Aero Gains question

Aero appears to be important in cycling. But are we being misled.

Every company touts this is going to save you so many watts. My question is are you only saving watts at yaw angles you never see.

For instance 80mm wheel vs 50mm wheel. At 0-5 degrees yaw the difference is less then a watt. When you go out to 5-10 degrees you see a 1-2 watts. When you go out to 20 degrees yaw you see the claimed 5 watts. Companies then take the data and jam it into an average. Which skews the numbers

Does that mean that aero gains really only matter if your solo?


Yes, the marketing usually touts the maximum gain, and that’s often at a specific yaw angle.

But, even at the minimum gain, small gains eventually add up.

Say each aero change you make is only 0.5W head-on. And you make 10 changes. That’s 5W. Over the course of a 4+ hour race, that’s not nothing. One of my big races is 100 mile gravel race on a flat, windy course. While 75 miles of might be in a group, I’m rotating through taking pulls, so aero matters there. And I’m probably solo for 25 miles, as groups break up and form over the course of the event.

And some of the aero changes are relatively cheap (compared to a new frame or wheels). Socks, helmet, body position, water bottles.


Absolutely not…it does, however, mean that the gains / advantages are somewhat muted when riding with others.

As for companies’ claims re: aero gains, this is one of the reasons why I tell people not to worry about which product is “fastest”. In reality, there is no way to know (especially in this day of excellent aero products across the board). So look for products that will be “faster” than your current setup, but don’t worry about if it is “fastest”.

Have regular alloy wheels? Get yourself a decent pair of deep rim carbon hoops…40mm, 50mm, brand, etc. who cares? They will be faster than what you are riding now.

Have a regular vented helmet? Get an aero road helmet…again, don’t worry about which is “fastest”, they will all be “faster” than a standard helmet.


Also, most aero gains seem to be calculated at 40 kph, which is really bookin’ in my book. I’d like to see a curve on the aero gains from a more mortal speed. Also not sure if everything stacks. It is possible that some gains cancel out others, possibly wheel depth vs. Aero down tube example or with bottles etc.


Swissside mentioned in a recent podcast the following quip - “At <18 MPH, aero is one of many considerations in regards to speed/watts. At speeds > 18MPH, it becomes (increasingly) the primary consideration.” This feels right to me. Obviously matters much more if you are the tip of the spear and you need to take into account head vs. tail wind into that. Your biggest gains are going to be to get more flexible - eventually requiring a longer stem. Also, you can feel free to relax the (bent elbows) aero hoods position when in tailwinds.


I’d say that before going into a rabbit hole of aero things, we (can I use we here?) should start paying attention to body position and ability to keep that position.

So, let’s say a pair of good wheels cost you X, and they save you 10w. If you’re unable to keep an aero position for long periods, which would be defined by the race/group ride how long, it’s worthless to spend that money. The 10w that the wheels saved you were spent in poor position.

Good position and clothes matter way more than wheels and aero handlebars. If you have deep pockets, is up to you. If you don’t, start with inexpensive/free changes before chasing the 1w here, 2w there.


I have checked all the easy boxes at this point.

I’m chasing minimal gains.

Aero gains go up at a cube rate with speed. I’m trying to maximize my road bike. My gravel bike can really only take a aero crank and deeper then 37mm wheels

Then you’re on that stage of 1w here and 2w there.

Answering the question

Does that mean that aero gains really only matter if your solo?

Not really I think. You don’t ride all the time suching a wheel - I hope so hehe. So I guess when you’re pulling, particularly on headwind, aero would matter a lot. When you’re on the bunch, it’ll help you rest.

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They are not mutually exclusive…you should be addressing both when possible. Yes, body position should take precedence, but that doesn’t mean you should exclude equipment choices.


Makes me think 70mm $2500 wheels aren’t worth it, but maybe a $100 crank cover is worth it.

It depends on many factors, not the least of which is what you already have for a wheelset in this comparison. Then consider the potential delta between those and the cover and choose appropriately.

If people are simply comparing $/w saved, that can be interesting but also needs a wider look to see the forest as well.


I would take the opposite approach and optimise through spending first then worry about everything else later as I know I’ll be faster than I was yesterday immediately…


If you already have 50mm wheels, that might be true. Certainly on a watts/$ basis it might be.

If you’re still on generic alloy wheels, then any aero wheel is probably a good bet.

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I haven’t seen many charts at slower speeds, but I have seen rough calculations of the time saved at various speeds (Dylan covered this last year). For a mid-pack finisher, the smaller wattage gain is likely to result in more time savings (gross, not %). IE, the winner might see 15W gain to my mid-pack 5W, but they’ll only see 3 min improvement (over 4 hours) to my 10 minutes (over 6 hours). That isn’t going to push me onto the podium, but it’s still a solid improvement.

As for stacking aero gains - they don’t stack perfectly in the additive sense, but I haven’t seen any tests where one aero gain completely cancelled (or worse) another.


Ben Delaney did a aero/wind tunnel vid and he said if you are in the 20 mph+ crowd minimal aero gains actually mean something. If you get down to 15-16 mph average rolling resistance is a more meaningful thing to focus on.
He did find that going to narrower bars, I think he went from 45’s-ish to 38 or 40, I can’t remember exactly, saved 15 watts. That’s a fairly cheap, easy and big gain.

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This is the most misleading part of the way they market aerodynamic gains.

I will say tho that I am completely convinced aero is huge. A have recently been riding with a new guy who is very into aero. We are the same size, but he has very narrow bars (making his profile less wide) and a smaller bike making him lower (I ride 58 and he rides 56). When we ride downhill next to each other, I put out about 275-300w to keep pace with his 250w. When we are next to each other on the climbs, nearly identical power. This really shaped my view on it. We both have similar quality bikes (carbon, fancy wheels, etc).
Now, to have a smaller bike and narrow bars isn’t anymore money. That’s what impressed me about position. However, I don’t want to be in the aggressive race position despite the gains.


I reckon at my speeds expensive aero gains are poor value for money, definitely not pushing enough power to be spending mortgage sized payments for 0.5 watts. This is probably true for lots of us here but don’t want to assume that you’re not all packing wattage bazookas like MVDP!

But ÂŁ15 for socks or a ÂŁ100 race suit or some narrow bars? The cost to performance ratio definitely swings towards worth getting.

Then the cost in time (and steel) for some kettlebells/yoga mat to improve my body definitely swings towards you should be doing this.


I’m on a pretty fast bike, with 50mm wheels that test very well. 42cm bars are being changed to 38cm. My fit is very aero also. Swapping into 32mm tires that work better with my wheels. I run aero socks and helmet.

I don’t have much left to scrub off. Pending a new skin suit to determine if I go with a rule28 under jersey.

Only thing I could do is
Road bike

  1. Deeper wheels
  2. Aero crank cover
  3. Faster bike mines at 211
  4. 54/56 crank for better chain line


  1. Deeper wider wheel, get closer to the 1.05 ratio
  2. Crank cover
    Can’t mess with driveline since I need that range. Already narrow on 40cm and have aero bars.
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Didn’t say they are. It all adds up. I, emphasys in the I, wouldn’t start putting lots of money into something if can get huge benefits for free. Aerodynamic Cycling | Ultimate Guide to All Things Aero in Cycling

The highest drag position was the classic upright riding position with your hands on the hoods, which required 430 watts to overcome air resistance. Lowering into the drops with straight arms saved a bit of energy, requiring 417 watts. Going even lower in the drops by bending the elbows and hunkering down saved more energy still, requiring 385 watts. But the most aerodynamically efficient posture was actually hands on hoods, arms bent with forearms parallel to the ground. In that position, the rider needed to produce 372 watts, a 13.4 percent reduction from the first hands-on-hoods posture.

Also, one thing is being aero, and another completely different is for how long. I can be as aero as MVDP for a few minutes, can I be for 20, 30, or 60 minutes? It’s pretty hard.

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Yep, it appears that you’re definitely looking for marginal gains. It’ll boil down to how much you are willing to spend as the list can be huge. Are they worth it? Well… your pocket might tell you.

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