You were there at the end. You just lost the sprint, despite presumably having more muscle mass! I don't have a ton of sympathy. Just learn how to properly deploy and fire a 10-second Wattage Bazooka.

I tend to agree that in general Zwift tends to reward "sprinters" who would not be good sprinters IRL. Particularly those using the CycleOps Hammer or gen 1 Kickr.

What's your height? The less-discussed issue is that Zwift disproportionately penalizes height more than Mother Nature does. Especially for a flattish course, height doping is more effective than weight doping.

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I don't Zwift, except for that one time at the Slowtwitch party in 2015, but does Zwift ask for your height?

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So I'm 192CM (or 6ft 3.5inches) - I hadn't realised height this was a significant factor in Zwift.

I find that hard to understand - yes height will impact CdA, but not massively whilst you are sitting in a pack!

Haha - I'm not looking for sympathy! I guess the point is, if I had needed to put in 50W less to stay in the pack (only half the difference!) I would have had been at a very low HR and had mega Watts to spare for the sprint.

Whilst Zwift rewards sprinters - I don't see how that explains needing to hold 100W extra just to cruise in the same pack.

It is virtual racing! If you want an actual result, you should see if the same participants can meet for a race!

I'd love to - but I'd struggle to fit flying around the world a few times a week in my schedule!

But I get the point - Zwift obviously shouldn't be taken too seriously, it isn't real life. The thing is - it is good fun and most people on here are probably the competitive type who will want to try and win by virtue of the fact it's a competition. So feeling like something which is entirely controllable in the system might be unfair just detracts slightly from the experience.

first, are you comparing result via zwiftpower (filters out some cheaters using cadence sensor)? was this other person using some weird bike giving advantage? tron bike, etc

ideal racer in zwift is a short stubby person https://zwiftinsider.com/rider-weight-speed/

That might be true on a hilly course but I think it comes down mostly to W/kg. I have felt the opposite as watts are king on flat courses.

Just cheat on your weight like everyone else, lol.


I've done about a half dozen Zwift races now and find the physics not even close to real racing.
The draft effect from being in the pack is marginal.
A Zwift race feels like a tempo session with a sprint at the end.
Real road racing has surges and a lot of soft pedalling in the pack.

I should be the king of Zwift! That description fits me perfectly.

I think this has been discussed here before, but their algorithm for power reduction from drafting isn't realistic. Sitting in the pack doesn't save energy, you just go faster for x watts.

Life unfairly biases against heavier riders... Being one myself, I feel your pain... I tend to try to avoid Zwift races on courses with much elevation gain, because inevitably you'll need to throw down massive power just to not get dropped...

That said, sprinting is less about the ability to throw down watts, than it is about the ability to throw down watts at the right time... And I agree with some that Zwift races tend to allow those who normally wouldn't have the skill to navigate a real bunch sprint, but that have good power output, to do well... I have a half decent sprint IRL if I manage to not get dropped before the finish romp, but that has as much to do with technique, and reading the race, than it does with the ability to throw down a wattage bazooka... Of course you need to do both in order to find success on the road, but on zwift you can get away without the technique and just the watt bomb....

This is exactly right, and I've been saying it for years!

Sprint off the line, tempo/sweet spot, sprint.

Zero coasting, zero extended max/attack efforts, zero comparison to real-life racing.

Zwift racing is really a time trial with two surges! And no bike handling or pack movement skills needed. No wonder top triathletes can do well against roadies.

You aren't wrong!

But in a time trial assuming similar equipment levels I would think someone doing 395W at 4.29W/KG would decimate someone doing 295W at 4.5W/KG, which is my whole issue.

But I get it - it isn't real racing.

Good point, so using Zwift power:

Me (4th place) - avrg 395W (4.3W/KG)
New 1st place - avrg 299W (4.2W/KG)

So slightly smaller delta of 96W, but point still stands.

I think what I've concluded is - "Yes - it is biased, but it's also unrealistic in lots of other ways'.

Biased towards heavier rider no, biased towards weaker riders mayve, unfairly biased towards any rider no. The algorithm Zwift uses was hammered out during the Beta testing period when the emphasis was Zwift is SOCIAL. Really this is still the emphasis for Zwift and so the drafting was optimized to keep riders together. Its not worth going into detail but riding Zwift with a 'real world' draft dynamics really sucked in terms of group riding. The best solution was to make it so once you got in group is was easier to keep everyone together. This means there is a much bigger spread in wattage in a Zwift pack than you might think. It may feel appear that you are efficiently drafting but you can still be working a lot harder than you have to to keep the same position. Zwift will work with you to keep in the group so the smartest racers are able to sit right on the limit of being dropped. At the same time Zwift is working to prevent the people working hardest from getting away so just by being towards the front you are doing more work than you need too.

It should be noted that the system was actually more extreme than it currently is until its popularity took off. At that point the algorthm was working too well keeping everyone together which resulted in an odd mass clumping effect on the maps which caused its own problems. This was addressed by making it much harder to latch onto a group if they are accelerating away from you. In effect you no longer tend to drag riders with you as you pass them. This is largely to blame for the mass start sprint dynamics that happen at the beginning of the race. You want want to be in the pack from the gun because Zwift makes it harder for you to bridge gaps and join later in the race.


The net result is a system that has been well optimized for its intended purpose. No its not like real life which means it is biased relative to what you would see on the road. The bias is definitely not against heavier riders though. If anything it rewards weaker riders but I am not sure that is any different than being a wheel sucker. The key difference is that on Zwift its not nearly as obvious as it is in real life when you are working harder than you need to just to stay in the pack.

Interesting.

Well, at least in Zwift races I don't crash and break bones and my bike.

Everything about cycling is biased against heavier riders (I am one).

Not the question and also not true in all circumstances - I don't think Chris Hoy would have been more successful at 63KG instead of 93KG (obviously very specific example)

At 4.5 W/Kg I would be traveling about 26.5 to 27mph (Edit 27 to 28mph) with my tri bike on a flat road with no wind.
Would you be significantly faster than that?

Someone’s sarcasm meter is broken.

Thanks for the insights - I hadn't factored the impact of being 4th back in the pack vs. 10 back in the pack which might be significant.

RE the 'sitting on the limit of being dropped' it isn't easy, even dropping back to 340W - 350W in tonight's race wasn't enough to hold position - a factor in my overall suspicion about the algorithm.

Anyway - all good fun.

What is your real world (outside) tested FTP?