Due to fortunate geography, this was my third time testing with Brian, @desert_dude, in Tucson. I once even had the pleasure to meet @marcag one time. I have a whole new bike set up this year and I was curious about the Rudy Dream vs. Wing, Multiple stacked BTA bottles, calf sleeves, and a new shoe company called Cadomotus , Cádomotus Transition bags and Aero helmets for Triathlon - Cádomotus Sports, vs. my Specialized S-Works Torch. Cadamotus comes from the Speed skating world and hava shoe called the Chronos Aero that resembles the Bont’s.
My bike is a QR VPR-i with TriRig Scoop Ultimate extensions. The only difference to the pic below is I added an angled spacer to the BTS bottle so the cage wasn’t angled down but is horizontal. These are also the wheels used as I wasn’t looking to test with my HED 8/Disc race set up.
The Baseline runs were with the Rudy Dream, I should have started with the Wing as it’s what I have been using, The Torch shoes, Zoot calf sleeves, and a single 750ml bottle BTA. We then did runs with the Wing. The Dream run produced a .210 while the Wing was .216. Then we switched the shoes which brought that .216 down to .213. Keeping the shoes and the Wing still, we went for the stacked bottles. Those runs produced .215, so for me that got worse. Leaving on the mounting bracket that provided about 10mm of lift to the BTA single cage allowed me to rest my chin on the bottle while in aero which brought is down slightly to .214. Lastly we removed the calf sleeves and I had a very low .206. In defense of calf sleeves the next day Brian tested someone who had aero socks and the calf sleeves were faster. He has no idea why he see’s so much variability with sleeves and maybe he can opine. Last runs were Dream, Chrono, one bottle, no sleeves. Here is the data:
So I probably saved 7-9 watts by fine tuning the equipment choices which tested best for me. Maybe :90 over a 56 mile ride. Here’s a shot from the test to see my position. Yes, my seat may be too high.
If anyone has any questions, ask away! Hopefully @desert_dude and or @marcag wil jump in as well as I’m a dummy. One thing I would like to add regarding the Chrono shoes. These are molded to the riders foot via heating them in an oven to acheive a great fit. I borrowed these from someone who had already molded them to their feet so they didn’t fit me great. With a terrific fit, I wouldn’t be surprised in the power transfer with them is superior to the Torch with the elastic laces as those laces will expand slightly on the pedal upstroke, potentially losing power transfer.
My thought was just if you’re really comfortable at the front or if bringing the front up a little would feel nicer with no penalty due to the bta bottle setup?
Any thoughts on keeping the rear axle removal tool installed? No penalty to leave that in?
And then with the 3 bottles plus the in frame bladder hydration, do you still need that aero frame bottle? Doesn’t that still have a penalty or are we seeing that filling in the frame as much as possible is better?
Brian suggested raising the front end 10mm and bringing the seat down a bit. I really didn’t even think about the axle tabs. We talked about the down tube Crono bottle and he said it can be of some benefit in crosswinds. I actually use that for gels or solid food. I don’t need that for 70.3 racing, just full IM’s. So just one BTA, the internal bladder, and one BTS is how I will race this year. That’s what I did in Kona.
It’s really easy to go down the rabbit hole of what about this or that. Yet you also have to see what the day gives you for testing, both with the athlete and weather, which is where an experienced tester running your tests comes into play.
For instance I saw an IG story where some coach was doing an aero test session here in Tucson a few weeks ago. They got something like a 20+ watt difference between the Aero Head and Adwatt. Which makes no sense to me. Do you want them running your testing session?
Yesterday was a really low yaw day when testing. The highest wind value I saw on my Kestrel all day was just under 3.5mph. Most of the time was <1.2mph. I took ~ 50 readings through out the session at various points on the course. I do a lot of walking to take pics & vids for each run from various angles. Super easy to take the kestrel along and whip it out anytime I notice the wind increasing/decreasing/changing.
From having run that exact down tube bottle test 100s of times, outside, on indoor velodromes and in the wind tunnel, my experience tells me most often you see a bigger delta between downtube bottle on vs off at higher yaw and almost nothing to very little at low yaw. It would have taken a lot of time to suss out that difference and probably even more time to figure out the skewer question. Easily could have burned an hour testing just those 2 questions.
Had we had 5-6mph winds then the story might have been different. Maybe that’s another session on a different day for someone?
Yet we still found ~ :01/km of savings or about 1.5min over 90km. Bryan really lowered my average savings rate between testing sessions since I found Justin Riele just over 20w when I had him in the wind tunnel earlier this year.
Regarding the calf sleeves it would be interesting if when you see a calf that tests faster than the calf sleeve you took a photo of the front, side and rear profile of the calf. Calf shape is so variable it seems like there’s something going on there.
Maybe that’s the next move, lipid injections into the calf!
A rear disc is 3-4w over a deep spoked wheel just from spoke drag.
At higher yaw angles drag can really drop. A deep wheel might see another 5w drop but a disc could see 10-12 15 or more.
That’s not going to be all the time. Maybe 80-90% of a racing season most people are going to be, my guess, 5-9w faster than a spoked deep wheel. The other 10-15-20% of your racing season could be 12, 15, 17w savings or more.
Do you mean to say that, without testing, a betting person would put an aero bottle there in the hopes that it’s at best a reduction in drag and at worst no penalty (or very minor penalty)?
I saw the raw data, I can add some light on what I saw.
The “no calf sleeves” had 2 runs, one showing more improvement than the other. The lowest run “could have” been weighed lower (more noise in it) bringing that bar slightly higher. Bottom line is both tests showed the calf sleeves to be slower. My “bet” is if their was another run or two in that configuration, the second to last bar would have been a bit higher.
But at the end of the day, the calf sleeves were slower. Maybe just a little less than that shows.
Interesting on the shoe result.
Dowsett did a similar test with the Bont Zero+ vs Torch in a wind tunnel.
In that test the results were flipped. With the Aero shoe (Bont) surprisingly slower.
Yeah I was aware of testing showing the Bont not performing as well including that one. I’ve never held one in my hands to know how it would have compared design wise to the Cadamotus. I have been racing the Torch for 2 years knowing it was considered a very solid aero option. The other thing I should mention is the Chrono’s are much heavier than the Torch if that plays a role in someone’s choices. But as I also mentioned, the fit of the Chrono being so custom is much better.
I guess I would add that the Chrono looks like a much cleaner, less bulky design than the Bont after rewatching that video.
A very low yaw angles it’s often pretty neutral. At higher yaw angles you can see various performance differences potentially good or potentially bad.
I remember testing 3 sizes of scott plasma 3’s one day and iirc 4 or 5 plasma’s in total during that testing trip. S, M, L. On the S it was faster to have a bottle on the downtube. On the M it was really not bad maybe 2-3w penalty yet if you needed fluids/nutrition and wanted to be sure imo that was the way to go. On the L the penalty was huge, >5w.
If you’re only 155cm tall I will (probably) have a different answer for you than if your 189cm tall
There are so many factors in play this is one of those questions where experience/knowledge base of person running the tests comes into play.
