Why do people seem to choose "aero hoods" over "aero drops"?

Question

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:

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?

Answer 1

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.

Answer 2

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.

Answer 3

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.

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

Answer 4

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).

Answer 5

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")

Answer 6

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 🙂.