carbon wheel built

[el condor]

On of these days I'm gonna build a full carbon wheelset.
Compared to an alloy rim what has to be taken in consideration?
Spoke lacing,-tension etc.?
please give me some input.

[Dellucci]

Hi,
you have to know some major things like:
-your weight
-your power in Watt´s
-what you gonna do with that Wheelset (time trial ,climbing , flat)
-what you expect from the Wheelset.
For example:
-I´am a 78 kg triathlete , 1,82 m tall and I push 370 on an Ergometer.
My Wheelset is only for raceday .It has to be used on different streets and hilly like flat races too.
So my conclusion was , it has to be stiff enough for my weight and my power , tough enough to resist different type of races and aero enough to be fast with them.My choice was the Lightweight´s in 12 spokes front and 20 spokes rear Wheel.

[divve]

When a wheel is suitably built for your weight and riding style or conditions, your power isn't relevant. The torque you put out adds next to nothing to the strain on the related components.

With carbon rims specifically, it's even more important to get a rim as round and true as possible, because there's not much you can change when you build them. Laterally there's a little room for truing, but radially, you basically get what you start out with. For the remainder sufficiently high and uniform spoke tension is very important.

[el condor]

Thanks for the tips so far.
Is there anything else I should know compared to lacing-up an alloy rim?
Is it better do put washers under the spoke nipples etc.?

[divve]

I don't think you have to mess with washers, unless the manufacturer of your rims recommends them. For the remainder, build it up just like any normal rim. Make sure you get it both laterally and radially true when the spoke tension is relatively low (don't radially true by trying to pull the rim inward, it won't work with carbon, you have accept what the rim allows for with uniform tension). Then simply tighten everything up. It's actually easier building than with an aluminum rim.

[el condor]

I don't think you have to mess with washers, unless the manufacturer of your rims recommends them. For the remainder, build it up just like any normal rim. Make sure you get it both laterally and radially true when the spoke tension is relatively low (don't radially true by trying to pull the rim inward, it won't work with carbon, you have accept what the rim allows for with uniform tension). Then simply tighten everything up. It's actually easier building than with an aluminum rim.

divve-you mean radially theres now way to true a carbon rim?
Radially it's as true as the manufacturer produces it?
If yes, I will do as you said.
Thanks for the input.

[divve]

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[divve]

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[divve]

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[divve]

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[divve]

That's correct. Normally speaking a carbon rim is radially very rigid and will resist changing shape more than an aluminum rim. Because of that a traditional radial adjustment will cause high localized spoke stresses. Something that you should avoid. The best you can do is to get the rim radially centered around the hub with uniform tension and ignore the small bumps you may find in the rim.

Also, take into account that there's a wide spread in quality. For instance, you'll find rims that have clear bumps or indentations at joints that haven't been smoothed out at the level of the brake track. You'll won't be able to true those bumps out either and they'll effect the smoothness of braking and may be the cause of loud squealing as well.