I notice that often that my w/kg does not correlate with other riders. Given all the variable with power output (watts) relative to weight, similar watt/kilogram between riders should yield similar speed/performance. I have a Wahoo Kickr and I am fairly certain that my performance in real world riding, compared to other well conditioned riders, is far more superior than on Zwift.
Yes I have done the spin down and I have tire changing the resistance from max to off.
Obvious question, but have you correctly entered your weight using the iOS/Android app or website dashboard?
If anything, I find my w/kg a bit higher on my Kickr (10-20w) after riding for about 30-45 minutes (a bit of temp related drift, even with the new firmware) which is why I started to use my Quarq p/m to drive the Kickr.
I have a Kickr and find a similar but not identical issue. I also feel my relative performance is off. I think the issue is watts to speed. First, I believe that watt output is what matters most, not w/kg. For example, I am pushing out 250 watts while another rider is pushing 130 and the speed over a long segment is the same (~23 mph). The other rider is significantly lighter (70 lbs) but it seems that is outsized in importance. We are not riding in the vacuum of space. Overcoming air resistance is the most important thing our watts are doing and my extra size only leads to a slight disadvantage there. My output seems right from a watts to speed point of view (similar to road), but I think lighter riders may be getting a huge advantage. According to this good watts-speed calculator (http://bikecalculator.com/) my speed should be 23.28, while the other riders speed should be only 18.71. I know it is just a video game and I should focus on my performance over time, but the excitement comes from competition. Seems unfair.
I also use a KickR and I’ve been wondering about similar things as in the post above. I’m thinking that real world riding is one thing but the virtual world is another - it depends on algorithms (both on Zwift and your trainer). I wonder what algorithms Zwift use to control our trainers - when I go uphill the resistance increases but is it increasing purely in relation to my weight or is it some other metric ? When I used to use TACX I had to add a notional bike weight to my body weight which I always felt was a bit dodgy because a 9kg bike is a bigger addition for a low weight rider than for a heavy rider (same in real world too), so holds a low weight rider back more … I presume … all depends on the algorithm that controls the resistance. So, I wonder if Zwift will let us know their algorithms ??