[QUOTE=Brian Ratliff;16189597]Depends on the course and the race. A good wheelset might weight a pound less than a training set, which will matter if it is hilly or if you are accelerating a lot (as in a crit). A good wheelset might be quite a bit more aerodynamic and might save you 5 or 10 watts at 25mph.

Carpediem says 10% - obviously his power is greater than 50-100 watts. So that clearly doesn't match the 5 or 10 watt answer
Homebrew gives the very technical "not very much"

I know if I buy some new wheels one of the first things I'm going to do is another FTP test in very similar conditions to my last test and see how much time I saved & obviously compare watts to quantify in my mind the benefits of the wheels. Has no one else done this who can offer solid, precise data.

To paraphrase Anquetil, the purpose of racing wheels isn't to go fast, it's to win bike races.

[QUOTE=mike12;16190788]I said that the wheels might save me 10% in a race, and my average in races is typically 160-200w, so rounding down a touch that would be 15-20 watts. There are races were I spend 10 minutes at 225w and then get shelled. If against the same riders I average 200w and I can finish, that's a 10% decrease in power. Obviously there are other factors but to me that's the gross difference.

For steady state analysis there's a site where you can plug in some numbers:
https://www.analyticcycling.com

However, and I haven't tested this nor can I prove it in terms of math or a fancy websit, but the difference in a mass start race is more than just what power you put out; it's about drafting. Let's take a theoretical example (so it's easier to relate to).

Situation: You can sustain 250w for 10 minutes, give or take. A person on a moped going 30 mph passes you while you're going 15 mph. Your goal is to have a high average speed for the next three miles. You and the moped driver are on that three mile stretch. You have two options.

The first is to accelerate up to 35-38 mph, catch the moped, and draft the moped at 30 mph until the end of the three miles. Once you're in the moped's draft your work rate drops significantly for your given speed, maybe from 450w for 30 mph to something more like 250w, maybe 220w (based on my own experience). This translates to a 200-250w savings in energy. You'll average 30 mph for the 3 miles because that's what the moped did.

Your second option is to simply time trial as efficiently as possible while holding the same wattage, ignoring the moped that just blew by you. Realistically, for me, that would mean going 23-24 mph and holding in the 250w range. Your average will be in that range, slightly less because of the time it takes to accelerate to whatever cruising speed you hold. Using aero wheels might get you 0.1 mph here and there. Say it saves 10% - that would bring power consumption down by 25 watts.

In both situations you're putting down about the same average power. In one you make an initial dig to get into a draft. In the second you ignore the draft.

So, yes, aerodynamics makes a difference, in that in a steady state effort they can make a small but consistent difference. As people have pointed out here if you have a more aero wheelset (or frame or helmet or whatever) it's always going to be more aero (given things like proper wind etc). Technically it'll be more aero at 3 mph but you may not notice the difference - I certainly can't tell at 3 mph. At 30 mph, yes, or 35 mph, yes, or 40 mph, yes.

But much more significant than "aero" is how you ride in a race (hence my reference to mass start races). If I can do one hard effort, get in the draft, and then really really really ease off, I can save much more energy than I could ever save by getting more aero equipment for myself.

This has nothing to do with average speed over an hour, but it illustrates how one can go much faster for that hour.

For example in one race I averaged 27.5 mph @175 watts, at least until I had to slow due to a crash on the last lap of the race. Without drafting, being on Earth, on a flat road, with normal level winds, there would be no way any equipment change would allow me to go 27.5 mph @ 175 watts (and I did have an aero wheelset and an aero-ish frame).

The point is that in racing the most important thing is drafting. The individual's aerodynamics (bike, body) comes in a distant second.

Therefore aero wheels can help in a race. I find that light wheels also make a huge difference, allowing me to get into the draft quicker, therefore letting me save energy sooner. Light aero wheels are the best, and in the wheels in my picture the race wheels are the lightest as well as the most aero, the non-aero training wheels a bit heavier, and the aero training wheels much heavier.

An example in terms of outright speed. My current max speed in a sprint is about 40 mph on a given level road without much wind. I've hit as high as 44-46 mph regularly in the past, and on one set of wheels I hit 48 mph a couple times. My anomaly effort was during Hurricane George, where on a flat road I hit and held 60 mph for about a minute, so about a mile. At that point I had at least a 50 mph tailwind and it was gusting up to 80-90 mph. (Getting to that area we were struggling at 8-12 mph going into that wind, it was brutal.) Anyway those are my absolute best speeds.

In this clip I'm going 49.x mph twice. One is on a slight downhill followed by a slight rise, the other is on a slight rise. Would aero wheels have made a difference? Maybe, but not so that I could hit 49.x mph. It's much more important that I catch the truck's draft. Once I'm there I'm okay for a bit. Keep in mind that in the yellow truck example I'd ridden a very hard 3 hours already and I was a couple miles from home base. In the second I chased the two white trucks up and over about a half mile climb, then rode hard down the following descent to catch them as they were leaving the light. I was already a bit gassed when I caught them yet I still managed to break 49 mph.

I have ridden tubulars for years and would rather change a tubular than a clincher. My spare tubular is one that has been glued and ridden on; when it goes on the rim again it has no problem staying put. I have ridden 80 miles or more on more than one occasion on a spare tubular with no movement. Clinchers are harder to change and easier to pinch. Why limit yourself to the nicer ride of a tubular only on race day?! I used to ride Vittoria Corsas before they became exorbitant. I now ride on Vittoria Rally; inexpensive and good for 1800 miles or so...

If you are actually racing, there's another reason to have a second set of wheels.

Most crits have a wheel pit where you place your spare wheels. If you have a flat or broke spoke early in the race, you can quickly exchange the wheel there and get a free lap.

On some road races a wheel truck will follow the pack. If you have a mechanical with a wheel, you stop the truck and exchange your wheel.

CDR, you rode your bike into and out of a hurricane, including gusting 80mph tailwinds? Weren't you worried about flying debris? Not that it wasn't fun, but that seems pretty dangerous...

Evidently he made it...

My "watts saved" numbers are an order of magnitude guess based on my experience. It depends a lot on the type of wheel you have, etc.; you know, the details. But 10% for power seems high. On the other hand, because I am a larger person than CDR, wheels will affect me less, so his experience might differ a little.

Honestly I didn't think about any debris. The last time I'd been near a hurricane at relatively high wind speeds was at school and we were all outside goofing off, "sledding" down a hill on dining hall trays, stuff like that. So with the hurricane I figured it'd be safer than going out the next day when wind speeds were supposed to peak at over 100 mph. It ends up that the wind never got really bad, not much worse than what we rode through, although news teams managed to find a small ship that got washed up onto a beach. Overall it was a dud, fortunately for the area.

While we rode we never saw anything that raised any red flags. It was just really windy and there was a lot of mist /light rain / spray.

Also, I didn't mention it but I was on aero wheels. We were in town for a crit and so I only had my race wheels. At the time I used dual TriSpokes, aka HED3s, so I rode in the hurricane on those wheels. My teammate had Mavic Cosmic Carbones, the first gen of that wheel, so we were both on stupid wheels for the conditions. His then gf (and now wife) was on the ride as well although she had just regular box section clinchers.

It's different times. Halfway decent tubies are extremely expensive now, and nobody knows how to take one apart to fix after a flat (and nobody has the time); clinchers at the same time have gotten extremely good and relatively cheap. I do ride relatively nice tubies at the track where that property whereas they don't come detached from the rim in the event of a flat is greatly appreciated.

What if the race is a time trial or a leg of a tri? I'd think the purpose of those racing wheels is indeed to go fast which would in turn help win races.

Off topic, but incredibly funny that you mention fixing a flat tubular. Back in the late 80's I worked as a mechanic and parts mgr at a shop and I'd have to bring tubies home with me for repair while watching tv. Probably 10 per week, un-stitching, patching, re-stitching, and then re-gluing the strip. I had happily put away those memories until just now (although to be fair I loved doing it)

By the time my Vittoria Rallys get 1800 miles on them they are ready for the trash anyway. Once in a great while I will flat a good one. To be honest, I don't notice a huge difference between the Corsas and the Rallys, only about $ 75.00. They have been extremely reliable and comfortable to ride. I do agree on the safety issue about flatting on a clincher at speed vs. a tubular. It is scary to see someone go down when their rim hits the road. That said, if I ever get a new bike I might go the clincher route...

I used to do enough that I considered buying the gizmo that allows you to sew together an entire tire so that I could put a new tube in each time.

tirealert.com in Florida has been doing tires for forever, I think at least 20 years if not more. They put in a new tube. The club I race with does a "team order" once or twice a year. So far my flats have been on totally worn tires so I haven't participated but it's well worth it, especially for those really annoying flats that kill a tire 50 meters into its life (which is the worst for me, literally did not get from the car to registration on a brand new tire).

For a tire to get fixed the tread should be pretty good, there should be no cracks, and the casing needs to be good (no bulges indicating a cut casing thread).

In a race two weeks ago I was right behind guy whose carbon zipps taco'd. Thats why I use alloy clinchers

That's why you never will be a pro

One time I saw a Ferrari hit a wall in a race, thats why I drive a Toyota...

Funny it used to be a badge of honor to be the one fixing them, now I see the horrible manipulation the owner subjected me to as a teenager!

I got Enve 3.4 recently... could use my old Mavic's ES anniversary ed. as trainers now.. but prefer to just keep the Enve's on all the time.

I don't blame you. Enve's look great.

One old thing some people do is save nice wheels for just racing. So after a few years, they have a few miles on some barely used wheels and something newer and much better is on the market.