 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 gains. Josh goes into detail about how much of a difference aero socks make, aero helmets, where aero 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 know, professional fitting, especially one with a, you know, motion capture and frontal area analysis and all that can be a lot of money. But you can really make some pretty good decisions honestly, you know, by putting a big mirror in front of your indoor trainer 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's hard to find that last 2% 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's funny, I feel like I sound self-promoting, but typically in 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 aerosocks on in the wind tunnel, we found watts of saving. You know, and in some cases, I mean, a good pair of aerosocks 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 aerosocks can save you more watts than that $500 pulley system saves you. So that's another cheap one. Sometimes people may roll their eyes when you start talking about aerosocks. 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 big a difference. Unless, you know, I mean, there are more traditionalists that probably wouldn't, 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's making your leg more aerodynamic and what kind of watt savings people are seeing with 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, you know, if I look at this end on, you know, the air is gonna flow around and it's pretty much generally gonna separate kind of at like 12 and six. And so it's gonna leave a wake behind the cup that's about the width of the cup. If this were a cylinder or a 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 dirty. As we add some texture to that, what happens is that 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 six, maybe now it separates more at like 11 and seven 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 turbo-lating the boundary layer, the smarter we get with that, the longer we can trick the air into holding on to that surface. And the longer it holds onto the surface, the smaller the wake behind it. And you think of the socks and the height of the socks become an issue because you think of your lower leg is actually not that unerodynamic of a surface, but you get up into like your calf with the muscle and it's a terrible aerodynamic surface. And so the higher the sock, the more effective 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 in cycling and other sports, triathlon to, you know, we don't need anymore. But it's a huge effect. And, you know, at 30 miles an hour, I mean, 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 even remember what team we were with now. It might have been, it might have been Sky. But we put 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, I spent years on the bandwagon of like aero socks, please, that's so stupid. And then, you know, every time we do it, it works. And like, well, okay, I guess we're all gonna do aero socks, you know? And of course the challenge with the aero socks and where I tried to find a spot in the market with our product was, because they're made from this sort of ribbed Lycra material 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 one of our teams a couple of years ago. We pushed hard to get the team on to speed play aero pedals and aero 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 win at one of the, I would say not minor, middle, one of the middle ranking kind of early season races. And I still have the email from the director of the rider 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. And the riders 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 chain ring and he's trying to pull it up and, you know, all of that. And so we've spent some time trying to develop a knit aero sock that'll stay up for that technology. But yeah, the clothing is just huge. And, you know, another type 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 is just huge. I mean, it's just huge. You know, think of every wrinkle in your clothing is a lot. I mean, they're maybe not literally, but probably not far from it. You know, you think of every single wrinkle is penalizing you in some small way. And, you know, you look at some of the skin suit advances and the race day suit advances that we've seen. I mean, 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, watt bike, watt shop, skin suit thing, or bi-racer, whatever, you know, just buying the clothing that you can afford at a size and a cut that really fits you well can make a huge difference. Yeah, definitely. It's pretty amazing the thought that is going into skin suits nowadays. I remember watching, I think Alex Dowsett had a video that's 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 other aerodynamic gains can people get cheaply? And once we've exhausted that, what are the more expensive aerogains that are worth it? Oh, gosh, you know, one, and this is so true of drivetrain as well, but a cheap aero savings that can also be 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 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 aero. You know, that dust, dirt buildup, the little wormy things, the worms that stick to your down tube. You know, I mean, all that stuff can start to penalize you and particularly dirt and mud buildup 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 it's generally not working that way. And largely because it's usually on, it's the same surfaces that are getting muddy are the surfaces that the air is 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 wanna 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 I think Pinarello's got some technology, BMC, where, you know, they've really designed a round, 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 aero gloves, like if you're gonna wear gloves, get the aero ones because traditional cycling gloves are actually quite on aero, much less so 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, you know, I would say for, as 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 aero challenges that the wide tires play. So an aero frame can, you know, really do you some favors there. So, you know, I think of like the stuff that 3T has done and a number of brands, those can make some big savings. You know, the cockpit, aero, flat top handlebars, huge difference. I mean, you know, some of the road testing we do, you know, 30 mile an hour wind tunnel test, a good aero top handlebar can be 25, 28 watts of savings. I mean, it's a shocking number over a round bar. The hidden cable thing is a giant pain in the ass as a mechanic, but it's a huge savings. You know, every few inches of exposed cable housing or wire is a water too. You know, we talked about that on the podcast, you know, the difference between the Le Mans, Fignon 89 tour time trial was essentially the aerodynamic equivalent of a cable housing the length of a pencil. Yeah. It's just hard to get your head around that, but you know, had you just been able to clean up, you know, I mean, truly had Fignon not had the ponytail. There's a lot of things he could have done, but. So many, yeah. I mean, 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 aero helmet and obviously how much a helmet is gonna benefit you is gonna 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. 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, you know, a $300 aero helmet might save you 30 or more watts over a road helmet. The aero road helmets can be quite good. I mean, we've seen 12, 15 watt savings on some of the aero road helmets. You know, one of 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 had 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 less expensive helmets with fewer vents actually, in a lot of cases, end up being, you know, quite aero. I laugh at, you know, Giro continues to sell the air attack that LeMond wore in 90. I think I actually have pictures of him, I actually have pictures of him on this bike 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's an extremely aero helmet because it's just a simple kind of teardrop-y shape. And it's got, you know, nine vents or something. So, you know, and then if you really have the money to spend, I mean, some of these, you know, the, I love the laser. And I think Cask has one as well. But the aero helmet that has like a sliding feature, so you can kind of like open and close the vent. If you saw the podcast, when we worked with Ronan McLaughlin on his 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 turnaround, close the vent, do the tuck. And, you know, we calculated out, I mean, I think on the descents, you know, that closing the vent on that helmet saves him, you know, three minutes or something over the course of his Everesting. 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 non-zero. Yeah, he really took aerodynamics seriously. He took weight savings seriously, as you would expect. I think when most people think of Everesting, you know, if they're trying to shave time, first thing they think of is weight. But you gotta turn around and you gotta 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 think of marginal gains, I think you could throw all the weight-weaning stuff in with that, but to me, that's obvious. Everybody thinks of weight savings. Maybe to put into perspective, how important would having an efficient drivetrain, an aerodynamic bike, and low rolling resistance, tires be versus having the lightest bike you can buy? You know, the climbing bike versus the aero bike. Of course, it all depends on what you're doing. You know, the truly lightest bike scenarios really only work out in pure hill climbing-type scenarios. 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. 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 absolutely plays a part. But working with Alex Dowsett 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 relative to some of the aero stuff, you know? And I mean, 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. 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 aero 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. You know, it really depends on rider power. You know, the trade-off for like a world tour level of power is gonna be a little steeper than for the rest of us, because they can just go faster up those steeper climbs. But you know, I would say for most of us in our fitness, it's probably somewhere between seven and eight percent. Which I think is probably steeper 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. Generally, because that starting from a dead stop is like 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. You know, even at the world tour level, you know, launching a sprint, I mean, 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'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. But again, I think it's what gets in your head really continues to play and affect your thinking kind of at all times and all places. All right, so to kind of bring everything together, take your average club rider, doesn't think too much about aerodynamics, has a baggy jersey, maybe cleans their chain occasionally through whatever tires the bike shop recommended on their bike, what kind of savings can this person make if they make all the right choices that we're talking about here? Maybe they don't go crazy with the spending, but they just make the sensible, right, reasonable choices. It's really the benchmark of where you're coming from. You know, if you're in, yeah, 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. You know, I'll tell you, I mean, you know, with some of these hour record attempts that we've worked on and things that we've done, I mean, even at that level, some of these aerosavings, I mean, you're talking kilometers of difference over the course of the ride and that's actually coming from pretty reasonable equipment. You know, I've got a calculation somewhere, the Campanerts 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's the pinnacle of the sport, right? So I think a slightly different frame, a different chain treatment, some other frictional related things. I won't say more than that. But yeah, to think, I mean, even at that level, we could find another 400, 500 meters 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.