That’s not what he said though. All he’s saying is that if RP is out front and you’re behind and getting a draft then you can do ‘much less w/kg than the RP’. But if others are out front and you and the RP are both in the draft then you’ll need to do the same w/kg as the RP (which is more than in the first example)
1 Like
The RP is just a rider like you, if the RP get draft benefit so does your avatar. so if you ride with the RP and if you are of the same length and weight you will need to do the same power as the RP no matter the group size. (except if it is only you and the RP then you can hide in the RP draft.)
But for all practical purposes the group size does not matter if you are with the RP.
OK,
Now how is this impacted by a) being on a pretty much flat course and b) the rider being 15kg lighter than the RP?
1 Like
Righto. Well I can average 2.9-3.0 riding with constance. When yumi is drafting riders the entire ride it also requires 2.8-2.9 to stay with Yumi. Just see the major difference between the equivalent robo in the different world. If you want 2.6 join Watopia Coco, but you can do 2w with Makuri coco atm.
1 Like
Don’t like being told I’m wrong when I’m not so I quickly did this. Summary in photo, as I don’t expect to watch. Chapters in vid though
1 Like
If you are riding in front of the RP (or any other group ) then you will have to produce more power because you are not in the draft anymore. That is how it Work IRL as well.
No one is debating that riding in front is harder than hiding in the bunch.
Of course. But the poster wants to know why his pacer ride was different with the same group. Because it can vary so much depending on the dynamic of the group!
1 Like
This is what I don’t agree with. If you always ride just behind the RP then you will always get the draft from the RP if there’s more people in front of the RP then you and the RP will get draft from them. You will go faster but you won’t need more power.
In other words if the RP rides on a flat route you can set your trainer on ERG mode and Dial the power so that you are just behind the RP and no matter how many people join in front or behind you will stay with the RP.
Many people used to do this before the RP’s became dynamic and increased their pace on climbs.
2.2w/kg and 3w/kg are different. The first 3 examples were all done sitting behind the robopacer the whole time, on the flat. The difference being the Robopacer was receiving 0 draft in the first two tests, making it much easier to sit on it.
The 3rd had other riders (not me) rolling thru the front at times making my ride in the bunch much more difficult (2.2 vs 2.8). I then went to the front and pushed the pace on the group and that required those sitting in to avg > 3w/kg to sit in.
Quite a range for a fella wondering why his ride feels different 
Finally someone says what is happening! yay! I think you’ve seen some Constance groups where some particularly powerful riders (2 or 3) at the front at punching much more power then everyone has to increase pace or get dropped when the pace surges so fast.
Back in the old days of Anquetil A grade pacer (before they all got heavy) two or three of us could punch quite big watts/kg in the jungle and drag Amelia onto the wooden bridge much more quickly and spit others who had been sitting in at the back right out of the group so they ended up 10 seconds adrift. Then they would have to quit and rejoin from 0km, if the location was right you could do the same thing again.
Now I can’t sit at the front because I don’t have enough power to do so anymore - so it really grates when someone comes along as says, no, you never have to put more effort in at the back. I’m pretty much permanently just trying to stay in the draft to hang on to the group because I’m riding with faster robopacer groups rather than ones where I could easily just sit in front.
The mountainous routes are a good change up from the robot groups.
1 Like
Another way to look at Josh’s excellent analysis:
No pulling
RP 240w @ 3.2 wkg @ 75kg
JH 140w @ 2.2 wkg @ 63.5kg
Pulling
RP 240w @ 3.2 wkg @ 75kg
JH 178w @ 2.8 wkg @ 63.5kg
@Gerrie_Delport_ODZ See how in both cases Josh is in the draft of - and keeping pace with - the RP while pushing significantly fewer watts than the RP.
There’s a complex relationship (quite possibly chaotic, non-linear) between raw watts, wkg, rolling resistance, rider weight, watts/cda and draft (and very likely 3 or 4 other variables) that determine the power output required to keep pace in the draft.
2 Likes
But do you get EXACTLY the same draft benefit from the RP irrespective of where the RP sits in the bunch?
Yes and as you both drop further and further back down the bunch do you not both end up getting exactly the same draft benefit ?
An image previously posted on this forum and by ZwiftInsider:
This would suggest to me that:
If the RB is at the front of the bunch and you are riding on the wheel you might receive around a 25-30% est draft saving against what the RP has to put out. [ I believe ZwiftInsider reports that if you rode a 2-up on the wheel of the other rider (RP) you would get a 30% saving on a flat route]
If the RP and you are both at the back of the bunch then you are both experiencing a 95-96% draft saving. You are now getting no additional draft savings from the RP. You are now both putting out the same power to hold your positions at the back.
I don’t know how Zwift deals with draft but if it is trying to be similar to real life I would think that:
Bunch size does matter and so does the RP position within that bunch.
As in real life once the front of the bunch starts to put the power down the weaker riders (and a rider riding a constant power) start to get spat out of the back because the power they were putting out is no longer enough to hold them in position.
I’m not quite sure the laws of physics work that way 
Edit - but I think I know what you mean, the same power allows you to ride faster as the bunch gets bigger but only until it’s no longer enough power to hold on.
If you can ride at the same power as the RP you should never be dropped by the RP.
If you can only ride at say 90% of the RP’s power then a powerful, fast moving bunch pushing the RP to the back will most likely cause you to be dropped from the RP.
1 Like
I don’t think the power numbers you quote for Josh is very accurate if you took it from the video, you need to pull the average of the 5 min from strava.
But you are correct in the conclusion, a lighter rider require less power on a flat road.
His 5 minute avg wkg is on the bottom of the screen, sourced from Sauce 
2 Likes
I don’t use sauce, so I missed that.
Sitting in the bunch (not pulling) 2.7w/kg 170w
Pulling the bunch 4.1w/kg 258.3w
All that this is showing is that draft savings are real, but we knew this already.
It also confirm that lighter riders need less power even on a flat road.
Why not, the RP is a rider just like you, if you sit on the RP’s wheel then you get the same draft advantage in the bunch than the RP.
That is true, but the point is to ride with the RP, so as long as you hold the RP’s wheel both of you will be spat out the back is the pace get to high.
Remember the RP hold a set power on a flat road. So on the RP wheel you also need to hold a set power.
1 Like
I think Josh’s numbers show a bit more than that. I think they show that the amount of absolute power a rider needs to push to maintain position in the draft as speed increases doesn’t scale linearly with regards to wkg.
Moreover, it appears that a lighter rider will need to increase their power output proportionally more to maintain position in the draft as speed increases.
I think. It’s a long time since I did any applied maths or physics. 
If the draft chart was comparable to how Zwift works, I think what is being claimed is there is differing relative draft benefits between the RP and one’s self riding behind the RP.
Far back in the draft, if we imagine the RP is sitting in the 13% box location, and you are in the 12% box location, your required power to hold same speed (for same height/weight) is only about 3% less.
If OTOH, the RP’s position is in the 64% box, and you ride in the box represented by the 35% value, there’s about a 45% relative difference there.
2 Likes
I’m not sure what those numbers are meant to represent, but riding in blobs while looking at the Draft numbers reported by Sauce, unless you’re clearly in the wind because you’re either off the front or there’s no one outside you, your Draft numbers really don’t seem to vary that much *for a given speed * as long as you’re in the blob.
Your draft numbers do vary considerably with speed, even if you maintain blob position.
1 Like
I don’t see how this will make a big difference, because the RP see the same effect as the rider. Also the speed only increase by a few km/h
As @Wannie has pointed out it is always easier to sit behind the RP because you get one level more draft saving.
my ride with Jacques.
5min power 234w
O and you can see what the dynamic pacing does on the 1.3% bump in the dessert. Going from 220w to over 350w just to keep up. 