The Most Effective Marginal Gain. Aerodynamics with Josh Poertner

we talk tire rolling resistance we talk drivetrain efficiency and today i'm back with josh portner for the final part of our conversation on aerodynamics this is arguably the most important marginal gain that you can make and in fact some of the speed differences that you get from making a few quick changes are so significant that i wouldn't even classify them as marginal gains they're just games josh goes into detail about how much of a difference arrow socks make aero helmets where arrow frames versus aero wheels may be more or less beneficial the most cost effective aero upgrades and more i saved the best for last in this series i hope you all enjoy your cheapest aero savings is your position and of course that can become quite high cost right you you know professional fitting especially one with uh uh you know motion capture and frontal area analysis and all that can be a lot of money but um you can really make some pretty good decisions honestly on uh you know by putting a big mirror in front of your indoor trainer and and just looking at yourself how do i make myself smaller the eyeball wind tunnel as we call it is not always right but it's often right and it's certainly i would say good at finding things that are just outright bad you know it it's hard to find that last two percent with your eyeball wind tunnel but it's certainly pretty easy to find a locked elbows or something it's like stop doing that you can tweak your position for free you know that's an easy one going up it you know it's it's funny i feel like i sound self-promoting but you know typically in thing areas where we see advantage we'll make a product and so you know for years before we made them i always said you know it's ridiculous how big a deal socks can be pretty much every pro rider i've ever put aero socks on in the wind tunnel we found lots of saving you know in some cases i mean a good pair of aero socks can be three or four times the savings of that oversized pulley setup right and so you know they're 20 to 40 for a pair of arrow socks can save you more watts than that 500 pulley system saves you um so that's another cheap one sometimes people may roll their eyes when you start talking about aero socks and i think also people roll their eyes when the uci is mandating a certain sock length but i think if they didn't do that everybody would be wearing knee-high socks because it makes that that big a difference um unless you know i mean there are more traditionalists that probably wouldn't but but maybe you could explain to people why the socks are so important just the shape of the leg and the texture on the socks why that that's making your leg more aerodynamic and and what kind of watt savings people are seeing with uh switching socks it's kind of crazy i mean it really is the dimples on the golf ball thing right so you know if i've got a starbucks cup um you know if i look at this end on you know the air is going to flow around and it's pretty much generally going to separate kind of at like 12 and 6. and so it's going to leave a wake behind the cup that's about the width of the cup if this were a cylinder or leg it's leaving a wake behind it that's about its surface area and you know that air is all turbulent and spinning and swirling and and dirty as we add some texture to that what happens is the airflow locally that's right on like the surface of the cup wants to stay adhered and so instead of separating it at 12 and 6 maybe now it separates more at like 11 and 7 and leaves a wake that big well you start to do the surface area kind of the math the simple math on that and you realize oh wow that is actually quite a bit smaller well the smarter we get with our texture and with our boundary layer we would call it tripping or turbulating the boundary layer the smarter we get with that the longer we can trick the air into holding onto that surface and the longer it holds onto the surface the smaller the wake uh behind it and you think of the socks and the height of the socks become an issue because you think of your your lower leg is actually not that unaerodynamic of a surface but you get up into like your calf with the muscle it's a terrible aerodynamic surface um and so the higher the sock the more effective uh this tripping of the boundary layer can be and so that's where and of course you know the uci doesn't want knee-high socks and quite frankly i don't want knee-high socks either i think that would just look silly we've done enough silly looking things and cycling and you know other sports triathlon to you know we don't need any more but it's a huge effect and you know it at 30 miles an hour i mean uh the best aero socks can be worth like 12 to 15 watts depending on the rider i mean it's like i remember the first time i ever saw that i was with steve smith from castelli and one of the i don't remember what team we were with now might have been might have been sky but we you know we put these things these things on and it was like 15 watts and we're just standing there in the wind tunnel like you've got to be kidding me like you know it you know i i spent years on the bandwagon of like arrows sucks please that's so stupid and then you know every time we do it it works like well okay i guess we're all going to do aerosox you know and uh and of course the challenge with the aerosox and where you know where i tried to find a spot in the market with our product was um because they're they're made from this sort of ribbed lycra material um that doesn't have a lot of compressive stiffness to it and so as soon as they get sufficiently wet or it starts raining they fall and you know i got into a bit of a pickle with with one of our teams a couple years ago we pushed hard to get the team onto speed play arrow pedals and arrows socks and we found all these amazing gains in the wind tunnel and i think we were like five or six races into the year and one of the riders had a uh a win at one of the the i would say not minor middle one of the middle ranking um kind of pre you know early season races and uh i still have the email from from the director of the writer crossing the line arms in the air one sock up one sock down and he just said like you know it's a little embarrassing um and and the writer is frustrated you know i mean he spent the last you know whatever 20 miles on a solo breakaway with a sock down around his ankle and it's catching the chainring and he's trying to pull it up and uh you know all of that and so we we've spent some time trying to develop a knit arrow sock that'll stay up and uh for that technology but yeah it's the clothing is just huge and you know another time of affordable marginal gains i mean you know clothing is expensive but spending the time to really find the fit and the brand that fits you and buying it as small as you can get it um is just huge i mean it's just huge you know think of every wrinkle in your clothing is a lot i mean maybe not literally but probably not far from it you know you think of um every single wrinkle is penalizing you in some small way and you know when you look at some of the the skin suit advances and and the the race day suit uh advances that we've seen i mean uh today's clothing can be 30 40 watts of savings over the clothing of just 10 years ago but a lot of that even if you can't afford the 800 hub you know what bike watch shop skin suit thing or buy a race or whatever you know just buying the clothing that you can afford at a size and a cut that really fits you well um can make a huge difference yeah definitely it's it's pretty amazing the thought that is going into skin suits nowadays i remember watching i think alex doucet had a video about just dedicated to his skin suit they've got different skin suits for different speeds i think he was saying that because he was doing his hour record on the track because they're turning one side of the skin suit had different texture than the other side it's pretty amazing moving on from that what what other aerodynamic gains can people get cheaply and and and once we've exhausted that what are the more expensive arrow gains that are worth it oh gosh you know what one and this is so true of drivetrain as well but a cheap aero savings um that can also be a a frictional savings is to clean your bike that sounds so so ridiculous like a dirty drivetrain can cost you six seven eight literally additional watts right and so you know you might be buying the the fastest best chain lube on the market but if you're not cleaning your bike frequently enough you can be throwing that away and the same is true with arrow you know that dust dirt build up the little wormy things that worms that stick to your down tube you know i mean all that stuff can start to penalize you and particularly dirt uh and mud buildup um over time you know it just changes the shape of the tubing and it really can affect the way the air flows around it and it's generally not in a you know i've had people joke that oh it's the you know that mud is like dimples but but it's generally not working that way and largely because it's it's usually on it's the same surfaces that are getting muddy are the surfaces that the air is uh impinging directly upon where you really want the surface to be smooth and clean and they're generally not on the parts of the surface where you actually want to like trip the airflow into turbulence and so you know just cleaning your bike can be lots of difference you know things like aero water bottles some of these newer bikes you know the 3t and the i think pinterella's got some technology bmc where you know they've really designed around the round water bottle but if you're not on one of those you know aero water bottles actually can make a really positive difference the arrow gloves like if you're going to wear gloves get the arrow ones because traditional cycling gloves are actually quite un-aero much less so than than no gloves at all and so i would look there and then as we start to get into you know spending money like so many cool things to spend money on um you know i would say for i'm saying road the wheels are generally a little more important than the frame in gravel it's the opposite because nobody's making rims that are really wide enough to truly solve the arrow challenges that the wide tires play um so an arrow frame can can you know really do you some favors there so you know think of like the the the stuff that 3t has done and a number of brands um those can make some some big savings you know the cockpit arrow flat top handlebars huge difference i mean you know some of the road testing we do a 30 mile an hour wind tunnel test a a good aero top handlebar can be 25 28 watts of savings i mean it's a shocking number uh over a round bar the hidden cable thing is a giant pain in the ass is a mechanic but it it's a huge savings you know every um every few inches of exposed cable housing or wire is is a water too um you know we talked about that on the podcast you know the the difference between the le mans finion 89 tour time trial was essentially the aerodynamic equivalent of cable housing the length of a pencil yeah it's just hard to get get your head around that but you know had had you just been able to clean up you know i mean truly had finno not had the ponytail there there's a lot of things he could have done but so many yeah i mean had he had he just worn the helmet that he had access to right had he tucked the ponytail and worn the helmet he wins the tour speaking of helmets so you know a lot of people don't like the look of an arrow helmet and obviously how much a helmet is going to benefit you is is going to be very dependent on your body shape and your head position but what do you generally see when people step up to an aero helmet in terms of savings helmets can be very dependent um you know if we're talking like true full-on time trial helmet i mean the savings can be really quite large i mean for a cost per savings that really can be one of the biggest um you know a 300 aero helmet might save you 30 or more watts over a road helmet um the aero road helmets can be quite good i mean i we've seen 12 15 watt savings on some of the uh the aero road helmets you know one of the the i think kind of dirty industry secrets is that typically cheaper helmets are more aero than the most expensive helmets because you know the most expensive helmets for so long have been so focused on like the number of vents and weight and so you know you end up with helmets that are more holes than helmet and you know the the less expensive helmets with fewer vents actually in a lot of cases end up being um you know quite arrow i i laugh at you know jiro continues to sell the air attack that lamonde wore in 90. they actually have pictures of him actually pictures of him on this bike um with that helmet and they still sell that helmet today for like 60 bucks and it's like the third most aero helmet in their line you know i think they sell it as a like a fun historical thing and you know they've whatever had the mold for all these years but yeah it it's an extremely aero helmet because it's just a simple kind of teardroppy shape and it's got you know nine vents or something so um you know and then if you really have the money to spend i mean some of these you know the i love the the laser and i think cask has one as well but the aero helmet that has like a sliding feature so you can like open and close the vent if you saw the podcast we when we worked with ronan mclaughlin on his uh everesting attempt we got him i think on the laser version of that helmet right where it was the opportunity to essentially open the vent do the climb make the turn around close the vent do the tuck uh and you know we calculate it out i mean i think on the the descents you know that um that that closing the vent on that helmet saves him you know three minutes or something over the course of his everest i mean clearly it's not gonna like get you the everesting world record but if you're at his level three minutes is three minutes it's it's non-zero yeah he he really took aerodynamics seriously he took weight savings seriously as you would expect i think when most people think of everest sting you know if they're if they're trying to shave time first thing they think of is weight but you got to turn around and you got to go back down the hill and go at a pretty high speed so aerodynamics is obviously important moving on we talked about rolling resistance drivetrain efficiency and aerodynamics that's kind of the three things that i think of when i when i think of marginal gains i think you could throw uh all the weight weenie stuff in with that but to me that's that's obvious every everybody everybody thinks of weight savings maybe to put into perspective how important would having an efficient drive train an aerodynamic bike and low rolling resistance tires be versus having you know the lightest bike you can buy you know the the climbing bike versus the aero bike of course it all depends on what you're doing you know the the lightest the truly lightest bike scenarios really only work out in pure hill climbing type scenarios you know so which you know is a thing our friends in the uk are mad for hill climbing and it's a very cool area of the sport that i really enjoy because it's just so crazy um and people have a ton of fun with that but yeah i mean generally for you know if we start off thinking flat weight really kind of doesn't matter and you know even as we start to get into rolling it starts to matter little and then you know as we get to the true climbing and elevation gain and steepness it it absolutely plays a part but working with alex doucet on his hour record you know there was some calculations done that were like well essentially we could add about five kilograms to this bike before it starts to really have an effect uh relative to some of the aero stuff you know and i mean you you we've got these beautiful computer models that you can play with and you know you can literally just keep ticking the weight up and up and up and it's like the time isn't changing um you know almost at all right you know you're having these slight effects and rolling resistance and some other things but you really want to optimize your setup for arrow and efficiency and then from that setup figure out how to make it as light as it can be without giving things up is there a gradient at which weight starts to matter more than aerodynamics the rule of thumb there is somewhere around that like seven and a half eight percent um you know it really depends uh on rider power you know that the the trade off for for like a world tour level of power is going to be a little steeper than for the rest of us because they can just go faster um up those steeper climbs but you know i would say for for most of us in our fitness it's probably somewhere between seven and and eight percent which i think is probably steeper than than most people realize i think it's steeper than where you feel like you can feel it the mental thing about weight is that we immediately when we set off from the parking lot can feel weight in the bike um generally because that starting from a dead stop is like the one of the biggest accelerations that happens when riding a bike you know when you're actually riding you know we all think like you know we can accelerate at these extreme numbers but i mean it's like fractions of a g um you know even at the the world tour level level you know launching a sprint i mean it it looks amazing in those top-down views but i mean the actual amount of acceleration is quite small compared to what you would find in motor racing or some other sports and so starting from zero though you know you push off and you get that first pedal stroke and the bike just feels like it moves under you that that's a higher acceleration than you're getting elsewhere and you think wow this feels like great and then of course we take that and we just process that through into all these other scenarios where it may or may not actually be true um but again i think it's it's what gets in your head really continues to play and affect your thinking kind of at all times in all places all right so to kind of bring everything together take your average your average club rider uh doesn't think too much about aerodynamics has a baggy jersey maybe cleans their chain occasionally uh through whatever tires the bike shop recommended on their bike what what kind of savings can can this person make if if they make all the right choices that we're we're talking about here maybe they don't go crazy uh with the spending but they just make the the sensible right uh reasonable choices it's really the the benchmark of where you're coming from you know if you're in your baggy clothes on a cannondale cad 9 with armadillos right a bike that i grew up training on we can probably on the same power input we can probably get you another couple kilometers an hour like call it two to three with the right tires the right clothes and then probably push that a little bit further if we start really investing some money in equipment um you know i'll tell you i mean you know with some of these hour record uh attempts that we've worked on and things that we've done i mean even you know at that level some of these arrow savings i mean you're talking kilometers of dist of difference um over the the course of the ride and that and that's actually coming from pretty reasonable equipment um you know i've got a calculation somewhere the camp inertz hour he probably left around 500 meters on the table through maybe four or five changes that could have been made i mean you think that that's at the the pinnacle of the sport right so i think uh you know a slightly different frame a different chain treatment some other frictional related things i won't say more than that but um but yeah to think i mean even at that level we we could find another 500 4 500 meters um is i think pretty crazy thanks for watching this is my first time doing a series of interview style videos on this channel and it's something i could see myself doing more of in the future if there's a guest that you think i should try to get on the show let me know down in the comments if you enjoyed this video be sure to give it a like subscribe and share this video with your cycling friends i'll see you in the next one

Channel: Dylan Johnson

Views: 570,662

Keywords: cycling, cycling aero, cycling aerodynamics, aero bike, how to get more aero, marginal gains, josh poertner, dylan, dylan johnson, cycling tips, power meter, cycling training, cycling wind tunnel, skinsuit, aero socks, aero gloves, aero helmet, aero frame, aero wheels, alex dowsett, factor bikes, aero handlebar, aerobars, time trial, road cycling, gravel cycling, mtb, bike racing, cycling power, aero water bottle, aero position, silca

Id: DKSIt1rprN4

Length: 20min 54sec (1254 seconds)

Published: Thu Apr 14 2022