I did some outdoor testing with ERO Sports in LA, and the combination of gloves and stacked hands gave me about 20 watts. Riding with stacked hands took a bit of getting used to, but was greatly helped by bridging my aero bars with a Profile Designs Aerobridge towards the end of the bars. Given that you have gloves, the Aerobridge is only an additional 20 bucks 
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Interesting… I’ve tried stacked hands while riding generally but didn’t like it at all. I seemed to become less stable as less contact area in the arm rests.
Is this something you just got used to or did you change pads?
Narrower shoulders is vital. There are newer way better arm rests and extensions these days that sort of force or hold your elbows in and hopefully your shoulders as well. They help you stay shrugged I guess is a different way to describe it.
A longer more stretched out torso is more aero as well. But besides working with a fitter I don’t know how to help you here other than it’s common for people to get bunched up in their pursuit of moving the saddle as far forward as possible.
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I didn’t change my arm rests out, and yes, it felt really awkward to me at first, and unstable in strong crosswinds. But the Aerobridge really helped a lot, and after several rides in the new position it’s become pretty second-nature.
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Most people can gain a few watts from upgrading to ceramic BB, jockey wheels, and waxing a Gucci race-only chain
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Yeah, I’ll investigate wax chain for the season as it seems an easy win. Already running a 56 front chain ring, but an oversized pulley system, ceramic bb is usually a final item of 
/W charts.
Doesn’t everyone.
What’s your current CdA and Crr?
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Somewhere ~ 0.21 - 0.22 with Crr at 0.003 and 3% drivetrain losses.
I tend to use my windsock for field testing - then do a quick sanity check in Aerolab later. For that I find it easier to keep Crr the same between systems to pick out relative changes in CdA. It seemed like a sensible approach.
In that case, there’s probably not going to be one single thing that’s going to save you 20 watts; instead, you’re probably looking at 5 or 6 changes that each might save you 3-4 watts. Sounds like your Crr is already pretty good so (unfortunately) you’re not going to find much savings there. You’re committed already to your skin suit, so that’s that. So 5 or 6 changes are each going to take you a while to identify, and you say you only have a limited amount of time to do testing. So I’d think if you can find 2 things that each save 3-4 watts, that might be more realistic. Are you talking 40k TTs, or something longer?
Also, how long are your cranks, where is the nose of your saddle, and how far forward are your extensions? Can you qualify for a morphological exemption?
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Usually shorter, around 10-20k, but the odd longer one. I’m too short for an exemption, cranks are 172.5s saddle is the Fizik TT specific short nose one. Saddle is over 5cm behind the BB. I have some room to play with extension length and height. We’re talking a few mm for safety when getting measured.
I’m intrigued by shorter cranks, I’ll keep an eye out for some.
Totally agree that I’m looking for the smaller wins. So far I’m looking at the following:
- stacked hands
- waxed chain
- saddle height
- tidy up the Di2
- bottle / no bottle.
- stack height
- disc
- helmet testing
In theory there is 5W to be had with swapping pedals, but that would require a new power meter.
Long term there is potential for faster bars on the front, better skinsuit, more helmet testing.
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OK, so 10-20K means you could save a few watts by going to Vittoria Corsa Speeds. They’re pretty fragile, much less robust than the Contis, but for that distance you can inspect before every race and still get several races out of them. But that’s a quick change that’s pretty much a no-brainer. Same with chain wax. The benefit is small but it’s relatively cheap and, like tires, you make that decision once and then never have to think about it again.
If you don’t already, it’s handy to have a high precision and accuracy pump so you can nail down inflation pressure.
In the longer run, shorter cranks open up a brand new world of possibilities, but it also can affect almost all other choices, from helmet to arm position to skinsuit, so that might be an off-season change. Helmet results depend on the individual, but the Rudy Project Wing (with the vent cover) looks like it’s been doing well across several riders. Skinsuits are about as individual as helmets: fit is key so a high-tech suit with high-tech fabric that doesn’t quite fit won’t be as good as an older low-tech suit that fits just right. Basebar/aerobar/aero chainrings are also areas where you could scrounge a few watts.
So, I’m optimistic that in the long run you can find more than 20 watts in a UCI-legal position, but if you’re time-constrained the quickest things you can do are: tires and inflation pressure, chain wax, hand/forearm position, bottle placement, shoulder shrug, and disc wheel. Of those, the disc is obviously the most expensive.
Best of luck.
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Not often you can get free advice from one of the sport’s leading aerodynamic experts…
I’m definitely intrigued by the new Rudy project Wing…if I was still doing tri’s, I’d be taking a hard look at it.
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Very very helpful thanks!
So far the shoulder-shrug and pelvis tilt have been ~20W of savings in testing. The biggest single thing I’ve gained. I’m sure with more time on the bike over winter I can make it a stable change and possibly some improvements there.
I will see what’s what with the skinsuits, and if I can race in a plain one. Helmets, I’ll see what I can get hold of or beg/borrow/steal.
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5.6w by switching inner tubes:exploding_head:
According to this: https://www.aero-coach.co.uk/time-trial-rolling-resistance-data
14.4 to go.
Apparently I saved circa 7.2 watts by switching my butyl tube for latex a few weeks back, I’ve not really felt it though 
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What tyres?
If you run clincher tires, latex tubes will save some watts
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And some latex tubes will save you more than others.
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Mitchelin Power TT clincher with the latex tube on the front. My disc on the back is tubeless and runs with a Schwalbe Pro One.
I’m using a Vittoria Competition its claimed to be the 2nd best out there according to Aerocoach. I maybe finally saw the benefit of it today. I was 4 years younger when I last rode todays course and despite getting stopped at 2 roundabouts (actually the same one twice, on the way out and way back) and racing in 30deg C; I provisionally I’ve came away with a 1min 41sec PB
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