Hello Ed, love the shoes btw.

I've done a fair amount of Chung testing and train regularly with a lactate meter. Caveat that aero can be pretty specific so YMMV, data for 5'6" 145lb rider.

I did some testing last year about this exact same optimization problem. Slammed the bars and did 4 or 5 runs bringing then up 1cm each time. The difference was surprisingly small. The lowest position was the fastest, but iirc the difference top to bottom was ~20w. I also remember the 0cm and 1cm height being well within the margin of error, and then fairly linear up from there. All tests at ~70.3 speed.

I did the same positions (minus 0cm) on a 5x8 min session at FTP taking lactate tests after each, full rest to minimize interference. Mmols and HR were higher at 1 and 2cm but practically identical above that.

I then did a final test the following week of 2x20m at HR ~5bpm below FTP. The first was at at 2cm and the second at 3cm. Lactate tests confirmed similar outputs. Take home message from that was that for the same HR and lactate the 2cm position was within 5w of the 3cm position. The 3cm position was 8w slower aero so the choice was easy.

There's some big complications here and if love to redo this testing. If I did it again I'd just take my lactate meter to the track and combine them. But if also like to have data from more extended rides in the different positions. My current position does start feeling aggressive towards the end of races and fairly uncomfortable at the end of IMs. Not bad enough to need to sit up, but enough to make me wonder if giving up 5w of aero may pay off in the run.

Wow, That was a lot of work, great info. To make sure I understand, it came out that 2cm higher than your baseline was the optimized position?

What kind of cockpit are you running? What kind of forearm angle?

Thanks.

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Ed O'Malley
www.VeloVetta.com
Founder of VeloVetta Cycling Shoes
Instagram • Facebook

The optimized position was 2cm higher than slamming the aero bars down as low as they go. I had played around and it's probably near where I would have picked naturally, although I do tend to like lower positions.

My forearm angle is about 15deg. I have access to a machine shop so my bars are actually a custom built job of aluminum stock with some fiberglass wrapping. Similar in shape to the new Evolve bars

Some of what you’ve written is above my pay grade, but I did come across an interesting piece by Steve Faulkner in the UK as a friend of mine was one of the test riders. He was involved with the HUUB Wattbike track team and does commercial work with HUUB and Parcours.

The headline result was that raising stack height doesn’t necessarily improve performance when you take it as a combination of aero drag & physiological efficiency.
https://www.researchgate.net/...ize_does_not_fit_all

Thanks - I wish they showed photos of the setups for this. It's exactly this kind of data that I'm wondering if carefully used, modern, almost airfoil-like cockpits can change this relationship.

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Ed O'Malley
www.VeloVetta.com
Founder of VeloVetta Cycling Shoes
Instagram • Facebook

You need to add in the third variable besides aero and power especially for Ironman being comfort and the trade off for how well you run off the bike. Minutes gained in the aero/power variable can be lost in several km's or miles for you over there... Mind you leaning towards the power side is probably helping your run but regardless as they say ride for show, run for dough...

Oh for sure. But if you can do all that with minimal to no aero penalty with a carefully selected cockpit and position, all the better.

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Ed O'Malley
www.VeloVetta.com
Founder of VeloVetta Cycling Shoes
Instagram • Facebook

This is a huge focus when I’m helping pros get set up on their bikes, and it’s really best captured by perception at this time. How would you suggest this quantitatively be captured? This is where my head has been and I’m curious what others think.
I’m looking forward to Ronan’s testing that Ed references above.

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wovebike.com | Wove on instagram

I suspect the only way to capture position comfort over 4h+ is to ride in that position for 4h+. 4h rides are pretty common in IM training. I don't think it needs to be much more complicated than setting up a position that's seemingly comfortable and testing it in training.

It's tough because it also comes down to the athlete's fortitude. A position that is uncomfortable in the last hour could still be worth the aero gains if the rider is able to suck it up and stay tucked in. There's a distinct break point (that's different for everyone) where the discomfort is overwhelming enough to sit up. Aside from the position and measurables it's also mood, motivation, etc. Idk how you'd quantify that.

You're "doing it wrong" if the discomfort is ever approaching anything close to "overwhelming" - anything more than "niggling" is questionable. Racing is painful enough, budgeting your reserve mental fortitude to shitty positioning just isn't a good payoff.

Agree - spending the last hour of the bike miserable and requiring extraordinary fortitude and pain tolerance to hold position is no way to set yourself up mentally or physically for a good run, aero gains be damned. You need to get to the end of the bike feeling pretty good.

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Ed O'Malley
www.VeloVetta.com
Founder of VeloVetta Cycling Shoes
Instagram • Facebook

Yes, definitionally. Overwhelming, like I can't take it anymore and need to sit up. If you hit that break point then your position is incorrect. The other side is true as well tho. 112 miles on a drop bar road bike is easy and dare I say comfortable, but nobody at the front is racing an IM on a drop bars. I have to disagree that "Racing is painful enough, budgeting your reserve mental fortitude to shitty positioning just isn't a good payoff". Racing being painful is a given, but at a certain point pain and mental fortitude aren't limiters, physiology is.

To grossly simplify it to one variable, there's going to be a curve for every individual of aero bar height v finish time (within reasonable positions, not like below the front wheel). You'll see times improve with lower bars as they go from comically high to somewhere in the normal range, and then you'll see them go up again as the bars get low enough for the position to become unsustainable. (For some there may be a trade off between bike comfort and run speed as well. There may also be individuals where the break point for their position is actually below the peak aero height.) Those abnormalities aside, the game then seems to be to get the position as aero as possible while just barely being able to maintain it over the race distance.

I would say the only real way to quantitatively capture this is to race and see the outcome. A bit like I learnt how to race an IM by racing an IM. After all the coaching and advice, thinking I was prepared and knew my limits I had no idea. Position you may get some idea in training and from previous experience but is it optimal racing? With me in training more often than not everything feels good but when racing it took me a long time and a lot of tweaking before I didn’t feel something wasn’t quite right, be it seat setback, angle, height, bar height, angle, reach… I even did crank lengths in every 5mm…

As discussed find the most aero/aggressive position limit but still comfortable that you get off the bike as fast as you can but unhindered as possible to hurt your run. Much like finding the power limit you can push for the same outcome. I have gone full mantis like bars angled up with a custom made cockpit ending up higher and more comfortable/fairing than ever like the OP is alluding to. I had worked out I prefer the bars at 33 degrees, more reach and they unexpectedly ended slightly higher than I ever would have run previously but super comfortable. I could have trimmed them a little to get slightly lower but as discussed with the modern positions I feel any advantage would be minimal and I enjoy riding my bike more especially longer rides. As an AG’er enjoyment is why I do this silly sport so that and safety having better vision is a good thing. I say that after colliding with another car 5 months ago… I’m still pretty fast so I’m fiddling with a few other things but no longer the front end of my bike.

The question you ask is the most fun things I find about the sport. It is one of the endless things you need to work out be it training, pacing, equipment, nutrition, position the list is endless! And then how it all fits in over the three disciplines and everyone is different.

Pic from my last IM…

The problem with that study is that raising stack height is being implied as being synonymous with raising the front end height of the rider. However, many practitioners will know that if you raise the stack height, the riders head or the shoulders may well relax muscle tension and subsequently drop as much or more than the stack height itself increased. At which point, they're not accounting for several confounding variables.