Should you draft on a climb? Uphill drafting Science!

No video

Should you draft on a climb? Uphill drafting Science!

Рет қаралды 15,134

FastFitnessTips: Cycling Science!

Күн бұрын

Пікірлер: 38

@dpstrial 5 жыл бұрын

Good analysis. I was paced up a fairly long hill by a good climber 25 years my junior. Sheer motivation kept me on his wheel all the way to the top. I got some more satisfaction at the top, finding out I could sprint far better than he could.

@carlosgomezzzzzzz 5 жыл бұрын

I think of climbing drafting being more like moral or mental drafting, to be more motivational than about actual aerodinamics

@samzagato 5 жыл бұрын

Interesting stuff because, as a triathlete and occasional race referee, I didn't really reckon that the drafting rules should be so strictly applied on the uphill sections of hilly courses. While I never draft when racing I will be less lenient as a draft-buster having watched your presentation- thank you!

@raphaeltiziani7476 5 жыл бұрын

I bet team Sky made those calculation already years ago :D Great video as always. I find the psychological effect tremendous. You just dont want to loose the rear wheel of the next rider. Of course if I can do 300 W for an hour and the other guy 380 its impossible but yes it helps.

@nielsbrand291 5 жыл бұрын

Well thank you for the extensive analysis, Was not expecting gains over a minute for alpe d'Huez! Now i know why my PR on Alpe d' Zwift from last week's TDZ was substantially faster, finished 6th and was only overtaking people (and they hanging on/taking turns) the entire way

@rzeckner 5 жыл бұрын

Thank you for the great information. I am glad to know that I was actually benefiting from drafting more during my ride during the tour of Zwift Alpe stage event last weekend than your Ed Laverack. That said, I still wish I could ride as impressively as he does; wow!. The finding regarding the importance of motivation brings to mind a quote from the iconic American baseball star from the 50's and 60's, Yogi Berra, who said, "Baseball is ninety percent mental and the other half is physical".

@michaelglidewell1524 5 жыл бұрын

In your analysis you held the wattage constant so motivation is not a factor. What's interesting is not only does the rider in the draft go up faster at the same wattage than they would have alone but that they use less energy overall (energy = power x time) to complete the climb. It would be interesting to redo this analysis holding energy constant. The issue, of course, is that a rider can hold for say 10 minutes is virtually identical for 9 minutes, so this would only be valid for slight increases in power.

@cypriano8763 4 жыл бұрын

LR has a good video explaining the sky train strategy for riding to watts to bring back attacks. its all about using teamates to draft to save watts till the very last part of climbs. great video FFT

@crazytrutas 5 жыл бұрын

Great stuff once again Alex. Thanks for your efforts. 👍

@andrewdeck7945 5 жыл бұрын

An eye opening video! Thank you!

@makantahi3731 2 жыл бұрын

btw: leading rider is slower when somebody drafts behind because , drafted rider takes opposite air circulation that would push leading rider, so leading rider will have less "tail wind" because drafted rider takes it

@makantahi3731 2 жыл бұрын

somebody sometimes said : race (tour/giro/vuelta) wins the least tired rider

@makantahi3731 2 жыл бұрын

13:00 you talk about force when talk velocity squared, but more important is power of drag/climb /rider and it is velocity on third , so double speed 4 times more drag force, 8 times more power needed,

@krisbowditch827 5 жыл бұрын

Brilliant video, enjoyed the information 👍👍👍💪💪💪🚴‍♂️🚴‍♂️🚴‍♂️🚴‍♂️

@HECTORBIDO 5 жыл бұрын

Great. Science facts Very helpful

@michaelmartin2172 5 жыл бұрын

Impressive analysis. does the rider on the front of the chaingang get any draft benefit when going uphill at say 20kph due to being followed closely?

@Fastfitnesstips 5 жыл бұрын

Hi, yes there is a very small aero benefit of being closely followed and our calculator does estimate this (put 0 in front, 5 behind). This effect is smaller when going slower and during climbs but not zero. However there is probably a large psychological effect of being followed although no one has measured this.

@karstenmeinders4844 5 жыл бұрын

Watching all this Zwift footage, I wonder how drafting can be trained on the turbo trainer... :-)

@thestopper5165 5 жыл бұрын

In Zwift it's easy: you get screen prompts when you're approaching a draught, and if you're at risk of dropping out of a draught. As the distance between you and the draught-able rider drops to ~3m, drop your W/kg to about 0.5W/kg lower than the guy you'll be draughting (assuming he's travelling fast enough to be worth draughting). It took me *ages* to work out how to 'ease' into the draught - but then again I almost never ride on Zwift to 'race'... I am only on there to try to get fitter. I did race once, and was *terrible* at draughting - mostly because I didn't really 'get' how much of a difference it makes so I wasn't focusing on draughting. (Also...regarding how to approach a draughtable position: I didn't "work out" how to do it, so much as read about how it worked). I've been practicing draughting recently, and it makes a noticeable difference to trainer difficulty (I have a KickR that gets feedback from the system and adjusts resistance). It's worth several seconds a lap even on short courses like Watopia Flat.

@forloop7713 5 жыл бұрын

I could bet you forgot to take into account the trail of air with a lesser concentration of oxygen left behind the front rider

@markgreenwood9343 3 жыл бұрын

Great video, love the application of science to cycling. I have a puzzling question for you on aerodynamics. If I am riding an out-and-back flat TT, what will be faster, either 1) a perfectly still day, no wind, or 2) a cross wind? Another way of asking this question is whether there is any evidence of a sail effect which reduces the CdA when there is a yaw angle? FYI, bestbikesplit.com model a lower CdA for segments with yaw angle, but I haven’t found any science to corroborate this. Interested in your thoughts.

@Fastfitnesstips 3 жыл бұрын

Thanks Mark, appreciate the feedback. Zero wind is always faster in a loop or out and back (sail effect in cycling is a myth): see www.cyclingapps.net/blog/how-to-pace-into-the-wind/ there is a calculator link on this page too

@markgreenwood9343 3 жыл бұрын

@@Fastfitnesstips Thanks for the article. I understand and agree that a head/tailwind on an out and back TT will be slower than no wind because the gain with the tail will never make up for the loss of a headwind, which is because the aero resistance is proportionate to the cubic of velocity. However, my specific example is an out-and-back TT with a perfect cross wind, meaning at constant power the out-velocity will be the same as the back-velocity. And as you say yourself in this article “the last reason is that aero components often perform best at +/-15deg”. Aero testing of disc wheels in isolation shows a sail effect. If that sail effect extends to the rider/bike combination then it may be possible. bestbikesplit.com will use a lower CdA for the cyclist when there is a yaw angle, which therefore predicts a faster TT time when there is a perfect cross wind in an out and back TT. I’m just trying to find any literature or studies that support this, and I thought you might know. Thanks again for your thoughts.

@Fastfitnesstips 3 жыл бұрын

@@markgreenwood9343 Yes this is a head scratcher! Swissside claim a sail (push) effect is possible only for a front wheel on the bike but not for the system as a whole...so any tiny "sail gains" are dwarfed by system losses. But this old 2014 article claims an optimal sidewind *is faster* www.codybeals.com/2014/08/crosswind-friend-or-foe-asktrinerd_32/ but I disagree. If you had a perfect 90deg wind, with no blustery variation then frontal component falls to zero (no gain or loss) but this is pretty much impossible in the real world and would negatively affect handling. Let's take a 15deg yaw wind at 15kph at a bike speed of 35kph. To maintain that on the bike on the outleg would take roughly 336w and on the return 245w (fft.tips/wind) averaging 290w but zero wind would average 287w....so there is (by my calculation) a net loss of 3w *but this is greater in real life* because here watts are constrained and speed is not; therefore there is increased time spent on the outleg into the wind. This is dependent on the course length (roughly 10% slower vs 3% faster or 3:1) which means on a hr course, the actual loss would be closer to 26w IRL (calc is =((335.7-287)*3+(245-287))/4). Bottom line, I stick with my answer that zero wind is best! If you have data to refute this let me know!

@SteveHofsaess 4 жыл бұрын

Great Video,, I am doing a Fondo this Sunday with 8500 feet of climbing and I need all the help I can get. Is it better to ride up with a slower group or go solo and look for the next group which may be faster

@Fastfitnesstips 4 жыл бұрын

Its better to ride with the pack unless the climb is of sufficient grade that "you can forget about aero" on this calculator (fft.tips/climb). Even then riding in the pack is usual best in a long ride, because if you break away on the climb, what will happen on the descent and flat?

@Advcrazy 5 жыл бұрын

Does Zwift estimate draft savings on climbs as accurately?

@Fastfitnesstips 5 жыл бұрын

Good question....we have backwards-calculated from 1000 zwift riders that it is about 6.5% speed difference using #doubledraft and 3% using normal draft on climbs vs solo.

@Advcrazy 5 жыл бұрын

FastFitnessTips: Cycling Science! Awesome!! Nice work and thanks for the info!! I’ve already shared the video with my club mates!

@dupondavignon869 4 жыл бұрын

7:34 : I think your model is not only wrong. It's totally absurd, for anyone who has ever ride a bike outdoor. 400w for 37.7km/h solo, really? I can go 40km/h relatively "easily", and no way I could push, for that long, the 470w required that your model supposes. Here are sportech.online.fr/sptc_idx.php?pge=spfr_esy.html MUCH more realistic numbers, which fit perfectly with what I can experience IRL (weight 64kg, equipment weight 9kg, wind nil, friction 0.0026, rolling 0.007, hands on the hood aerodynamic 0.35; on the drops 0.3). Watts needed on the hoods/on the drops : 44km/h = -/396w 42km/h = 397/-w 40km/h = 348/307w 37.7km/h = 298/263w 30km/h = 165/148w (that's why I know zwifters are cheaters in majority in group rides, even endurance group ones, since, when I push 2.6w/kg, only competitive cyclists could be able to stay in z2. 30km/h in z2 IRL on flat road alone, hands on the hoods, not much can do that, and certainly not all the profiles I can check ingame). On the field confirmation : kzfaq.info/get/bejne/o8t4gtuDyrazm2w.html He pushes about 300w, and goes about 24 miles/h (39km/h) with a 3/4 head win, so the model just above could even be under reality (but I trust more the model, since it fits better to my own experience), and you could push less watts in reality for the same speed (the GCN experience could be in a slight descent to explain that).

@bobmajew53 5 жыл бұрын

Whatever you can do to be faster. But just don't draft me because I don't tolerate it. Rarely with an excellent Rider it's fine but normally the riders have inferior brakes and I'm scared they're going to plow into me. The skill level required for this is beyond the average Rider, and on the street most don't possess it.

@danielweatherspoon2642 5 жыл бұрын

Steady on Lance! Its talking about uphill

@hambernat6444 3 жыл бұрын

Even more difficult is when your ass is screaming to the gates of hell...

@janeztomazic5546 3 жыл бұрын

400watts FTP a semi pro ? come on he he

@Fastfitnesstips 5 жыл бұрын

For the 4th time, this video has now been copied by GCN with absolutely no thanks or mention. Flattery without due credit or underhand behaviour from play sports network? kzfaq.info/get/bejne/fuCUfKiL2payc4k.html

@mhchen6868 5 жыл бұрын

sorry...but the background music is too loud...barely cannot hear the voice clearly...

@Fastfitnesstips 5 жыл бұрын

apologies, volume down, subtitle on?

@mhchen6868 5 жыл бұрын

@@Fastfitnesstips subtitle works well, but I'm trying to practicing my listening skill by your videos, so...I apologize for complaining this kind of little thing. BTW, your videos help me a lot on cycling.