Field Testing: Handlebar Width

Some time ago, my ‘Bend It Like Clancy‘ blog looked at narrow bars for road riders, I promised I would be doing some testing a while ago, I have been, the results are not quite as I expected.

The Findings

From the outset, I’d assumed that wide bars would allow better breathing, it’s what I’d always been told, but rather surprisingly I found the opposite to be true. It kind of makes sense now, when riders are climbing on the tops, their arms are in a narrower position than their shoulders, the elbows are naturally used to regulate the open-ness of the chest. I’ve found the same rules apply to the drop bar position, with the neutral setup (of not actively trying to tuck my elbows in by having the correct bar width) as the ideal position for breathing & for body mechanics.

For this experiment I used 3 sets of bars, all with shallow drop, in widths of 38cm, 40cm & 42cm. Each was initially on a different bike, but with identical saddles, saddle position (fore/aft & up/down) & identical reach. With a few short sessions on the rollers, what became immediately apparent was that the 42cm bars feel absolutely wrong compared to the narrower ones. Surprisingly, I found that attempting to get the elbows tucked away, in-line with my shoulders, actually closed my chest with the wider bars. The effect of this was quite surprising, the general historical opinion that gets passed about is that wide bars allow better breathing. This may be correct to some extent, but only if the bars are the correct width & you don’t try to bring your elbows in. So effectively, when you’re riding at your hardest, you may have a detrimental breathing effect with wide bars, but otherwise you may feel better when you don’t require the extra lung function, not ideal for performance or comfort really.

What I Found

The 38cm bars felt best for me, here’s why.

Measuring across the recommended bones, the acromium, gives me a slightly wider position than 38cm on paper. But I think there’s a posture issue here, the back may become arched, posture when hunched over is quite different to taking the measurement standing up. So if you’re going down this route, bear that in mind, your bones may adopt a different position when riding than when standing up (this may be identical for some body types). So for me, the ideal way to sort out your bar width for cycling, is by cycling (see below for how to do this).

If you’re riding behind somebody, quite often you’ll see their hands gripping the bars & the wrist rotated to (consciously or subconsciously) bring the arms in line, some tuck their forearms inside the line of their levers when riding ‘aero’ on the hoods. You’re best to avoid these twists altogether by simply riding the correct bar width, then you’ll never have your hands sticking outside the profile of the rest of your body. I’ve now realised that I’ve probably not paid too much attention to bar width on the road, on the track I always rode narrow bars. I didn’t think it was too important on the road & thought that there was some kind of breathing advantage on climbs by choosing wide bars, I was wrong.

Your body wants to be perfectly aligned, that’s when it’s strongest, it’s when it uses the least energy to fight things other than propelling yourself forwards. As an example, take your pulse sitting down, raise an arm, watch your pulse rise. Everything you do, no matter how small, that forces your body to use additional muscular energy to counter any misalignment or dodgy bike setup, results in energy diverted from forward propulsion.


I did some power testing on the various bar widths, I didn’t really find any absolutely huge differences between 42cm & 38cm, but readings were always a little lower, somewhere between 5 to 15 Watts in general for the 38’s at 40kmh. Although that’s a wattage gain that’s hard to get from training alone, it’s in the margin of error zone & I don’t think I spent too much time trying to get exact measurements. I’ll take it as a gain, if it’s 5 Watts, great, if it’s 15 Watts, even better. I expected an advantage somewhere around this, but wattage gains of 40 or 50 Watts I’ve seen hinted at are probably false, but they may exist as you reduce bar width even more.

The main advantage I found was in overall efficiency, having everything in line makes a huge & significant difference to how your bike feels, it also seems to make riding on the drops much more comfortable. I’d go as far as saying the mechanical differences I found were dramatic. I rode 38cm bars while on one of those warm very windy islands, I’ve never felt so strong & stable in cross winds, bigger riders were getting blown all over the place & I felt very secure & controllable. A week after I used the wider bars at home on an old bike & I’ve never felt so bad in a lesser crosswind & felt very unstable, it wasn’t a fitness thing, the additional control was down to posture & alignment. Seated accelerations also felt like seated accelerations on the track, could that be down to alignment & efficiency too, everything seems to work much better. I’ve been riding the wrong bars on the road for many years!

How To Choose For Yourself

First, give this a try…..

  • Set up a mirror directly in front of your rollers (or turbo will do if it’s all you’ve got), but not too close, so you can get a good look at what’s going on without too much foreshortening.
  • Ride on the drops in your normal position & RPM, get relaxed, roll along for 5 minutes.
  • Start making some observations.
  • Are your hands straight & in-line with your arms? (sometimes riders compensate by twisting hands out to keep things in line)
  • Are you upper-arms & forearms in-line vertically?

If everything is perfect, you’re probably on the correct bar width already. If not, or you think something could be improved, you need to start experimenting with different bar widths.

I’ve worked out a simple way to go about this without buying new bars, simply base it on one side at a time. Loosen the bars in the stem & slide the bars across a little, you’ve probably got at least a couple of centimetres you can move without the handlebar reducing in size in the stem clamp, but a reduction in 2cm on one side, results in a 4cm drop in overall bar width (remember the other side will be way wide). Repeat the steps above & get one side aligned, then check that the other is more or less the same, get a happy medium for both, in case you’re built kind of funny. Now you can source new bars, they’re generally measured centre to centre.

The Gist Of It

Bar width was probably something I never really saw as terribly important, I always opted for narrow-ish bars, but didn’t realise until I tried a few different ones is succession how dramatic the effect of having correct bar width actually is. If you’re riding the correct width, you won’t need to listen to the advice to “tuck your elbows in”, you’ll already be perfectly aligned. The only reason you’ll need to tuck your elbows in is if you’re already on the wrong bar width, otherwise you’re creating more frontal area with angled forearms & it might even close your chest.

The number-one thing to learn from this is that your bike set-up is best tested on the rollers, if you’ve not got them the turbo is a poor second best. Rollers allow you to develop a much more balanced & natural position, with nothing supported artificially compared to riding on the turbo. Set up your position this way & you’ll be able to spot smaller differences easier & also realise what really doesn’t work for you (its ideal for aero positions that don’t make you too extreme & end up losing watts by fighting the bike, the turbo will lie to you in this case).

From my experience during this experiment, I’ve become a convert to a narrower bar than would be traditionally considered ‘correct’ for me, even by the bone measurement. I’m not quite as sure about keeping reducing the width for an aero advantage, as I found the biggest differences to be technical rather than watt-saving (which may in itself result in some watt-saving through more efficiency). I’m assuming (but I’ve not tested it yet) that the mechanical gains would reduce as bars get narrower, unless you have the muscle bulk of a track sprinter to counter the mechanical losses & reap the aerodynamic gains that must exist. Everybody will have a different ideal width, but increments are generally in 2cm steps, so choose wisely, from what I’ve found I’d err on the lower value if you think you’re in between. It’s really worth checking out for yourself & it won’t take you long to find out if you’ve got rollers (or a turbo) & a mirror.

Bike fitting is becoming a bigger deal these days, but if you set up yourself up in a mechanically correct position it is beneficial & from what I’ve found, you’ll not lose out on breathing efficiency. Don’t just go for the bar width I chose, do your testing as explained above, my 38cm maybe your 44cm, it’s all down to body shape & alignment. One thing’s for sure, I wish I’d done this little test years ago. If you’re not sure, get an expert to have a look over you, whether that’s in a shop like Hardie Bikes or one of the mobile bike fitters like VisualBikeFit, or many more now appearing across the country, they’ll be able to sort you out. Happy testing.

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