Yesterday, Zwift enabled an adjustment/fix for drafting which will be particularly noticeable on descents. Here’s what was posted on their forum:
We’ve made an adjustment/fix to the drafting effect that’s now enabled for game version 1.102 and newer. Here’s how you can check what version you’re using.
Up until now our drafting algorithm didn’t properly use road incline/decline percentage in the equations and this change will fix the issue. The steeper the climb or descent, the more the change will be noticeable.
The end result is:
- You’ll be able to stay with riders just ahead on steep climbs with slightly less effort than before.
- Staying in the draft behind a rider while going downhill will be much easier than before – you should be able to draft supertucked riders easily now.
- Pack speeds on the downhills will be slightly higher than before in general, on the order of 10-15% on steeper descents.
- Drafting on flat roads is unchanged, and speeds while riding solo are also unaffected.
- For group rides and races making it to the top of a climb with the group is more important than before because of the points above
What Was Fixed?
Zwift says, “Up until now our drafting algorithm didn’t properly use road incline/decline percentage in the equations and this change will fix the issue.” So what was actually broken (and fixed)?
It’s an interesting little bug that is easy to understand. In Zwift, as in real life, every rider casts a draft “shadow” behind them as they cut through the wind. If you’re in another rider’s draft shadow, you’re hitting less air resistance, making it easier to move forward. Cycling 101.
But Zwift’s algorithm was calculating perfectly horizontal draft shadows regardless of road pitch. This works fine on flattish roads, but as the gradients get steeper, horizontal draft shadows will impact riders behind less and less! Zwift confirmed with me that the draft shadows now now extend parallel to the slope of the draft-giving rider.
How Does It Feel?
In my tests, the results of Zwift’s draft update are exactly as described above. It’s particularly noticeable on descents, where the draft is simply stronger than it used to be. Riders used to have to put out some power to hold the wheel of a supertucking rider, but you can now sit on that wheel at 0W, because the draft off that supertucking rider is stronger.
So while supertuck is still a fast and easy way to descend steeper hills, its utility as a weapon of attack has been blunted.
One important result of this change is that it’s now easier for lightweight riders to hold a good pack position on descents, as they sit in the stronger draft.
Coming Soon: More Tests
It’s time for me to run fresh tests and update this post, which showed how much power it took to sit on another rider’s wheel while they were descending in the supertuck or at certain wattage, in race events or group rides.
Questions or Comments?
Go do a test ride or two, then report back your thoughts on the updated draft for climbing and descending. Chime in on the Zwift forum topic, or comment below!
wpDiscuz
