Nobody has yet demonstrated clearly that wide matters anywhere. You dropped pressure to 85-90 and it got comfy. You can do that on a less wide rim too. In fact you should achieve the same comfort on a less wide rim at a slightly higher pressure.

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Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter

You're right about the pressures. But taking a 19mm rim and dropping it to 85-90psi will make the tire corner poorly at high speed. A 23mm tire handles better at 100-110psi (for me). I will respectively disagree with you on the 19mm rim at higher pressure being more comfortable- IMHO.

And Jack, we could also add in that if you ride a 32 hole 14/15 traditional wheel you're going to be more comfortable also, since you get suspension from the spokes, as opposed to a high tension, low spoke wheel.

Does this matter for TT's/Tri? Probably not. I was giving my personal experiences. However, those wheels get used for road racing and crits mostly. The tire conforms to the rim and has a more even profile with less of a trailing edge with a wider rim. Not as much of a bubble. If you don't believe me, go hit a turn at 30mph. They handle better. Exact some thing mountain bikers are finding now. The balloon effect of tires make the handle poorly at lower pressures. The wider rim spreads the tire out and gives it a round profile.

As for the aerodynamic benefit- Im solely going off what I feel, and what the data points to. The wider rims are more aerodynamic in the wind tunnel. Hed, Zipp, etc, all show it.

Im scheduled to go to the tunnel in a couple weeks. I'll see if I can borrow some 19mm rims and see if there is a difference.

Apparently not from people who have objectively measured that kind of thing. Basically no impact.


At high yaw, yes. But yaw is almost always < 10deg



What would be interesting to see, to me, is the low yaw performance of, say, a pre-C2 Jet9 with a 20mm or 19mm tire on it vs the new ones.

Because for front wheels in tris/TTs, there is no reason not to go with a narrow tire up front in 99% of events.

For crit/road racing, yes I agree the wide wheel thing is probably a good idea.

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Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter

"At high yaw, yes. But yaw is almost always < 10deg"

Seems like there's not unanimous agreement on this. Hed's website seems to imply otherwise and it's pretty easy to get higher yaw angles than 10 degrees out of their online calculator even at relatively low ground wind speeds, assuming triathlon type of speeds such as 20 mph rather than pro or elite amateur speeds as 30 mph. Trek's white paper for the second generation Speed Concept includes some research on yaw angles on Ironman courses, and the average yaw angle varied from 3.6 for IM Arizona to 10.6 in Hawaii. So clearly for Hawaii a substantial part of the yaw falls above 10 degrees.

Seems like the one thing that everyone agrees on is that the faster the rider the lower the yaw angle, and it's probably pretty safe to assume that very high yaw angles such as 20-25 degrees are not that common.

Yes, slower ironman athletes are the people who will most want to look at the high yaw wheels. They going the slowest, and they are out there in the middle of the day when winds tend to be higher.

Faster ironman athletes, even at hawaii are ~90% under 10 degrees. I figure most males at hawaii are in that range, who qualified anyway. Those coastal races that will tend to have a direct crosswind a lot of the time will be your biggest high yaw producers. Maybe Galveston 70.3 as well?


If you do sprints/olympics/time trials, or are a fast ironman - low yaw probably matters more.

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Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter

No idea how but I completely missed that article :p
Thanks for the heads up.

I remember it but the charts were too fuzzy =)

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Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter

@Jackmott

Maybe I'm missing something (entirely possible), but when I set the HED yaw calculator at a rider speed of 25 mph and a wind speed of 10 mph I get a huge percentage of wind angles that generate over 10% yaw for the apparent wind to the rider. Something close to 55% of the possible directions of the wind.

Granted in half of the possible wind angles the actual wind is coming from behind. Because of forward motion, however, the calculator indicates that for a lot of the angles the apparent yaw of the wind that the wheels are actually experiencing is still a headwind, and over 10% yaw.

Assuming that HED yaw modeler is calculating the effects of tailwinds correctly, these "high yaw" wheels are going to make a pretty big difference on most days. Especially on an and out and back course, even with relatively moderate winds of 10 to 15 mph.

Interestingly at Kona there is quite a bit of variation in wind angle, despite its despite its prevailing wind and being point to point. This is shown in a real world test last year, ridden at 40Kph that measured the yaw over the entire Kona course in typical race conditions.

Maybe more interesting is that even at that pro speed yaw of the apparent wind was greater than 10% more than 40% of the time. And for another 38% of the time it was over 4%.

rstalk.mavic.com/yaw-angle-measurement-in-real-conditions-on-kona-ironman-course/

How did you get on with the 25mm on your P2? Considering the same set up, with new Conti GP4000s ii on my SRAM S60's. Hoping a bit more forgiving for IM racing, with reduced RR for good measure.

Jack, know of any data that compares the Jet+ disc to their Stinger disc?

It depends on the courses you ride, here in the UK it is incredibly rare to experience wind of 10+mph on a TT course. The windiest day I can remember riding was 40kph one way and 57kph the other way with pretty much a straight head/tailwind. Even that only implies a wind speed of around 8.3mph. The vast majority of days I only see a difference between out and back of a few kph, implying a wind speed much lower than 8mph.

Kona may well be different, it's a case of horses for courses to some extent.

So, has anyone seen any testing on the new h3+ ???

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