I just read the story on Hawaii IM Top 10 Finisher Bikes http://www.slowtwitch.com/cgi-bin/articles/page.cgi?g=89.html;d=1 and noticed that not one of them had a disc wheel. I have read repeatedly on ST that a rear disc wheel would be faster in almost all conditions than any other type of wheel. Any idea why the pros didn’t ride with a disc (was it simply too windy), or are the other deep dished rims actually faster? I ride Hed 3’s and have been thinking of building a PT rear wheel with cover.
Disks aren’t allowed at the Hawaii Ironman.
It’d make the first 7 miles into and after the turn around fun though!
Dewd. they are not allowed in that race.
Welcome to Slowtwitch!
As the other posters have said, disks are not allowed in Kona because the course tends to be very windy. In the wind, a disk can be like a sail making handling difficult. People, lighter riders especially, would literally get blown off to the side of the road. Some do even without disks.
In the wind, a disk can be like a sail making handling difficult
It can also act like a real sail and make you go much faster under certain conditions. Experienced disk wheel users will know what I speak of. Typically when you get a moderate side wind that is coming from the rear quarter, the wheel really acts like a sail and you can feel the effect pushing the bike along the road. It’s a weird, but very cool feeling.
Only problem is Hawaii doesn’t have ‘moderate side wind’ 
IMH '91,'96,'01.
it should be. that would make things interesting.
I get the sense they work well at close angle as well as a reach. Could be wrong.