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Wheel buildup question(6 posts)

Wheel buildup questionhaydensimons
Jun 3, 2002 6:31 PM
I currently am running campy vento wheels. While they are aero, I'm getting the impression that they are heavy. I haven't weighed them, but I do know that in tris I blow by guys on the downhill and they inch back on the uphill. Eventually I'm getting ahead of them. I suppose a lighter wheelset might help in these hilly tris I've been doing.

Question 1. Can some of you bicycle gurus tell me the difference between mavic open pros, cxp-33's, and velocity aeroheads.

Question 2. What spokes/pattern. I weigh 175 and am 5'11.

Question 3. I'm building these up with Record hubs. What kind of weight will I be looking at and how does this compare to the Vento's?

Thanks for your help in advance
Hayden
re: Wheel buildup questionLeisure
Jun 4, 2002 4:57 AM
Well, my priorities aren't in the realm of racing, but I usually suggest sticking to the basic 2 or 3 cross lacing for wheel longevity and long-term steering feel. The weight benefit of radial lacing is less than two spokes' worth in weight per wheel; use it only for the front and you lose two spokes in weight. Use a radial lacing on one side of your rear hub and you'll lose one more spoke's worth. That's three spokes in weight max. I think that's kind of a small gain compared to using 24 or 28 hubs, and not worth it for potentially diminished hub longevity (and voiding the warranty). Whether or not to use butted spokes depends I think on how abusive you are on your wheels; my weight is similar to yours, but I'm a fairly mellow rider on my equipment and I don't think I'd worry about using butted spokes on a spare/racing set of wheels. That's about all I know; can't tell you anything about different rims or what the weight of the Ventos are.
Actually,Spoke Wrench
Jun 4, 2002 6:19 AM
The difference is closer to one spoke weight saving on a 32 spoke wheel. I calculated the spoke length difference on one hub, rim combination. The result was 277mm radial and 289mm 3 cross. About 5 grams difference.

I think every high quality wheel should have butted spokes. How often do you see a spoke that broke in the middle? The only drawback I can see to butted spokes is they have less torsional strength and are more likely to wind up. Real skinny spokes like Revolutions (14/17) are a pain to build and true, but I think a properly built wheel is just as reliable.

I'm not crazy about 15/16 gauge butted spokes because they fit more loosely in most hubs and they take smaller, much less common, nipples. I don't take 15 gauge nipples with me when I do out-of-the-shop tech support.
Did the same calculation way back-hub diameter plays a role.(nm)Leisure
Jun 6, 2002 2:45 AM
re: Wheel buildup questionjustina
Jun 4, 2002 6:32 AM
Disclaimer: I'm quoting #'s I recall off the top of my head.

CXP 33's: somewhere in the high 400's (g)
Open Pros: ~425g
Aeroheads: ~415g

Here's the thing, Open pros are brass eyeletted allowing you to use alloy nipples, saves you about 15-20g per rim when built. Aeroheads aren't eyeletted, you can't use alloy nipples as they can fuse with the like metal rim over time and under the pressure of tension and riding, I believe the term may be vulcanization. Therefore they'll both weigh about the same when built. Aeroheads are slightly more aero than open pros, hence the name, and if you're budget conscious you can get them at Nashbar for $20. 33's are much heavier, but truly aero. I'd say as a tri guy you'd probably want the 33's generally, but maybe the aeroheads as a hilly course wheelset. You can probably find the rim weight of your current wheels on the web or by calling the manufacturer and then compare them to the 33's and aeroheads to see the savings (if any). I've found all the number crunching in the world and careful specing is no substitute for trying the damn things out. Also one last note, when climbing if you spin a steady cadence extra rim weight just costs translational work, carrying the extra 100-150g up the hill. It's when you stand and the power stroke is uneven causing slight accel/decel over the pedal stroke that the heavier rim begins to suck more energy due to its greater rotational inertia.

Justin
re: Wheel buildup questionLen J
Jun 6, 2002 4:03 AM
1.) Cxp-33's are a little heavier than O/P's but are more aero. I'm not sure about the aeroheads. For tri's Aero is probably better. Diff in weight is around 140 grams for the set (33's vs O/P)

2.) I'd do 32 spoke 3x 14/15. I'd use brass nipples but you can save some weight (at the expense of durbility, with alloy nipples. You can use 2x on the non drive side. I wouldn't go radial, void hub warranty with small advantage.

3.) O/P Record 32 spoke will weigh around 1,560 grams, compared to the ventros which weigh 2,003 grams, you'd save over a pound.

Len