Zwift is not fair to lighter riders

Now Flyby in Strava finally properly works for Zwift activities, it is a nice tool to compare your ride to others with who you ride with.

But take a look at my effort yesterday:

I lose about 1-2 mins on the short flat sections. Even at the last flat section I did 2.5+watt/kg and well above 30km/s but still losing 1-2 mins in about 5km.

Something needs to be carefully looked at within Zwift because I am quite sure the calculation for speed is not always correct.

To be honest - I know this seems unfair when you are a lighter rider, but it’s the same as when you are riding outdoors. W/kg does not matter that much on flat roads. If a 50kg riders rides at 3W/kg this means 150W, for a 80kg rider it would be 240W. Of course the heavier rider will be faster there.


Ofcourse that is true, but I don’t expect that most other riders will be far above 150watt at the last section.

I will check it later in more detail. But if you just click around and look the differences you should immediately notice that something is not right there. So just take a look before you will fall back to any common sense, and you will agree with me.

Try weighing 90kg and not beeing a superman and then go up a hill with a 70kg rider.


Losing allmost 2 mins to this ride in the last “little bit hilly” section.

I think what is happening is that during this uphill/downhill parts the heavier rider has a lot of advantage with gaining and maintaining his speed. IRL the difference will be far less.

See here:

Specifically, the bit about ‘getting dropped on downhills’.

I’m 133kg and have consistently thought Zwift was not fair. I’ve ridden hills in real life. I go up them MUCH faster than Zwift. But I will murder small children and fairly large trees on the way down without doing much of anything, so, six of one, half dozen of another :).


I think you have a good point in this. My past setup was a Booster with P1 pedals and now a Neo. I noticed some differences especially when the grade just suddenly increases or drops.

Also I noticed a delay in resistance and I am losing speed in the start of the climb just because of this. So according to Zwift the grade of the climb is already set but my Neo still has a faily low resistance and so my output in watt is still now.

@Art Mills. No offence, but with heavier riders I meant heavier but also still having a relative good fitness level. At 133kg you need to put at least 400watt @ FTP to be competitive. :wink:

I’m not really trying to be that competitive. I will say I have ridden more miles than you since October or so, I think, and some of the rides you’ve run that are similar, like Watopia, you don’t seem that much more dominating than I am, so be careful assuming much about fitness levels :). And I’m a fat boy. If I lost 30, I’d crush ya :). Hills do kill me utterly on Zwift for sure though.

Our last four weeks though:

Last 4 Weeks
Avg Rides / Week 4 7
Avg Distance / Week 76 mi 91 mi
Avg Time / Week 4h 51m 5h 52m

I’m smashing ya. :slight_smile:


What do you have your trainer difficulty set to? If it is set to 100% then you can spin out coming over the top and lose ground faster than you can cycle through gears.

Alexander, Have a look at the Zwift power results, you will see that those that was ahead of you was producing about 50W average more than you. 50W on a flat road is a lot of speed.


not in zwift. its all about w/kg

It’s more complicated than that.


explain if you know

I am guessing you know how speed within Zwift is calculated, but lets review.

Zwift uses your watts, the weight you entered, in-game bike used (can make more of a difference than you think), in-game wheels and in-game drafting. All of these factors can be applied to climbing along with how and when you use your watts and the speed at which you enter the climb.

This is just a brief explanation on why it is much more complicated than just w/kg.

I am sure this is not anything you didn’t already know.


Please Art, don’t be foolish to look at those 4 weeks. I was suffering a flu and a cold. Please look at the previous months for more realistic stats.

If I found your Strava profile, here are the numbers for 2018.

Afstand 3.331,2 km 9.260,9 km
Tijd 113u 39m 329u 48m
Hoogtetoename 4.201 m 66.687 m

Indeed you smash me :wink:

But don’t look at just me. It is just a fact that at a weight of 133kg you need to push at least 400watt @ FTP just to be a little bit competitive and at least 500watt @ FTP to start being in front with the B’s.

Exaclty, and it seems to turn out that riders who produce more watts or are heavier have quite some advantage. And from my expierence I can tell everyone I see it in practice.

About 60%. I am riding on my old bike with 50/39 x 12/30. My climbing bike has 50/34 x 12/34. The trainer difficulty is set to simulate lower gearing. Next to this my experience is that my Neo gives a little bit more resistance than the actual grade. That’s why I set the difficulty a little lower.

But you have a great point on your suggestion. You have to learn Zwift when to push wattage to get the most benefit out of it. IRL you can feel and notice it. On Zwift you have to discover and try and you are right that when you push some wattage at the top op the hill you really benefit from this.

Yeah. Sadly I moved this year and basically didn’t ride from mid-April until basically October. I did here and there but mostly just tried to get through the whole move situation. I only got my home config set up in time for Minnesota’s first snow :). You can go back to the May of last year when I found Strava and May of this year when I moved to see how we generally compared as well. And it’s, again, not too different though you are faster, as I’d pray almost everyone is :slight_smile:

I do not debate with you that at 6-5, 295, I have to put out more FTP to stay with a tiny dude. I know this is so. I also said I’m not really trying for competitive. And from a comparison I see with your recents and mine, you’re not really motoring that much better than me and you’re teeny tiny, which is cool. I have to work a LOT harder to stay up with you and I suspect some of your rides are you not pushing as hard as you can.

In total, though, I’d probably worry less about how Zwift scores you. It probably doesn’t have bias. It has a formula. It’s the same one for us both and all others. And within that formula you motor as the game provides. And for that it’s pretty cool and at least for me keeps me interested and wanting to push harder and ride a bit further. Hopefully it does for you as well.

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I really admire your hard work to get yourself fitter. It must be very hard I can imagine. Please take care of your heart since it needs to pump quit hard.

But it is very difficult to compare the efforts with such a big difference in weight. If we put the same wattage it doesn’t mean we have the same score. I can tell you, when I dropped my weight last year from 70kg in the winter time to 59kg in july I lost a lot of power in the vo2max en anaerobic zone and I had a hard time to keep the same level in tempo/treshold. Losing weight also means losing muscle (power).

Btw, I am 5-6, so about 28cm smaller than you. This means we really can’t compare our efforts on wattage.