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wheel inertia vs. ultra lightwheels
Posted: Mon Feb 16, 2004 10:54 pm
What is everybodys take on the concept of an aero wheel with greater perimeter weigt ie. Cosmic Carbone verses some of the ultra light aero wheelS ie Zipp404, AmerClassic 420 etc.
Mavic claims the inertia and the accompaning roll or momentum is " much appreciated". Is this roll or momentum perceptable in an ultralight aero wheel?
Posted: Mon Feb 16, 2004 11:24 pm
It really depends on what you are using the wheels for, if you are seeking an area advantage (tri or time trial) then the heavier areo whelset is the way to go, however if you are seeking a wheelset that can climb or accelerate quickly then the lighter wheel is the way to go.
We have a therad titled "lightest clincher wheelsets currently available on the market" which lists the weight, spoke count and (some) rim depth. You might find it useful.
Re: wheel inertia vs. ultra lightwheels
Posted: Tue Feb 17, 2004 1:15 am
ross313 wrote: Mavic claims the inertia and the accompaning roll or momentum is " much appreciated". Is this roll or momentum perceptable in an ultralight aero wheel?
That's because Mavic's Carbones are total pigs! Every study I've seen that really dug into it said you did not gain ANYTHING from having heavy wheels (due to momentum of inertia).
Now, if you're just going to roll them up to speed and keep them there, then fine. If you plan on repeatedly accelerating, get some lighter aero wheels. The Carbones are about the WORST example of an aero wheel.
Posted: Tue Feb 17, 2004 3:13 am
The Carbones are about the WORST example of an aero wheel.
No, there a great aero wheel. There just heavy. There a great aero wheel, just in need of a remake with lighter materials.
Posted: Tue Feb 17, 2004 4:55 am
Posted: Tue Feb 17, 2004 5:25 am
On the track doing an hour record a heavier wheel could help. Moser used an unusually large rear disc on one of his hour records. From a strictly physical point of view the wheel can store only the energy you put into it, so if the wheel is storing more energy it just means you had to work harder to put it there.
In the real world where road surfaces change, winds and shelter from it change, grade changes slightly constantly, you have to accelerate out of corners, avoid obstacles etc, I think rotating weight is simply a burden. Whether the burden is more than the savings from improved aerodynamics would depend on the grade, your power output and how much of a weight penalty the aero equipment costs you.
John Cobb has done a lot of research on weight vs aero and according to those aero is superior on almost any course unless it's all uphill and more than 7-8% grade (at least if you can put out the wattage and reach the speeds of his test subjects like Lance Armstrong).
Posted: Tue Feb 17, 2004 5:57 am
Good points Mises, can you tell us what weight the areo wheel Cobb tested was?
The WH540 is very areo but damn heavy, at what point is the weight/areo trade worth it?
Posted: Tue Feb 17, 2004 6:50 am
From a subjective point of view, a 38mm to 44mm aero section rim seems a whole lot faster and more energy saving than a box section rim ie.(Helium, Gel330). The effort expended in a very fast ride/ race with typical jumps, attacks and bridging up, seems to be less. I usually have a little more left at the finish with an aero set-up . . . Assuming the course is mostly flat.
Posted: Tue Feb 17, 2004 1:49 pm
read the article that mr. cobb released. however, the original thread was comparing the carbone to 404's or the american classic (which uses the same rim as the 404's). if climbing is the issue the later is much lighter than the carbones. if we're talking about aerodynamics the 404's are much deeper and it's rim shape decreases wind drag.
inertia would be difficult to measure in the real world since you are not excerting a constant force.
i'd go for the lighter wheelset (lightweights
)that performs well although most tdf racers use the carbones (d/t sponsorship) since i'm a weight weenie.
Posted: Tue Feb 17, 2004 2:02 pm
TDF riders get paid to use Mavic wheels, don't buy cause you think it's their wheel of choice.
Posted: Tue Feb 17, 2004 3:42 pm
Bruiser wrote:TDF riders get paid to use Mavic wheels, don't buy cause you think it's their wheel of choice.
Thats why you dont see the Main tour riders on the cosmic in the mountains!