Child W/kg Vs Speed on Zwift


I setup my childs account on zwift and set his height/weight (128/25kg), wheel size (20"), etc correctly. The speed it calculates for this size wheel and watts produces seems to be crazy? He puts out about 70-80watts - seems to put out about 3w/kg on the flat and 6-8w/kg on every hill (when he really goes for it).

Problem is his speed at that output is around 35-50% faster than other riders on every climb.

I am missing a setting somewhere? I have setup the trainer the same as when I used it and it used to give me an accurate (for me) 2.5-3.5 depending on effort, 4.5-5.5 on climbs and speed was close to what I put out on climbs in real life.

There is no way on his 20" bike he can cycle at 10-12mph up a 14% gradient…

Zwift doesn’t handle super-lightweight riders well at all.

This is a problem where kids enter races and can go much faster than they’d be able to in real life. Ok, it’s fun for the kids, but not fair on other racers and also not really fair on themselves if it sets unrealistic expectations for outdoor performance.

Ah ok! thanks so it sounds like a known issue. We are not interested in races etc, but it makes it really difficult for us to ride together on Zwift. I may have to just keep over adjusting his weight until we can find a middle ground that works and holds him back a little on the climbs. Just need to ensure it doesn’t negatively impact his flat speed too much and just move the problem to there.

I have used meetups with stay together feature, but this loses the ability to change the routes on the fly which he often wants to do! also I find on the meetups for some reason when cycling together we get more drop outs than just regular riding (although this may be coincidental)