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aero vs. low weight wheels(6 posts)

aero vs. low weight wheelsdan ida
Dec 18, 2001 8:55 PM
Obviously both low weight and aero would be the best. But if budget were limiting the choice to one or the other, which is preferable. 47 year old 158 lb. rider, beginner tri races, avg speed on hilly courses 19-20 mph.
thanks
re: aero vs. low weight wheelspmf1
Dec 19, 2001 5:18 AM
Won't all the tri-guys laugh at you if you show up with anything other than 650 c deep dish HED wheels?

Just kidding. I go to a tri-shop sometimes and do notice a different preference with people in that sport.

I guess for a time trial type situation that you face in a triathalon, maybe the deep dish type wheels are the best thing. Seems to be the choice of pro riders who do in time trials. The best thing would be a set of Zipp 303 or 404. These things are strong, light, aero, and (unfortunately) pretty expensive.

There are a lot of wheels out there these days which offer the advantages of a light clmbing wheel and some aero advantage (e.g., Mavic Ksyriums, Speed Dream Aerolights). Personally, I like these wheels because they are a nice combination of both. I have a pair of Spinergy Rev-X, but I hardly ever use them anymore. They're kinda heavy and they really get your attention in a cross wind.

If you're predominately a runner (as most tri-atheletes I've met are), you probably need to ride your bike more and might benefit from wheels you could use all the time rather than special event wheels. It reminds me of when I was in Davis, CA and people would pass Dave Scott on their bikes. They'd brag, hey, I passed Dave Scott yesterday. I'm faster than Dave Scott. I'd always ask them, yeah, and can you run and swim faster than him too?
Check out analytic cyclingMcAndrus
Dec 19, 2001 5:44 AM
At http://www.analyticcycling.com there are technical analyses of the performance differences of aero vs low weight.

The conclusion? Aero wins in all instances except extended climbing.
Aero is not always bettermclements
Dec 19, 2001 6:53 PM
There is a lot of emphasis on aerodynamic wheels, with technical articles "proving" that aerodynamic wheels are faster than equally strong, yet lighter wheels. The math is correct and incontrovertible. But remember that conclusions are only as accurate as the assumptions.

If you read these articles carefully, you'll notice they usually assume the ride is relatively flat and the cyclist is moving at a relatively constant speed. These assumptions simplify the mathematics. However, you have to consider whether this describes your typical ride.

If you ride on hills, then you spend far more time climbing the hills than going down them. At climbing speeds, aerodynamics are irrelevant. Even when going down the hills, you need to brake for the turns and accelerate as you exit the turns.

On the analytic cycling web site, if you compare their "standard" aero wheels with the lighter Mavic wheels, you will find that on any grade over 5% steep, the lighter wheels are faster. And the steeper the grade, the more advantage to the lighter wheels.

The converse is also true: anything under 5% grade and the aero wheels are faster even though they're heavier.

Conclusion: for hill climbing and twisty descents, go for the light wheels. For pounding the flats and gently rolling hills, go for the aero wheels.
assumptionsDog
Dec 20, 2001 6:56 AM
Yes, the Analytic Cycling site is wonderful, but as they say, "garbage in, garbage out." I think the key is plugging in realistic power (watts) numbers. When power is low, weight matters more (as you won't be riding as fast, where air drag matters more). They don't give any guidance as to what watt numbers to use, though, but this might be a guide:

*Marty Nothstein at full tilt: 2000 watts
*Mario Cippolini at full tilt: 1500 watts
*Yours truly at full sprint: 1000 watts
*Lance Armstrong on hill time trial, ave: 500 watts
*Cat 1 racer in time trial: 375 watts
*Cat 4 racer in time trial: 275 watts
*Club rider on long climb: 200 watts
*Leading paceline at 20 mph: 175 watts
*Back of paceline at 20 mph: 75 watts

Same of these are educated guesses, but likely are good enough for a reference. I think it is extremely important to get good information from the equations that power is somewhat realistic. Try different numbers and see how it affects the outcome.

BTW, an good coach ran an estimate of the difference between using aero and light wheels the entire route of the Furnace Creek 508, which has 35,000 feet of climbing, 64 mph descents, and lots of wind and bumpy roads. The conclusion was that aero won out by a whopping 6 minutes - in 508 miles.

Dog
re: aero vs. low weight wheelsJimP
Dec 19, 2001 6:55 AM
I raced tris for a number of years before knee surgery and chose aero but light. I am able to ride now but not run and still prefer good aero wheels. Nimble has several different sets of wheels that are light and aero. I have settled on the Nimble Crosswinds tubulars. The current set is about 1500 grams and you can run tires that are about 225-250 grams. The major weight advantage with this setup is rotational with the rim and tire weight being low. This setup is very fast - quicker and lighter than the performance of an ultralight bladed front with an old J-Disk rear.