The Draft Effect


(Frank SolTiz ODZ) #1

My wife did a group ride. The stated pace of the ride, in W/kg, was do-able for her. She got distracted for a short time giving Ride Ons, and she also fell back a little on the climb up to the Road to Ruins. She could not catch up to the group and ended up totally dropped. However, at the end of the ride, her power output was actually slightly higher than the stated pace. The people in the group likewise did not exceed the stated pace. Is the draft effect so powerful that it could account for this?

Also, I was on a group ride where I inadvertently got way ahead of the beacon. I was slowing down, and i could see the beacon 45m behind me. The beacon (and his group) made up that distance in what seemed like 2 sec. and flew past me and dropped me. Again, was this a draft effect?

Thanks


(Nick Adams (B)) #2

Hi Frank, 

The draft effect, particularly in large groups, is huge both in real life and in Zwift. Drafting is estimated to be about 30% power savings in real life, and some Zwifters have estimated it to be 25% in the game. It seems to be greater than that in large groups. Check this out: https://zwiftinsider.com/zwift-drafting/

Like your wife, I was in a Zwift race once and was holding with a strong group for 40 minutes before getting dropped on a short hill. I fell off the back and despite putting out a couple hundred extra watts for a minute or two, I never was able to catch up. This is exactly what it’s like in a real race, too. Once I was doing a competitive group ride and I was drafting with a group of 20+ riders. I was at the back of the pack and when we came up on an intersection, I slowed down for a car that was coming. I fell off the back and never caught back up with the group, despite cranking like a madman for several minutes. 


(Cary Sporinsky TeamZF ZHR(F)) #3

Draft effect is a couple tenth’s of a w/kg.

Scenario A: Group leader’s tend to go fast when it is level and quite slow on uphill’s. You slowed after a hill and they whipped by afterwards.

Scenario B: What you saw was warping, maybe combined with the above. It happens, shake it off.  :slight_smile:

That’s great you and the wife are riding. When I look at my health, pre and post Zwift, I just can’t imagine ‘getting old’ like I was before.

You cannot compare Zwift to real riding.


(Frank SolTiz ODZ) #4

Warping. That’s an excellent way of describing it. Any idea of the cause? On one particular group ride that I do, it occurs regularly. I’m not complaining; just trying to understand. When I see it starting to occur, it seems no matter how hard I get on my horse, they ar going to blow by. I would almost describe it as “glitchy”.