No drafting benefit


(Daniel Aberdeen Wr3) #1

I seem to get no drafting benefit, or change when in a pack

I never see the ‘close
the gap’ graphic pop up or any other indication in the GUI that drafting works…

I tried a hare and hounds race as cat c and got dropped immediately despite showing and doing about 300 watts… so this is a real problem!
This is with the tacx flux smart trainer on a desktop PC with ant + dongle… everything else seems to work normally…

Any ideas??


(Jim) #2

Are you riding a TT bike, for which there is no draft?


(Mark O'Neal) #3

I also feel no difference whatsover in the draft or not in the draft. I do get the graphic though

I’ve quit even bothering to draft since it makes no difference


(Jim) #4

I’m pretty sure that drafting only affects in-game velocity for energy expended, not the “feel” (I.e. trainer resistance). At least, I’ve never felt it. Nonetheless, the effects are quite obvious.


(Mark O'Neal) #5

I’ve read that but it doesn’t make any sense to me. If I go faster in the draft I should have to expend less power to stay in the draft. Hence I should feel it as a reduction in power. Else I would blow past the person I’m drafting

There is a similar statement Zwift makes about the overall difficulty slider bar. That it doesn’t make the climb easier ( less power ) it just makes the grade less. That also makes no sense to me as a 10% grade is quite a bit more difficult than a 5%

I may need to spend an evening just playing with this to understand it. It’s clearly different than a real bike


(Jim) #6

Drafting allows you to ease up on the power and maintain the same velocity. It’s effects are noticeable when riding in a group. If you drop off the back, it gets a lot harder to keep up, but only because your in-game velocity drops…not because trainer resistance increases.


(Mark O'Neal) #7

I’m sure they have their reasons for why they programmed it the way they did, but it seems like a better implementation would be to have the “grade” lower by 1-2% in the draft. I can totally feel when the grade eases off and it seems like that’s what it should feel like to draft.

Maybe the reason for the current implementation is the smart vs dumb trainer thing


(Mark O'Neal) #8

I’m probably the only one who cares, but the engineer in me has to verify these things.

Drafting: I joined a large 2.2 W/kg ride. I found if I dropped off the back of the pack I would immediately lose the draft. I had to go at 3+ W/kg to catch back up. Even if I only slightly lost the pack. I think some of the issue is the delay between when I would ease up and start pedaling again. But I had to go much harder than I would outside to catch back up. A large pack definitely seemed to have a drafting effect. Single drafting was much harder to tell if it did anything or not since there is no tactile feedback. I’ll assume it does something but since random riders never seem to maintain a constant pace it was hard to tell

Difficulty Slider : I did the Hilly Loop KOM three times. Once at 50%, once at Max, and once at Min. All three I tried to ride at 100% of FTP. Times were 3:20, 3:05, 3:09. I probably wasn’t warmed up for the first run, but it’s interesting that my fastest time was on Max. The main difference was as Zwift says, the gear that I was riding in. Min was really weird as I never shifted. Max felt more normal.

So with my quick and dirty “scientific analysis” I’m going to have to go with what Zwift says is accurate


(Lin) #9

Drafting: When you’re outside and in the draft of the group ride, it gets easier not because the gradient changed. It’s easier, because you can go the same speed with less power. Zwift is the same, if you’re in the group draft, you are going the same speed but on less watts than if you were solo.

Difficulty Slider: The biggest problem with this is the name “Trainer Difficulty”. Best to think of that slider as virtual gearing or a virtual cassette. You can do 200W in your 54x11 or 200W in your 39x23. The time to the top is the same. But if you are climbing a 14% grade in a 39x23, unless you like to grind or are super pro, you’ll be hating life. Decreasing the “Trainer Difficulty” is analogous to swapping your cassette. Suddenly you have a 11/28 or 11/34, which makes climbing feel easier. The hill hasn’t changed, it’s your gearing that has changed, just like in real life.