Drafting
#1
Full Member
Thread Starter
Join Date: Jul 2019
Location: SC
Posts: 203
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 146 Post(s)
Liked 51 Times
in
29 Posts
Drafting
Watching the Tour, I am trying to learn and understand a little more about racing. I have read that the benefit of drafting increases as you get farther back in the peleton, but only up to a point. What I have not been able to find is what happens after that point. Does the benefit stay level, e.g., after the 7th position (or 8th, or whatever it is) does the benefit stay the same, or does it decrease so that there is a position that is too far back?
Likes For eduskator:
#3
Senior Member
Join Date: Oct 2014
Location: Portland, OR
Posts: 12,980
Bikes: (2) ti TiCycles, 2007 w/ triple and 2011 fixed, 1979 Peter Mooney, ~1983 Trek 420 now fixed and ~1973 Raleigh Carlton Competition gravel grinder
Mentioned: 131 Post(s)
Tagged: 0 Thread(s)
Quoted: 4860 Post(s)
Liked 4,005 Times
in
2,601 Posts
The effect of drafting increases as you move back in the peloton - at uniform speeds as the riders create a mass of air moving with the peloton. But, if the speed is uneven, accelerations tend to string the peloton out toward single file, that cloud effect vanishes and long after the leaders have sat up and are now resting, those at the back are still powering away at full throttle to bring the strung out line back to a peloton.
Likes For 79pmooney:
#4
Senior Member
Join Date: Mar 2006
Location: Chicago, IL, USA
Posts: 2,896
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 1466 Post(s)
Liked 1,492 Times
in
875 Posts
The problem with riding in the back of the group is that while the draft may be slightly better, the "accordion effect" is worse. Tiny changes in speed at the front get magnified as they ripple through the group, so the speed at the rear can be very inconsistent, requiring constant braking and accelerating to stay in a tight group. The rear is the worst place to be if you're struggling, because those constant little accelerations start to add up and pretty soon you're yo-yo'ing off the back and gaps start to open up.
Pro riders are also aware that the chances of being involved in a crash are significantly higher at the rear. This is part of why top teams with high placed overall riders work so hard to stay on the front.
Pro riders are also aware that the chances of being involved in a crash are significantly higher at the rear. This is part of why top teams with high placed overall riders work so hard to stay on the front.
Likes For msu2001la:
#5
I'm good to go!
Join Date: Jul 2017
Location: Mississippi
Posts: 15,224
Bikes: Tarmac Disc Comp Di2 - 2020
Mentioned: 51 Post(s)
Tagged: 0 Thread(s)
Quoted: 6330 Post(s)
Liked 4,922 Times
in
3,388 Posts
PM's (power meters) for bicycles are getting less expensive. If you ever decide to get one, then you'll see first hand how much energy you save when you ride behind another. Even just one person in front of you is quite a bit of savings. Depending on the wind speed and direction you are riding to it, you might see more than a 30% savings of energy behind that one person based on my little experience since I got a PM a few years ago.
But as for your thinking that further back is better, it's very diminishing returns soon after that third person if you are in a single file pace line.
But as for your thinking that further back is better, it's very diminishing returns soon after that third person if you are in a single file pace line.
#6
Senior Member
Join Date: Sep 2008
Posts: 785
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 483 Post(s)
Liked 282 Times
in
158 Posts
So, no. The effect isn't a bell curve, i.e., The decrease in resistance doesn't peak at 4 or 7 or whatever, then reverse. The decrease decreases at a slowly decreasing rate.
But, and it's a big but, like the guys already said, that according thing is real and wipes out any aero advantage. The back of a big peloton can be brutal.
But, and it's a big but, like the guys already said, that according thing is real and wipes out any aero advantage. The back of a big peloton can be brutal.
#8
Senior Member
Join Date: Sep 2008
Posts: 785
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 483 Post(s)
Liked 282 Times
in
158 Posts
Oh but wait... the guys in the tour are exponentially better at this. As rough as the back of a pro peloton is, we mortals have it worse. Amateurs are much worse at being smooth, anticipating lifts in the pace...
in my first road race (been riding forever), I watch several guys brake so hard they skidded. Two guys went off into the grass/field. These were separate occasions. At one point, I yelled "Guys, relax. It's a Saturday morning group ride. You've done this before." That got a few chuckles, a few "no #$&@. come on guys... " All that from the accordion.
in my first road race (been riding forever), I watch several guys brake so hard they skidded. Two guys went off into the grass/field. These were separate occasions. At one point, I yelled "Guys, relax. It's a Saturday morning group ride. You've done this before." That got a few chuckles, a few "no #$&@. come on guys... " All that from the accordion.
#9
I eat carbide.
Join Date: Jan 2006
Location: Elgin, IL
Posts: 21,627
Bikes: Lots. Van Dessel and Squid Dealer
Mentioned: 25 Post(s)
Tagged: 0 Thread(s)
Quoted: 1326 Post(s)
Liked 1,307 Times
in
560 Posts
Oh but wait... the guys in the tour are exponentially better at this. As rough as the back of a pro peloton is, we mortals have it worse. Amateurs are much worse at being smooth, anticipating lifts in the pace...
in my first road race (been riding forever), I watch several guys brake so hard they skidded. Two guys went off into the grass/field. These were separate occasions. At one point, I yelled "Guys, relax. It's a Saturday morning group ride. You've done this before." That got a few chuckles, a few "no #$&@. come on guys... " All that from the accordion.
in my first road race (been riding forever), I watch several guys brake so hard they skidded. Two guys went off into the grass/field. These were separate occasions. At one point, I yelled "Guys, relax. It's a Saturday morning group ride. You've done this before." That got a few chuckles, a few "no #$&@. come on guys... " All that from the accordion.
__________________
PSIMET Wheels, PSIMET Racing, PSIMET Neutral Race Support, and 11 Jackson Coffee
Podcast - YouTube Channel
Video about PSIMET Wheels
Podcast - YouTube Channel
Video about PSIMET Wheels
Likes For Psimet2001:
#10
Senior Member
Join Date: Jun 2021
Location: Australia
Posts: 828
Bikes: 2002 Trek 5200 (US POSTAL), 2020 Canyon Aeroad SL
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 317 Post(s)
Liked 685 Times
in
330 Posts
The image below assumes smooth, constant, and efficient riding in a professional peloton. As pointed out above, in real-life amateur conditions being so far back can be far less efficient than this.
#11
Habitual User
Join Date: Jan 2020
Location: Altadena, CA
Posts: 8,147
Bikes: 2023 Niner RLT 9 RDO, 2018 Trek Procaliber 9.9 RSL, 2018 Storck Fascenario.3 Platinum, 2003 Time VX Special Pro, 2001 Colnago VIP, 1999 Trek 9900 singlespeed, 1977 Nishiki ONP
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 5050 Post(s)
Liked 8,316 Times
in
3,927 Posts
Well...yeah. The guys at the pointy end don't see the bonehead moves happening behind them
__________________
"Swedish fish. They're protein shaped." - livedarklions
"Swedish fish. They're protein shaped." - livedarklions
Likes For Eric F:
#12
Klaatu..Verata..Necktie?
Join Date: May 2007
Location: SF Bay Area
Posts: 18,203
Bikes: Litespeed Ultimate, Ultegra; Canyon Endurace, 105; Battaglin MAX, Chorus; Bianchi 928 Veloce; Ritchey Road Logic, Dura Ace; Cannondale R500 RX100; Schwinn Circuit, Sante; Lotus Supreme, Dura Ace
Mentioned: 41 Post(s)
Tagged: 0 Thread(s)
Quoted: 10544 Post(s)
Liked 12,122 Times
in
6,206 Posts
I'd love to see the same plot but instead of percentage of solo rider's power, it would be likelihood of crashing.
__________________
"Don't take life so serious-it ain't nohow permanent."
"Everybody's gotta be somewhere." - Eccles
"Don't take life so serious-it ain't nohow permanent."
"Everybody's gotta be somewhere." - Eccles
Likes For genejockey:
#13
Senior Member
Since you don't provide a reference, I'll assume this is your work. How do you explain the 10% difference in the draft benefit between the second row rider on the left and right?
#14
Habitual User
Join Date: Jan 2020
Location: Altadena, CA
Posts: 8,147
Bikes: 2023 Niner RLT 9 RDO, 2018 Trek Procaliber 9.9 RSL, 2018 Storck Fascenario.3 Platinum, 2003 Time VX Special Pro, 2001 Colnago VIP, 1999 Trek 9900 singlespeed, 1977 Nishiki ONP
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 5050 Post(s)
Liked 8,316 Times
in
3,927 Posts
Just guessing...slight crosswind.
__________________
"Swedish fish. They're protein shaped." - livedarklions
"Swedish fish. They're protein shaped." - livedarklions
#15
Senior Member
Then you would expect the outside rider on one side to always be working harder than the equivalent one on the other side. This is not true. 2nd row right 64%, left 60% would imply wind from the right, but fourth row has right 54%, left 64% (and why is draft increasing decreasing on the left from row 2 to 4?)
Last edited by asgelle; 07-11-23 at 08:43 PM.
#16
Habitual User
Join Date: Jan 2020
Location: Altadena, CA
Posts: 8,147
Bikes: 2023 Niner RLT 9 RDO, 2018 Trek Procaliber 9.9 RSL, 2018 Storck Fascenario.3 Platinum, 2003 Time VX Special Pro, 2001 Colnago VIP, 1999 Trek 9900 singlespeed, 1977 Nishiki ONP
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 5050 Post(s)
Liked 8,316 Times
in
3,927 Posts
Then you would expect the outside rider on one side to always be working harder than the equivalent one on the other side. This is not true. 2nd row right 64%, left 60% would imply wind from the right, but fourth row has right 54%, left 64% (and why is draft increasing on the left from row 2 to 4?)
__________________
"Swedish fish. They're protein shaped." - livedarklions
"Swedish fish. They're protein shaped." - livedarklions
#17
Senior Member
Join Date: Jun 2021
Location: Australia
Posts: 828
Bikes: 2002 Trek 5200 (US POSTAL), 2020 Canyon Aeroad SL
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 317 Post(s)
Liked 685 Times
in
330 Posts
Likes For tempocyclist:
#18
Senior Member
Join Date: Jul 2009
Posts: 6,053
Bikes: Colnago, Van Dessel, Factor, Cervelo, Ritchey
Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 4009 Post(s)
Liked 7,507 Times
in
3,024 Posts
The model had all the riders with the same foot at the same position -- it creates an asymmetry.
Last edited by tomato coupe; 07-11-23 at 05:43 PM.
Likes For tempocyclist:
#20
Senior Member
I saw that after looking through the paper. Given the non-linearities, I wonder if his correction of averaging right and left side of the peloton is adequate. My issue with Blocken's work has always been he goes for volume (more riders, more cases, etc.) over depth (accuracy, margin of error, quantification of uncertainty,...). That said the results are probably more than qualitatively accurate.
#21
Senior Member
Join Date: Oct 2014
Location: Portland, OR
Posts: 12,980
Bikes: (2) ti TiCycles, 2007 w/ triple and 2011 fixed, 1979 Peter Mooney, ~1983 Trek 420 now fixed and ~1973 Raleigh Carlton Competition gravel grinder
Mentioned: 131 Post(s)
Tagged: 0 Thread(s)
Quoted: 4860 Post(s)
Liked 4,005 Times
in
2,601 Posts