With all other factors being equal, you'll always be faster on the aero wheels. Here's the explanation:

http://home.hia.no/~stephens/aero.htm

As a roadie, i can only answer for draft legal races, and there I feel that, when using my Rolf Elans vs my campy shamals, it is far more easier to attack, jump out of a corner or, more likely, closing a gap when I am hanging on for dear life at the back of the bunch ;-). This being said I shall always choose the Shamals over the Elans for a flat non technical TT.

Plus I believe in Dr Ferrari's theory of micro-acccelerations while on a climb, which makes me think that the lighter the rim the quicker I climb. But I have no scientific background and others will sure disagree.

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Pardon my French.

What is your question?

I'm in the process of riding the same course (10 mile out and 10 back) - with a powermeter - and with different wheels to see what I can learn. I log all times and watts - only log early a.m. data with little or no wind. Its still in the works - so I've only ridden it with Hed Alps, Zipp 909's, and Velomax circuits - Hed 3's are coming - some of the above on tubulars - some on clinchers.....

Dave

when you get the Hed 3 vs a Zipp 999 disc, or a Hed disc vs Zipp disc data I would very interested what the real condition comparison comes out to be. Put out a post and let every one say why it is flawed. yada yada yada

I am considering getting a disc but am still torn on which to get.

I know others here will say why spend the $$ on a Zipp when I can get a Renn....the answer is I want the spinning disc of death sound comming from the back so I feel faster even if I am not.

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GO4 SMOOOOOOTH AND FAST

 
http://forum.slowtwitch.com/gforum.cgi?post=474268;search_string=cbtt;#474268

Funny you mention that "spinning disc of death" sound. I've got a new HED Alps tubular front and a new Renn disc rear. I'm racing tomorrow and I got the bike all set up and did a test ride today to check everything out. I know that "disc of death" sound to which you refer. But it's one thing when it creeps up and passes you and then goes away. It's entirely another when it sticks with you for the duration. Since it's looking like wet conditions and a course that's not entirely flat, I used the excuse to put the training wheels back on and stick with them for tomorrow. At least I'll appreciate the peace and quiet ... if not the pace and quiet.

Bob C.

I did a couple runs with a Renn rear and Alps front - but I think only 2 runs as I had to send it back to my friend (and I flatted on 1 of those). That set-up did well (clinchers - mixed type) but fairly limited data. I can do some Hed3 runs - tubular - yet I'm not sure what tubulars and how they'll be mounted - my friend has them and has only glued/taped the front. I have no access to any Hed discs....

Dave

Best thing about the Renn is that the cut-out is big enough to fit the micro-flate CO2 thing in. It does not fit in the Zipp. I hate crack pipes. How do you fill a zipp if you flat in a race? Carry that crack pipe and attach it to the CO2 - I have not tried it but those crack pipes are a pain and leak like mad - a 2 person pump job!