Probable reason for half unzipped rain cape being more aerodynamic: The air fills the vest, making it a smoother and more of a round shape . Because the air can't leave the vest there is no flow through the vest, so instead the air just flows around you. So the vest filling with air doesn't act as a parachute because the air can't leave and there is no flow.
Liking that you got the probably the most aero rider to come and do the testing... Opie always looks aero when he is riding in general but it does go to show that if you just make small changes they can really add up and reinforces the message of how you are positioned on the bike really does make a huge difference. Hope that you guys get to go back into the tunnel and do a bit more testing... would be very interested to see what makes a bigger difference, position on the bike or changing components (deep section wheels/aero cockpit etc) Thanks chaps! Oh and please one day can we get Mr Boardman in... would love to see him on the channel especially since he does know a bit about the subject!
@@simedinson984 in their Beer Belly video they tought us that a camel bag in the front is vorbidden. But I really cant imagine that they have a general rule that vorbides to put your rain jacket up your front. Or is there? #askgcanything
@@Starclimber Yeah, name it something like Wahoo positioner. Sensor pads on the tops, hoods and drops that can detect where your hands are and send it to Zwift. Only 300$. Maybe steering angle hits the market first.
I also wanted to know how much helmet design changed the numbers, also helmet vs no helmet, although that might have been seen as contributing to unsafe riding?
Guys, CDA is a coefficient of drag CD multiplied by frontal area A. The video suggests that it's “Coeficient Drag Aerodynamic”. Apart from that, it's another great video!
thanks for the great video. Something i haven't seen covered is whether higher or lower cadence makes any difference to aerodynamic drag, let's say 70rpm compared to 100 rpm.
Good stuff chaps.. myth busting results there with Mr Disley. I rode with a front "Non-Aero" number at the weekend for 4.5hrs.. I had no choice but to zip-tie it across the front of the bars as per instructions from the event team.. I think it's time sportives begin using the rear mounted number like the pros. Its well Aero, looks tidy, it's smaller so saves on materials and cyclists WILL like it.. a lot! There seems no reason for the front mount at all.. no one looks at your number, other than to locate emergency contact numbers. #rearnumber .. and down off the soapbox.. 🚴🚴😀😀
Love the Video GCN. Needed to comment. 1.The unzipped jacket was faster most likely because the air that hit the chest of the rider had an exit path around the torso and out the tail of the jacket. The closed jacket spoils the air over the front and flappy jacket actively spoils all of it. The half open jacket created a 'duct' for the air to neatly pass the rider. This works in the same way on race cars. Its not always best to divert air around the body, it will provide less drag to keep the air 'clean' through a guided duct through the body. 2. I think the aero of the face is over looked in racing. This bearded clearly guided the air over the face and around the neck more efficiently. There are a lot of curves and crevasses on most people's faces and your head is the leading edge of your body in the profile. I wonder if an 'aero mask' that smooths the air over the face would create wattage gains in a similar fashion.
Maybe an aero-science video on all the contemporary frame pack, jelly-roll, attached to aero-bar, seat-post, etc. bags currently popular? Ultra-roadie (self-supported) and XC disciplines that require both a lot of on-bike gear and higher average speeds (with rider usually on aero-bars, events like the US events Trans-America as well as the Tour Divide, etc.). I think I heard one of your folks mention that a seat-post bag provides a marginal aero gain…
HAHA, thank you for starting your new aero video in front of the fatface store, you have now become my favorite presenter. :-D I realize nobody will get the joke, but it is in reference to my comment on the "Can You Ride Aero Wheels In Crosswinds?" video and I at least find it hilarious. haha
What's the gain of resting your forearms next to the stem ( as if you were using an invisible tri-bar ) in comparison to the aero-hoods position? Subjectively I can maintain a high speed more easily this way during a breakaway. Very interesting stuff, keep it coming please !
CDA: Coefficient Drag Aerodynamics is wrong, it is actually CdA: Coefficient Drag Area. This comes from the drag equation F= 1/2 * ρ* Cd * A * V^2. The wind tunnel has the known values of V, ρ and the force F so a simple rearrange can give you Cd*A. Using this wind tunnel you cannot say which type of drag, skin friction or profile drag is causing the Watts saving.
Great video! I’d really love to see a comparison with rider on board between a non-aero frame (like a Cervelo R3-R5) versus a Cervelo S3 aero bike. Identical wheels, fit, handlebars between the two bikes. With rider on board I bet you wouldn’t see much in the way of difference.
Could we see the results of a normal mid range bike along the differences between say 28, 33 and 40mm tyres (as these are the sizes often used by road, cyclocross and gravel riders and perhaps the upgrades people might do such as a bar change, or 20, 30, 40mm deep rims. Finally what difference do different helmets make and do sun glasses help aero dynamics?
@@PrzemyslawSliwinski If you are asking for commuting to and from work, I wouldn't care as I think one would rarely go over 30 km/h. And if you do go over, consider it a training for a race or gran fondo as I doubt you would need that extras for the event :)
@gcn tech, any thoughts about what is the effect of having a drafting rider behind you? intuitively, wouldn't the front rider see some efficiencies due to less drag? as in, the back rider will be facing the drag themselves and taking some of those loss wattages front the front rider, so the front rider would go actually faster if someone sits on their wheel, given same conditions of power and position?
I wonder how similar the number pinned on the front of the bike is aerodynamically equivalent to any of the many cool handlebar bags for snacks and camera stuff. Seems like it would be similar, but almost 10 watts difference is a lot.
I would be interested to know the penalty time for removing a rain cape. I.e if you are to pullover, take the rain cape off and put in your back pocket versus just unzipping it and carrying on. How long would it be before you caught up as there was a clear difference in watts. Also be useful in terms of the point in the ride. For example, If you have 5km left should I just unzip and go but if it's 15km left pull over and take it off? Any insight would appreciated.
Chris pedalling Technique Shows a lot of toe down or toe dipping. There are Tons of opinions in regard to what is "better"... Maybe worth a Closer look in a Future Episode? I myself do it like Chris, but always have that Voice in my head telling me i am doing wrong... any opinions?
The aero hoods position, is there generally a time when you want to be in this position? For instance, only in a head wind so that the wind goes over your head instead of into your chest?
I’m so glad we have yet another information-free video from gcn on aero with wind tunnels to point out the bleeding obvious that we have known since the dawn of bicycles (look at the guys on penny farthings getting into an aero tuck)
I like the number pinning hacks. Not sure that a CTT timekeeper would be impressed though. Might be one for a club event only. Just need to grow a beard now :-)=>
another suggestion for the next time: high drop from saddle to bar vs long reach. ive always wondered if its more aero to stretch out forward vs reach low. sagan and cancellara for example have/had moderate drop (10-11cm) but very long reach (62-63cm).
i would recon its mostly up to the torso angle. so you can either have a long reach with moderate drop, or short reach with bigger drop, as long as your torso has the same angle it will almost be identical.
the frontal area would be the same but the airflow on sides and back different, most likely better in a stretched than bulged position. thats why some of these ironman bikes have these "shark fins" on front and back.
i’d love to see how water bottles influence drag. i heard that a single bottle in the seat tub cage is faster than a single bottle on the down tube, but have zero wind tunnels to back that up.
Reference the beard findings, is there a case for some kind of spoiler to attach to aero helmets to fill the void between chin and shoulder. We see the clip in visor on aero helmets, could this also be applied from below to close this gap, or are there UCI regulations against this? Interesting! Ride on! Tim
Could the half zipped cape create a venturi on the rear helping with drag? And the beard made me want to try a "hairy" bike, maybe having a "bike-beard" in the right places can help.
@zurri dont see how the half zipped cape would give a venturi effect. i think the slight benefit may relate to the smoothing of the passing of the air. it would have been nice to see the use of smoke in the video to see how the air flow is affected.
When I was getting my bike fitted they told me I would be better off being on the hoods in an aero position then on the drops in one since im not as flexible
I'm getting the mental image of the "old school" BMX number plates that were like sticking a magnicently huge plastic wind catcher on the front of the bike, bigger was better. How many 80s tight finish races might've went the other way if 2nd place had used a smaller perforated number plate? I'd love to see some 40 years later rematches to settle it, though I'd imagine the riders would also have lost some aerodynamics by now :)
I ride with a Duck Dynasty beard. The only real problems are that it gets caught when I zip up my jersey, and if the ride recovery is in a windy place, the wind will blow it into my mouth when I try to eat.
The most aero bike is a rcumbent velomobile, check Saukki vid: ua-cam.com/video/7wvbVa4-Ewo/v-deo.html, at 250 W and single rider : Road bike on hoods: , 35.3 kmh ; tribike : 37.4 kmh ; SWB bent : 39.1 kmh ; low racer swb: 42.8 kmh ; low racer SWB with tailbox: 44.6 kmh ; and velomobile is typically 49.3 kmh
@@Bad_Science_Channel 45km/h is a lot... I ride at let's say 30km/h and if this function is linear, then it would be 13,4 W. Maybe that is not a lot, but quite a bit.
More wind tunnel videos please! Aero wheels vs regular wheels, tire widths on the same rim compared, aero bike vs round tube bike, etc..
Probable reason for half unzipped rain cape being more aerodynamic: The air fills the vest, making it a smoother and more of a round shape . Because the air can't leave the vest there is no flow through the vest, so instead the air just flows around you. So the vest filling with air doesn't act as a parachute because the air can't leave and there is no flow.
Calculated CdA Results
hoods (baseline) - 0.3161
Hoods Aero - 0.2210
Drops - 0.2377
tops - 0.3248
Rain jacket zipped - 0.3522
Rain jacket half zipped - 0.3440
Rain jacket fully unzipped -0.4005
beard - 0.3125
front number rectangle - 0.3398
front number wrapped - 0.3150
Back number fin shape - 0.3124
(P = 0.5*rho*CdA*v^3)
Nice job delegating the hard work to Chris while you talk to camera. Respect.
Liking that you got the probably the most aero rider to come and do the testing... Opie always looks aero when he is riding in general but it does go to show that if you just make small changes they can really add up and reinforces the message of how you are positioned on the bike really does make a huge difference. Hope that you guys get to go back into the tunnel and do a bit more testing... would be very interested to see what makes a bigger difference, position on the bike or changing components (deep section wheels/aero cockpit etc) Thanks chaps! Oh and please one day can we get Mr Boardman in... would love to see him on the channel especially since he does know a bit about the subject!
Great work GCN! This is such good content.
oh mates you haven't stuffed your rain jacket up your front. That would have been the opportunity to check your beer belly theory.
isnt that against the rules of the uci
@@simedinson984 in their Beer Belly video they tought us that a camel bag in the front is vorbidden. But I really cant imagine that they have a general rule that vorbides to put your rain jacket up your front. Or is there? #askgcanything
@@anonym7122 i thought it was for everything that filled up the jerceys front side to make you more aero
Chris and Ollie were great hires by the way! Good stuff GCN
This is cool material. Good job, thank you.
Why do I love this so much?!
Can't believe you fell for the old "merkin beard" trick, Opie.
Watching this as I ride on the trainer. As I practice the different positions my zwift avatar is not going faster.
Wouldn't it be interesting if Zwift could scan your position on the bike once per second or so, and apply aero gains or penalties accordingly?
Starclimber next level!
@@Starclimber Yeah, name it something like Wahoo positioner. Sensor pads on the tops, hoods and drops that can detect where your hands are and send it to Zwift. Only 300$. Maybe steering angle hits the market first.
Or just go out into the real world and ride your bikes!!!! 🤣
@@danielandersson3539 I think it’s spelled Positionr* 😉
That number wrap around and pin up were great hacks. Was expecting the helmet design to be included there as well in relation to watts saved.
I also wanted to know how much helmet design changed the numbers, also helmet vs no helmet, although that might have been seen as contributing to unsafe riding?
It was "free aero hacks"....
Very good video well done you 2 keep up good work.
Guys, CDA is a coefficient of drag CD multiplied by frontal area A. The video suggests that it's “Coeficient Drag Aerodynamic”. Apart from that, it's another great video!
Your best video ever.
Well this is useful! Doing my first local 10 mile TT tomorrow and just have a standard road bike, aero on the hoods it is! :D
Very interesting video. 👍
Ollie is the professor and Chris the digger! Great video GCN!
love that shark fin theory on pinning the race number!
Will keep wearing my buff based on this
Please do more videos with Xavier Disley, he is brilliant!
Im seeing Aerocoach everywhere. From cade videos to your videos
thanks for the great video. Something i haven't seen covered is whether higher or lower cadence makes any difference to aerodynamic drag, let's say 70rpm compared to 100 rpm.
So fascinating how the presenters keep looking at you via the camera. Watching GCN videos while high reveals many things........
awesome vid! Im gonna let my beard grow now
We need more
Your personal bike is awesome
38 seconds in and I already love this video :D
I wish they thought of testing handlebar bags because I use those sometimes. Still a great and informational content though!
Can you tell your buddies over at GTN to do some similar tests on a triathlon bike?
Did you also test the capron? At 95% confidence interval, what was the wattage that was statistically different?
That beard was hilarious!
CdA stands for Coefficient of Drag AREA (not Aerodynamics). It's your coefficient of drag (Cd) multiplied by your frontal area.
Good stuff chaps.. myth busting results there with Mr Disley. I rode with a front "Non-Aero" number at the weekend for 4.5hrs.. I had no choice but to zip-tie it across the front of the bars as per instructions from the event team.. I think it's time sportives begin using the rear mounted number like the pros. Its well Aero, looks tidy, it's smaller so saves on materials and cyclists WILL like it.. a lot! There seems no reason for the front mount at all.. no one looks at your number, other than to locate emergency contact numbers. #rearnumber .. and down off the soapbox.. 🚴🚴😀😀
Love the Video GCN. Needed to comment.
1.The unzipped jacket was faster most likely because the air that hit the chest of the rider had an exit path around the torso and out the tail of the jacket. The closed jacket spoils the air over the front and flappy jacket actively spoils all of it. The half open jacket created a 'duct' for the air to neatly pass the rider. This works in the same way on race cars. Its not always best to divert air around the body, it will provide less drag to keep the air 'clean' through a guided duct through the body.
2. I think the aero of the face is over looked in racing. This bearded clearly guided the air over the face and around the neck more efficiently. There are a lot of curves and crevasses on most people's faces and your head is the leading edge of your body in the profile. I wonder if an 'aero mask' that smooths the air over the face would create wattage gains in a similar fashion.
They should done more tests on beards!
I want to see numbers in few more yaw angles.
Great vid........ Just leads to the age old question....... to shave the legs or not to shave the legs (or to put some cardboard over them)
Maybe an aero-science video on all the contemporary frame pack, jelly-roll, attached to aero-bar, seat-post, etc. bags currently popular? Ultra-roadie (self-supported) and XC disciplines that require both a lot of on-bike gear and higher average speeds (with rider usually on aero-bars, events like the US events Trans-America as well as the Tour Divide, etc.). I think I heard one of your folks mention that a seat-post bag provides a marginal aero gain…
HAHA, thank you for starting your new aero video in front of the fatface store, you have now become my favorite presenter. :-D
I realize nobody will get the joke, but it is in reference to my comment on the "Can You Ride Aero Wheels In Crosswinds?" video and I at least find it hilarious. haha
What's the gain of resting your forearms next to the stem ( as if you were using an invisible tri-bar ) in comparison to the aero-hoods position? Subjectively I can maintain a high speed more easily this way during a breakaway. Very interesting stuff, keep it coming please !
Curious to know the effects of normal prescription glasses/sun glasses you'd wear daily.
CDA: Coefficient Drag Aerodynamics is wrong, it is actually CdA: Coefficient Drag Area. This comes from the drag equation F= 1/2 * ρ* Cd * A * V^2. The wind tunnel has the known values of V, ρ and the force F so a simple rearrange can give you Cd*A. Using this wind tunnel you cannot say which type of drag, skin friction or profile drag is causing the Watts saving.
The aerocoach hack is awesome !
Gonna use it everytime now.
5:30 - Whoa, hold on there professor! Rain capes keep you dry from rain?!
What about the number on the side of the torso (usually track races)?
Great video! I’d really love to see a comparison with rider on board between a non-aero frame (like a Cervelo R3-R5) versus a Cervelo S3 aero bike. Identical wheels, fit, handlebars between the two bikes. With rider on board I bet you wouldn’t see much in the way of difference.
Yeah the frame doesn't make that much difference
Aero bottles? Flat top bars? R vs disk, etc etc.
Great video. That Bell helmet though😕
Could we see the results of a normal mid range bike along the differences between say 28, 33 and 40mm tyres (as these are the sizes often used by road, cyclocross and gravel riders and perhaps the upgrades people might do such as a bar change, or 20, 30, 40mm deep rims. Finally what difference do different helmets make and do sun glasses help aero dynamics?
GCN cause a 50% rise in Beard Wax sales...
A Beard Oil company was the real sponsor of this video. #MissionAccomplished
I'm sure Óscar Pujol had already caused a boost of mustache wax sales..
Handle bar bags have to make you so mush slower than a top tube bag !
Thank you GCN, that was great content. More of that please.
I agree! I would like to see how many watts does the everyday stuff (fenders, lamps, bags, racks, wider front/rear tires, etc.) cost.
@@PrzemyslawSliwinski If you are asking for commuting to and from work, I wouldn't care as I think one would rarely go over 30 km/h. And if you do go over, consider it a training for a race or gran fondo as I doubt you would need that extras for the event :)
Now can I expect beard waxes on GCN merch shop?
@gcn tech, any thoughts about what is the effect of having a drafting rider behind you? intuitively, wouldn't the front rider see some efficiencies due to less drag? as in, the back rider will be facing the drag themselves and taking some of those loss wattages front the front rider, so the front rider would go actually faster if someone sits on their wheel, given same conditions of power and position?
I wonder how similar the number pinned on the front of the bike is aerodynamically equivalent to any of the many cool handlebar bags for snacks and camera stuff. Seems like it would be similar, but almost 10 watts difference is a lot.
When I had a road bike I lived in the drop's when I get a new road bike I'll move there again
I would be interested to know the penalty time for removing a rain cape. I.e if you are to pullover, take the rain cape off and put in your back pocket versus just unzipping it and carrying on. How long would it be before you caught up as there was a clear difference in watts. Also be useful in terms of the point in the ride. For example, If you have 5km left should I just unzip and go but if it's 15km left pull over and take it off? Any insight would appreciated.
What about a backpack for committing or transportation?
Only problem with the “aero” number wrapped round the headtube idea is that it will ruin the timing chip on some of them...
Chris pedalling Technique Shows a lot of toe down or toe dipping. There are Tons of opinions in regard to what is "better"... Maybe worth a Closer look in a Future Episode? I myself do it like Chris, but always have that Voice in my head telling me i am doing wrong... any opinions?
The aero hoods position, is there generally a time when you want to be in this position? For instance, only in a head wind so that the wind goes over your head instead of into your chest?
You didn't measure with the rain coat down the back of the jersey or in the pocket. Just assumed it would be more aero.
What were those glasses Chris was wearing?
What about bike computers, is there an optimal way to place your computer unit ? (On the stem, out in front, on the top of the handlebars, etc.)
Great stuff! Next: yeti vs fully shaved man!
yeti hahaha
Is it normal for belly strike when riding on the drops?
(1st road bike and working on losing the belly - about 10kg overweight).
Can you test wearing a buff around your neck? It's quicker to put on than a beard.
I’m so glad we have yet another information-free video from gcn on aero with wind tunnels to point out the bleeding obvious that we have known since the dawn of bicycles (look at the guys on penny farthings getting into an aero tuck)
Cool insights! Thanks for the video. Question: if aero trumps all, why do mfrs continue to make non-aero carbon road bikes?
I really wonder how a normal outfit compares here. How many watts does it take? My guess would be up to 30 watts.
I like the number pinning hacks. Not sure that a CTT timekeeper would be impressed though. Might be one for a club event only. Just need to grow a beard now :-)=>
Within 1 week, everyone is gonna go from wrinkled numbers to making fins. I’m gonna try this out
What about shaving legs for aero gains??
another suggestion for the next time: high drop from saddle to bar vs long reach. ive always wondered if its more aero to stretch out forward vs reach low. sagan and cancellara for example have/had moderate drop (10-11cm) but very long reach (62-63cm).
i would recon its mostly up to the torso angle. so you can either have a long reach with moderate drop, or short reach with bigger drop, as long as your torso has the same angle it will almost be identical.
the frontal area would be the same but the airflow on sides and back different, most likely better in a stretched than bulged position. thats why some of these ironman bikes have these "shark fins" on front and back.
What was the improvement in the Caleb Ewan position?
i’d love to see how water bottles influence drag. i heard that a single bottle in the seat tub cage is faster than a single bottle on the down tube, but have zero wind tunnels to back that up.
EDIT!
answer!
m.ua-cam.com/video/3eRtGIs7MeE/v-deo.html
Reference the beard findings, is there a case for some kind of spoiler to attach to aero helmets to fill the void between chin and shoulder. We see the clip in visor on aero helmets, could this also be applied from below to close this gap, or are there UCI regulations against this? Interesting! Ride on! Tim
Chris in that fake beard was hilarious! I thought Ollie should have taken one for the team here though
what glasses is that?
Mantap
Have to change you bike from an Orbea to OrBeard 😀
Could the half zipped cape create a venturi on the rear helping with drag?
And the beard made me want to try a "hairy" bike, maybe having a "bike-beard" in the right places can help.
@zurri dont see how the half zipped cape would give a venturi effect. i think the slight benefit may relate to the smoothing of the passing of the air. it would have been nice to see the use of smoke in the video to see how the air flow is affected.
Why didnt they do different kinds of helmets?
When I was getting my bike fitted they told me I would be better off being on the hoods in an aero position then on the drops in one since im not as flexible
At 7:58. So that's how Keemstar looks on a road bike. xD
I'm getting the mental image of the "old school" BMX number plates that were like sticking a magnicently huge plastic wind catcher on the front of the bike, bigger was better. How many 80s tight finish races might've went the other way if 2nd place had used a smaller perforated number plate? I'd love to see some 40 years later rematches to settle it, though I'd imagine the riders would also have lost some aerodynamics by now :)
... what about clothing, helmet, glasses, bottles ?
Ollie's fresh haircut gets a "super nice" *ring ring ring ring ring*
that royalty free version of grandmaster flash tho lmao
I ride with a Duck Dynasty beard. The only real problems are that it gets caught when I zip up my jersey, and if the ride recovery is in a windy place, the wind will blow it into my mouth when I try to eat.
Also... the CDA was 0.221 after the change to the drops. Not 0.221 'faster'!
Chris Opie has the smoothest pedal strokes of all the GCN presteners. Well except maybe Jon. But how would we know?
Legend has it, that Jon Cannings' pedal stroke is so smooth, small animals gather by the side of the road to watch him pass by.
I can't believe you have not measured whether shaved legs give you any advantage! :)
I wonder how much watts do we really gain with aerobike compared to good "normal" bike. 10 watts or more? I am also curious about TT bike.
Sempoo depends on the speed you are travelling. With all the testing I’ve done there’s typically 20watts difference at 45kph
20% of the drag is from the bike but usualy isnt much and 20 sounds about right
The most aero bike is a rcumbent velomobile, check Saukki vid: ua-cam.com/video/7wvbVa4-Ewo/v-deo.html, at 250 W and single rider : Road bike on hoods: , 35.3 kmh ; tribike : 37.4 kmh ; SWB bent : 39.1 kmh ; low racer swb: 42.8 kmh ; low racer SWB with tailbox: 44.6 kmh ; and velomobile is typically 49.3 kmh
@@Bad_Science_Channel 45km/h is a lot... I ride at let's say 30km/h and if this function is linear, then it would be 13,4 W. Maybe that is not a lot, but quite a bit.
@@taufikabidin412 "The most aero bike is a rcumbent velomobile" wrong channel grandpa.
What do people do on sportives? I'm slow enough as it is without increased drag.
Have fun riding with friends.
No data on the Caleb Ewan 2:28 position?
woody938 different vid! It’s coming!
Surely one should wax a beard rather than gel for maximum gains?!
I think my gut slows me down more tham any of these things.