lopsided that is causing uneven loading in the knee
I’ve only been on a turbo once in my life (for someone’s phd) but if I’m remembering correctly the bike was fixed and I couldn’t move it at all. I have a stupid knee and it’s much happier with me standing plenty (especially on my singlespeed) than sitting more and using gears.
I had the same with hip pain, never a problem on bike normally but then issues when i first started using turbo. I think that fixed position amplifies any problems.
I think a lot of it is the fact that it is such a fixed position, turns out i had saddle a little too high, and not normally noticed or got used to it on road, but locked on turbo it was more evident.
I have my Wahoo KICKR on two soft gym mats which i find helps a lot it allows bike to move sideways a little but not too much and try to get out of saddle every 5-10 minutes.
I’ve been ramping up zone 2 work on the same bike and did 12 hours outside last week with no pain, today I’ve just aborted a turbo session within 20 minutes due to knee pain.
Your fit might not be quite right, but moving around outside masks the issue. Sitting still on a turbo doesn't.
I had exactly this and the (eventual) solution was shorter cranks.