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WIND TUNNEL SECRETS FOR AERO GAINS ON YOUR BIKE | ROADMAN PODCAST

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15:36·15 June 2023

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KEY TAKEAWAYS

Josh Poertner's biggest free-speed lever: get rid of the round handlebar. Aero-shaped bars buy 20-30W at race speed and round bars are the worst possible default.
Hood-in position works because it forces elbows in too. Poertner teaches it as: hands here, forearm in contact with the bar — not elbows flared. The bar shape is the enforcement mechanism.
The 70s had this figured out. 35-38cm bars were normal. The 90s widened bars and we lost the trick. Now narrow is back.
Wind-tunnel testing with EF this year found ~30W of savings at 45kph just from upper-body position. Long and narrow beats low and long.
Saddle aero gains exist but most don't survive the comfort test. A 3W aero saddle you can't sit on for five hours is useless at WorldTour level.

TOPICS

CYCLING FOR TRIATHLETES

Josh from Silca joins us to dive deep into the aerodynamic secrets that pro cyclists use to gain free speed on the road. We're talking handlebar shapes, saddle design, body positioning, and the often-overlooked fact that the rider's body accounts for about 80% of drag — meaning small changes to how you sit on the bike can unlock massive watts of savings.

Key Takeaways

Handlebar aerodynamics matter hugely: switching from a round bar to an aero cross-section can save 20-30 watts, and narrower bars (35-38cm) are faster than the wider bars that became standard in the 90s
Turned-in hoods force a more efficient riding position by naturally keeping elbows in and hands narrower, which is why you're seeing younger pros adopt this technique on the road
Body position trumps bike components: the rider makes up roughly 80% of drag, so positional gains and clothing/helmet choices deliver far more watts than tweaking rim shapes or spoke counts
Saddle aerodynamics exist but comfort is the real limiter — even a 3-4 watt gain means nothing if you can't sit on it for five hours during a stage race
UCI regulations are holding back innovation: changes like narrower Q-factors, longer/steeper frames, and nose-to-BB saddle rules could unlock more aerodynamic gains if the rules were relaxed
Wax-based chain lube is the next frontier for everyday cyclists, and Silca's new chain stripper removes the biggest barrier to adoption by making the setup process fast and simple

Expert Quotes

"You should never ever ever be riding around a handlebar. It's the worst of all the possibilities — it's more pressure on your hands, less vertical deflection for comfort, and significantly less aero."

"We had this secret in the 70s and then we kind of lost it. It was really only in the 90s that bars started to get wide again — and now we're finding it again."

"The human on the bicycle is 80% of the drag. We can find tons of marginal gains around spokes and rim shapes, but that's all just playing within that 20%. The real gains are in the body, clothing, helmet, and position."

CLAIMS FROM THIS EPISODE

Each tagged with the strength of evidence behind it.

STUDY
Switching from a round handlebar to an aero-cross-section handlebar saves approximately 20-30 watts at race speed — Josh Poertner's wind tunnel data covering multiple manufacturers and athletes.
Source: Josh Poertner, CEO of Silca, on the Roadman Cycling Podcast
EXPERT
Hood-in (rotated inward) handlebar position improves rider aerodynamics primarily by mechanically forcing the rider's elbows inward — the bar shape acts as a position-enforcement device, not an aero shape itself.
Source: Josh Poertner wind tunnel coaching practice
STUDY
Modern WorldTour aero optimisation (working with EF Education-EasyPost this season) has identified approximately 30 watts of savings at 45kph from rider position changes alone — independent of equipment changes.
Source: Silca / EF Education-EasyPost wind tunnel testing
ANECDOTE
Pre-1990s pro cycling used 35-38cm handlebars as standard, and the widening trend of the 1990s reversed an aerodynamic optimisation that the sport had previously discovered and lost — current narrow-bar adoption is rediscovery, not innovation.
Source: Josh Poertner historical observation
EXPERT
Aero saddles claiming 3-watt or larger savings are typically compromised by removing the hammock-style suspension that allows comfortable multi-hour use, making them unsuitable for stage-race or long-distance application despite measurable aero benefit.
Source: Josh Poertner saddle analysis

KEY QUOTES

“just making the handlebar of an arrow cross section can be 20 to 30 Watts um which is nuts I remember first discovering that 20 years ago when we're playing with the the very first carbon handlebars and you're like oh wow I you know you come out of school and you know that round is bad right cylinders are just terrible aerodynamically”
Josh — Aerodynamics and cycling performance expert at Silca

“the human on the bicycle is you know 80 of the drag so you know we can find a ton of marginal gains around the spokes and the rim shapes and the tires and the tube shapes of the frame and this and that but I mean that that's really all just playing within that 20”
Josh — Aerodynamics and cycling performance expert at Silca

“you put him on a bike with a you know God I think like a 45 or 48 millimeter wide bottom bracket a single chain ring and you know I mean just the you know boom it's like 12 15 watts right there just by like narrowing the Q factor up by um you know by 20 millimeters”
Josh — Aerodynamics and cycling performance expert at Silca

EPISODE TRANSCRIPT4 SECTIONS

Turned-In Hoods and Handlebar Aero

Cause it's amazing the the just making the handlebar can be 20 to 30 Watts we still get these guys oh yeah but this is a special it's made for me in Germany and it's on which is nuts I mean 150 grams like I don't care yeah you can find huge differences but funny enough and we knew this in the 70s they're actually manipulating the Reuters position on the bike and forcing them into a mall we had this this secret and then we kind of lost it I think the hard thing with the saddle is just there are absolutely gains to be found there but solving them Josh welcome back to the real monster podcast hey thank you for having me we've seen a trend on particularly road racing less so on gravel of pros and I almost think it's like ah restricted if you're under 30 years of age you get to ride with your holds pointed in if you're over 30 years of age you rushed your holds straight what's the deal with this is there an aero advantage to this yes and no um and that's we've actually worked a lot with uh a number of athletes I mean particularly we've done a ton of work with ef guys this year and you know not in any way going to take uh credit for the success that the teams had this year but I mean that team has gotten insanely focused on Arrow and efficiency um and and you know we we've been helping them with that um the the thing with the turned in hoods is they allow for a much more efficient Rider body position in that we can just bring the rider the Riders hands in and then it kind of forces them to keep their elbows in because they you know as as I teach it you know you want your hands here and then you want to feel the handlebar in your forearm because it would be easy to put your hands there and then let your elbows stick out right which would undo a huge part of the game um you know I I think the movement we're gonna see from a product standpoint is we're going to start to see more bars that you know have say like a 34 35 millimeter kind of a top and Hood section with a little bit more of a flare that you get a you get a slightly better sprinting position you know so maybe 35 um centimeters you know at the hoods and 42 centimeters or 44 centimeters at the drops um so that you can have that sort of better control when you're sprinting but also have that really narrow uh upper body position I think the other thing that you're it's harder to see in the footage but you know the the bikes are they're just getting longer um and so I think we've been so focused in the old days on Pros being low long and low but you know in a lot of cases it it you don't necessarily need the low if you can hit the long and the narrow and so some of the the road bike wind tunnel testing I mean we've done I've seen we can make some changes up there and pretty quickly find 30 watts of savings at 45k an hour did you see the arrow coach ornix handlebars they're purported to be 21 Watts faster than a round bar and I think that testing's at like 45 kilometers an hour now it's their own data so again I'm not sure what we read into the is it just an arrow like an arrow flat like the flat top of the bar is Arrow shaped or no it's actually almost mimicking the position that you would turn your holds in so it's quite a you know a full interesting design yeah yeah no I'll take a look at yeah I mean it because it's amazing the the just making the handlebar of an arrow cross section can be 20 to 30 Watts um which is nuts I remember first discovering that 20 years ago when we're playing with the the very first carbon handlebars and you're like oh wow I you know you come out of school and you know that round is bad right cylinders are just terrible aerodynamically um but then you actually make the top

Why Narrow Bars Win Back Watts

Of a handlebar into a wing and I mean you don't even have doesn't have to be that good of a wing you don't have to be all that smart you didn't even have to try that hard and it's 20 watts um on the bike so you know that that is you know one of the things we tell our athletes I mean you should never ever ever be riding around handlebar I mean it just um it is the worst of all the possibilities right it's it's more pressure on your hands it's less vertical deflection for Comfort um and it's significantly less arrow and and so you know we still get these guys oh yeah but this is a special you know it's made for me in Germany and it's 150 grams like I don't care back to like weight will matter for two percent of uh you know whatever event you're in and if if you're a world tour pro we're already adding weight to your bike so stop getting hung up on taking 10 grams out of this part that just makes some poor mechanic have to put 10 more grams back in somewhere um and yeah you can find huge differences with with arrow shapes up front and then also I mean just getting narrow and and funny enough and we knew this in the 70s right I mean I you know the guys I grew up uh kind of being mentored by you know they were all racing like 35 and 38 centimeter bars it was really only I think in the 90s the bars started to get wide um again so it was kind of like we we had this this secret and then we kind of lost it and now we're finding it again about the subtles is there a game to be made there I've seen again Sycamore Arrow coach just because I had to go to look around their website before they have one called access saddle which there again internal testing is claiming to be three to four what's faster than the next fastest subtle I think the hard thing with the saddle is just that you have to sit on it right so um there absolutely gains to be found there you know aerodynamically and and otherwise and I know um you know what is a tune makes like the speed needle and and I know that there's a number of um companies that have done some interesting work with like you know running an arrow post right into the saddle and there's no rails and you're trying to clean up all the air under there and um one of the big problems with a lot of those those products historically has just been like you take away the sort of like hammock suspension from the saddle and then it's miserable to ride um and so you know maybe it's good for a time trial or whatever but you know particularly at the pro tour level it's like you know even if it is three watts can I sit on it for five hours um so that that one's a little bit harder for me you know there's also been and I don't know this particular saddle but there have been Saddles over the years I know in physique originally did the arioni saddle you know they claim that the wing Flex added Watts by not disrupting the Riders you know inner thigh motion or something and you know there are these claims it was like it's 20 watts faster and you know you can really instantly just go and and debunk a lot of that stuff um that you know there's not there's not 20 watts lost to inner thigh rubbing um on a saddle so I I don't know this particular product but yeah I mean there's absolutely Arrow gains to be found uh everywhere still on the bicycle and then some areas are just harder than others with the fact that you know is it comfortable what's an interesting Trend with some of the Innovation is the recognition that position makes up so many of the gains that we can get like physically how we hold ourselves our posture on the bike so a lot of the Innovation be that the saddle we've just talked about there are the handlebars that are kind of forcing you into the tucked in holds position they're actually

Rider Position and UCI Rule Limits

Manipulating The Writer's position on the bike and forcing them into a more aerodynamic position is there other parts that we think you can you know when when you look at someone the wind tunnel and you manipulate the position you move everything around and you're like okay here's the Pareto Principle here's the the four or five things that we know work every time is our order areas on the bike that you see that technology adapting to force Riders into certain postural changes oh I think there's a lot further you could go uh you know I mean I was at a tunnel test in probably O2 with uh with Trek and and Lance and you know when that whole circus was happening and and you know they put him on a bike with a you know God I think like a 45 or 48 millimeter wide bottom bracket a single chain ring and you know I mean just the you know boom it's like 12 15 watts right there just by like narrowing the Q factor up by um you know by 20 millimeters um you know things like that are still out there as possibilities they just have these offsetting consequences right you know we narrow up your bottom bracket and your Q factor and all that and now we're gonna we're really limiting like how wide attire you can run and you've got to run single chainring and you know you start to get into these other areas so yeah I think the stuff that's happening uh and if the UCI would just back off of some of their rules I think you might see it go even a little bit further um you know I think we would probably see the bikes steepen and lengthen a little bit um if the rules changed right you have some I mean some of these things with the you know nose of the saddle relative to the bottom bracket you know you can solve that with a shorter saddle but you can only you can really only go so far with it um so there there's definitely stuff that's still there and then I think a lot of it too is just training the writers for the feel um and and giving them reference points and and things to think about you know I I there's tons of writers we work with you you try to come up with little you know like I said the thing of um you know horizontal forearms are are faster right and so you know with the turned in hoods that's one of the things of like you know hey you don't just ride in the turned in hoods you need to have your forearms horizontal and the way to do that is we'll set it up in a way that like you're touching like you're not resting on it because that's not comfortable but you know you should feel it touched that means your position is good and so you can certainly train riders into certain like spatial reference points uh with things like that you know um back back when Arrow helmets were much longer you know we would this is a little bit mean but um we do a thing where you'd put like a toothpick uh in the the tail of the helmet in the foam sticking out and then you tell the writer like you need you know you need to feel it poking you in the back um you know if it's not poking you in the back it's sticking up in the air and that's slow and and so you know you would and and then you get into funny things like you know could we just like tape it down to the road and of course that's not legal and but you know you think all the way I remember making Velcro on the end of my old cheero helmet and I had put vehicle I'm velcro onto the Vault if I could feel her peeling off yeah exactly I mean it's you know and that's not exactly legal but it it sure is effective and um you know but again this isn't new right I think of you know the Italians uh Italian Pursuit team right with the cables you know we're just gonna like sorry like you know hold your chest to the bicycle with a cable to make sure that

Chain Stripper and Wax Lube Frontier

You're low um you know some of this is stuff that we we really are rediscovering but it really does show them that the human on the bicycle is you know 80 of the drag so you know we can find a ton of marginal gains around the spokes and the rim shapes and the tires and the tube shapes of the frame and this and that but I mean that that's really all just playing within that 20 um the stuff we can do in the body with the clothing with the helmet uh and then how that ties in with the position you know there's for the vast majority of riders they're still huge gains to be found there and you know I mean you could be someone like a I don't know like Ben Healey or or one of these guys who I mean you know he's he's doing everything as right as can possibly be we could still probably go to the wind tunnel for a couple of hours and find another couple of Watts um of savings through some of these positional uh or or position equipment interaction type things just to finish up Josh is there anything you're working on over silica at the moment that you're really excited about honestly this this chain stripper that by the time this airs will have launched I mean to me that is the next Frontier you know the the it's the democratization of wax chain lube um you know that is the everybody I've ever converted to wax chain lube is a is like a mad convert right like you said people wanna you know everybody who converts to wax wants to talk to you endlessly about how amazing it is and how you should be doing it and the thing that's keeping people from doing it is this huge pain in the ass cleaning and stripping of the chain at the front end of that process and so by solving that uh in a very simple fast fashion I mean we have spent I think a year and a half and a lot of money developing this this stuff um but solving that really makes wax based chain loop a possibility for anybody I mean it's you can literally drip this stuff on uh we've got a two-step cleaning process you drip it on let it sit for 10 minutes do another drip to flush through hose with water to kind of blow all of it what it does is it lifts and encapsulates the grease so that it can be flushed out and then the residue it leaves behind is actually a wax adhesion promoter to the metal unbelievable and so with you know traditional chain cleaning what you're trying to do is like go from solvent to solvent to remove the residue of the prior solvent and with this stuff it it's actually stuff that wants to stick to both wax and metal and so um you're actually going to get a slightly longer uh per application lifespan using it than not using it and it saves you hours of time so to me I think that's the you know the next exciting Frontier from a product perspective um that's out there and then you know a lot of and you'll will probably see some stuff at the tour this year you know we've just got probably a dozen uh 3D printing projects that we're doing for different teams or or Riders um some of which will be debuting at the tour this year and that that stuff is always fun you know it's I mean personally it's fun for me because I get to travel and wind tunnel and and do you know work with the athletes uh and you know really design stuff that nobody's ever done before and then actually make it and see it come to life and uh you know that's that's a great experience so hope hopefully it all those things work out and make it on the bikes and uh and hopefully we get some results Josh I've Loved this conversation I could literally have you on the podcast every week to talk about this nerdy stuff thanks very much for joining me on the Roman podcast thanks so much for having me

FREQUENTLY ASKED QUESTIONS

How much does handlebar shape affect aerodynamics on a road bike?+

Switching from a round handlebar to an aero cross-section can save 20 to 30 watts at 45 km/h, making it one of the most impactful equipment changes available. Josh Poertner explains on the Roadman Podcast that bar shape is often underestimated compared to flashier upgrades like aero wheels or helmets.

Why do turned-in brake hoods make you more aerodynamic?+

Turned-in hoods work because they force the elbows inward, narrowing the rider's frontal area rather than because of any aerodynamic property of the hood shape itself. Josh Poertner makes clear that it is the resulting body position, not the hood angle alone, that produces the saving. Replicating that elbow position through other means would achieve the same result.

Does rider position or bike equipment matter more for cycling aerodynamics?+

Rider position is far more important, with body drag accounting for roughly 80 percent of total aerodynamic losses. Josh Poertner argues that optimising how the rider sits on the bike will produce larger gains than swapping components in almost every scenario. Equipment upgrades matter at the margins, but they cannot compensate for a poor position.

Are modern road bikes getting longer or lower for better aerodynamics?+

Current bike design trends towards longer, not lower, geometries. Josh Poertner explains that placing riders in a longer, flatter position reduces frontal area more effectively than simply dropping stack height, and that many manufacturers are now reflecting this in their frame geometry.

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Key Takeaways

Handlebar aerodynamics matter hugely: switching from a round bar to an aero cross-section can save 20-30 watts, and narrower bars (35-38cm) are faster than the wider bars that became standard in the 90s

Turned-in hoods force a more efficient riding position by naturally keeping elbows in and hands narrower, which is why you're seeing younger pros adopt this technique on the road

Body position trumps bike components: the rider makes up roughly 80% of drag, so positional gains and clothing/helmet choices deliver far more watts than tweaking rim shapes or spoke counts

Saddle aerodynamics exist but comfort is the real limiter — even a 3-4 watt gain means nothing if you can't sit on it for five hours during a stage race

UCI regulations are holding back innovation: changes like narrower Q-factors, longer/steeper frames, and nose-to-BB saddle rules could unlock more aerodynamic gains if the rules were relaxed

Wax-based chain lube is the next frontier for everyday cyclists, and Silca's new chain stripper removes the biggest barrier to adoption by making the setup process fast and simple

Expert Quotes

"You should never ever ever be riding around a handlebar. It's the worst of all the possibilities — it's more pressure on your hands, less vertical deflection for comfort, and significantly less aero."

"We had this secret in the 70s and then we kind of lost it. It was really only in the 90s that bars started to get wide again — and now we're finding it again."

"The human on the bicycle is 80% of the drag. We can find tons of marginal gains around spokes and rim shapes, but that's all just playing within that 20%. The real gains are in the body, clothing, helmet, and position."

KEY QUOTES

“just making the handlebar of an arrow cross section can be 20 to 30 Watts um which is nuts I remember first discovering that 20 years ago when we're playing with the the very first carbon handlebars and you're like oh wow I you know you come out of school and you know that round is bad right cylinders are just terrible aerodynamically”
Josh — Aerodynamics and cycling performance expert at Silca

“the human on the bicycle is you know 80 of the drag so you know we can find a ton of marginal gains around the spokes and the rim shapes and the tires and the tube shapes of the frame and this and that but I mean that that's really all just playing within that 20”
Josh — Aerodynamics and cycling performance expert at Silca

“you put him on a bike with a you know God I think like a 45 or 48 millimeter wide bottom bracket a single chain ring and you know I mean just the you know boom it's like 12 15 watts right there just by like narrowing the Q factor up by um you know by 20 millimeters”
Josh — Aerodynamics and cycling performance expert at Silca

FREQUENTLY ASKED QUESTIONS

How much does handlebar shape affect aerodynamics on a road bike?+

Why do turned-in brake hoods make you more aerodynamic?+

Does rider position or bike equipment matter more for cycling aerodynamics?+

Are modern road bikes getting longer or lower for better aerodynamics?+

WIND TUNNEL SECRETS FOR AERO GAINS ON YOUR BIKE | ROADMAN PODCAST

Key Takeaways

Expert Quotes

CLAIMS FROM THIS EPISODE

KEY QUOTES

FREQUENTLY ASKED QUESTIONS

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WIND TUNNEL SECRETS FOR AERO GAINS ON YOUR BIKE | ROADMAN PODCAST

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KEY QUOTES

FREQUENTLY ASKED QUESTIONS

NEVER MISS AN EPISODE

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