Zwift released Pack Dynamics 4 in early April, and over this past weekend announced three race events testing the next iteration, labeled Pack Dynamics 4.1.
If you’d like, you can read the entire announcement from Zwift’s David P., who led the charge on PD4 and is continuing to lead the charge with dialing in Zwift’s Pack Dynamics. I’ve summarized it below.
Pack Dynamics 4.1 Changes
Overtaking someone that is not drafting should now be harder. With the goal of reducing “churning” at the front of groups, for you to overtake someone that is not drafting you will need to put out enough “net power”.
Net power is the power to overcome the opposing forces as if you are not drafting. So basically you will be “tested” as if you are not drafting to see if your power is enough to produce the speed to overtake. This doesn’t necessarily mean you need to do more raw power or watts/kg than the person in front.
Dynamic CdA Changes
Zwift now has the possibility to configure CdA penalties or bonuses in three different situations:
- While drafting
- While not drafting and “attacking”
- While not drafting
For this initial iteration, there are only changes to the first two situations.
While drafting, you will have an increased CdA, which is the equivalent of you raising your upper body and having a greater frontal area, just like you see your avatar doing.
If you are not drafting and your power is 10% above your last 10-second average power you will get a 5% CdA decrease, which is the equivalent of a more aero position.
Zwift says they have not changed the baseline CdA (while not drafting), because that would involve a big discussion into slowing everything down on Zwift, which is what David calls a “last resort measure.”
Draft Cone Changes
Zwift can now configure some important parameters of the drafting mechanics:
- Draft cone angle
- Draft fall-off
- Draft scale
For the first test events the draft cone will be narrower, the fall-off will be “steeper” (meaning the draft will be stronger closer to someone but will diminish greatly when there is a gap), and also the draft scale will be higher in “high draft situations”, so deep in a big group the draft will be stronger.
Ride a Test Event
The three test events happen tomorrow – see them and future PD41 test events at zwift.com/events/tag/pd41. They are all 2-lap events on the Sand And Sequoias route, which is a nice choice for testing flat roads as well as rolling roads and climbs. Categories will start separately.
Zwift says it’s possible that pack behavior in the first events will be very different from usual. However, if the changes are in a good state, other race organizers may soon be able to request PD41 for their events so that more events start using it, just like last time with the PD 4 tests.
Questions or Comments?
If you participate in a test event, be sure to post your feedback on the forum thread.
Silly question but can you spell out the acronym CdA? Thx
CdA is an abbreviation for the coefficient of aerodynamic drag. It’s a dimensionless number (no units), which is the result of a body’s drag size, shape and surface texture.
CdA is the CdA is drag coefficient (Cd) multiplied by the Area (A) of a moving object https://mywindsock.com/page/help/navigating-and-understanding-the-information/virtual-cda/
Zwift should lower the drag of someone who is the front of the draft by about 10%. This would mimic real life physics.
@Eric Schlange can you do an article on how to use tags to filter zwift.com events…. realized from this that you can add in things like https://www.zwift.com/events/tag/steering and filter the events better than the “filter” option. Do all the tags from zwift hacks / events work here?
or “idea for an article” 🙂
Recommending https://zwifthacks.com/app/events/ for easier filtering and searching.
Will the Draft fall off change make it quite a bit more brutal if you’re dangling off the back of a bunch?
How unrealistic are the attacks going to be? Ramping up until max, taking a 10sec breather and then ramping up again to max!
Now the main issue for lighter riders is that they will constantly get pushed to the sides, out of the draft even more than before, is my guess. This due to the “power” aspect and more narrow draft cone. Lower power (like a lighter rider) pushes you to the side and you constantly need to sink and sprint to get back into the draft, meaning not as comfy in the pack as a heavier rider who can just sit in the middle comfortably. I don’t have steering but noticed when tested a kickr bike that i could steer myself back… Read more »
This is really interesting – I had no idea the behaviour I saw (me being pushed off to the side all the time) had anything to do with my weight (<70kg). I have a KickR bike too and don’t like steering with it because you spend all your time pulling yourself back to the “centre”. It seems like you pushed to the side even more often when steering is on…..
Well, that explains a lot. Happened repeatedly yesterday, so frustrating. It’s bad enough that I seldom benefit from a draft because the rider in front is bigger and putting out way more raw power than than me. Now I am fighting to get the little draft I can? 😢
Gen3 racers still churning in PD4.