New Pack Dynamics [February 2021]

There’s been an open question if Zwift is testing new pack dynamics - we are! We’ve been hard at work on recoding how the game calculates relative rider positioning. In some events since early February, Experienced Zwifters may have noticed changes in the way your avatar moves around other avatars.

In Bike group events with new pack dynamics enabled - it affects the shape of the blob, and avatars don’t pass straight through each other like ghosts. They move around each other a little more realistically most of the time. You’ll see it happen still - it’s not perfect yet.

Are the new pack dynamics enabled full time, everywhere?
No, not yet. We are still in development and testing this in selected events.

When can I ride an event with the new Pack Dynamics enabled?
All of the make-up stages of Tour de Zwift will have this enabled.
Make up week runs from February 13 - 20, and there’s a stage every 15 minutes, around the clock. See webpage, or your Companion app and filter the Tour de Zwift events.

Besides these specific events, what else do I need to try it?
The best experience should happen with the latest game version. Please make sure you’ve updated to the latest build, especially on Android, iOS and Apple TV, which do not auto-update unless you specifically enable it.

What else are you noticing besides the avatars moving around each other? Please let us know!

Please include in your comments:

  • Did you manually update to the latest game version?
  • Which OS platform you’re using to run the game
  • If using a mobile device: the brand / specific model you’re using
  • If you took any screenshots of what you’re seeing - please add them to your response.

Is this new feature what people are calling sticky draft?

Sticky draft is not new. Maybe new pack dynamics include a fix for sticky draft.

Any indication of which events this has been trialled in? Thought I saw some different pack behaviour in my race this evening, but could be just placebo.

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You did this race tonight, yes? The Events team confirmed that Pack Dynamics was not enabled in this one

We public-trialed Pack Dynamics in selected Tour de Zwift stages earlier this month. Moving forward, this coming week is the surest time to try it, as all of the TdZ makeup stages will have it enabled.


The new pack dynamics is not “sticky draft.” This is a set of improvements that make

  1. game physics more accurate, including the positioning of the bikes on the road.
  2. the movement and shape of the pack smoother and more human-like.

Thanks for confirming I imagined it. :laughing:

On the basis of this then, drafting in races will be affected? I suppose it has to, since rider position is what determines that draft ‘shadow’ cast behind them.

Ok, thanks, is sticky draft a feature? Because I often get sticky drafted when riding with C Cadence and then get dropped… It is quite frustrating and annoying

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We didn’t change the math behind drafting, but the draft effect should be more realistic because avatar positionings are more accurate now.


This is really great news. I was afraid there may be some reluctance to work on the pack dynamics now so many people are used to them.

What I would love to see is some slowing around corners based on pack size and a more realistic terminal velocity. This should help with breakaways over the tops of climbs. At the moment if there is a pack behind you there is no hope. Ideally if you push past the front of a pack you should slow as you hit the wind, so that the pack doesn’t just keep accelerating. Can’t wait to test the changes (or watch videos of others test them!).

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In my opinion, nailing the draft and pack dynamics are much more important than new roads (even though I still want that). Having the possibilty of attacks sticking at the end of races if nobody takes responsibility would completely change the racing dynamics👍


Is tihis only on for specific events or also for freeriding in some situations? Over the past few weeks, I have been noticing my avatar quite often taking an unusual zigzag line when going past others on the sprint segments, where I would have expected just going through the others.

As for the sticky draft, it definitely needs some work as well. For me it seems to work exactly the opposite of what I’d want it to do: when I’m coming from behind and just trying to latch myself on to the last rider, I go past and stay out of the draft until I can manage to wedge in, and on the other hand when I’m approaching and already accelerating to get past someone, I just get stuck to them and lose significant momentum.

@shooj Very cool. Can team event organizers already request this Dynamics Pack for their events or is it too early for this ? Happy to test it out for sure. Cheers,Stephan

Watching a catch up TdZ event and some people are buzzing around the pack very unusually - could this be because they’re not on the latest version of the game? It’s specifically mentioned in the OP so I’m guessing if you’re not up to date it has some funky side effects.

I haven’t updated the app since like January and haven’t gotten any new update since… there is supposedly a mid February update so maybe that will drop sometime next week? Should have the new Colnago in it.

Rode the TdZ Stg8 MakeUp at 545am PST as a warm up for the Chasing Fabian TT (aka The Bloodbath) this morning. I will say it is different but ZwiftHQ still has some work to do, IMHO.

It seemed like the pack in places was more like an outdoor ride with my buddies and we’re talking about what we’re going to do this evening. In other words, not tight enough for a good group draft like we would be if we were racing. Literally at places the group was spread out across the road and without steering (which, of course, was not enabled 'cuz it’s never enabled) you couldn’t position yourself to be in a draft.

My avatar didn’t ride back and forth through the pack at the start or go on the wrong side of the road (yay!) but most of the time managed to foul up the line through corners like a rookie (grrr…). And sometimes when we’d get to the big roundabout, everyone would get squirrely for a second to the point I would almost get motion sick. Really weird.

I gotta ask, did ZwiftHQ actually do testing or are the TdZ MakeUp rides the test? This is an improvement but it doesn’t seem to be as fully realized as it could be.

People on Apple TV/iPhone/Android could be on versions way old. There were a bunch of people the other day shown to be using a version from November.

Yes, they are testing in TDZ makeup.

Wonderful. So if the 47 people who frequent this forum would go do a TdZ MakeUp ride and post feedback maybe we can get this straightened out. Seems a little weird to be spending resources on Pack Dynamics when there some pretty glaring issues in the basic app that may need to get resolved by moving the entire thing to another software platform. I’m not a software person nor do I have any insight into how Zwift is staging the next level but this is a little like rearranging the deck chairs on the Titanic, IMHO…

I’d say don’t look a gift horse in the mouth. I would rather zwift throw out MVP, get our feedback and interate, rather than keep it in house for 12 months, completely miss the point and then decide not to release anything.

Pack dynamics is a big one that if they get it right can massively improve the experience.