Are you willing to volunteer to handle all the complaints? 
This change only impacted the jungle route 8km and people are still complaining. see this
People just love the fast virtual speed and many miles they can record virtually.
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Not sure what you mean here, but the current system still uses the same auto-braking framework that was developed in earlier iterations, just not to the same extent because the parameters were tweaked to be less frequent/aggressive.
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Also no idea what you mean here. There aren’t any group speed buffs or weighed speed coefficients… (?!)
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From what I understand, you propose to apply different draft calculations depending on where the rider is positioned in the pack?
Currently the draft calculations are already analysing all riders around you within a certain radius, and to be honest I believe it is an ingenious solution.
Where I believe there is some further ground for improvements is tweaking some draft parameters like draft cone angle, draft strength fall-off and maximum draft caps in operation. -
That is the point where I believe I mentioned many times, that without ubiquitous steering and manual braking we must always provide a simplified solution. This is a game, not a simulation. Can you imagine being behind a group of 50 riders and potentially having to wait several km to do an attack just like IRL until you find the space to breakaway
I do intend to work on some new iteration, specific for racing experiments, where I will test some of the proposed solutions or improvements, just don’t know when I will be able to, so just hang on a bit longer.
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[quote=“Daniel Jamrozik [+R], post:282, topic:605018, username:Daniel_Jamrozik”]
If I’m doing 6.5 to 7W/kg sustained for sub 5 minutes, and the peloton lead rider(s) pull at around 6 or under and also weigh less than me, usually, they either maintain the gap or pull back fraction of seconds, depending on the terrain.
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People forget that raw watts are what is necessary to go fast under 3% upwards slope or descending.
The peloton leaders are never lightweights, except in A category. If you are 65 kg doing 6.7 wkg that’s 435 w and the riders pulling are two 85kg beasts doing 510w at 6 wkg you don’t stand any chance.
That used to be my life.
But now I see some possibilities with pd4… the peloton don’t come back as fast as before on flat and is a lot slower on long downhills.
I tried to get away on uphill, it worked as before, but now I am able to keep the gap open after, when descending.
That will make races seem extra hard for everyone but it is not because of the direct effect of pd4, but because people like me are now trying to get away uphill for example, so the pack have to work to get back, thus the race is getting harder.
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I would genuinely love to be able to officially field said complaints on behalf of Zwift.
But also, you’re less and less likely to ever reach the records set when younger.
Sure, an all-time best is cool, but as one’s ability to reproduce it declines, they become less and less interesting to me. I’m 54 now, and there are plenty of indoor rowing bests from 20 years ago I’m pretty sure I won’t ever see again.
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I’m a 70kg+ and 180cm figure; however, I have noticed the names who have chased me down often are under that weight. Probably majority shorter than 180cm for that lower weight. I’m doing anywhere 455 to 500+W for 3+ minutes for crying out loud. 3 minutes would average 500+, and I still get caught without an organized QuickStep lead out. It’s pathetic!
I well understand when 80kg big watt folks chase me down on shallow grades. Benefits actually extend out to about 7% grades.
I am not the only A+ category guy to remark these changes are insignificant. A big flaw still remains.
Probably another difference between the two of us: I’m contesting against 40-odd people in the bunch. You may have experienced 20 or less chasing you? My case has more people available to churn, but they are far away dedicated to the Quick Step train approach. Very lazy.
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I had thought the auto braking mechanics of the current, live PD system are a nuanced version from earlier trial experiments? Not as rigid and allows for more churn to result.
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You or Zwift made mention that there is an added “speed coefficient” (my terminology) to a small breakaway group for PD 4.0, in order to help establish separation.
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This is correct. It sounds to me like whatever math Zwift is using does not correlate well to large packs. I believe Zwift applies draft mechanics for a 4 to 6 man single-file paceline and extrapolates the same power savings that 6th (or final) person receives and applies it to any position beyond 4th/6th in a mass peloton. That’s highly flawed!
If you have a pack of 50 riders, those deeper in position should have in excess of 50% draft savings. I attached one example graphic. The green zone is nearly 0% required power input! This is missing on Zwift
- Position is crucial in bike racing. Much more important than fitness! Patience is an aspect that absolutely should be rewarded, as should taking chances.
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[quote=“Daniel Jamrozik [+R], post:289, topic:605018, username:Daniel_Jamrozik”]
If you have a pack of 50 riders, those deeper in position should have in excess of 50% draft savings. I attached one example graphic. The green zone is nearly 0% required power input! This is missing on Zwift
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You are reading that image wrong. “Fig. 20. Drag of every cyclist in Peloton A as a percentage of the drag of an isolated cyclist riding at the same speed.” Source available here:
That is only the drag as a percentage of isolated rider.
It does not equate to 0% power required.
You or Zwift made mention that there is an added “speed coefficient” (my terminology) to a small breakaway group for PD 4.0, in order to help establish separation.
What? I would love to see where that was mentioned… certainly not by me.
I believe Zwift applies draft mechanics for a 4 to 6 man single-file paceline and extrapolates the same power savings that 6th (or final) person receives and applies it to any position beyond 4th/6th in a mass peloton. That’s highly flawed!
No it does not. Where did you get these ideas from? Zwift applies the physics of the player (the one running it) depending on their current surroundings. Slope, rolling resistance and wind resistance, with the wind resistance being subtracted or not, depending on the draft situation. Draft takes into account the currently surrounding players position and the potential draft they provide.
It’s blind to large groups or small groups. Doesn’t do any “magic” based on that.
The problem with that realistic model you posted, is that if we don’t do any draft cap for riders that are deep in the pack doing steady watts, they will fly to the front because there are no collision consequences and because their draft savings are massive, so we need to introduce these unrealistic safeguards to account for the lack of collisions, etc.
- Position is crucial in bike racing. Much more important than fitness! Patience is an aspect that absolutely should be rewarded, as should taking chances.
if we get complains as it is now, imagine if you would have to tell people to wait for some action while you can’t steer or move away from a certain position. I believe the experience would be quite frustrating.
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Half the comments complain that pack speeds are still too fast for breakaways to succeed. Half the comments complain that pack speeds are faster now because people know that breakaways can succeed. Half the people in each group are also members of the other group. Half the comments approve of PD4. Overall, I think that’s a win for PD4.
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To your 2nd and 3rd points (out of 3 total), coupling draft and position/auto-braking:
I made the hypothesis based on required power input settling deeper in a 50+ rider peloton. You have proven that hypothesis — not theory — to be wrong. That said, “draft cap” is very unacceptable, as it then gives bias to rider fitness. I get that this was the framework to date to TRY and circumvent missing auto-braking, but “racing” is not solely a “workout.” Racing is a tactical battle. A game theory of strategies to accomplish goal(s) in competition. Position and luck contribute. Racing is to test your fitness capabilities
Draft cap + pack churn leads to acceleration as the finish placing determinant. It is why in Cat. A the “1 minute specialists” gets brought up frequently. They are the phenotype (puncheur) that wins Zwift races the most. We can argue short formats etc. as factors, but it boils down to Zwift physics flaws as you responded at length to
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Thank you for catching this. I can illustrate numbers under the following assumption: drag force at 80% and rolling resistance + gravitational + other losses at 20% power required
Suppose lead rider does 400W. 320W is to overcome drag at their velocity. The rider at 5% in peloton then needs 16W power at their pack position PLUS a 20% of total power input to maintain their momentum/inertia. The former overcomes drag; latter overcomes the other force losses. I reckon it still yields 100W total or lower power required?
David already mentioned the “draft cap,” so we cannot (unfortunately) dive deeper into the analysis. We do know that power required exceeds 100W because of the cap
It is why in Cat. A the “1 minute specialists” gets brought up frequently. They are the phenotype (puncheur) that wins Zwift races the most. We can argue short formats etc. as factors, but it boils down to Zwift physics flaws as you responded at length to
If we want to compare Zwift physics with real life physics then we also would need to make the question, would those same riders be successful if the average Zwift races were between 3 and 5 hours long like regular IRL cycling races?
That said, “draft cap” is very unacceptable, as it then gives bias to rider fitness.
I understand your frustration but I also already explain why we can’t avoid these “fake boundaries” for the time being: steering, manual braking and collision consequences.
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10 posts were split to a new topic: The success rate is much greater on Zwift than IRL
[quote=“Daniel Jamrozik [+R], post:294, topic:605018, username:Daniel_Jamrozik”]
I reckon it still yields 100W total or lower power required?
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I have been riding for many years in big groups and I can say from experience that you need a lot more than 100w to stay in a pack that big.
Flat 8km section of: (more than 50 riders)
Lap1: pulling and riding in the front 41km/h 300w average
Lap2: hiding in the bunch 42km/h 265w average
Lap 3: got dropped and had to TT to the finish 40.2km/h 316w average
@DavidP I’m trying to understand how the auto-braking works. I wonder if this parameter is in use and if it is 40% of 10 sec avg power, 40% of current speed or something else? How long does it last? When is it applied? You have already said that weight/power does not matter, so I wonder what this 0.4 refers to.
Are you referring to IRL group rides? Then I’ll establish conditions to make it clearer:
- Velocity is steady state. That pulling power of 400W is steady, so no attacking off the front nor surging. It is an instantenous snapshot that assumes said power to be constant
- On the flat. No corners. No wind. No external drafting to vehicles. No slow downs of speed
- Where in the bunch were you hiding? Id have to count the number of riders on aforementioned CFD graphic to determine the 5% power required to overcome drag force
- Its very important you mention both avg power (AP) and normalized (NP) and/or variability index (NP / AP) for your efforts. Ive seen flat criteriums where riders have AP of about 200W for prolonged periods while the avg speed for that duration is around 49Km/hr. NP suggests that effort typically to be unsteady
(1) greatly implies no acceleration and deceleration effects.
No accel/deceleration of (1) means that VI should theoretically be 1.0 and NP can be ignored from (4)
[quote=“Daniel Jamrozik [+R], post:300, topic:605018, username:Daniel_Jamrozik”]
Are you referring to IRL group rides?
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IRL racing. It was not a crit it was a 70km race that had 3 laps and that was a flat section no turns.
There was surges just like any Zwift race.
That is the amount of braking force applied. Imagine you have a brake lever on your hand and you press 40% of the way in, instead of squeezing with full force. So it’s a semi gentle tap to the brake 
In the early versions of PD4 it was configured to 60%.
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Then my hypothetical comparison is apples to oranges against this particular dataset you share
Perhaps you can narrow your analysis into smaller time windows such as under 5 seconds, where the conditions I specify are satisfied? The goal is to remove the accel/deceleration and surging components in your example dataset
In other words, my 400W example is steady state dynamics. Your current data is transient dynamics