https://flocycling.blogspot.com/2013/...saves-day.html

Interesting article about web servers, maybe, but definitely not about wheels.

He probably meant to post this one ? https://www.flocycling.blogspot.ca/20...vs-weight.html

Oops! Thanks warp!

Makes sense. Bad news is I love light Al wheels and hate deep carbon wheels so I'm not going to save a lot of time. Good news is I'm not in any hurry.

Very interesting. Aero wins in all cases over saving weight. But since these are long races where the rider is pretty much going a constant speed, it makes sense. For those of us that do group rides and crits I figure a lighter wheel can have its advantages as there are many times where you have to accelerate depending on other's speeds.

Incomplete. The author neglected to account for wind. Read to me like a fine sales pitch not an informative blog post.

Yes, seems like a good article. Merge that with everything already written and I stand by my opinion that upgrading wheels for either weigh or aero isn't practical at all for most of us. A well built average wheel will do more for most of us than anything. Glad you posted this so I'm not tempted by marketing to get new wheels because they are a couple hundred grams heavier than some and only slightly aero, with round spokes.

Now tires - that's something I'll obsess about this spring.

It's a blog not a scholarly article.

Also this is for a TT. If you are racing and a 1kg lighter wheelset made the difference between staying with the group or not on a long climb the weight then becomes more important.

+1.

The testing only applies to constant efforts like tris or TT. There is no accounting for the energy needed to accelerate the wheels hundreds of times.

I am a fairly decent sprinter, not good enough to be pro tour caliper, but I have won a few pro 1\2 races in field sprint. I have also gotten beat in quite a few more. Coming out of a final corner and trying to accelerate, only to get nipped at the line by a couple centimeters or less really sucks.
So aero usually trumps weight, but you still want to have light weight for the type of rides a lot of us are doing. It's a sport of millimeters at times, not a sport of time at all times.

Aero savings will also be lessened in a draft situation.

As for sprinting, its an interesting balance because you have accelerating wheel weight balanced against aero savings at sprint speeds.

The FLO article wasn't even about tests. It was a computer program simulation. Notice how they didn't post all the results, just some of them to make their points. I'm very skeptical. For one thing, they are saying that in the Alp d'Huez "ride", which averaged somewhere between 7-8 mph, the aero qualities almost erased the significant weight disadvantage. At 7-8 mph??

Do you happen to know of a test showing rider results (or even simulated) showing this? I have seen plenty showing added watts for single accelerations, usually from 0 to 30kph. But nothing showing something more typical of a crit, like multiple 35 to 55 kph over a time period. I realize not the easiest test to do, but at least a simulation should be possible.

I tend to be skeptical of weight advantages of a few hundred grams simply because I would expect somebody to publish some convincing data to answer stuff like this Flo study or aero charts that Zipp puts out.

Yeah, but most importantly, carbon aero wheels look way cool. (Which is all that really matters.)

Skeptical is good.

Sorry, nothing but anecdotal evidence from racing hundreds of crits. I would like to see something as well.

qft

I read that with some interest, but my mind works funny so I need some help from you guys. One of the wheelsets they used was the Flow60 and the flow 90, I assume that was the 60 on the front and the 90 on the rear since most people write it that way and most people would put the more aero wheel on the rear. My funny thinking is this, since the front takes the blunt of the air coming at the bike and the rear wheel is sheltered to some degree by the bike frame, why don't people put the more aero wheel on the front instead?

Try riding in a cross wind with wheels like that and the answer will come to you.

I think if you do that math, you'll find the same result.

I understand all of that, but if you are already running a Flo 60 on the front that has a pretty good wall anyways for the wind to hit, a 90 is not all that much more. And I assume the test was done where there was no cross wind, plus one of the tests were with 90's on both front and rear thus they didn't care in the test so why not, for test purposes, put the 90 on the front and the 60 on the rear? I would think there would be test data improvement vs 60 on the front and 90 on the rear.

While it's true that it's easier to accelerate the lighter wheel during that period that you are accelerating it, the aero wheel will be more efficient all the other times. The accelerations in crits, for example, tend to be short bursts most of the time, so you are definitely spending most of your time not accelerating too much. Therefore, it makes sense to me that even though the light wheel may conserve some energy during the actual accelerations, the aero wheel may still be the more efficient wheel overall since most of the time you are not accelerating. This is why a lot of us will just race deep tubulars because you get light weight and aero, so it eliminates the debate. Re: the draft, you will still be more efficient in a draft with aero wheels than on box wheels, maybe proportionately less, but I'll take anything I can get to be able to hold on!

If they accounted for wind then that would make their argument even stronger, since they claim that better aerodynamics has a greater impact than less weight.

The "significant" weight disadvantage was 524 gm. I'm going to make a ballpark guess that the bike weighs 15 lbs, they said the rider was assumed to weigh 170 lbs for a total mass of 83.9 kg. The extra weight is a 0.5% change in total rider mass. The rider is assumed to be putting out 250W, so to compensate for an extra 0.5% mass, the wheel will need to save 0.5% power (to first order), or a savings of 1.4W.

A savings of 1.4W at 8mph doesn't seem unreasonable considering people are routinely quoting 10+ W at higher speeds.