Racing wheels

Just bought some Mavic Ksyrium Elites. They are so much lighter than my training wheels, but do I really go faster?
They certainly feel faster. I have Continental GP Attack tyres. On the training wheels I have Maxiss tyres, which are pretty good as well.

I've read in a few places that good wheels are the single most important piece of equipment.

Any opinions on this?

Ksyriums have excellent hubs and slightly aero design. They might add a tiny amount to your speed on the flats. If they are lighter, especially at the rims, than your former wheels, you might notice some acceleration improvement and easier climbing.

I have both original Ksyriums and Eurus wheels, which seem to be an improvement over my standard Record/Open Pro, but I wonder if most of it is psychological. They are close in weight, and I doubt scientific tests have confirmed (or would) a significant difference.

Enjoy the Elites!

Three things make you go faster:
1. the motor
2. the motor
3. the motor

Mavic Ksyrium Elites are fine wheels and Continental GP Attack tires have super low rolling resistance. Both are a psychological boost. The positive attitude has a good influence on the three things that make you go faster. This is a great setup for racing.
GP Attack tires compromise wear to gain lower rolling resistance.

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David Ornee, Western Springs, IL USA

[QUOTE]Originally posted by daveornee
Three things make you go faster:
1. the motor
2. the motor
3. the motor

Mavic Ksyrium Elites are fine wheels and Continental GP Attack tires have super low rolling resistance. Both are a psychological boost. The positive attitude has a good influence on the three things that make you go faster. This is a great setup for racing.
GP Attack tires compromise wear to gain lower rolling resistance. [/QUOTE

Great response, couldn't agree more....it's the motor. Style and psychological factors are certainly important too. When I was doing Weds night citizen crit races (long ago), the ritual of taking off the seat wedge, water bottle and frame pump before the race sure made me feel faster.

Good wheels and tires certainly are key to a bike's ride, handling and durability, but "good" doesn't mean just the lightest, lowest spoke count or most expensive wheel you can afford to buy.

As a non-racer, I'm looking for strength to stand up to road hazards a long way from home, durability to run for many trouble-free miles, and good ride qualities. These are more important than going 0.2% faster. I've concluded that high-quality 32 spoke hub and rims are still the best wheels for my use.

You mention low rolling resistance on the GP Attack tires. I see tire weights everywhere, but has anyone tested rolling resistance of popular tires? Tire weights are everywhere, but haven't seen any data on rolling resistance at all.

Dan

Static wheel weight is only a partial indicator of what to expect. Where the weight is distributed on the wheel is most important with respect as to how the wheel will respond. The further away the weight from the hub, the heavier the wheel will feel. Therefore, to wheels of identical static weight may feel different, and the faster you turn them, the more pronounced this difference will be. Of course, tire weight could be a factor here as well.

A hub with better bearings (less friction) will likely offer less rolling resistance.

Naturally, a more aero wheel and aero spokes will create less resistance at speed, but the benefits are only as significant as your capability to attain higher speeds (back to 'the motor' argument).

Regarding the rolling resistance of tires, I suspect high pressure tubular types probably offer the least rolling resistance.

That being said, while I use Mavic OP w/chorus hubs for training, I've opted for a set of Campy Hyperon tubulars for events. When I get the Hyperons in, I'm going to make a very conservative approach at determining the real differences. Whatever real differences there may be, they should *definitely* be apparent given the contrast between these two wheelsets.

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Originally Posted by Flyer:
It is a matter of reading comprehension that you challenged by.

rotational weight ...rotational weitgh is what you don't want. If the weight is mostly from the hubs, that's not as bad.

Spider1977:

Nice wheels!!! It's good to see that you are one of the few people who have a set of heavier, slower wheels for training and trick, faster wheels for special occasions.

Some of the well know professional riders I have seen on training rides have shown up on 36 spoke wheels with ultra-heavy tubes and 700x25 tires (or bigger) for an enhanced training effect.

Wheels can make a BIG difference in speed, or the amount of power to sustain a given speed. It's NOT in your head. If it were, what's the point in spending many hundreds of dollars on trick wheels if slow, 36 spoke wheels would allow you to go just as fast for a fraction of the cost???

Fast wheels are very important and even though it may not seem so, they are usually well worth the money!!!

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I think everyone who has put in their two penneth worth to my query has made some good points. Some interesting discussion.

I do agree, that the motor is the most important. Mine is getting better with every ride. Hey I won my first Graded Handicap this week, with my new wheels, I might add. Only another 59 wins to have them paid off!

Interesting argument about rolling resistance of tyres. I suspect the road surface probably has more influence. Notice when you get onto a smooth surface how the noise changes. My Maxxis Hors Categorie 700x23C training tyres are slicks, while I note the Continental GP Attacks do have a tread.

By the way I love the sound the Ksyriums make at speed. Bugger the cost, they just make me feel like a pro!

Values for cr for typical bicycle tires and surfaces range between 0.0015 and 0.015. This is a range of 10 times, and includes the surface you ride on as well as the tire.
cr is the coefficient of rolling resistance, dimensionless
Where your power goes in mathematical formulae are at URL:http://www.sheldonbrown.com/rinard/aero/formulas.htm

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David Ornee, Western Springs, IL USA

Thanks Dave, checked out the mathematics. I struggled to work out what it all meant. The wheels still sound great though!

J-MAT: Can you scope the BIG difference in speed for me? My guess, based on sketchy data and my own (very rough) estimates, is that we are talking about speed improvements around 1%. Nothing to ignore for a racer, but not a huge deal for me as a club rider either.

The only wind tunnel test report I could find comparing several aero wheels to a conventional 32 spoke wheel. If the front wheel drag force is 0.6 N at 30 mph, and the best wheel reduces that down to 0.4N in best case (zero yaw) conditions, how much have we saved relative to the total drag of bike and rider?

At 30 mph, isn't that total drag in the range of 25 N, or 6 lbs? If so, best case speed improvement would be about 0.8%....or 0.24 mph. Certainly that could be significant to a racer or time trialer.

What does it mean to me as a club rider? On a good day, I'm able to crank a finishing pace of 20 mph (unless I'm sucking a faster wheel). Assuming a real-world improvement potential of 0.5% (slower pace, crosswinds, rough road rolling resistance), that gets me 0.1 mph at 20 mph.

Not huge, but wait, over a 3 hour ride, the finish comes 0.3 miles sooner. That's about a minute gained...just enough time for me to get off the bike, sit down and pretend I've been there "5 or 10 minutes"....

That's not a bad deal either, unless I have to compromise wheel strength or durability, or handling in crosswinds to get the 0.1 mph speed improvement. I want to spend my bike time riding, not truing wheels or replacing spokes. Having to finish a long day with a broken spoke and wobbly back wheel just isn't a good trade-off.

Just back of the envelop stuff here. My rough assumptions and rusty physics may be way off. Would appreciate if you have more accurate figures to work with.

Dan

A good aero wheel, deep section aero rim with bladed spokes and a narrow tire, will save approximately .5 secs per mile.

From 'High Tech Cycling' by Edmund Burke.

With all due respect to the late Ed Burke, there is no way such a broad statement can be used at face value, simply because there are many upon many influencing factors. Take it with a grain of salt!

This web site allows you to see the effects of wind and surface roughness on your power output. The effects are small but interesting.

http://vigyan.nsu.edu/~jan/simulatesi.html

Agree it's a generalization, but 0.5 sec/mile at 30 mph would be a 0.4% speed increase.....that doesn't seem at all far fetched for a "deep section" aero rim.

Dan