Not seeing any speed boost from race wheels

Triathlon Forum
1

Last winter I acquired a set of race wheels at very good prices: Zipp 404 front, Hed 3D rear, both sew up. My training wheels are Mavic Ksyriums, clincher. Well, I’ve got a good amount of experience with these now, and I’m failing to see any noticeable speed increase over the Mavics.

Example: I ride a 7.7 mile training TT. It’s rolling, with about 400’ of climbing spread over four hills. My last three efforts have all been within 4 seconds of one another; I used the race wheels twice, and the Ks once.

For the last two runs, conditions have been very similar: hot and humid, with a bit of a breeze. I was 4 seconds faster with the race wheels, but on a purely subjective basis my legs also felt fresher on that day; on the slower day I felt sluggish on the hills.

I also ride another TT, which is a somewhat flatter 12 mile course, and have only used the race wheels this year, but comparing my times with last year I have yet to match my best time from last year with the Mavics; I’m a bit faster this year on the 7.7 mile course than last year.

OK, lots of variables here, and I don’t have a power meter, but my subjective impression matches the times I’m turning in; that there is no substantial speed improvement over the Mavics. I have good rubber on the race wheels: Zipp front, Vittoria CX rear. I use Vittoria Evo CXs on my Mavics. I run 120-130 psi on both sets of wheels, using the lower psi on the bumpier course and the higher psi on the smoother course.

I can think of some possible reasons for this, but my best guess, and this is partly based upon subjective observation, which is that I am getting higher rolling resistance with the sew up wheels than with the clincher wheels and that this is mostly offsetting the better aerodynamics.

Of course that is just speculation, I have no proof to offer. But I’m leaning towards selling the race wheels and replacing them with a clincher set over the winter. Oh yeah, that’s right, “Clincher wheels aren’t race wheels”, right now I’m wishing I hadn’t listened to that particular piece of wisdom, all in all I feel like the time and money I’ve invested in these wheels has been wasted.

2

You mean race wheels make you go faster?!?! I thought they were for looking cool? Don’t give into the marketing hype, spend more time and money on the engine to get faster.

3

Make sure you forward this info to Team Discovery, CSC and others who use aero “race” wheels with tubulars so they can make the switch as well.

Quick thought: if your POSITION on the bike (about 70% of total drag is you) is not “Aero” or optimal, then aero wheels aren’t going to help much.

4

I had a rear disk from a small manufacturer that was one or two MPH slower than my training wheels. I tried everything, even sending it back to the manufacturer, but it was still a dog. In the end I got rid of it and replaced it with a Zipp. I’m still not sure why it was so slow, but I think it was tied to a poor-quality hub and the wheel being out of balance.

Even my current 2002 Zipp disk is a little touchy— I have to loctite the rear dust caps to the right setting or that wheel will slow down as well. (On my model of Zipp disk, the dustcaps also hold the hub together, and they press against the hub body, so they have to be tight enough to avoid lateral play, but loose enough to avoid excess friction with the hub body.)

You might want to have a mechanic give your race wheels a once over. Also, Ksyriums are sweet wheels so you’re not going to see a huge improvement when switching to other wheels.

-Marc

5

I am certainly not an expert, but I have experienced a similar situation with my wheels vs my Ksyriums. My race wheels (spinergy rev-x’s) look awesome, but they are heavier than the Ksyriums. I think this hurts me when climbing and I need all the help I can get there.

Lets also not forget that most studies with aero wheels produce a gain, but they are small gains. Something like a few minutes over an iron distance course. This would be important for a pro team when every second counts, but the gain is so small that me as a mere mortal might not even notice the difference.

Josh

6

“most studies with aero wheels produce a gain, but they are small gains”

Here’s one of them:

http://home.hia.no/~stephens/aero.htm
.

7

I have had a very similar experience this year with my new tubular Zipp 404s compared to my clincher Richeys which came with my Cervelo three years ago. I’m still experimenting (ditched the Tufos for Conti comps), but am tempted to race in my next tri on my clincher Richeys. I fantasized all winter how I would be sooooooo much faster on my new Zipps. So far…zip.

8

With any study, there is a degree of error. Based on the study, the “Predicted time saved in a 40k by using aero wheels compared to standard wheels” seems to be in the 1-2 minute range depending on body position and level of fitness.

First we don’t exactly know what the ‘standard’ wheels are. The poster has a set of Mavic Ksyriums, hardly standard wheels. Also, what are the aero wheels in the study? Plus the study seems like it was in a controlled environment, probably not very realistic of real racing.

My point is that: Racing wheels are probably faster, but probably not significantly. But I do think they look sexy, and that would be the reason I would buy them because they look good. I would not expect a gain in speed. Perhaps there could be a placebo affect that gives you confidence boost and causes you to go faster.

9

The time savings of aero wheels is probably over-rated. Your observations in training are probably not consistent enough to detect the slight advantage. For professional cyclists where time trials can be won or lost by seconds they make a difference. In most triathlons that probably don’t change the outcome. I have had at least one multi-heat triathlon where I won my age-group by one second over someone in another heat so at times it can make a difference.

10

Standard wheels are box-section rims with 32 spokes in a 3x pattern.

Kysiriums will be faster than these wheels as they have:

  1. bladed spokes
  2. fewer spokes

Aero wheels WILL be faster than Kysiriums, especially the H3/404, which are two of the very best. By a noticable margin. And the lab studies are actually very representative. That is why the range of time savings is given. It is a range based on straightline speed and potential crosswind angle.

The testing “methodology” used here is really flawed. I’d also look at the quality of the gluing job.

11

One – you’re not using a clean testing method.

Two – if the aero wheels are not noticeably faster, then you’ve got a slow-rolling tire on the wheels. The wrong tire can easily wipe out the aerodynamic benefits.

It’s not hype – deep-rim wheels are faster, especially in cross winds (which are present 90% of the time).

At a minimum, it’s a minute over 40k; as much as 7 minutes in an IM. Each racer has to decide for him/herself if it’s worth it.

12

hmmm. Zipps white paper (consider the source :)) I believe shows that the Ksyriums are slower than a standard box rim, and that spoke cound has very little to do with drag. Could be wrong though. BTW, I train and race on Ksyriums.

13

hey ashburn, i have to ask - what are some of the faster rolling tires? i have michellin pro race on mine. clinchers.

14

Hed actually publishes their aero drag data for the different wheels. There is a difference:

http://www.hedcycling.com/wheels/

15

I am seeing the opposite in gains from my aero wheels. My training wheels, Cervelo p2k stock Ritcheys with bladed spokes are in the LBS getting a rear hub fixed. Last night I road my typical 40 mile ride. By no means is this scientific, (traffic lights, wind, etc) but my avg speed was about 0.4 mph faster then my previous faster ride, while my avg hr was 4 bpm slowers. Last night’s wheels are a renn disc and hed jet 60 (clincher, ya ya not race wheels if clincher :stuck_out_tongue: ).

As a side I passed two roadies, and I am sure they got a huge laugh at some tri-geek doing a ride in the middle of no where, with a disc.

Just wanted to share a different perspective.

Peace,

RF

16

I agree - the aero rims (I have Ksyrium SLs I train on and race on Zipp 404s) are faster. I figure on about 90 secs over a 40K course. Now a minute and a half might not be worth the money to many, but I lost many a hardware/places by 1 min as I have gotten faster over the years. Do you know how much extra swim training it would take to save 90 secs on the 1500m swim? A ton.

17

The technical articles on the Zipp homepage are well worth reading. Note th article about how wrong tire width can foil an aero wheel by up to 20%.

http://www.zipp.com/tech/aero-drag.shtml

18

I have a set of 2003 Zipp 404’s. Are the dust caps those carbon fiber circles on the outside of the hub? Mine tend to rattle and even spin making almost like a grinding sound and sensation. Dumb question, but this is probably slowing me down, huh? What should or can I do to fix?

Thanks, Andy

19

That is suprising that they are slower. Even if spoke count has very little to do with drag, it does have SOME effect (there is a reason that Zipps are 32 spoked…), bladed spokes are generally faster. Elliptical spokes are the fastest, but bladed spokes are usually faster than round spokes. But maybe not at higher yaw angles.

Do you have the location of the white paper? Couldn’t find it on the Zipp site. Thanks.

20

Make sure you forward this info to Team Discovery, CSC and others who use aero “race” wheels with tubulars so they can make the switch as well.

Quick thought: if your POSITION on the bike (about 70% of total drag is you) is not “Aero” or optimal, then aero wheels aren’t going to help much.

I hear this same argument over and over again, if the pros use sew ups then so should we. I don’t think this holds water. Sew ups are hand made and hand installed, and it is my belief that the actual performance of sew ups likely varies considerably in the real world, from comparable rolling resistance to the best clinchers (or even lower, as in track silks) to much worse rolling resistance than clinchers. Presumably the pros can pick and choose the best sew ups, with the least hop; and presumably the mechanics have the art of gluing them on down pat. By and large, us mere mortals take what we get for tires, and how many of us are super expert at gluing technique? And if you have a shop do it, how good and/or careful are they?

For what its worth, I measured an average .010" of hop on my clinchers. My front sew up wheel (Zipp tire) has .035" hop, and my rear (Vittoria CX) has .027" of hop. During the process of installing the Vittoria, I experimented a bit. When I first stretched the tire on the dry rim, it had nearly .040" of hop. With careful stretching as I tried a dry run, I got the hop down to .020. When I did the final glue job, it didn’t come in as round. In other words, installation technique is important. It’s reasonable to speculate that hop is going to add rolling resistance, just as riding on rough pavement adds rolling resistance.

My point here being that if you don’t get the pick of the litter for tires, and if you don’t have the best gluing technique, you may be better with clinchers in terms of performance. I’d love to see some extensive testing of all this, I suspect it would be very eye-opening.

As for my position, I’ve been working on my position for a year, it’s neither the best nor the worst; but I’m not sure that is relevant to the issue of whether my race wheels have a real world performance advantage.