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Wheels, Zipps vs Speeddreams...(5 posts)

Wheels, Zipps vs Speeddreams...ankhaw
Oct 4, 2001 9:10 PM
I've posted this in a few other places, let's see if I can get opinions here...

Okay, my wheel research has narrowed to a set of used Zipp 530's laced to Dura Ace hubs, 28/32... or a set of Speeddream wheels, the ones built on the Velocity deep V rims, 16/24... cost on these is about the same, so I'm weighing weight vs aerodynamics. The Zipp website is very informative about aerodynamics, the most drag coming from the last 3 inches of spoke zooming around... but I wonder which wheelset is more aerodynamic, the Zipps have a 58mm section, eliminating a big chunk of those last 3 inches of spoke, but the Speeddreams have a lot fewer spokes, but with 28mm more spoke showing (30 mm rim).

So, any thoughts? Anyone? Anyone? Beuller?

Thanks,
Ted
re: Wheels, Zipps vs Speeddreams...Wayne
Oct 5, 2001 6:57 AM
Although I'm no engineer, nor did I stay at a Holiday Inn last night, but I try to read this technical stuff when I see it. Seems to me that aerodynamics are far more important than weight, in fact, one ride estimate showed them to be an order of magnitude greater over a long fairly hilly route (approx 3% power savings versus .3% as compared to a standard wheel). Check out the articles on bike.com, also analyticcycling.com seems to indicate that even accelerating out of corners an aerodynamic wheel will "beat" a light wheel. One caveat I can think of is that you always get the benefit of the light wheels but aerodynmic wheel benefits are going to decrease when drafting. Looks like most theoretical analysis assume you're riding by yourself. Also, I've gathered that to get the aerodynamic benefits, you have to get a fairly deep rim, and that alot of mid V rims really don't do much aerodynamically speaking. I also don't think spoke numbers matter very much in aerodynamics, it's largely the depth of the rim. So, I would say you're Speeddreams may provide very little aerodynamic benefit over even a box rim, where as the Zipp 530's provide quite a bit of aero advantage. Another, factor I would think would be stiffness, but the bike.com article seems to indicate that it doesn't really matter unless they're so flexy they're rubbing the brakes. Hopefully, more informed people will add to this discussion since it's something I've been wondering about. I guess the ideal would be light and deep V but none of the deep rims are as light as the true light weight wheels, are they? The Zipp 303's come to mind, but I'm not sure if the rim depth is deep enough to provide significant aero advantages.
You asked for opinionsPaulCL
Oct 5, 2001 7:03 AM
I own a set of Speeddreams, so I'm biased. But to cover your questions...

Using your own comment about the "drag coming from the last three inches of spoke" then I would guess (trully a guess) that bladed spokes, though very aerodynamic, are going to create more drag than a high profile rim. Make sense?? To take it to an extreme, I would believe a total disc wheel would create little drag compared to a spoked wheel. But will 28 mm (< 3/4 in) of rim depth difference between the two wheels make any real aero advantage?? Doubt it. Will the bladed spoke over 25in of the wheel make a difference, oh yeah!

But aerodynamics is only part of the question. Wheel weight. My 'dreams weigh a whopping 1428 grams for the pair built on rear record, front AC hub. What weight are the Zipps?? Gotta be heavier with such a deep rim.

Warranty, service etc..Personally, I would never spend $500 on a used set of wheels. Dave warranties his 'dreams for two years. Since I purchased mine in Feb, I have talked to him twice about the wheels (they got 'squished' in an airliner box). Great service.

I said I was biased. Just my opinion. Let us know what you decide. Paul
You asked for opinionspmf1
Oct 11, 2001 5:53 AM
After waiting to get mine since May, they are coming this week. I can't wait.
re: Wheels, Zipps vs Speeddreams...Duane Gran
Oct 5, 2001 4:45 PM
I'm personally very fond of the Zipps and have a set of 440 tubulars that I use for racing only. I haven't had a set of Dave's wheels, but they come very highly recommended. I doubt if you will be dissatisfied with either choice. A few thoughts I have collected about the zipps so far:

* They spin up a bit quicker than my Rolf Vector Comps or my Spinergy Rev-X's. I think this is due to their lighter weight.

* Once you get rolling, there isn't much difference, however I have hit faster top speeds on the Zipps. This isn't terribly controlled as experiments go, but on a particular fast decent I hit 48mph on my Rolfs and hit 51mph on the Zipps. It could be aerodynamics, but it could be hubs. Other high speed experiences reafirm this for me.

* The carbon braking surface is a bit sketchy. I understand that new models have a kevlar surface that helps. I don't know from experience, but I can practically guarantee you that it isn't as sure of a braking experience as aluminum. My zipps can be a bit grabby and they eat up pads faster than my clincher wheels. Of course, if you are looking at clincher zipps this may not be an issue.

* Crosswinds have never been a problem for me. Even with a 58mm depth on the rim it hasn't caused a problem, but very light riders under 140lbs may feel more effect.

* The wheels climb very nicely. It may be psychological, but I love climbing with these wheels. The light weight surely helps, but I love these wheels in the mountains.

Anyhow, that is my thought. I can only compare them with my current wheels, which aren't Dave's, but I hope it helps. You can't go wrong, but I will say this about Zipps... they are race wheels foremost. I personally wouldn't use them for general riding wheels, but that is because it feels great to bring them out of the bag for special occassions. That is just me.