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It seems to be accepted that riding low on the hoods is more aerodynamic than riding in the drops. The explanation is that it puts the forearms parallel to the ground/ parallel to the direction of motion.

But we could get the same position in the drops, if our handlebar was just a bit higher. See this stick figure drawing:

Drawing comparing two stick figures, in the same riding position, but with different handlebar heights.  The rider with higher handlebars grabs the drops, and the rider with lower handlebars grabs the brake hoods.

This leaves me wondering why everyone drops their handlebars way down to be aero on the hoods. Raising the handlebars has the obvious benefit of making a very relaxed upright position available. What's the downside that keeps everyone from doing it?

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    I'm comparing a bike to a bike that is identical in every way except the handlebars are higher. No regard to what the different geometries are conventionally called.
    – Edward
    Commented Jan 3 at 3:12
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    @Edward Nice drawings. I agree that the general category of the bike is unimportant in the context of this question.
    – MaplePanda
    Commented Jan 3 at 7:01
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    An unrelated note on the drawings is that they show how the forearm is masked from the wind, which is why aero hoods is aero. Your forearm is roughly a cylinder. Cylinders are high drag.
    – Weiwen Ng
    Commented Jan 3 at 16:23

6 Answers 6

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Short version: If you raise the bars, now the drops are too high for their best use: steep and technical descents.

Longer version: “Aerohoods” are used in flats. You can get the brakes if you need to, but you probably won’t. You can shift easily and your weight is balanced between the two wheels.

When it’s time to descend, you want to get your center of gravity as low as possible and load the front wheel so there is plenty of traction in sharp turns.

If you raise the bars, you lose these as two distinct options. The non-“aerohoods” and tops will also probably be too high to climb comfortably while putting down a descent effort.

The point of drops bars is to have multiple hand and body positions.

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  • Might also be worth talking about the safety element. You can grip the drops and get good leverage of brake levers, not so much on the aero hoods. Of course, you can quickly alter the position to the tops but that might be too late for an emergency stop or on rough terrain. I was nearly dropped off the hoods at least twice when it hit a bump, since then I often slightly alter the position to hook in behind the brake lever a bit, even though it slightly offsets the grip from the full "aero hoods" and more cautiousness could avoid such events in the first place.
    – DoNuT
    Commented Jan 3 at 12:02
  • Do we want to ride even lower in the drops position than the "aero hoods" position? Or do we want straighter arms in the drops position?
    – Edward
    Commented Jan 3 at 18:14
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    @Edward both. It depends on the situation and rider. Again, the point of drop handlebars is to have many options.
    – Paul H
    Commented Jan 3 at 19:23
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    Steep descents already transfer weight to the front wheel, and that limits your ability to brake and to roll over potholes. Being in the drops also makes it harder to stand to handle rough bits, and mich harder to manual or bunny-hop. An experienced gravel racer or CXer might be more capable of this - but they'd be on a different geometry to those of us using off-road skills in road rides. So while your third paragraph is true, it's more applicable to racing (when the road is checked and cleared) than to other riding.
    – Chris H
    Commented Jan 4 at 14:08
  • @Edward and others, consider the first photo in this answer - depending on setup, your torso angle can be similar in drops vs aero hoods.
    – Weiwen Ng
    Commented Jan 7 at 11:49
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If you raise the bars, you'll also have a more upright position on the hoods, that is the most used position. If someone is riding dominantly on the hoods, it makes little sense to optimise for a position that is only used in specific cases, versus the general case.

As you pointed out, it would be a more relaxed position, but not everyone is looking for that, and I would suspect that the ones who are choosing a less comfortable position for aerodynamic purposes in specific cases will also favour a more performance oriented position for the general case.

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    Do we optimize hoods because it's the most used position, or is that the most used position because it's the one we optimize?
    – Edward
    Commented Jan 3 at 18:16
  • @Edward it’s the “middle” position.
    – Paul H
    Commented Jan 3 at 20:46
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    @Edward For me it’s the most comfortable hand position (because of the shape of the « handle » and the orientation of the hand), and also the intermediate one. So it’s the one I would prefer to optimise for.
    – Rеnаud
    Commented Jan 3 at 21:03
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You'd need very high bars to do your aero drops setup. That would mean your other hand positions are seriously compromised both for comfort and aerodynamics - and you wouldn't be much lower than on aero hoods.

My road bikes are both set up for endurance, so have fairly high handlebars. The drops with straight arms are comfortable for long periods, as are the hoods with straight arms (cruising along) or more tucked (headwinds, making up time).

If I get in the drops and really try to tuck*, I reach the limit imposed by my thighs hitting my ribs before I can get my forearms horizontal. While I'm not pro racer skinny, it really is muscle (quad) vs. bone (ribs) and not belly. To avoid doing that I'd need my bars about 2-3cm higher, or my saddle too high.

As most of my descents are on twisty roads with poor surfaces, I prefer to descend on the hoods for extra control and longer lines of sight.


* I have a phone mount on the bars, with a little rain/windshield. Into a headwind I can try to get behind that.

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Keeping your forearms arms parallel to the ground is less effort on the hoods than the drops.

In the drops you keep your hand in a handshake position. The position depends on grip strength since there is little support for the lower edge of the hand.

What is more, you stabilise your arms and support your upper body with your wrists. The forces on your wrists are perpendicular to the straight axis from your elbow to your hand (cantilever). This is strenuous. You have to work against your hands sliding down the bends to a more comfortable position where part of the force is running along the direction elbow to hand. This position is less aero though.

On the hoods riders rotate the forearm, thumbs inward, to grab the hoods from above. The hand is in a stable position and mostly supported from the thick muscle pad at the base of the thumb. The forearms can often rest on the ramps of the bars reducing the cantilevered load on wrists. Even in cases where load isn't much reduced the hands and wrists are in a stable position that needs little mental effort to keep it (ie there's no sliding down).

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TLDR:

It is the aerodynamically most efficient position in a range of available positions derived from a typical road bike geometry, where the main focus is to sustainably ride fast (comfort is considered but never the main priority) - this varies depending on the type of bike but you'll never want to sit as upright as on a cruiser bike. You could change the bar height but that would also impact other positions, so it is a bad compromise, in my opinion. Your normal hoods position would be even more upright and so is the regular drops position. If you change a bike as suggested, you could ride full aero in the drops but everything else gets worse.

The longer version ...

A drop bar bike gives you multiple grip positions, you typically choose it based on the demands of your current riding situation and pick what suits you best. Unless you have a very monotonic riding profile, you'll very likely use various positions during your rides and they have obvious advantages and disadvantages.

You can think of it as one of those triangular diagrams in which you can either get extremes or compromises but never the best of all dimensions.

In terms of (road) cycling with drop bars, these attributes could be:

  • Speed/aerodynamics
  • Control/handling
  • Comfort

Let's think about the main positions and score the three attributes from one 1 to 3 points (worst to best)

Hoods

  • Speed/aero - 1 point - simply the most upright position and thus the slowest/least aero one
  • Control/handling - 2 points - You have a solid grip and can reach the brakes but the upright position might not be ideal while cornering.
  • Comfort - 3 points - You are sitting as upright as you can get on your bike and should be able to ride like this for hours

Aero hoods

  • Speed/aero - 3 points - the most aero position on dropbar bikes
  • Control/handling - 1 point - You don't have good leverage on the brake levers and no good grip to the bars. Steering in this position might also feel akward
  • Comfort - 1 point - It is aero but the hunched-over position has the highest demands on your back and core muscles

Drops

  • Speed/aero - 2 points - Aero but allegedly not as aero as the aero hoods
  • Control/handling - 3 points - The best grip on the bars and access to the brakes, so you will opt for the drops when descending technical roads. The low position also provides a lower center of gravity and more weight/grip on the front wheel. When sprinting, you are still aero but very unlikely to slip off the bars and crash.
  • Comfort - 1 point - Pretty much the same as the aero hoods, hard on the back

(Positions like the 'puppy grip' are not listed because the UCI doesn't approve of...)

A good and comprehensive listing on aerodynamic efficiency of bar positions can be found here: https://silca.cc/blogs/silca/body-position-and-aerodynamics-on-a-bike

So, people will typically ride the aero hoods on non-demanding straight roads because you want to go fast and can compromise on handling abilities. That doesn't mean you can't corner in this position but you can only reach the very top of the brake levers and thus, input force is limited. You may also get knocked off the bars when you hit a pothole, at least more likely than in the other grips.

Changing the bar height as suggested would only compromise your options because you compromise on aspects like lower center of gravity or your general bike fit, at least when you are an performance-orientated cyclist. If you're looking at the height difference between the top of the hoods and your drops, that would easily be 10 cm, I guess many pre-build road bikes don't even have enough steerer tube to accomplish this without extenders, etc... You could do this when your back demands an upright position and only ride in flat terrain but then you're potentially better off with a flat-bar sports/cruiser type of bike, anyway.

I'd personally find it odd for somebody to look for a super-aero drops position (so, clearly aiming at performance) but sitting like a sail in the wind in any other case and compromising on pretty much all other riding positions for it...

P.S.: Perhaps I've overshot a bit with this answer but I wanted to give some context on the pros and cons of various riding positions to outline the "why ride aero hoods")

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    I don't think the TLDR answers the question- aero hoods are the most efficient position because people put their handlebars at the height which makes aero hoods the most efficient position. The question is "why are bars at that height?" Your direct answer is that when raising the bars, "you compromise on aspects like lower center of gravity or your general bike fit..." So do we need a lower center of gravity than the "aero drops" position in the question gives?
    – Edward
    Commented Jan 4 at 0:04
  • @Edward I don't think that the height is determined by the correct offset for aero hoods, the starting point is a suitable normal hoods position, i.e. straight back, upright position and the rider is comfortably able to reach the bars and controls - everything else is derived from it with the aim of providing a decent range of "operational modes" if you will. +10 cm for the sake of "aero drops" pushes the upper position out of the "negotiated" window and make it unusable for many, i.e. people would ride in the drops as their relaxed position but then lack a more aggressive position, etc...
    – DoNuT
    Commented Jan 4 at 0:46
  • Not sure how to put that into a TLDR but all of that is a bit like somebody insisting to fit a higher seat in a convertible and then having your head stick out above the windscreen when you could have just adjusted the rear view mirror... it's all there, you just have to use it as intended^^
    – DoNuT
    Commented Jan 4 at 0:49
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    IMO there are 2 versions of aero hoods. (1) the hands are in almost a normal hoods position and can reach the brakes trivially, but the forearms are horizontal. (2) the fingers are over the hoods in a puppy-like position but more secure - and with slower access to the brakes. The extra reach of (2) means the forearms can take more weight, while in (1), your back and triceps have to hold you up. (1) is good in changeable riding conditions, such as short sprints or sudden headwinds, and when you might need to brake. (2) is better for sustained use, when you might use aerobars if you had them
    – Chris H
    Commented Jan 4 at 13:52
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    BTW drops can be much easier on the back than aero hoods, because you can take a fair bit of weight on your arm bones rather than your arm muscles
    – Chris H
    Commented Jan 4 at 16:14
-4

No answers yet have mentioned the use of the drops in a race sprint finish.

Despite many road bike owners never really racing in any form (even just being first to the cafe), they still like to look racey, and therefore slammed stems, inwardly pointed levers, 5-figure aero oriented frames, minimal tools/water, boringly thin walled tyres and the rest are a common enough theme.

The opposite being the over-accessorised commuter bike with all its awkwardly installed, upside down, backwards bar/lever, fork, posts, QRs and mounts still there for long lost gadgets.

I guess inbetween are the bulk of reasonable people just enjoying cycling that can be swayed either way depending on what YouTube channel or targeted advertising was yelling at them that week.

Try out what you're suggesting, see how it works for you 🙂.

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    Someone’s got an axe to grind.
    – Paul H
    Commented Jan 3 at 20:45
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    The only useful aspect of this answer is the first paragraph about sprints (even though it lacks the reason why: control) - the other 90% are just a rant on the current state of cycling, and even that is just a social media bubble clichè, even on race grids I don't see as many Tarmac SL7/8s as on my Instagram timeline but endurace frames and 2010s rim brake bikes, instead^^
    – DoNuT
    Commented Jan 3 at 20:53
  • I talk about the bulk of people being reasonable and just enjoying cycling. Personally I think that if you're reading rants and axes to grind here it says more about you guys than me. I have this feeling like I need to apologize for some reason, but I'm not sure what about 🤷🏻‍♂️ Commented Jan 3 at 21:40
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    No need for an personal apology but it's not really a neutrally written answer to the initial question. :)
    – DoNuT
    Commented Jan 3 at 21:46
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    OK I now understand it as an odd way of saying you do you but I'm not sure if that is good advice when the general consensus in most answers is that you essentially give up other positions for the sake of solving a problem that didn't really exist. Unless somebody really only wants to ride in the drops and doesn't care about any other aspect, i.e. never descends or rides on the hoods, you'd have to raise the bars between 5-10 cm for that adjustment and that's a lot to throw your fit off.
    – DoNuT
    Commented Jan 3 at 23:20

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