People say disks are faster in wind tunnel testing and there our a lot pf published studies confirming. But in real life, with winds coming in many different directions and courses varying in terrain, I am wondering whether empirically one is truly faster with a disk. Would I be better of with a disk rear or alternatively an aero wheel, say the Hed 3 Carbon rear (which is still quite aero and weighs much less).
My understanding is that discs are more advantageous on flat, constant speed, headwind type rides (IM Florida) whereas a trispoke may be better for rolling terrain, with crosswinds (IM Lake Placid) - basically anything (everything?) else.
You would have to figure also that ultimately, it comes down to rotating weight, and making that wheel rotate as fast as possible before you worry about cutting through the wind. Any type of varying terrain, and the trispoke would have to be advantageous. Am I wrong?
It’s all preference. Try racing both and decide which you like best. Despite having raced on a disc, trispoke, and Rev X, my favorite race wheels are Mavic Cosmic Carbones. However, there are a lot of Carbone haters on this site. Everyone has a different race day wheelset they swear by. You must carve your own path, grasshopper.
Hed had Lance ride the Hed3 in the last time trial. That, in itself, speaks volumes.
You may as well ask if allegedly “aero” frames are really an advantage. Some will say absolutely, others like me will say that all the aerofoil shaped tubes are just marketing (I have ridden a Cervelo for a year, so I’m not just pulling this out of thin air). It really comes down to who you want to believe. Wind tunnels say discs are the fastest wheel you can ride, but you can’t really test this out in the real world because its impossible to duplicate conditions.
Some discs are lighter than others and may be less of a disadvantage on hilly courses making them faster then H3s.
In the end I doubt either one will win or lose you a race if your legs don’t have it.
Chad
I just got my HED H3’s the other day! AWESOME wheels, I got the clinchers. Quick pick-up speed and once you hit top speed it seems easier to maintain it. A disc will be next new toy! Either a HED or RENN.
Disc/H3 for flatter courses and H3’s for rolling courses or courses with hills!
Good luck on your choice!
I believe the impression of the wheelbuilder.com PLASTIC (EDIT – I said carbon) covers is very good. So you could then get a set of 404’s (or I think any other spoked deep rim – Alps, 808, etc. – not sure on this though). Then you would have the lighter all-purpose wheelset, plus a disc when you wanted. The marginal cost for the cover is not that high, especially compared with buying a disc and a race rear wheel. I think this is really a great solution and you don’t have to really pick…
EDIT – just checked. Covers start at $65, and will be $5-$10 more for trimming. Hard to find any disc for that price! http://www.wheelbuilder.com/closeup.asp?cid=25&pid=185&offset=0
“Hed had Lance ride the Hed3 in the last time trial.”
That was a very technical course. Lance was willing to sacrifice some strait line speed for the better handling characteristics of a non-disc.
BTW, check out the Hed site as it publishes their aero drag figures.
“All the tests say a disc is the fastest”, but I’ve had my fastest times on Spinergy Rev-Xs, I’ve used both Zipp and Renn discs.
Wind tunnels say discs are the fastest wheel you can ride, but you can’t really test this out in the real world because its impossible to duplicate conditions.
That conveniently ignores the fact that you can’t duplicate whatever “real world” conditions you test in either since every day presents a unique set of temperature, humidity, wind, etc. conditions. The difference is that at least the wind tunnel results are for known conditions making some comparison possible while the conditions for the “real world” test are, for the most part, unknown.
I, for one, don’t understand the total mistrust of windtunnel data. Somehow, it is good enough to design the planes that we fly in and to design million dollar F-1 cars, but it is not good enough to tell us which wheel is the fastest? Like somehow, the windtunnel is this magical space that bears no resemblance to reality… But, if someone has their PB on a set of XYZ wheels, then that is much more valid than all the windtunnel data in the world… I don’t get it…
Buy a disc and ride it. Learn to handle it. It will go…
Of all the TdF TT’s, Lance ride in a disc in all but ONE, and it is that one that people talk about. A DISC IS THE FASTEST. Maybe not if you are hill-climbing Mt. Washington, but otherwise, it is.
If you don’t have the legs, though, it doesn’t matter at all what is attached to the rear of your bike…
1- Disc is faster
2- HED 3 is only marginally lighter than a Zipp disc
3- a disc is more stable and easier to ride. The windier it is, the more this holds true.
4- Lance chose to eschew the disc in the final time trial because he was convinced that on the highly technical course for that day, a disc would not corner as well. I’m not sure he’s right, but that was his rationale
“Hed had Lance ride the Hed3 in the last time trial. That, in itself, speaks volumes.”
Lance chose to eschew the disc in the final time trial because he was convinced that on the highly technical course for that day, a disc would not corner as well. I’m not sure he’s right, but that was his rationale.
It was not HED’s decision.
gigs,
A disc is faster almost all the time (unless riding in gale force winds, 35+ mph) or until the grade exceeds 6% or more for significant portions of the race. Weight does not really enter into the equation significantly until the grade really kicks up quite a bit! If you question this advice, check out Kraig Willet’s analysis of Chris Horner’s victory at Redlands a few years back. If someone can’t supply the link, just Google for it.
A disc with a trispoke is actually more stable and easier to handle than a pair of trispokes. That said, a pair of trispokes are pretty easy to handle even in windy conditions, 10-20 mph winds variable directions, after you have a little experience riding on them under similar conditions.
To qualify my comments, I have both, a pair of Hed3 trispokes and a disc, Renn 575. I have a lot of experience riding on them. I wouldn’t think of time trialing on anything but the disc/trispoke combination. The Hed3 trispokes are great for racing, especially long distance road races where they can make a bigger difference.
those look interesting. have you seen them in person? know anyone who has used them?
A trispoke rear and 50-ish mm front is a fine setup for many conditions.
XYZ’s? No… They are the ULTIMATE vaporware. Everywhere and nowhere at the same time…
XYZ’s??
no, the wheel covers you gave the link for!
Oh, sorry. I thought you were joking around…
I’ve not used them. But wheelbuilder has a very good rep. And I’ve seen some at races. The aerodynamics are sound. And I’ve only seen good reviews. Seems like a great option in my opinion…
I think that a disc is pretty usable for almost any TT/triathlon course, but if you are also races crits, it is nota good choice. I only race triathlons, so a disc is the best choice for me, but for someone that needs more versatility, it may not be the best choice, and then a wheelcover is a great option.
JRapp
I just got some of the covers from wheelbuilder.com for my wife and myself. They are very nice, but they are not carbon, just thin plastic. Still seem plenty durable. Weight weenies would probably have a cow though, since the covers weigh about 400 grams.
Anyway for other poster that asked, I went from a Renn disc (which I really liked, but decided to put the money elsewhere), to the wheel cover and I’m pretty happy with how the cover works and they way they feel when riding. I “think” I can feel the difference in effort/speed when riding. Who knows if that’s true, but the mental benefit is definitely positive at this point.