Velocity A23 OC 700C
Short version: Assymetric rims offer better triangulation for the spoke line when laced to cassette hub.
Longer, wheel-geek version below the jump if you'd like to dig deeper.
The A23 OC offsets the spoke bed 3.5mm to the non-drive side, substantially increasingly the bracing angle of the drive-side spokes and decreasing the tension disparity between the drive and non-drive side spokes. Both of these are good, and make the wheel stronger.
In addition, the triangular shape of the A23 extrusion withstands relatively high spoke tension. There's a reason cross racers like it (and it's tubular iteration, the Major Tom). It's a tough, tough road rim. Using the off-center version for rear wheels just makes it tougher.
"Tubeless ready" and even if you're using tubes use tubeless tape. Cloth tape is too thick for this rim and will make mounting tires needlessly difficult. Velocity doesn't recommend using Veloplugs with the A23 or A23 OC. 21mm Stan's tape works perfectly.
Made in Jacksonville, Florida.
With components manufacturers compulsively cramming more cogs onto rear cassettes, the drive-side flange of rear cassette hubs creeps closer and closer to the center of the hub. As a result, spoke tension on the drive side has to increase and/or the non-drive spoke tension must decrease to keep the rim centered in the bicycle frame. Both options can be problematic. Non-drive side tension that is too low means the spoke will slacken completely at times and/or flex too much each time they are loaded and un-loaded, leading to spoke breakage and/or loosening (absent tension spoke nipples can unthread). Raising the drive side spoke tension is desirable in theory, because it mean you can keep the non-drive side tension high and high spoke tension creates a stronger wheel, but tension that is too high will crack a rim around the spoke holes, and the lighter the rim is the more likely it is to crack at a given tension (all other things being equal, other rim factors are at play). And of course the kicker is the lightest rims are used for road bikes that use hubs with the least amount of space between the drive side flange and the centerline of the hub. This was already a problem with some rims and some 10 speed hubs, but the introduction of 11 speed hubs means that the problem will be more pervasive, and off-center rims will become more necessary for more rear wheel builds.
Please note: Wheel component inventory regularly fluctuates and stock is primarily maintained for wheelbuiding. If you're ordering wheel components a la carte and the part isn't on the shelf it will usually ship in 2-4 days. If there will be a longer lead time I'll contact you immediately. If your wheel component order is urgent, contact me at the shop and I can let you know if the part is on the shelf or, if not, give you an exact lead time.