Zwift racing - talk to me
Discussion
I jumped on Zwift this lunchtime given how grim it is outside at the moment, and decided I'd give a "race" a try.
Seemed like a good idea at the time
Quite enjoyable, gives you something to think about that's got a bit of dynamics rather than just using a rigid workout. However, I did get dropped hard and I don't really understand why.
At the start I was in a large group, riding at about 4.5-5w/kg, so not sprinting or anything and solidly in my 5min power range. When I looked at the leaderboard thing, the majority of riders around me were doing 3-4w/kg and were dropping me. Obviously when I started getting near to my max time at that power I was gone. The same thing happened again with the next group that I fell back to later in the race.
When I looked at the finish placings at the end, sure enough, my average power/kg was equal to riders who finished 40 places in front of me.
Am I doing something wrong? Do you have to do something special to get a drafting effect that I don't know about?
I mean I got a good workout, so it's not all bad!
Seemed like a good idea at the time
Quite enjoyable, gives you something to think about that's got a bit of dynamics rather than just using a rigid workout. However, I did get dropped hard and I don't really understand why.
At the start I was in a large group, riding at about 4.5-5w/kg, so not sprinting or anything and solidly in my 5min power range. When I looked at the leaderboard thing, the majority of riders around me were doing 3-4w/kg and were dropping me. Obviously when I started getting near to my max time at that power I was gone. The same thing happened again with the next group that I fell back to later in the race.
When I looked at the finish placings at the end, sure enough, my average power/kg was equal to riders who finished 40 places in front of me.
Am I doing something wrong? Do you have to do something special to get a drafting effect that I don't know about?
I mean I got a good workout, so it's not all bad!
k all relevance on the flat. Your height apparently has a significant impact on the aero factor.@oddball - different problem..
In your case, 200w & 80kg giving you 8kph up some of the zwift climbs is ballpark correct. They're generally somewhat more severe hills than most of us ride IRL (in the UK at least), which will accentuate the watts per kg problem, and 200w at 80kg isn't much.
Unless you have a powermeter telling you so, I *VERY* much doubt you're only doing 200w up your local climbs. The first thing you notice when you get one is just how much you spike on the climbs. Personally I also find that the perception of effort is far greater on the trainer / less outdoors. That, plus a flatter gradient and more power would easily explain the difference.
Also, you'll find quite a lot of quite a high proportion of stronger / well trained folks on zwift I suspect.
@OP - drafting is strong in zwift. Once you're above a threshold speed (can't recall what, but relatively low), the rider 'sits up' when in the draft. If he's down on the drops you're not in the draft. Otherwise, the watts per kg as noted is not so important as pure watts when on the flat bits, and rather more important on the hills. Again, there's no a problem with the pre-zwift side as you're seeing reasonable numbers in game - it's all down to the games dynamics and model.
In your case, 200w & 80kg giving you 8kph up some of the zwift climbs is ballpark correct. They're generally somewhat more severe hills than most of us ride IRL (in the UK at least), which will accentuate the watts per kg problem, and 200w at 80kg isn't much.
Unless you have a powermeter telling you so, I *VERY* much doubt you're only doing 200w up your local climbs. The first thing you notice when you get one is just how much you spike on the climbs. Personally I also find that the perception of effort is far greater on the trainer / less outdoors. That, plus a flatter gradient and more power would easily explain the difference.
Also, you'll find quite a lot of quite a high proportion of stronger / well trained folks on zwift I suspect.
@OP - drafting is strong in zwift. Once you're above a threshold speed (can't recall what, but relatively low), the rider 'sits up' when in the draft. If he's down on the drops you're not in the draft. Otherwise, the watts per kg as noted is not so important as pure watts when on the flat bits, and rather more important on the hills. Again, there's no a problem with the pre-zwift side as you're seeing reasonable numbers in game - it's all down to the games dynamics and model.
upsidedownmark said:
@oddball - different problem..
In your case, 200w & 80kg giving you 8kph up some of the zwift climbs is ballpark correct. They're generally somewhat more severe hills than most of us ride IRL (in the UK at least), which will accentuate the watts per kg problem, and 200w at 80kg isn't much.
Unless you have a powermeter telling you so, I *VERY* much doubt you're only doing 200w up your local climbs. The first thing you notice when you get one is just how much you spike on the climbs. Personally I also find that the perception of effort is far greater on the trainer / less outdoors. That, plus a flatter gradient and more power would easily explain the difference.
Also, you'll find quite a lot of quite a high proportion of stronger / well trained folks on zwift I suspect.
@OP - drafting is strong in zwift. Once you're above a threshold speed (can't recall what, but relatively low), the rider 'sits up' when in the draft. If he's down on the drops you're not in the draft. Otherwise, the watts per kg as noted is not so important as pure watts when on the flat bits, and rather more important on the hills. Again, there's no a problem with the pre-zwift side as you're seeing reasonable numbers in game - it's all down to the games dynamics and model.
Interesting... I'll look out for that. Does the drafting kick in whenever you're in the vicinity of other riders or is it only when you're behind them and not to the side?In your case, 200w & 80kg giving you 8kph up some of the zwift climbs is ballpark correct. They're generally somewhat more severe hills than most of us ride IRL (in the UK at least), which will accentuate the watts per kg problem, and 200w at 80kg isn't much.
Unless you have a powermeter telling you so, I *VERY* much doubt you're only doing 200w up your local climbs. The first thing you notice when you get one is just how much you spike on the climbs. Personally I also find that the perception of effort is far greater on the trainer / less outdoors. That, plus a flatter gradient and more power would easily explain the difference.
Also, you'll find quite a lot of quite a high proportion of stronger / well trained folks on zwift I suspect.
@OP - drafting is strong in zwift. Once you're above a threshold speed (can't recall what, but relatively low), the rider 'sits up' when in the draft. If he's down on the drops you're not in the draft. Otherwise, the watts per kg as noted is not so important as pure watts when on the flat bits, and rather more important on the hills. Again, there's no a problem with the pre-zwift side as you're seeing reasonable numbers in game - it's all down to the games dynamics and model.
In absolute terms my AP while trying to hang on to the group was 347w, which I managed for 6 minutes (without a warm up, oops!) so I would have expected that to be able to keep me on a group where the front rider is riding at 450w. Maybe the chap on the front was doing that, in which case chapeau!
Edited by BMWBen on Wednesday 24th January 18:18
Generally behind.
I have limited zwift racing experience, but so far it seems that they go out insanely hard. The other factor is that a surprising amount completely mis-categorise themselves. Usually if you look at the results on zwiftpower, you'll find many have been promoted, DQ'd etc..
I have limited zwift racing experience, but so far it seems that they go out insanely hard. The other factor is that a surprising amount completely mis-categorise themselves. Usually if you look at the results on zwiftpower, you'll find many have been promoted, DQ'd etc..
Just done 25km around london and the mystery deepens — averaged 190w and was generally pushing 230w up box hill. Rather than getting annihilated by 99% of the riders i seem to have gone mid table which is what i kind of expected. Not changed a single thing but can only conclude some maths somewhere was a bit out of whack and it’s now sorted itself out?
BMWBen said:
This one I think:
WBR 4 Lap Flat RACE #pst (17.1 mi / 27.5 km)
Today at 13:30
OK - flat course, therefore W/kg largely irrelevant - absolute power generally decides the placings. Which group were you in? The A group is pretty fast usually and I get dropped (FTP around 260W, 4 w/kg). The first lap is usually pretty mental in all groups, but does settle down if you can hang on for the first 5 or 10 minutes.WBR 4 Lap Flat RACE #pst (17.1 mi / 27.5 km)
Today at 13:30
Marcellus said:
Does Zwift take in to account what gear you're in?
I'm just thinking won't 200w in 39:28 will be much slower than 200w in 53:11?... bit of an extreme example but if so what would the speed difference be between 53:11 versus 53:14 which might be more realistic?
In order for the power to be the same in the easier gear, the cadence has to increase.I'm just thinking won't 200w in 39:28 will be much slower than 200w in 53:11?... bit of an extreme example but if so what would the speed difference be between 53:11 versus 53:14 which might be more realistic?
Power = ( Force x Distance ) / Time
if you reduce the force (easier gear), either the distance has to increase (longer cranks - that's not gonna happen!) or the time has to decrease (increased cadence).
If you can't increase the cadence enough, then you won't do the same power in the easier gear. If you can, you'll do the same speed.
BMWBen said:
In order for the power to be the same in the easier gear, the cadence has to increase.
Power = ( Force x Distance ) / Time
if you reduce the force (easier gear), either the distance has to increase (longer cranks - that's not gonna happen!) or the time has to decrease (increased cadence).
If you can't increase the cadence enough, then you won't do the same power in the easier gear. If you can, you'll do the same speed.
Agreed, but how sensitive are each of the metrics and do they effect the riders Zwift speed?Power = ( Force x Distance ) / Time
if you reduce the force (easier gear), either the distance has to increase (longer cranks - that's not gonna happen!) or the time has to decrease (increased cadence).
If you can't increase the cadence enough, then you won't do the same power in the easier gear. If you can, you'll do the same speed.
Just thinking if rider a) is at 200w, 100prm in 53:14 and rider b) at 200w, 85rpm in 53:11 and both at same speed then rider a) changes to 53:13 drops rpm to 95 but stays at 200w would his speed remain constant? his w/kg wouldn't.
I don't know the answer, nor really understand zwift, nor have a smart trainer, nor can pedal very well but know on my dumb turbo if I have the resistance at 3/5 clicks, pedal at 90rpm in 53:11 I'm putting out 200w but if measured at the wheel is something ridiculous like 35mph, if i slow to 70rpm in 53:11 power drops to about 160w and speed to nearer 30mph. so rpm down 22%, power down 20% and speed down 15% and using this wondering if therein lies some of the answer why you were being dropped in zwift races.
Marcellus said:
BMWBen said:
In order for the power to be the same in the easier gear, the cadence has to increase.
Power = ( Force x Distance ) / Time
if you reduce the force (easier gear), either the distance has to increase (longer cranks - that's not gonna happen!) or the time has to decrease (increased cadence).
If you can't increase the cadence enough, then you won't do the same power in the easier gear. If you can, you'll do the same speed.
Agreed, but how sensitive are each of the metrics and do they effect the riders Zwift speed?Power = ( Force x Distance ) / Time
if you reduce the force (easier gear), either the distance has to increase (longer cranks - that's not gonna happen!) or the time has to decrease (increased cadence).
If you can't increase the cadence enough, then you won't do the same power in the easier gear. If you can, you'll do the same speed.
Just thinking if rider a) is at 200w, 100prm in 53:14 and rider b) at 200w, 85rpm in 53:11 and both at same speed then rider a) changes to 53:13 drops rpm to 95 but stays at 200w would his speed remain constant? his w/kg wouldn't.
I don't know the answer, nor really understand zwift, nor have a smart trainer, nor can pedal very well but know on my dumb turbo if I have the resistance at 3/5 clicks, pedal at 90rpm in 53:11 I'm putting out 200w but if measured at the wheel is something ridiculous like 35mph, if i slow to 70rpm in 53:11 power drops to about 160w and speed to nearer 30mph. so rpm down 22%, power down 20% and speed down 15% and using this wondering if therein lies some of the answer why you were being dropped in zwift races.
Marcellus said:
Just thinking if rider a) is at 200w, 100prm in 53:14 and rider b) at 200w, 85rpm in 53:11 and both at same speed then rider a) changes to 53:13 drops rpm to 95 but stays at 200w would his speed remain constant? his w/kg wouldn't.
Erm, you appear to be confused.Unless the rider's weight changes, the only way to change their w/kg is to change their watts (by definition) - you just stated his watts stay the same, their w/kg cannot change.
200w for rider a) will produce the same speed (given the same gradient), no matter what gear. IRL or in zwift.
Gearing has no impact on watts. (of course rider may not be able to produce 200w in a different gear).
On a more picky note, you specified watts, rpm and gear. Unless the trainer is in erg mode and changing the resistance to compensate, that doesn't work either - one of them has to float
ETA: In terms of calculated power, trainers have a non-linear resistance/speed relationship.. you then have a curve to calculate power. It's a crapshoot, and not particularly accurate. But it's still a straight wheel speed-resistance relationship, gearing / cadence have no bearing.
Edited by upsidedownmark on Thursday 25th January 12:52
upsidedownmark said:
Marcellus said:
Just thinking if rider a) is at 200w, 100rpm in 53:14 and rider b) at 200w, 85rpm in 53:11 and both at same speed then rider a) changes to 53:13 drops rpm to 95 but stays at 200w would his speed remain constant? his w/kg wouldn't.
Erm, you appear to be confused.Unless the rider's weight changes, the only way to change their w/kg is to change their watts (by definition) - you just stated his watts stay the same, their w/kg cannot change.
upsidedownmark said:
200w for rider a) will produce the same speed (given the same gradient), no matter what gear. IRL or in zwift.
Gearing has no impact on watts. (of course rider may not be able to produce 200w in a different gear).
We've agreed that for a rider to maintain 200w in a easier gear then his cadence will need to increase, the question is about how Zwift then calculates a riders speed from this data and whetehr it just says 200w = x mph or takes other considerations in to account.Gearing has no impact on watts. (of course rider may not be able to produce 200w in a different gear).
upsidedownmark said:
On a more picky note, you specified watts, rpm and gear. Unless the trainer is in erg mode and changing the resistance to compensate, that doesn't work either - one of them has to float
agreed which is why in my example rider a) is at 100prm and rider by is at 85rpm and then asking what would the effect be on zwift calculated speed if rider a) changed gear to 53:13, dropped rpm to 95 if this kept his wattage at 200 and what the sensitivities are in each of these.upsidedownmark said:
ETA: In terms of calculated power, trainers have a non-linear resistance/speed relationship.. you then have a curve to calculate power. It's a crapshoot, and not particularly accurate. But it's still a straight wheel speed-resistance relationship, gearing / cadence have no bearing.
So, going back to the OPs query, which if I've interpreted correctly boils down to "why are riders with a lower w/kg dropping me in a Zwift race", what data metrics does Zwift collect to then convert to riders speed in a race and how?Ahem, apologies, appears I need my reading glasses - I read that in the opposite sense.
I think we're massively overcomplicating the issue:
If vaguely non-dumb trainer or powermeter, zwift offloads power to that. It takes what it gets.
If dumb trainer plus speed sensor (zPower), it does it's best guess at power based on the wheel speed, and a 'known' resistance curve for the trainer. The wheel speed is ONLY relevant to calculating power - it has no direct bearing on zwift speed.
Cadence/gearing has zero bearing on the calculation - it has zero bearing the power being absorbed by the trainer.
Given a power output, a known gradient, mass, and an assumed CdA (derrived from height), it's (relatively) straightforward maths to derive in-world speed.
ETA: Answer to the OP's question is 'There is more to speed than w/kg'.
I think we're massively overcomplicating the issue:
If vaguely non-dumb trainer or powermeter, zwift offloads power to that. It takes what it gets.
If dumb trainer plus speed sensor (zPower), it does it's best guess at power based on the wheel speed, and a 'known' resistance curve for the trainer. The wheel speed is ONLY relevant to calculating power - it has no direct bearing on zwift speed.
Cadence/gearing has zero bearing on the calculation - it has zero bearing the power being absorbed by the trainer.
Given a power output, a known gradient, mass, and an assumed CdA (derrived from height), it's (relatively) straightforward maths to derive in-world speed.
ETA: Answer to the OP's question is 'There is more to speed than w/kg'.
Edited by upsidedownmark on Thursday 25th January 14:18
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