I Wish I'd Known This Earlier About My Racing Shoes - Wind Tunnel
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- Опубликовано: 19 мар 2024
- My Giro D'Italia Stage Winning Shoes, my Hour Record shoes, Specialized's shoes, some MTB shoes and some trainers and some results that make very little sense.
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If it's all about tripping, then surely leaving them untied would be fastest. You'd be tripping all the way to the start line! :DD
did the maths. At 90rpm and with a 170mm crank, your foot is traveling at 5.8km/h (assuming your foot is the pedal). So at the top of the pedal stroke the foot is going 5.8km/h faster than the actual speed of the bike.
surely the opposite is happening to the other side of the bike, therefore offsetting this difference.
It sounds like the most aerodynamically minded decision is to not pedal at all. But a ~340mm crank would be a rational step in the middle
@@tombladon8064 drag is not lineare so that 5.8km/h increase matters more than the 5.8km/h decrease in speed. Shorter crank would be ideal purely talking about drag i think.
@@drym3943 shorter crank means more rpm for same power.
Just did the same calculations. Got 5.77 km/h. Less than you'd think
We did some CFD work on pedals and in all parts of the pedal stroke except for the short moment at bottom dead center of the pedal stroke when the foot is momentarily flat, the air around the pedal has long separated and become very turbulent so that we could not measure a difference between speedplay aero pedals and Shimano. Also, frontal area of a shoe is very dominant over other effects for drag. For trailing edge effects, though, if you transition rapidly from the "front" of the shoe to the sole, meaning the air has to bend around the shoe more quickly (especially in the arch area) the air will detatch more quickly and you will have a larger low pressure area behind the shoe, increasing drag.
The real mystery is why the Simmons carbon shoes were so poor. I suspect it may be due to the heel shape as pointed out above.
@@carlosflanders518 the Simmons shoes have tested well for riders too... There are a lot of things that feed into wind tunnel results, especially when you have a human being moving around as a part of the system. This is just one data point. It's not the final answer for all riders. Unfortunately (or fortunately depending on how you like the process) searching for the best aero setup is never-ending. You will never arrive at the early perfect solution. You just have to make the best decisions you can with imperfect information.
Get an old black lace, cut into appropriate sized portions and glue them onto the surface of your carbon shoes ( and the cover of the bonts...)... Then test again :)
Painting white laces on should also work
@@veganpottertheveganmaybe if the boa shoes identify as lace shoes they will be faster?
@@veganpotterthevegan The painted laces have to look realistic enough to fool the air.
Did you adjust the Saddle hight with every shoe? Watching the footage it seems that with the road shoes you pedal toes pointing down. Whereas with the MTB shoe, probably because the stack is higher, it's a rounder pedal stroke and less of the shoe hits the air
Really wish you did shoe covers too to test the lace theory!
I have some new specialized lace covers I could send. Afair, Spec measured 1.5w advantage over laced.
@@carlosflanders518now that's confusing.
THIS! That lace curveball really puts shoe covers in to question
Concerning the MTB shoe: maybe as the heels are lifted up moving the foot forward above the top dead center, the really bulky pedal fills out the gap of the airflow, and when using really flat pedals and aero kleats, the airflow detaches somehow and causes turbulences. Concerning the carbon shoes, they seem to have a big dent where the arch of the foot is; this may cause turbulences as the airflow does not keep attached to the shoe at that point. Perhaps if some smoke could be used to visualize the airflow over the shoes, in slow motion one could see surprising things.
Maybe the heel up pedalling style reduced the impact of the bottom of the SPD shoe and SPD pedal?
I was thinking the stack height differences, with the mtb particular, might affect pedaling style -how toe down.
The higher stack of the SPD pedals would have decreased your effective saddle height and therefore frontal area; that may contribute to why they tested fast?
I wondered the same... 🤔
it absolutely did
Empire SLX routinely tested faster than s works sub 6 / s works lace as a range of yaws, and 45 km/hr. Consensus appears to be that the ribbed nature to the upper material of the SLX adds to the tripping done by the laces...?
Where can I find more about the testing? Sounds very interesting
same,@@pierrex3226 @georgec2894 you speaking of the first empire slx or the last ones with mesh ribs like giro imperial ?
10 + years ago on Slowtwitch they said lace ups where faster
And that Bonts were slow shoes
Interesting! Wind tunnel tested or?
That was insane indeed!!! Thank you for continuously inform and educate the rest off us....
Possibly sticking something similar to laces on top of your hour record shoe to break the flow might suffice.
Something like adhesive rubber dots.
Tadej Pogacar also uses a pair of lace up shoes. Really good looking ones as well, not old school but really sleek DMT ones
Again, really interesting findings, Alex. Not sure what to do with them, apart from get lace ups next time but really interesting 😉 I’d also like to say that, after the swim hat, my next favourite thing about these videos is the “big gains” guy. Please pass on my thanks for his highly entertaining 3 second slot 😂
Big gains! 👍👍
Thank you for the content - interesting. I guess the laces create a turbulent boundary layer and thereby more aero - like skin suits with 'fancy' textured surface. How about (a) stick on a few fake lace segments on the top of the smooth carbon shoe - maybe increase the number of laces over a few runs with enough fake laces to the toe of the shoe and/or (b) cover the fancy smooth carbon shoes with textured skinsuit style fabric? The boundary layer aero improvement also applies with aero socks.
So what about placing the dials in the center, wouldn’t they act similar or even more as trips like laces?
I’d be interested to hear at the end if all this the difference between the fastest and slowest complete set ups. Maybe not the trainers but the kit people are likely to use.
Also if the tread on the mtb is cutting up their a bit more and that’s where the extra is coming from.
This misic during the B-rolls is on repeat all day in my head because this is the only piece i listen to almost everyday. 😆
uhhmm... that gives me the idea of putting something underneath my aero overshoes, like these aero baselayers / sleeves that you put under a skinsuit... with similar texture. to keep the air atttached..
Just missing the Shimano SPD sandals
Yeah that's my go-to shoe for most of my rides, especially in winter and summer. You have to test it with socks on (aero and non-aero) and then only bare foot. That thing is just super comfortable. In winter with socks and overshoes on it's actually a LOT warmer than the other shoes. Guess the overshoe forms an air pouch creating a big insulating layer. Big surprise though.
With white sock on
The test I'd like to see would be a comparison of the old bont chrono new velovetta Vs lace ups.
I find myself staggered to recognise that I was excited when the notification dropped that you’d posted and fascinated with the whole video. I guess I have to buy my “I am a cycling nerd” t-shirt now. It makes not a jot of difference at my level of riding but I was pleased the MTB pedal works (I use Shimano M-520s). And then I have to say I love boas.
Thanks for these great videos, time to rethink shoes.
🎉
I think like you said it's the trip effects of the laces
With some quick math, assuming a 173mm crank (to take an average measure) pedaling at 80rpm the tangential velocity of the pedal is 5,2kph while at 100rpm it is 6,5kph relative to the bike. To calculate the velocity of the foot in kph easily you can use my specially developed Pi-less formula V=Crank Length (in meters) x RPM x 0.377
I don't even cycle but I love your wind tunnel videos, keep it up!
Great content Alex
the custom shoes cover less of the ankle and cut in more in the arch area, that could be why not as good as you might think. Also they have a flatter profile, so the transition between top and bottom is sharper which can increase drag when direction of travel of the shoe is not perfectly aligned with airflow. But real world air flow is much more choppy than in a wind tunnel, so the differences between all of them except the trainers might be nothing at all in a real TT
On top of the SPD shoes having a high stack height you also went with the most bulkiest SPD pedals possible, that is the Garmin Rally XC pedal that has to be bulky since it has a power meter inside of it. There are super slim SPD pedals that are designed to not strike the ground when MTBing rather than those ones which would most certainly always hit the ground. Also doesn't help matters that you are comparing it to the Speedplay pedal which has one of the lowest stack heights for a pedal to begin with.
Help me understand. I think you are saying that the MTB pedals are significantly thicker and thus he should have adjusted his saddle upwards to compensate, and because he didn't the aerodynamics around his legs were different compared to other shoes?
@@FrostbikerNo, MTB pedals aren't usually this thick just this powermeter version. I'm saying he should've used the thin SPD version to minimize bias. Yes while it does impact aero drag elsewhere by raising your overall height and the whole adjustment shebang, which he did comment on, it also impacts the aero drag of the pedal since it introduces a profile to the wind so if you're looking for those gains comparison it would make sense to use a slimmer pedal body that won't introduce that aero drag to the wind.
The mtb shoe/pedal combo was not as surprising as one might think. If you pedal even remotely 'toes down', the messy bits are hidden from the wind. If you drop your heel through the forward part of the crank rotation, then you'd see a much bigger difference with those shoes. The same applies to the Speedplay/Wahoo aero pedals, depending on one's foot orientation, you may see no benefit at all, or you'll see a little.
I would have loved to see the BOAs + Aero covers vs laces vs laces + lace covers. I guess the laces would be fastest, but I'm curious if aero covers over the BOAs would close the gap. Also curious if the Specialized lace covers they sell would make the shoe faster or slower.
Alex's heel is up a fair bit when peddling. I bet if was more heel down through the pedal stroke the speedplay would give more gains.
@Alex Dowsett Did you adjust saddle height with the mtb shoes? If not, the rest of your body would have been a bit tighter and with less frontal area (higher stack height). That would be faster in the wind tunnel, but not on the road, because of the wrong working angles.
I didn’t, and I think I mentioned either in this vid or the earlier one on shoes that that was a caveat to the test. If I raised saddle height I’d have had to raise handlebar height by 5mm or so as well and thats wires, cables and all sorts. I think i was confident that laces do a lot of good, and the underside isn’t as important as we thought in conclusion. ☺️
@@AlexDowsettOfficial Sure, I just wanted to know. And I didn't mean to criticise. Great tests with really interesting results.
For people who point their toes downward the underside of the shoes doesn't make a difference. Heel droppers might have more of an advantage with your streamlined speedplays.
Laces might cause controlled turbulence, which, with foot angles changing all the time, could generate a bit of an advantage here.
Have you tested any shoes with Velcro fastener? I am currently using pretty cheap ones from Shimano and I am wondering how it would compare to laces.
How about adding in some Nopinz overshoes?
so does that mean having aero over shoe covers could also have a negative effect on cda; this data suggests that to be the case, easy to test Alex.
With cranks 170mm and cadence 85rpm (seems like that could be a typical setup): angular velocity will be around 5.4/5.5 km/h. That means if bike speed is 55kmh - that will 60.5kmh
Are we assuming the shoe is used WITHOUT a shoe cover, thus negating the laces being trips? Or are we now using tall/aero socks, and bare shoe, so the laces are exposed? I have been using lace shoes for TT for a couple seasons, but so I could more easily get my shoe covers on and off easier. The Boas were snagging and making the process take way too long.
It took you a while to get to the word, but the "trip" effect of the laces was my first thought as well. Conversely, I think the Boa dial has a negative effect because it is TOO pronounced on the surfaces.
Separately, if a change in the stack height had a positive effect on your Cda, seems as though you might want to investigate your position? I'm not saying that like I am a bike fitter (I am certainly not), but you've got the data right in front of you to show it's worth investigating.
I would be very interested in knowing more about "sampling variation" in aero wind tunnel testing. That is: If you repeat (what is meant to be) the same setup multiple times, how consistent are the results? If that error is significant relative to the difference between products, that would matter very much for interpreting the differences between type of shoe.
I have Specialized Sub 6 with laces and it came with shoe covers to make them even more faster. So now I'm wondering if they are faster with covers or that your theory is right and the laces brake the wind. In that case I'm curious which lacing pattern is the fastest: criss-cross lacing or a parallel pattern like on your shoes. Maybe something for your next testings in the wind tunnel. :)
I wish someone would aero test the DMT krsl (pogacar shoes). They are lace up but they also have a textured surface with raised stripes running down the sides of them. Simmons has made many lace up shoes before, bradley wiggns had a pair for his hour record, but perhaps you could glue on some turbulators along the top of the shoe and see if that makes them as aerodynamic as the lace up shoes or even faster which would confirm that tripping the air over on the top is the key to a fast cycling shoe. The laces tripping the air may also be the reason why some people test faster without overshoes on when you'd usually think overshoes are always faster.
Very silly idea but … what about adding something like “laces” features to the aero helmets :) if they make shoe laces faster than very clean lined shoes they might just the same do helmets :)
Good job. J’ai aussi remarqué dans ma petite soufflerie faite maison que les lacets sont plus rapide que les boa
Did you also test overshoes?
I would think that the width of the bont shoes would be the cause of the drag. I have a pair in wide (which is what I need for my feet) and they are visibly wider than my giros. Bummer that I just spent all this money on the bonts...
What is the difference between pedaling and not pedaling (clipped in, just not turning the crank)? What about different stationary crank positions?
back of the shoe is most important for the aerodynamics of shoes, not laces or boa
What would happen if you put overshoes on for all of them?
Good thing that Bont just started making Vaypor Lace...
I hope we see shoes with really long tails, soon. None of those Kamm tail shoes.
Wow!
Probably like the wave shape on rims, the laces are doing a similar effect with the wind. Very interesting results.
Wave shapes aren't faster. I thought they were, then upon investigation, I couldn't find any claim that it's faster. Princeton carbonworks doesn't claim it's faster for example
Then why do it? @@pierrex3226
Watching in 0.25x speed, and without taking screenshots and tracing angles, it seems, somewhat, that the sworks are kept more horizontal vs the custom shoe especially, at the top of the stroke, looks more vertical? With an ankle narrower than a foot, are some of the differences due to shoe angles? I might be imagining things.
How bout an aero foil shaped bottom of sole? Thats gotta be faster lol. It likely can be made within any uci regulations too.
What about velcro?
You have the high pressure zone on the top surface of the shoe. You don't need a trip, it's the other surface, the bottom where you do. That's why that bottom positioned boa is complete shit, and the side boas are slower.
You should try a conplete knit upper like a DMT KR0 for comparison.
The laces are put on the high pressure zone region for the same reason why aviation puts all the draggy stuff there. It has less overall pressure impact
Did you have to adjust anything else due to differing stack heights on each shoe?
And literally as
stick on tape “laces”?
It’s very hard to take the results with much utility because saddle height/foot shape through the pedal stroke wasn’t controlled through the test. I have to imagine that it’s going to have effects on the results.
it would've been great to also have included a set of shoes with velcro fasteners
The difference is probably the stack height? 1cm would make your leg more bent and present less of a straight cylinder to the wind
Try red laces!
How about any shoes with overshoes?
ok, what should we do as a triathletes? its impossible to jump on the bike with the lace shoes ((
Elastic laces?
Simmonds with horizontal ridges added in lieu of laces.
Do holes in your socks do anything for aerodynamics?😂
Missed a trick not having the Shimano TR9 for us Tri guys 😢
Need to do gloves vs no gloves as well. Maybe I just haven’t got round to watching that video yet though ???
How does cadence affect things? I know you did the aero of cadence at the start but does a cadence of 30 at 200w equal.the same as 100w at 60 rpm? Or is it not as linear as that, excluding aero?
It definitely isn’t as linear as that, they’re separate things. 200w is 200w whether you’re doing 150rpm or 10 👌
Commenting having just gotten to the results summary, and not watched whatever reasoning later.... So laces are aero? Tripping the flow? And the pedal smoothness (or lack of) doesn't matter cause with any kind of heel up pedal stroke it's all angled so it's the top of the shoe hitting the airflow and the pedal is hidden behind?
Indeed, the fatter MTB pedal might be filling in more of the low-pressure behind the shoe, and /aiding/ the aerodynamics that way (the way Dylan Johnson found that bottles in jersey pockets or even a bladder back-pack had an aero benefit)?
Guess we're all buying laces now 🤣
Aero is the quantum mechanics of cycling. As Richard Feynman famously said, "No one understands quantum dynamics."
Can you put a photo of a close up of the laces? Did you just tuck them in on the front of your foot?
How about Bont Vaypor T? Laces and a strap?
Everyone wears overshoes though, so you need to do this again with overshoes on plz 😀
Lace shoes with aero socks VS lace shoes with overshoes. Which one should be the fastest? Thats what i want to know :)
You do seem to move your ankle/foot quite a bit and also have a fairly toe down position, which perhaps removes any value from your 'aero' pedals ...
Will Alex be totally transparent and test with Nopinz overshoes on laces shoes and risk overshoe sales??????
Well to start with the vast majority of people don't use lace shoes. These sleeves probably help at least boas and straps shoes.
At some point in future I will, these were NoPinz hypersonic aero socks so we have that ☺️ it has got me thinking about overal overshoe construction and we’re going to work on some prototypes with NoPinz off the back of this.
and now pls with overshoes :)
First due to low CDA thanks to these videos.
Pi in the Sky / Ineos.
Prioritize fit, 2nd go laces
The case when you could spent thousands of dollars on cycling shoes, but can`t find 2 dollars for a new pair of socks. Should have tried them for aerodinamics, may be they are even more efficient 🤣
I today realised tadej pogacar never seems to wear oversocks in a race even if the weather is SHIT. maybe his signature shoes are secretly aero. They have laces and ribs down the side of them similar to aero fabric. Conspiracy or truth??????????
Hot glue or 3D pen and fake some laces. Non-destructive trip-layer...
If your socks cover your big toe, that is also a marginal gain. Not for aerodynamics, just got everyone else
Please replace those socks, dear god those socks are long past its lifespan.
LIES!! LIES, I TELL YOU!! BONTS ARE BEST!! 😢😭😭😭 UNFOLLOW!! UNFOLLOW!! 😜