A disc is the fastest wheel. The % of time saved is always the same so as a % the actual amount of time saved is more the slower a cyclist you are.

Remember - a disc is disc is a disc. In otherwards you can spend $$$$$ or $69.95 for a CH Aero disc cover that will be just as fast.

Run the disc. Then you'll be faster and feel like you can justify it ;)

Besides, if anyone thinks you're a poser with a disc they'd think the same with a pair of 404s. And they'd be wrong anyway.

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"if anyone thinks you're a poser "

That's the nice thing about a CH Aero cover - nobody thinks you're a poser and the dummies who spent the big bucks who everybody else thinks is posing don't know that it's just as fast.

A disc is a disc is a disc.

if you've got money to burn, great, buy the disc. i did this season and i've only run it once. why? i'm just more comfortable on my training wheels. if i had it to do again, i would wait until i'm so close to a kona slot that a couple of minutes might matter. better to get a coach or swim lesson imho.

The actual amount of time saved with aero wheels vs 32 sp box rims is discussed here

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

I've heard that the second most regulated bicycle offense ( other than excessive stem spacers) is unwarranted use of a disc. I think there is a chart post on-line indicating a sliding scale factoring in age and speed and if you don't meet the grade and are found riding a disc, your entire bike will be confiscated.

Seriously, making your self happy (and faster) is your primary concern. A disc will make you faster, however, will the increase in speed be proportionate to the cost? (that is a hard arguement many components we use in this sport). That is a subjective question based on your priorities.

I say buy a disc and don't look back

these aero covers are easily fit onto any wheel system? Including the Ritchies on my Dual?

And by someone who is the Mr. Bean of bike mechanics?

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kiwipat

per ardua ad astra

If you can afford it, then get it

Or get the Renn

If weight is a concern, go with 404's

The disc cover weighs 550 gms, so add that to a 1000 gm rear Mavic Cosmos wheel and you are at 1550gms!

Compare that to a 950 gm Zipp 909 and you are saving 600gms of rolling weight!

Go with the Zipp

NO

They definitely don't fit the OCR's.

I tried the OCR's, kysriums, and only succeeded with plain old mavic 32 spoke box rims.

At those speeds not many people will be passing you, get or make a disk. I made my for $25 in materials and allways get compliments on the color (red).

jaretj

The disc is faster and it stabilizes the bike better in a crosswind. It counters the wind steer caused by the deep front.

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Dick

Take everything I say with a grain of salt. I know nothing.

That's an urban myth tossed about by cyclists, wheel companies and bike magazine writers.

It is faster, that's for sure. But it doesn't enhance front-end stability.

I agree that a disc doesn't enhance front end stability. But, I disagree that it doesn't affect handling, often positively, when paired with a high-surface-area front wheel.

When the wind come from the side, it pushes the front wheel away which tries to turn your handlebars...since the front fork is positioned with the axle ahead of the headset. Pick a bike up off the floor with a straight ahead wheel, and have someone turn on a fan to your side....the wheel will turn away from the fan.

As for the rear disc, the wind still pushes it away and "out from under" the rider. Assuming you are familiar with counter-steering, this front end turning away, followed by a leaning into the wind, is a good description of counter-steering...the net effect is to swerve a little, but keep a fairly straight direction.

I've ridden an H3 up front with a regular-spoked rear wheel as well as with a disc. The H3 up front with a regular-spoked rear is harder to keep straight in a crosswind than if paired with a disc rear.

I don't want to overstate the beneficial steering effect of having a disc rear with the H3 front; of course, a disc rear and regular spoked front is easier to keep straight than the H3 front and disc rear. And spoked front and rear are least affected of all these combos.

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Quid quid latine dictum sit altum videtur
(That which is said in Latin sounds profound)

daveinmammoth,

Perhaps the parallel question is, "Can you be slow (relatively) and ride an expensive bike?" One sees it every day! I rest my case.

Next question?

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Ben Cline


Better to aspire to Greatness and fail, than to not challenge one's self at all, and succeed.

I tried it with an Open Pro rim and it was OK but the cover/rim interface isn't that great. I'd highly recommend a plain box rim, nothing deeper.

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I have 2 H3's for races. (Wish I had a disc instead of the H3 rear. I tried a friend's disc with my H3 front for 10k after my 2 H3's for 10k in a significant cross winds. Clear difference.

When you are tilted over to counter a cross wind (let's say it is from the right), an decrease in the wind makes you steer right because of the tilt. An increase in the wind makes you go left.

When you have a disc at the rear, the wind pushes your tail around to the left trying to steer you right. An increase in the wind increases this steer to the right, countering the winds tendency to push you left. A decrease in the wind, lessens this rear push, decreasing the right steer countering the increased right steer cause by the decrease in the wind while tilted to the right. (I hope that's clear and right.)

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Dick

Take everything I say with a grain of salt. I know nothing.

i've listened to you praise the virtues of the CH aero cover as being the equal of a disc (regardless of brand) for sometime now, and am curious, do you not believe that the stiffness of a disc wheel contributes to a more efficient transfer of energy from the rider into the wheel, and therefore would translate into a quicker velocity when compared to the CH cover, even if the aerodynamic qualities are identical?

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"Failure is an event, not a person."

Why would a semi-hollow-honeycomb-mesh-whatever disc be stiffer than a 32-spoke box rim wheel?

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"I tried the OCR's, kysriums, and only succeeded with plain old mavic 32 spoke box rims."

I've got a Mavic equipe and I can't fit the cover without at least one hole being over a spoke. Can I just drill a new hole for the mounting screw?

Which Mavic rim do you have - I might just go and get a new wheel.

I believe it is the Mavic MA-40.

I used DA hub, 32 spokes and it fit perfectly.

It was frustrating discovering first hand that it would not fit the ocr's.

I blame the bastard who gave the review on the excelsports.com site who said it fits a rim identical to the ocr's.

Believe me, it will go on much easier and the MA-40 with DA hub is quality and fairly light.

jhc,

You already know this answer.

The disc has no rotational flex. It is solid. It also has no vertical compliance, save for the compression of the tire which typically is at very high pressure on a disc. A disc is also more "stiff" than a low spoke count high spoke tension rear wheel, that is commonly referred to as "stiff" because of its more limited rotational flex and limited vertical compliance as a result of the higher spoke tension compared to a traditional 32 or 36 spoke wheel.

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Ben Cline


Better to aspire to Greatness and fail, than to not challenge one's self at all, and succeed.

"do you not believe that the stiffness of a disc wheel contributes to a more efficient transfer of energy from the rider into the wheel, and therefore would translate into a quicker velocity when compared to the CH cover, even if the aerodynamic qualities are identical? "

Good question. I'll guess that for the average 200-225 watt producing AG'er then the answer is likely no. If you're Jan or Lance riding the TDF TT then the answer might be completely different.

Let me tell you why he praises the virtues of CH aero - he has shares in the company that makes them!!!

You don't belive me - check this post:

http://forum.slowtwitch.com/gforum.cgi?post=144721

Then scroll down to and read his reply.

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