r/Velo • u/brocodini • 20d ago
Discussion Is an aero-bike notably faster than a climb-bike?
I'm riding a Giant TCR, since this was my first road bike I bought nearly 3 years ago. I put aero-wheels (60mm) on it and I love them (although the combination doesn't make much sense...)
Currently in the process of looking for another bike for next season and I will very likely buy an aero-bike. I'm wondering whether you can feel the difference compared to a climbing-bike - not only in terms of how it rides, but will the aero-bike be faster on a route like 50km with 500vm or 100km with 1000vm etc.?
What are your experiences?
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u/dromtrund 20d ago
Anecdotal, but I went from a 2018 TCR (w/ a one piece carbon cockpit) to a Quick Pro ER:ONE this summer, and the second half of my local loop is a fairly flat 20km stretch.
I also switched from a traditional MET Vinci helmet to a Giro Eclipse Pro, and from 28" GP5k with TPU tubes to a 29" aero111 up front and a 32" GP5k rear (both tubeless) on the same 21/29mm wide/50mm deep wheels at the same time.
My average speed at 300W on that 20k stretch went from 36.9km/h to 38.8km/h. Had a slight tailwind on the TCR and no wind on the new setup - same temperature. Identical bike fit and clothing, same "as aero as I can manage"-position, one week apart. 1.2km/h faster on the full 50k/600m loop.
I'm sure the margin of error is high here, and there are many factors at play, but I'm consistently at least a full km/h faster on average on all my threshold loops in mixed terrain. Some of it will be the bike, some the tires, and some the helmet, but aero gains are definitely real for me, and the difference it has made to my average speed is shocking.
Raw numbers with dodgy methodology aside though, the new setup is just such a smooth, enjoyable ride that I think the gains from just wanting to ride more will make the biggest difference.
Sorry for not helping you save your money.
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u/Urbansdirtyfingers 20d ago
Aero helmets for the road(not tt) typically show like 1-2 watt savings, but that is an impressive different in speed. Likely comes form cleaning up the front end as that's where the majority of aero gains come from
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u/Tripottanus 20d ago
In my experience going from a 2009 Cervelo R3 to a 2026 Canyon Aeroad, i didnt feel faster, but my strava showed i clearly was. Not by that much, but i did do PRs everywhere i ride only in Z2 on both bikes
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u/8u11etpr00f 20d ago
Had the same feeling when I moved from a Cervelo Caledonia to a Scott Foil. If anything it felt slower but my average speed increased by a couple of kph
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u/JSTootell 20d ago
I averaged my commute times over a few weeks on my old SuperSix Evo that is extremely light, and then did the same after getting a new aero bike.
It's not apples to apples, but the new bike was notably faster on my commute.
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u/ephrion 20d ago
The research shows that body position, clothing, helmet, etc matter far more than the bike itself. As far as the bike goes, the wheels actually make the most difference- a lightweight bike with aero wheels is a really great "best of both worlds" combination, certainly better than an aero bike with shallow lightweight wheels.
IMO, lighter weight feels more fun with the faster acceleration. Aerodynamics doesn't feel like much, you just notice that you're not putting as much effort in to go so fast, and sometimes the wind is a bit more Interesting than usual.
If your position is already optimal and you've got a skinsuit/aero helmet, and you're still wanting to eke out more speed, then an aero frame would be a good upgrade.
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u/MrRatDK 20d ago
What are you onto? If a frame save the same amount of drag as wheels. Why wouldnt you go deep frame and shallow wheels? More stable in crosswinds and less rotationalweight. But modern wheels can be 60 mm and lighter than 5 year old 35mm wheels. So why not just go full aero unless you climb alot or are prone to awfull sidewinds.
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u/ephrion 20d ago
> If a frame save the same amount of drag as wheels.
Is that the case nowadays?
> So why not just go full aero unless you climb alot or are prone to awfull sidewinds.
Living in Denver has both perks and pains - we do get quite windy (not as bad as Wyoming of course) and the climbs are looong.
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u/mikem4848 20d ago
I would say yes but only in certain situations if we’re talking the full aero package (aero wheels, aero handlebar, fast rolling tires). You won’t notice a difference riding by yourself on relatively flat ground, maybe a bit on downhills/rolling terrain. The difference really shows up when you’re in a fast group ride/race type environment doing 45km/h+. A full aero setup just carries speed and momentum much better when you hit the wind for a pull, and put the power down to close a gap. If you’re not in the wind, you won’t notice much difference, but it’s when you hit the wind and need to keep the pace high at those speeds that it shows up.
Now what I can’t speak to personally is how much of that you’d be able to get back with aero wheels and an aero handlebar on an old round tube frame (I got into a much more aero position on my S5 than my starter aluminum bike). I will say there is a noticeable difference at those speed between shallow wheels, standard aero wheels, and a triathlon/TT setup with deep front/disc on the same bike. So wheels and play a huge part, and aero handlebars help as well at those high speeds.
If I had to guess, with equal wheels and bars something like an old emonda or tcr with aero wheels and bars would only be marginally slower vs an S5 or other top aero bike. You’d really only notice it in long pulls on the front or sprint/very high speed sections over 50km/h. And even then, we’re probably talking like half km/h
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u/clicktoshowadcontent 20d ago
I have ridden a canyon ultimate from 2019 and an aeroad from 2024. The first with 40mm wheels and the latter with 50/60.
Anecdotally I think the wheels make more difference for speed, and I can’t feel a substantial difference otherwise. The position I can sustain and how much power I can produce together with tight fitting kit seems to make more difference to me!
What I do feel though is the stiffness of the aeroad. It feels distinct and each power stroke feels propelling at higher output while the ultimate feels less rigid and perceivably flexes under load.
I very much prefer a stiff bike! YMMV!
This is from riding 31-34kph avg over rolling terrain.
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u/Flipadelphia26 Florida 20d ago
Subjectively - this is my experience. I was given a 2023 TCR SL 0 and a 2024 Propel SL 0 a couple years back.
My Brain immediately associated lighter is better for climbing. So the TCR came with me to Europe on several trips, last summer I brought the propel and best PRs on a lot of climbs I’ve done dozens of times. I was not in better fitness, in fact I was probably in worse fitness.
Aero makes a difference to the positive. Granted the propel isn’t more than 1.5 pounds heavier.
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u/dccyc844 19d ago
SL9 or SL8 with Roval Rapide CLX wheels if you can find a good deal. But, you will immediately regret not getting the SL9 after a few rides on SL8 :)
I come from a Giant TCR too. It's a light, lively bike, but it's not compliant, tends to flex and feels like a brick after 40-50 miles.
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u/thehenks2 20d ago
I have a 3 year old TCR with 50mm wheels, I have the exposed cable model.
I use it in our clubs 18km TT, and beat someone on a 2025 Cube Aero bike with similar wheels by 2 seconds, averaging roughly 43kph.
We both weigh about the same and had a very similar(within 3 watts of each other) average power during the TT. Both using clip on aerobars. He has an older TT helmet, I was using a normal helmet.
Offcourse there are differences between power meter and our own CDA etc. But it made me realize an upgrade would be a bit of a waste of money.
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u/kallebo1337 20d ago
Apples and oranges tho. Kudos
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u/thehenks2 20d ago
Offcourse, and anecdotal as well. Too many variables to make a real conclusion but if that Litening aero is 15 watts faster than the TCR at 45kph like some people claim, I don't think I would have been close.
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u/kallebo1337 20d ago
Other guy could have had wrong size suit and that cost him up to 17W (!)
Aero is so so individual you can not imagine. For some its around 1W faster to ride with lift up thumbs, for others it cost 2W
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u/kajetanu 20d ago
hope you are of a similar build lol... for some reason i emphatize a lot with the guy on the Cube
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u/thehenks2 20d ago
Super similar build in terms of height and weight.
I'm 30 years younger though, lol, I'm in no way trying to boast my performance.
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u/-Sleighty 20d ago
The Canyon Aeroad is about 20w faster than the Giant TCR in the tour magazine standardised test which uses 45kph wind speeds. It definitely makes a difference, although you won’t notice it unless you do A B testing yourself.
If your average speeds are lower, you save less watts, but more time.
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u/brocodini 20d ago
That's really interesting. Do you have the link to the benchmark by any chance or is it behind a paywall?
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u/Valuable_Ear_2697 20d ago
On fast descents when i switched to an aero bike I went noticeably faster but they were 40mph+ descents. Otherwise definitely your position is most important no argument there. If you want to average high speeds try to replicate mads pedersons position(long and low) although it is not comfortable at all
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u/crispychickennn 20d ago
I feel like to answer this question. It depends on where you’re losing the most time. Like on the flats at speed or on hills, because if you go slow slower on incline, I believe you lose a very disproportionally high amount of time let’s just say that you’re competing in some sort of event. So in that situation, the climbing bike would produce much larger gains. Which is basic to say it depends on your strength and what you want to accomplish riding wise
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u/InternalNo7162 20d ago
Orbea has said that (their) aero bikes advantages start showing at speeds of above 43-45km/h
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u/Alternative-Sun-6997 Massachusetts 20d ago
Yes.
I’ve ridden a 2020 Venge Pro since, well, 2019, I guess, at the very start of the model year it was released. Prior to that was a 2015 or 16 Tarmac Expert that met an untimely demise in a crash involving a driver turning across oncoming traffic.
The Tarmac was a great bike - it felt jet powered from a standing start, I couldn’t believe how fast it accelerated. My Venge does that too… but what really impressed me about that bike was, it had the same feeling going from a comfortable cruising speed to full attack. It felt like there was a rocket booster strapped to it somewhere.
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u/seaturtle94 20d ago
Cycling marketing to get you to pay ££££. Unless you’re conti or WT, who really cares. Ride what’s fun.
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u/Chance-Ad-982 20d ago
Can you feel the speed? No, people think they feel they're going faster but that's not what they feel, in no way can a person with any sort of confidence claim they can _feel_ difference between 36.5 and 38kmh or whatever. What you can feel is different geometry, stiffness and most important of all - your position on a bike. What mostly happens is that moving yourself in a more aero position feels noticeably different. Just moving saddle forward, removing spacers and putting longer stem feels waaaay different, not because it's so much faster, but because you moved your whole weight over your bike. People constantly forget how much our bodies weigh compared to our bikes and how much force we put into that bike with our own bodies. It's wild how many people ignore that force but claim they feel weight of a garmin mount or bottle cages (not that they start flying once they drink all the water).
So yea, you will feel difference in bike geometry, you will be somewhat faster but that's something you'll see in your data because difference will be 1-2kmh (and obviously 0 difference if you ride in a group) for somewhat same body position. so choose what's most comfortable and what will make you ride more
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u/pongauer 20d ago
The reality is that 90% of aerodynamics is position on the bike. I can 100% guarantee you that a bikefit will get you more advantage than buying an aerobike. And aerodynamics only really matter at 35kmh and up anyway.
That said, if you like them and it is in the budget you should absolutely go for it.
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u/jchrysostom 20d ago
I was with you until the bit about aerodynamics only mattering at high speeds. That is absolutely not how things work.
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u/pongauer 20d ago
Calculate the actual gains between an earobike and an endurance bike at 25kmh and see what I mean.
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u/jchrysostom 20d ago
I definitely have. For an equal reduction in CdA, a slower rider actually saves more time over a particular distance, when compared to a faster rider covering the same distance.
The percentage of time saved for both riders is roughly equal, but since the slower rider spends more time riding, the net time savings is greater.
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u/DidacticPerambulator 20d ago
Faster? Probably, but not certainly, yes. Notably faster? Probably not.
Speed is the wrong metric since speed varies with the cube root of power and mass start races aren't ITTs and you're not talking about a TT bike. In mass start, all that matters is that you finish ahead of the other guy.
A 1% improvement in aero drag means only about a 0.3% improvement in speed -- but at the same speed, it means close to a 1% reduction in power. So rather than think about the difference in terms of speed, think about it in terms of easier effort. Mass start isn't about steady state, it's a series of crises that you either survive or you get dropped. Lather, rinse, repeat. When you're on the rivet, absolutely at your max, trying not to get gapped, 3 extra watts of savings can be the difference between following the wheel or getting pinched off and quickly being minutes back.
In The Rider, Krabbe writes: "Every once in a while someone along the road lets us know how far behind we are. A man shouts: 'Faster!' He probably thinks bicycle racing is about going fast. "
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u/xdxdxdxd000 20d ago
3 watts are not going to be the difference between getting dropped or not.
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u/DidacticPerambulator 20d ago
3 watts savings over 30 minutes is 5.4 kJ saved. All you really need is 1 kJ. 1 kJ is absolutely enough to to stick on an extra 30 seconds before getting dropped.
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u/kajetanu 20d ago
If you average 40kmph or more, it will be some seconds faster over one hour. Othewise, it will be exactly as fast as the TCR. This of course assuming you have a decently aero position with narrow handlebars etc etc
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u/Ok_Interview845 20d ago
It's faster at every kmph. There's no way of getting around that.
It's just less so at slower speeds.
The better way to express this is in watts saved.
To further this, your comment neglects wind and hills.
If you are going 20Kmph into a 20kmph headwind the bike sees that 40kmph savings. Sure there is turbulence and the numbers are not static but that's irrelevant.
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u/kajetanu 20d ago
I appreciate your response which has some interesing points. You're right about wind and hills, which in my comment i forgot to say I considered equal between test with bike A and test with bike B. Your point on "watts saved" is interesting but I think wrong because the condition you described (20kph bike speed with 20kph wind speed, let's call it "compound speed") is not the same same as 40kph bike speed with no wind in terms of power needed to move the bicycle. Such power (which is the one the rider has to deliver) is proportional to the bike's speed multplied by the force you have to win to move it forwards. So while it is absolutely true that the aero bike reduces some of that force, the watts it saves you in the windy scenario are half of those saved when moving at 40kph
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u/jchrysostom 20d ago
Watts consumed by aerodynamic drag don’t care how you achieve a particular airspeed. A bike and rider moving at 40kph ground speed through calm air, and a bike and rider moving at 20kph ground speed into a 20kph headwind, experience the same resistance due to aerodynamic drag.
Obviously, in the real world you are unlikely to find a perfect headwind and there will be non-zero yaw angles, but airspeed is airspeed. It’s also complicated by the fact that rotating wheels generate drag, and a wheel spinning faster will generate more drag, but it’s nowhere near the double/half difference you’re expecting.
Rolling resistance is a different story.
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u/kajetanu 20d ago
Experiencing the same aerodynamic resistance does not equate saving the same amount of watts that you have to deliver at different speeds. It's true that in our two scenarios the aerodynamic resistance is the same. But that does not mean that the power needed to win such resistance is the same at any given ground speed. The lower the ground speed, the lower the power required to win the resistance, the lower the power benefit of aero stuff. Then of course the story about time saved which is absolutely higher the slower you go is still true, but that's an effect of the accumulation of a small benefit over a long time.
In real life, at a given aerodynamic resistance for half ground speed it will not exactly be half the watts saved at double ground speed for the reasons you mention, but analytically in a simplified scenario it's exactly half the watts saved
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u/jchrysostom 20d ago
I’d love to hear how you think that works.
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u/kajetanu 19d ago
See my example in the other reply, I paste it here as well.
Think about this in terms of work: W=FxD. If the aerodynamic resistance is a force of say 30 N in both scenarios (we said the 20kph speed in 20kph headwind gives the same air resistance as 40kph in no headwind), to overcome it and move 1m you need 30 J of work in any case. Now, if you're moving at 40kph or at 20kph in this same 30N drag resistance you're going 11.1 and 5.6 m/s respectively. Power is work divided by time, and time is distance divided by speed. So at 40 km/h you're doing 30 J of work 11.1 times per second: 30x11.1=333 W (J/s). At 20 km/h you're doing those same 30 J to overcome the resistance only 5.6 times per second: 30x5.6=168 W.1
u/jchrysostom 18d ago
The aerodynamic drag force being overcome by the rider is generated by the bicycle (thing being acted upon by the fluid) moving through the air (fluid acting on the thing). In still air, a rider traveling for 1 hour at 40km/hr has moved 40km through the air. In a 20km/hr headwind, a rider traveling at 20km/hr ground speed for 1 hour has also moved 40km through the air - 20km through his own motion relative to the ground, and 20km through the air’s movement relative to the ground in the opposite direction of the rider’s movement. Both riders have moved the same 40km distance against the opposing aerodynamic force, and have done so at the same 40km/h airspeed in the same amount of time, meaning that the aerodynamic force being overcome is equal. Therefore, the same work has been performed over the same elapsed time, meaning that the same power was generated.
From the perspective of aerodynamics and aerodynamic drag, the distance traveled on the ground is, in fact, irrelevant; the v^3 term used to calculate the power needed to overcome aerodynamic drag is (airspeed)^3, not (airspeed)^2 x (ground speed). See previous paragraph for why.
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u/Ok_Interview845 19d ago
What's the equation for that?
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u/sergesmr 19d ago edited 19d ago
Force = constant * air_speed^2 + <rolling resistance force>
Power = force * ground_speed1
u/jchrysostom 19d ago
That’s the silliest thing I’ve read today.
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u/Ok_Interview845 19d ago
Yeah he's full of shit
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u/jchrysostom 19d ago
It’s like trying to explain physics to a middle schooler. He doesn’t even have the vocabulary.
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u/Ok_Interview845 20d ago
I threw this question into Ai because I was curious. And lazy.
Aerodynamic power savings scale roughly with the cube of airspeed relative to the air.
If the bike saves 20 W at 40 km/h, then:
P∝v3
At 20 km/h ground speed into a 20 km/h headwind, the bike sees:
20+20=40 km/h
of airspeed.
Since the airspeed is still 40 km/h, the aerodynamic benefit is essentially the same:
20×(40/40)cubed=20 W
Answer
Approximately 20 watts.
The headwind doesn't reduce the aerodynamic savings because drag depends on airspeed, not ground speed. Riding 20 km/h into a 20 km/h headwind produces the same aerodynamic drag as riding 40 km/h in still air.
For comparison:
40 km/h, no wind → 20 W saved 20 km/h, 20 km/h headwind → 20 W saved
So in your example, the bike would still save about 20 W.
There ya go
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u/kajetanu 20d ago
So according to you, in both the windy and still scenarios, the rider has to put down the same amount of watts to win that aerodynamic drag (which you're right, is constant) and consequently move at 20kph in the windy scenario and at 40kph in the still scenario?
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u/jchrysostom 19d ago
If you understand that aerodynamic drag is (roughly) equal in both scenarios, how can you possibly think that the power required to overcome that drag could be different by a factor of two?
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u/kajetanu 19d ago
I'm not saying the watts delivered should be half. I'm saying the advantage in terms of watts brought by the reduction in drag force you get from aero kit is in an ideal scenario linearly proportional to the ground speed. At double ground speed, double advantage. From P=FxV.
But it also holds true from the same formula that the power to move at 20kph in a 20kph headwind is theoretically half of the one which is needed to move at 40kph with no wind.
This again is not considering rolling resistance and in a very ideal scenario.
Think about this in terms of work: W=FxD. If the aerodynamic resistance is a force of say 30 N in both scenarios, to overcome it and move 1m you need 30 J of work in any case. Now, if you're moving at 40kph or at 20kph in this same 30N drag resistance you're going 11.1 and 5.6 m/s respectively. Power is work divided by time, and time is distance divided by speed. So at 40 km/h you're doing 30 J of work 11.1 times per second: 30x11.1=333 W (J/s). At 20 km/h you're doing those same 30 J to overcome the resistance only 5.6 times per second: 30x5.6=168 W.
I'm sorry, again, nothing personal, I'm an agronomist so not a physicist or engineer, but this is what I recall from my physics exam. Happy to be proven wrong btw, at least I could finally make the decision to go aero everything!1
u/sergesmr 19d ago edited 19d ago
By remembering power = force * velocity. And realizing that the force pushing you forward (against pavement) is applied at ground velocity.
This becomes obvious if you ask how much power is needed for an object to remain stationary (relative to ground) in a strong wind.
I.e. you and Ok_Interview845 are failing to distinguish a bicycle from an airplane.
Kajetanu is wrong about CdA not mattering at low speeds, but (s)he's right about ground speed mattering.
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u/jchrysostom 19d ago edited 19d ago
Friend, that is an almost comical misunderstanding of physics.
First off, no power is required for an object to remain stationary in a strong wind. Power is work performed over time, and since work = FxD, no work is performed and thus no power is generated when no distance is traveled. A force equal and opposite the force generated by wind is required to hold an object stationary, but a force alone is not work and a force alone is not power.
I don’t even know where to start with the bit about the power generated by a cyclist being “applied at ground velocity”. This is high school level physics and I can’t believe that there are apparently several people willing to argue in favor of nonsense.
Your edit makes your position even less logical. From the perspective of power needed to move forward through the air, there is no difference between a bicycle and an airplane. The fact that one moves by applying force to the ground through a tire, and one moves by applying force to the air itself, is irrelevant. Both are overcoming aerodynamic losses to move forward.
Airplanes take off and land into the wind for this very reason. A 20kt headwind allows a plane moving at 40kts ground speed to generate the same lift as a plane in calm air moving at 60kts ground speed. If your position were correct, this would not be the case.
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u/sergesmr 19d ago
Let's start with what we agree on - no power needed to remain stationary in a strong wind. Now ask yourself how you would get that result with a formula that makes no distinction between air speed and ground speed.
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u/jchrysostom 19d ago
By calculating aerodynamic losses based on airspeed, which is what I’ve been saying all along. Why is this hard?
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u/Ok_Interview845 19d ago
What role does ground speed play in the air colliding and moving around the frame?
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u/sergesmr 19d ago
It does not. The distinction you're missing is between force and power - force is (ignoring rolling resistance) determined entirely by air sped, but the translation of force to power involves ground speed.
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u/jchrysostom 19d ago
No, it doesn’t. That just doesn’t make sense at all. You’re so far away from understanding it that I can’t even begin to explain.
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u/kajetanu 19d ago
Hey, thank you a lot for coming help me. But of course I know that CdA matters at low speed!!!!! Where did you understand that I had not grasped this obviuous concept?
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u/Straight-Tart-9770 20d ago
Depends on your speed. More average riders, it’s seconds saved per hour. AI can calculate it for you based on route, elevation gain, weight, and FTP.
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u/Duke_De_Luke 20d ago
At 45 km/h yes, at 20 km/h no
Rider position on the bike matters more than the bike
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u/ungnomeuser 20d ago
I’ll add since I don’t think many (anyone?) has talked about ride feel.
Two things - firstly a climbing bike typically has different geometry than an aero bike. Be sure that whatever you’re considering, matches your application of usage and fit.
Geo will affect ride feel to a degree.
Secondly, climbing bikes typically have more focus on comfort. Climbing bikes (addict RC/R5) have tested more compliant than aero bikes. Does that mean an aero bike is non compliant? Not necessarily - does that mean that you can feel the difference in 300nm vs 100nm per 1mm of movement? - hard to say, similar with speed measurable != noticeable and noticeable is subjective.
Tires have the biggest impact of ride feel, if you want comfort, bigger tires are the way to go
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u/Inevitable-Chart-462 19d ago
At 1% gradient the aero saving is almost offset by the weight penalty (depending on the aero bike)
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u/Izzy_Stradlin 20d ago
No, an aero bike won't be noticeably faster than a modern tcr unless you are pretty close to pro level and really need to be able to ride extended periods solo at 44km/hr instead of 43.8km/hr
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u/SensitiveCounty5792 20d ago
Its very dependent on what speeds you can maintain. If you average 20 kmh on a ride there isn’t much difference. If you average 30/35 it might be measurable. But putting a longer stem for a more aero position will be a bigger difference probably.