The 2012 version of the Alpha 340 features a 33% thicker spoke bed for stiffer wheels and less likelihood of spoke pull-through. Even with this extra material they are still one of the lightest aluminium road clinchers available at around 370-380g, but with better strength and stiffness than many 450g rims.
Actual weights and dimensions: we've weighed a couple of the new rims at 383.8g and 384.5g. External width is 20.2mm, internal is 18.1mm.
The Alpha 340 is designed to be tubeless compatible, but works fine with inner tubes too. The Alpha 340 uses Stan's yellow tape to seal up the spoke holes (go twice round) and a dedicated 44mm road tubeless valve.
The Alpha rims are ideal for cyclocross use, they are best used with normal tyres such as NoTubes' Raven or the Maxxis Raze or Mud wrestler, or any other suitable tyre.
The rim is available in black only, with a machined braking surface, there is a non-machined (disk brake) version but it's only available as a pre-built NoTubes wheelset.
"Tubeless is the future of road and cyclocross racing and NoTubes will be leading the way. The rim is a bit wider than traditional clincher rims with an eye towards exceptional tyre stability and ride quality."