I've never used them but my wife has used Rolf Vectors, Hed Deep/60 and now Zipp's on her P2K. Her fastest TT times have been on the Rolf's. Go figure.

When I spoke to John Cobb four or so years ago about this he told me that the Rolf Vector Comps (lacing pattern similar to the present Bontrager wheels) tested better in the windtunnel than the Rolf Vector Pros (spokes paired closer). You might try to email John at Blackwell if you want to see his data.

The "when I go back and look at my log, my fastest rides were 3 years ago when I was using Rolf Vector Pros" evidence is anecdotal and useless... too many other variables to attribute the additional speed to the wheels.

   

Since a wheel is aerodynamic or not aerodynamic primarily based on rim shape, I would say it is not possible that a Rolf Vector Pro would be as fast as say a Zipp 404/808 or other deep aero rim. It is possible that paired spoke could somehow make the wheel more aero given the same rim, I have no idea, but the improvement would likely be incremental at best.

Additionally, paired spoke wheels break much easier than regular spoke wheels.

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Dimond Bikes Superfan

So you don't think that the number of spokes and the shape of the spokes can also be a significant factor in drag?

You say that it "it is not possible that a Rolf Vector Pro would be as fast as say a Zipp 404/808 or other deep aero rim". So you can say this with 100% dogmatic certainty for every real world use or application? Even if, say, the Rolf had a very fast-rolling clincher tire mounted and the deep aero wheel had a poorly mounted or manufactured sew up that had much higher rolling resistance? (If you don't believe this is possible, then you'd better do some research.) Or, say it was a windless day, and wind tunnel test show that deep rims primarily offer an advantage when there is some degree of crosswind?

A) I'm well aware of the data and debate regarding rolling resistance as it pertains to clinchers versus tubulars, and within the various tubular lines. We are talking about wheels, not tires.

B) I believe the numbers from an article I've read by Willet at biketechreview put the number/shape of spokes at about 15% of drag, which was dwarfed by rim shape.

C) You need an attitude adjustment.

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Dimond Bikes Superfan

Link to the original thread???

FWIW, I have always loved my Rolf Vector Pros. Except I've been blowing through bearings and they're getting harder and harder to get serviced. I've always felt fastest on those wheels. (Yes, I know "felt") I've not nothing concrete to backup any performance impressions. But the wheels are a little flexy laterally (I have weighed anywhere between 190 and 225 when riding them) and they are relatively heavy. I swear that there's something to be said for heavy rims though, once you're up to speed.

Hey ericlambi, no offense intended, sorry if my attitude bothers you.

I think we need to make a distinction between real world performance and theoretical performance. On a theoretical level, I don't dispute anything you say. But the context here are some anecdotal reports of paired spoke wheels providing better real world performance than wheels with theoretically better aerodynamic performance. You may have meant to say "it is impossible for a Rolf Vector Wheel to have better overall performance in the wind tunnel than a deep wheel such as a Zipp 404", which is likely true. But you said it is impossible for it to be faster, which implies real world performance; and in effect, that it is impossible that the anecdotal reports of faster performance are true. Of course, the anecdotal reports could be total bunk, but there are also a number of reasons why, in the real world, a wheel that is supposed to be faster is not in fact actually faster, whether that be due to rolling resistance of the tires, or the particular wind conditions of the day, or some mechanical issue, etc. etc.

I just think sometimes real world performance is a bit more complex than the simple rules that people like to reduce it to, and I'm jumping on you a bit as an example of that. Just looking for people to say things like "in most instances" instead of "always" or "unlikely" instead of "impossible". Again, no offense intended.

a number of years back, when the vectors were first introduced, i read an article about the aerodynamics of the various models. one interesting observation they noted was that whenever you pair something (such as spokes) it INCREASES drag. when the wheels were actually tested for drag, the vector comps outperformed the vector pros (which had the spokes closer together, creating more air turbulence). so i highly doubt a paired spoke wheel would yield lower drag results compared to an alps and especially not with a rear disc.

i train on paired spoke wheels and was always under the impression that they were designed with strength as the main concern, not to be particularly aerodynamic.

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____________________________________________________________
"I'm happy when life's good,
and when it's bad I cry.
I've got values but I don't know how or why."
- The Who

[reply]a number of years back, when the vectors were first introduced, i read an article about the aerodynamics of the various models. one interesting observation they noted was that whenever you pair something (such as spokes) it INCREASES drag.[/reply]

Absolutely true. I have the exact opposite experience, I ride a 30mm deep 16 paired spoke 807g Velocity Spartacus front with 20mm GP3000 for training. I swap that out with a Spinergy Tilium 43mm deep 16 radial spoke 837g with 20mm Pro Race occasionally (my race wheel). On my standard 20 mile TT course I gain approximately 0.6-0.9mph average speed under similar conditions. I usually ride the same course within 0.2-0.3mph variance, so my conclusion is the Spinergy is about 0.3-0.7mph faster. The only advantage that the Rolf has over either of these wheels is weight...IIRC they are in the mid 600s in weight. But if you put a 20mm tire with a smooth sidewall-to-rim transition on a 30mm deep rim you could be almost equivalent to a poorly fit 23mm on a 404.

With the Spinergy and Renn on the back I can go about 1.5mph faster even under windy conditions than with the Velocity and 32H Mavic Open Pro on the back. I found the Hed Jet60 to be roughly equivalent to the Spinergy (too small of a difference to be statistically significant) and the Jet60 has a 65mm total depth...pretty hard to handle in heavy winds. The 43mm is no problem even in 20-30mph gusty crosswinds.

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On a track a Rolf Vector Pro is faster than various deep rim wheels, the testing has been done. Of course there are no crosswinds on a track, and deep rims test better than shallow rims when there is wind coming from an angle, so you can read this anyway you want.

I doubt that there is a big difference. If there was a big difference in aerodynamics and strength, then I think more wheelbuilders would move toward the paired spoke trend.

And, if paired spokes hindered performance in any way, I doubt that Discovery Channel would ride on them.

Well, I'm not suggesting you believe everything on Zipp's website...but their comments on aerodynamics do seem pretty legit.
Here's their propoganda on the subject:

http://www.zipp.com/tech/whrims.shtml

By whom and where is it?

By a friend and teammate (who happens to be extremely fast) for his own personal use. A few years ago the British WCPP found the same thing in their testing on the track, hence Yvonne McGregor's use of a Rolf Vector Pro on the front in the Sydney Olympics pursuit, where she won bronze.

That's what I thought... and it's more valid because he's fast ;-)

This thread is going to deterioriate into one of those threads full of claims supported only by anecdotal evidence. Do you think Yvonne might have pedaled faster?

LOL

[reply]That's what I thought... and it's more valid because he's fast ;-)
[/reply]

Actually on a track it is quite possible for the Vector Pro to have slightly lower drag. The head-on drag for various rims isn't necessarily better for a deeper dish wheel. See Zipp's or Hed's data. Hed's data shows the Hed3, disc, Alps, Stinger38, Stinger51, Jet 40, Jet60 and Jet 90 all within tiny amounts of drag (less than 0.02lb difference) at 0 degrees. At 5 degrees there is a big divergence, with the deeper dishes being substantially better. This was data from 2 years ago. The current Zipp data at 0 degrees shows a range of 0.41 to about 0.51lb, so some improvements may have been made at the 0 degree angle in the last few years that makes previous data irrelevant. Zipp claims that their 404 has improved by about 0.05lb at 0 degrees since 2001.

Of course velodrome testing is *absolutely* irrelevant to the real world. My anecdotal evidence goes exactly with the windtunnel testing of the two rims, which nominally should have a 0.1-0.15lb difference in drag. This equates into about a 1.5-2.5% increase in speed at a constant wattage...or 0.3-0.5mph improvement at 20mph.

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That's some smooooooooth talkin'

All this testing was conducted in a velodrome using SRMs by people who know how to conduct experiments. As for whether it applies off the track, see triguy42's post, which more fully explains what I commented on in a previous post.

I think you'd be hard pressed to prove that pairing spokes makes the wheel more aero. I don't even think Rolf claims pairing is more aero. He just claims it's different technology, which I agree with. Kind of like internal headsets.

Thinking back to why he made these wheels, they were in essence a Campy Shamal. Then Trek got a hold of them and they became something else (machine build, lower profile, exposed nipples, etc). If you could get a test of a Shamal and a Vigor I doubt that there would be much difference aero wise. Same rim depth, same (I think) number of spokes, internal nipples, etc. I like Rolf, he's a cool guy, hopefully made some good money out of the Trek deal (now Bontrager), and his wheels really are good.