If you are considering buying or building a set of handbuilt alloy wheels, I suggest you don't fixate too much on weight. Why? Because it is hard to match the weight benchmarks set by the pre-built wheels from Shimano, Campy, Fulcrum, Mavic, and Easton. They all offer alloy wheelsets around 1500g at $700-1500. Going under 1500 grams usually requires $1000 on up.
If you want to build a light wheelset, getting to that 1500g benchmark can be tricky. By the time you select your rims and hubs there's not much room left before you hit 1500. The following amounts are for White Industries T11 and Pacenti rims.
Front: 100g (hub) + 450g (rim) = 550g
Rear: 250g (hub) + 450g (rim) = 700g
You can go below these amounts by about 10 percent but not much beyond that before you're soon paying double and reducing reliability. Basically, you are playing with 250g when choosing spokes and nipples.
Let's assume you want to build a 20/24 hole wheelset for training and racing. Here are some weight scenarios:
Sapim Race (2.0/1.8/2.0) for front and rear
with alloy nipples: 676 + 852 = 1528
with brass ripples: 688 + 866 = 1554
Sapim CX-Ray (1.7/0.9/1.7) for front and mixed Race and Laser (1.7/1.5/1.7) for the rear
with alloy nipples: 648 + 836 = 1484
with brass nipples: 658 + 850 = 1508
Of course the actual weights will vary by spoke length and lacing pattern. The calculations assume 280mm spokes, which is a good median value.
You could knock off about 50 grams by using a Chris King R45 hubset (215g for the rear) and Stan's Alpha 400 rims, but that would add about $200-250 and there are drawbacks.
If you're wary of the low spoke count, the numbers for 24/28 are 675g and 875g or 1550. Add 25g when you add 4 spokes/nipples.
Lightweight wheels are expensive for two reasons: 1) the components cost more; and 2) the builds take longer. Working with alloy nipples, which save 30 grams per wheelset, requires extra time because a hasty build can strip nipples. Working with light spokes is tricky because spokes will stretch, and you will be fighting spoke wind-up. Spoke wind-up is your number 1 enemy as a builder.
Weight is on my mind because my current project is a long list of shit you should avoid: 2:1 spoking, CX-Ray spokes, alloy nipples, and a center-drilled rim. More on that soon.
