No drafting effect felt

(Claude Biron) #21

Explain “blob” effect?


(Gerrie Delport TeamZF) #22

That is what racers in zwift call the draft, most racers think the draft is to strong and makes a group of riders so fast that it is impossible for a single rider to get into a break away.

I am a sweeper (someone that ride at the back and help people pace back to the group) for a lot of group rides and once you get out of the “blob” draft by about 20 seconds you have to work you butt off to get back on. (it will take 3 to 4 w/kg to catch a 2w/kg group)

Search this site and face book for “blob” 


my personal opinion is the the draft is pritty good. 


(Claude Biron) #23

Thanks for the explanation. I’ll experiment further, but I’ve kinda come to the conclusion pursuing a ‘draft’ isn’t worth the effort, like it is outdoors.  Does it work differently on a ‘Group Ride’, to aid in keeping up with the group?

btw Is it possible it works differently for different smart trainers?  Could the Traxc Neo have little to no effect?


(Ken Ridout) #24

Thank you Gerrie.
Sounds like real road riding. I’ve seen the pack get smaller and smaller in front of me too many times in my almost 35-year cycling career. It’s tough getting back in if not impossible solo.
I’ll keep trying to experience Zwift drafting.


(Anton) #25

Actually, they are not the only two people. I use a Kickr and have no draft benefit. I checked my power output both in a group and dropping back and drafting provides no benefit. Actually, I have noticed that sometimes I am in the middle of a bunch and have to do ~3w/kg to stay there while those around me are doing below 2w/kg. 


(Claude Biron) #26



(Ken Ridout) #27

I’ve done a couple of Zwift raced in the past week.  I also did a real race this past weekend.   There is a huge mental comparison, but very little physical comparison.  In the Zwift races.  There was absolutely no advantage perceived for being in the draft in the Zwift races. 

 In comparison, without the draft in real racing, only the strongest would be competitive.  And sprint finishes would look silly without taking advantage of lead-outs and other sprinters. Oh man, this weekend it was so nice to fall into a draft and rest with a huge decrease in effort. Rest up for the hills, rest up for the sprints, and rest because you simply need it from taking pulls.  

There are only two things that should break up a race:  Wind and climbs.  (oh, and crashes . . . but we don’t have to worry about that on our trainers.)

Zwift has the climbs down very well.  Extremely realistic.  We don’t have any cross, head, or tailwind-factor … and that’s OK.  Occasionally, real races are held in dead calm conditions.

But for Zwift virtual races, we should be able  to take advantage of the draft.  Would make for a much more interesting race with more tactics involved and sprint finishes that are  much more realistic. 

For group training rides on Zwift, no draft makes it the same for everyone. Good deal.  But for races, realism would be greatly appreciated.




(Claude Biron) #28

My feelings precisely. Don’t know why Zwift can’t apply an immediate decrease of 30% - 40% trainer resistance, when in the draft,  scaled to speed. Seems like simple math. Should also be able to better detect and control technical doping.


(Gerrie Delport TeamZF) #29

The draft is not something your trainer do it is a simulation/calculation performed by zwift. If it was on a flat and you weigh less than the other rider than you will need to put out more w/kg to stay at the same speed. If you had to maintain 3w/kg to stay in the group and you drop more than 10m behind them you will need a lot more than 3w/kg just to stay at the same distance let alone catch them.

Once you get in a big group Zwift reduce the CdA (drag from air) then you need less power to maintain the same speed. 

F= CdA p [v^2/2]

F = Aerodynamic drag force in Newtons.
p = Air density in kg/m3 (typically 1.225kg in the “standard atmosphere” at sea level) 
v = Velocity (metres/second).  



(Ken Ridout) #30

Gerrie, are you sure this is true?  

If it is, then we should all feel a huge decrease in effort when in the draft versus not.  In Zwift, I can never feel less effort or see less effort on my wattage display, either from my Garmin pedals or from the CycleOps Hammer display on the screen.   

In the race I did on Zwift on Saturday, drafting relief didn’t exist.  In real life racing, the draft is everything!

Maybe I have something set up wrong?  I’m not on a time trial bike and it does tell me to “Close the Gap”.   Is there another setting?

There was a psychological effect of being in the draft in the Zwift races, but extremely hard to stay there with virtually the same w/kg as the others.  The leading riders weren’t putting out any more w/kg than others.    

In real life, there’s no doubting when in the draft, either single file or in echelon.  In groups, it’s like riding downwind!.  


(Claude Biron) #31

“Once you get in a big group Zwift reduce the CdA (drag from air) then you need less power to maintain the same speed.”
I think this is what some of us are saying does not translate into noticeable change in the physical effort required to keep up in the virtual world, unlike reality. I’ve simply stopped thryi g to keep up with anyone. Been doing workouts lately, so drafting not happening by default.


(Anton) #32

Gerrie you are missing the point. 

a) there is no way in hell, or in watopia, that there is such a big weight difference between me (just me) and all those (everybody) around me in a bunch every single time. 

b) As I have explained, I have done the tests. Riding in a group requires x watts from me to maintain my position, less than x I get shelled out the back. I can easily keep up with the group from a distance if I maintain the output I used to stay in the group.

I think most people are aware of the formula for drag coefficient but that is physics that nobody is disputing, what I am disputing is that this is actually applied in a way that translates to a noticeable difference within zwift races. My experience and testing using a kickr is no, sitting in a bunch have no impact on the amount of power I have to produce to maintain a certain speed i.e. my position in the peloton.


(Brian Jones) #33

Using Elite Direto. Bike Zwift Carbon - had to use more w/kg in the group than say being infront of the group which seemed noticeably easier and less watts (at the front 2.2w/kg - drop into the group 3.0w/kg). Also people around me seemed to be using a lot less watts than me - don’t really understand why.


(Claude Biron) #34

I may have found the problem to not feeling the draft effect on Zwift. I just got a new Quarq DZero power meter on my bike, and discovered my Tracx Neo is under reporting my wattage by 30 Watts, compared to my power meter. This could explain why there’s no draft effect. What should Zwift give me a boost of 30% when
my power output compared to the rider doing the pulling is already lower!! Also explains why I can’t keep up with group rides. I’m putting out the power but not getting the credit for it in Zwift. I raced for over 35 years and do ok keeping up on the road. Next ride I’ll take power and cadence from my power meter instead, and see what happens.


(Ken Ridout) #35

I’ve done about a thousand miles of road riding since my last time to Zwift.  There’s no doubt about it.  I can rest when drafting in real life.  But in Zwift, I have to keep the power up as if I’m up front pulling a group or another rider.  My uneducated opinion is that the draft should be much more apparent.  MUCH MORE! if realism to cycling is what they’re after.  

So I consider every Zwift ride a solo ride, even if I’m in a group ro “closing the gap” to another rider.  There’s absolutely nothing to be gained.