LOL...Duh

You're absolutely right, of course. Keep power constant with the changes I spelled out.

Like i said, I'm sure the disc is faster, I'd just like to see what the actual aero data in a frame is. Rotational data can be gathered elsewhere.

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Styrrell

http://forum.slowtwitch.com/...um.cgi?post=4033301;

808 on the front. Too hard to manage the spare for the back given the short valve required and difficulty pumpnig it up, so 808 on back too. Disappointing as I really only bought the disc for IM.

"808 on the front. Too hard to manage the spare for the back given the short valve required and difficulty pumpnig it up, so 808 on back too. Disappointing as I really only bought the disc for IM. "

Unless you see 10+ mph wind you want be giving up a lot with the 808 and even less with FC808. A lot of time I see disc on a calm courses (which is frequently the case in many races up and down the east coast) and I believe in these cases it has very little advantage, although I am still a believer in a disc for the rear even though the gains are small.

Running a disk looks too fast. It's hard to live up to that kind of pressure. Plus people think that if their wheels don't match that its somehow inferior.

Visit a wind tunnel...you'll probably save more watts than a disc for about the same price and you want have any of those issues.

I've done IMWA (that's Western Australia, not Washington :-) ) a few times, the last with a cover on 808. The profiles are pretty similar, so judging by the course profile and the write up at http://beyondtransition.com/...ronman-florida-bike/ I can't understand either. Sure, if you have to fly in, carrying 2 rears "just in case" is often not an option, but with a cover you have the choice to take it off, even on race morning.

And this from the guys at BeyondTransition:

"This is the ideal course to be bringing a tri bike, an aero helmet and a disc wheel. There’s no real need for any other gearset than an 11-23 on the back. In fact, you may even want to experiment with a 54t or 55t chainring. It’s that fast a course"

So why wouldn't you pop for an additional $120?

I'm doing IM FLA next year, and I was getting nervous that they don't allow disc wheels. The videos I have watched, I have yet to see any. Can anyone confirm or deny?

If this is a serious question: disc wheels are allowed.

It was and thank you

Desert Dude,

I did IMFL on Saturday. I used a disk. I had a great race and qualified for the first time. I conclude that disk wheels are made of super power go-fast turbo alien thermoepoxydreamciclejuice.

And your old buddy Carl Bonner had a great comeback to the Ironman world as well on Saturday. He's a great training buddy!

Bruce Richter

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thechromedome
http://www.favoritefinishlines.blogspot.com
http://www.cupcakecartel.org
My 20% off code for 2018 FS Series races: tricred18
"there are no drafters in heaven" - C Bonner

A disc wheel needs 3-5 watts to spin to 25 mph. Very good spoked wheels need high teens. Efficiency doesn't change much with weather conditions, frame type or rider dimensions.

How much speed or time savings would one expect by going from 808 Firecrest to an 808 FC Front with a Disk Rear?

Thanks for putting a number on it. Further illustrates my point as well. Even if there is only a 10 watt differencein rotational drag between a disc and spoked wheel you are looking at an equivalent savings of 100 grams of drag. For a good comparison the Non-UCI version of the p5 fork saves 18gram and costs ~1500 more.

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Heath Dotson
HD Coaching:Website |Twitter: 140 Characters or Less|Facebook:Follow us on Facebook

If a disc is so much better than why doesn't Zipp advertise it's faster than 3 seconds per 40K tt over a 808FC? I'm trying to understand why spending a crap ton of money to get 15 seconds is really worth it to people unless they are trying to qualify for Kona, trying to beat a buddy who is equal speed, etc.

I bought an 808FC combo front and rear a while back before I educated myself on the rear disc. It would be nice to have both setups but that new Super 9 clincher Zipp is releasing soon and is going to cost like $2,300. That's insane if you only get 3 seconds per 40K tt? Unless the new Super 9 clincher is a lot faster than their other discs? I have a cover for my 808FC just debating if I should run that for IM AZ in two weeks or if I'm better off just saying F it because if I flat its quicker to change the tire and that saves me more than 15 seconds alone. Using the crack pipe kind of sucks IMO.

One could imply from some of the data that it is more like 20 secs per 40k, but I am not certain about that which is why asked a couple posts up. Like you I have a pair of 808 Firecrests and like you I would sacrifice some time for an easier wheel/tire change especially if it is only a matter of 15 seconds.

In fact there have sources claiming that the 808 FC is faster than some discs.

sounds all to familiar....... right down to the iPad and the half lit garage.

Tim

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Tim

I ran one but I noticed that too while racing. I believe its because there were a lot of first timers out there. I didn't see many power meters either which was surprising to me

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"Keep those feet moving!" Me

I know we could imply more like 20 seconds per 40K, but if Zipp says 3 seconds per 40K (808FC versus their best Disc) which source is more creditable? Its their wheels. Not sure how really world their tests were or if just a wind tunnel.

I saw that information too about Zipp claiming the 808FC is faster than some discs. It would be nice to know which discs.

Just curious why it takes longer to change a flat? I run a disc cover on Hed Jet 60's and don't see any difference changing a flat. I also don't have to use a crack pipe since the cover is flexible enough that I can get the pump on without a crack pipe.

-Jeff

Not sure why you think a disc flat is tougher to change than a regular flat.

Ever try inflating a disc wheel, in the field, with a crack pipe, a CO2 inflator, sweaty fingers and a HR that's through the roof? Good luck!

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coming soon...

With the CO2 inflators you don't need a crack pipe do you? I use an Innovations (I think its called) and the head is spring loaded.

http://www.trisports.com/air-chuck-sl.html

Still, explain how this is different than a normal tube change. And take out the crack pipe, because it's unnecessary.