# Absolute power on flats vs w/kg... getting passed by people putting out way less watts

Ok.  First things first.  I’m a big guy 105kg so in general my w/kg is pretty low even if I’m putting out some good wattage.  I’m also not on a smart trainer but so far the game has been pretty good for me with the Zpower in comparison to my real life efforts.  I get there may be errors but I don’t think its of too much. I also get that going up a hill my weight will have a huge impact.  However, it shouldn’t matter that much on the flats.  This is where I’m getting confused. I checked someone who rode with me for a stretch on Strava today and despite averaging >125W on the flat section at 0%grade they were at 2.3 w/kg and passing me even though I was putting out 250+…so I get it they are light…but I’m putting out double the power and getting dropped on the flats.  Its beginning to feel like there is a serious weight penalty on the flats as well…more than what normal drag would be accounting for.  In the end I get a great workout and I’m dropping some weight so who really cares but does anyone have ideas on this? Am I doing something wrong? I understand that doubling watts doesn’t double speed.but is my math just way off? Why doesn’t absolute power factor in better on flat sections.

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You may be right.  According to Bike Calculator, at 150 watts on a level surface, a 220 pound person should go 17.1 mph and a 140 pound person should go 17.8 mph.

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If you are riding the TT bike and they are not and in a draft that could also account for them passing you.

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Nope not on the TT bike.  In this case it was a 120lb rider at 125W riding next to and pulling away from 230lb rider at 250W.  No drafting.  Flat grade.  Bike calculator says they should be doing about 16.6mph and I should have been doing 20.7mph.  Even accounting for different Cda’s it shouldn’t make up for a 4mph difference.  Anyways, maybe its just equipment error.  But it sure is hard to ride with people even on the flats based on w/kg when you are a big guy.

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Word. Relatively short 110kg rider with designs on getting below 100kg this year. Gave up on Zwift last year after experiencing similar results putting out decent wattage. I’m now back after a long layoff off the bike and taking advantage of the grandfathering deal. Have got my classic trainer sorted to a much better/more fair level but I’m still being left for dead by lighter riders and suffering serious drag on 1/2% flats (heck, even at 0%) if I stop pedalling, much more so than IRL (not sure if that’s a Zwift thing to encourage constant pedalling/stop the meters going to sleep). I’ve also noticed issues with cadence/watts being a bit off at levels below 60 RPM. Can’t put my finger on it but something is off with the power-to-weight calculations. It’s not stopping me though since I’m tending to ride harder uphill and on false flats, which can only help real-world FTP if nothing else. Upvoted though since I would like the devs to take a look.

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