Unable to pedal out of the saddlle


I’m not sure I this is the right place for this but here goes. I’ve been cycling IRL for 30+yrs, I’m used to gears and hills but am relatively new to Zwift and extremely new to smart trainers. I recently bought a Wahoo Kickr and a dedicated bike to go on the trainer. Everything is fine pedalling in the saddle and I love the feel of the hills but I’m struggling to pedal out of it like you would in real life.

For example, I did Alp Du Zwift today but as soon as I got out of the saddle, it’s as if, to use a clock analogy, from 6-12 is fine with appropriate resistance then from 12-6 its like there’s not enough resistance and the pedal sort of clunks down which means I can only ride in a completely unnatural jerky style which is not only not ideal on a 3000ft climb but which is also making me wonder about the stresses on a bike frame clamped into a trainer not to mention the stresses on my knees so I basically did the whole climb seated which was no joke especially as spinning was completely impossible (for me) the easiest gear was 50rpm at best.

I run the trainer at 100% difficulty as I want to get better at climbing hills for real. I tried changing to a harder gear, I even changed into the big ring but as soon as I got any cadence going I found the same thing…grind, clunk, drop, grind. I’ve seen people sprinting out of the saddle on Zwift so I’m pretty sure this is user error as I can’t imagine getting any kind of speed up out of the saddle as it feels like there’s not enough resistance to push against.

Any ideas, I’m pretty sure this something I’m doing wrong so any help would be appreciated???


Is that a direct drive or wheel on Trainer?

It’s direct drive. I bought the Wahoo Kickr less than a month ago

Ok that rule out wheel slipping.

Hi Nicky, it definitely sounds like there is a problem. As you say it should definitely be possible to sprint out of the saddle. I’m a big lump and can generate 1,200+ watts sprinting in Richmond etc. (also using a kickr).

The first thing that come to mind is the belt tension, that could slip on the teeth if not correct. There are loads of videos on Youtube on how to check and correct that. If that isn’t the problem I would also check out some of the other video clips on fault finding.