New Pack Dynamics [February 2021]

Just posted this: Zwift Tests "New AI" Pack Dynamics - Zwift Insider


I did a TdZ make-up ride today and found that we were thrown more sideways. I asked in the chat if someone could notice a difference, but the only reply I got was someone got dropped as usual (no difference) :slight_smile: But I experienced something different. Imagined or not. If I came from the back and wanted to find a back, the rider in front of me would move to the side and I had to go for the next rider in front. I also noticed that there often opened a gap between the first riders in the group and the rest. I also think that it was easier to fall off the back of the field and harder to get back, but that could be just me having a bad day :slight_smile: I also noticed that the group did not hold together as good as I’m used to. That could be because of the increased sideways movement and harder to draft. I also noticed that if I had a position at the left or right of the field, I could hold that position longer than before, so less movement. Previously I would have been pushed into the center of the field after a while. I can confirm that there was less “churn” and you had to do a conscious decision to go to the front, not just suddenly being at the front by accident.

Yes, we’d be glad to add this to your rides. Hit up the events team as you usually do and we can add this to rides in the next couple of weeks.


Right now this is only enabled in specific events. Freeride, including riding with Pace Partners, hasn’t been changed.

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Hey Mark,

We’ve been testing this for several months and making changes/mods daily. The TdZ make-up stages represent the biggest rollout/test event we’ve staged thus far.

This forum’s feedback is super helpful to our engineers to hear what your experience was like. We’re not done, this is just a step in the process and we’re including the community in this testing and rollout.



I really appreciate the openness from Zwift and the willingness to get feedback on new features/changes from the community. Way to go!


Awesome !! Thanks…Have a great weekend Mark. Cheers , Stephan

You have no idea how pleased I am to hear this. Thank you very much.

I’m really, REALLY hoping this will bleed over into some of the other issues brought up on the forum. Zwift is an important part of my and many other’s fitness program and the frustrations can make it difficult to live with at times.


Ok, thanks for the info! Guess the zigzag motion could be related to earlier changes then (see Avatar excessive movement, weaving and juking ). I have been experiencing this in some event starts as well to the point of having to look away to avoid nausea.

Glad to see that this part of the product is getting some attention as well for a change. If you haven’t already, you may want to keep the possibility of riding through others still there for the first x meters or seconds of an event to make starts less chaotic/unfair.

Did the London Greater Loop event (think that’s Stage 1 A group). Up the mall it was very apparent there were riders being shunted to the right both going up and down the mall when in a group of about 20. It didn’t happen every lap but it did happen. It was usually about 5 or 6 riders who would suddenly flick to the right by about 3 or 4 metres. Only really saw it happen on the mall though.

I did see a couple of cases of people quickly moving forwards and backwards by a metre or two.

In terms of feedback from what I saw, it was the 2pm TdZ event on London; the A category. I watched the lead group which consisted of 10-15 riders out on their own doing very strong numbers as you’d expect. Two riders in particular (one from France*, the other from Japan) were noticeably jerking around the pack. When watching as them in the default 3rd person camera view, this jerking was producing a distracting stutter disturbing the smoothness of the game that I wouldn’t personally be comfortable with if it was my ride. This could have been to do with internet latency from their system to mine (I’m in the UK) but I’m unsure about that since it’s not something I usually see when watching others for testing purposes. For clarity, my system was running at 80-90fps in 4K at this point on an adaptive sync display, so it wasn’t a PC resources issue. And when switching to others in the pack the stuttering issue went away immediately - but I could still see those two riders moving around unnaturally. This is what led to my question above about whether this could be due to them not being on the latest version of the game. I obviously am, being on PC.

*Edit: if it helps, the chap from France finished in first place on ZwiftPower.

Kudos for the update and the new feature.

At the same time, obviously new pack dynamics was higher on the priority list than screen capture issues that persist for about three years now, as well as abundant feature requests by (paying…) clients.

We had our first event already with the Dynamic Packs and had some good feedback during the ride. It’s great and feels more realistic. I was using the sterzo as well without issues.



Would be really interesting to test this in a big race…

Hey up - I posted a video on the ZPCMR Facebook group and was directed here.

I think I experienced some weird side-effects of this trial during a ride yesterday. It was the Make Up stage 4 ride in the France world at 1800 UK time on Saturday 13th Feb.

Group riders appeared either to slow and then put a sprint on, or dive randomly for the undergrowth like the pack leader had yelled “SCATTER!”. In each case it appeared that my rider responded to their position, ie I dropped out of the draft when they “sprinted”.

I have a video showing some of this behaviour if there’s a way to upload it?

You know what would help realism is just making steering default on everything. You create steering, push the selling or sterzo devices then dont support it.

Feedback seems to be posted a bit sporadically around the various social media platforms, but for me the main issue is that when riders are repositioning it happens very sharply - so they jolt side to side or back and forth. If its happening a lot it can look very messy. When it isn’t happening, the general look and feel of the pack is much better.

I’m interested to see it in more of a race setting. You can end up with a thinner line of riders all drafting, but you will be moved the side with no draft and quickly find yourself moving backwards. Without steering, is there any way to move back in to the draft of your own accord? e.g. By spiking your power or something?

I’m also still keen to see if it makes any difference to the ever-accelerating pack speed, or the speed around corners.

All in all, an exciting development and I hope it can be iterated quickly now there is community feedback.

A couple of ideas - have a popup at the beginning of events with this switched on. The vast majority of riders won’t know about the change, and I have already seen people reporting ‘bugs’ that are actually just the new dynamics.

Secondly, many apps don’t let you start them unless you are on the latest version. Why not force the latest updates on users so that the issues of multiple versions go away?


New pack dynamics is a pretty important update. I appreciate there are a long list of things that seem to be easy fixes (why can I only take a 1080p screenshot on 4k resolution?) but this change is very welcome in my opinion and is a positive sign compared to what we have seen (or haven’t seen) over the last 12 months.


Not a comment on the pack dynamics, but this is awesome.


I really hope “sticky” draft gets kicked to the kerb. It’s annoying as heck to be coming up behind someone, catching them due to higher speed only to get stuck in draft treacle and have to surge to break out again.