So, 34s have been out of stock for a little while and we've been vague about the restock timeframe, because, well... there isn't one. It was time to cut a new mold, so we had to decide whether to reinvest a lot of money in the 34, or reallocate those resources to other projects that we think are better opportunities for us (don't ask yet, we won't tell).
Shallow carbon clinchers exist in an odd space. They're not appreciably lighter than aluminum rim options, they don't give a big aerodynamic kick like a 52 does, and at the end of it all they still have carbon brake tracks. We're sending out a set of Pacenti SL23s with Tune hubs today, and they weigh 1370g. The lightest set of 34s we ever built was heavier than that. Enve's new SES 2.2 clinchers, which they very nicely and openly state prioritize weight savings over aerodynamics (you have to click the "learn more" button), weigh 1400g per Competitive Cyclist. Zipp claims their newest 202 clinchers weigh 1450g. You can't use them tubeless, either. With our testing having shown that good alloys can be within a loud whisper of the aerodynamics of Enve's 3.4, is it realistic to think that the weight-prioritized-over-aero 2.2 is at all better in the wind than a good alloy? I'd bet they're worse.
Built right, alloys are as stiff as carbons. Add tubeless-ready and the weight gap can grow (it would have for us had we done a tubeless 34). Today's SL23 set was built with 20/28 lacing and slightly heavier Sapim D-Light drive side rear spokes and brass nipples. It's no weight-weenie special use freak wheel set. And it's $565 less than a standard set of 34s - you could get a set of Nimbus Ti wheels with DT R460 rims to keep them company with that. Our standard Nimbus Ti 20/28 clocks in at almost exactly the same weight as a set of 202 clinchers, but gets you much better hubs and saves you $1505. The price differential to the Enve 2.2 is even greater - a set built with DT240s (to which we much prefer the T11/Nimbus Ti) is $2900, for a difference of $2305. Since a portion of you are right now thinking "but the SPOKES!!!" - well, Zipp quietly changed from CX Rays to CX Sprints, which are a wider, heavier OEM-only version of CX Rays. Enve uses CX Rays. Doing a custom set of our alloys with colored T11s and CX Rays would knock the price difference with Enve down to a mere $2125.
On the other side, the aerodynamics of shallow carbons don't compare well to Rail 52s. There are few situations where the math works out in favor of the modicum of weight saved in the 34s versus the significant aerodynamics benefit of the 52. For quite a while, we've answered the "I want to go fast, which wheels should I get" question with an unqualified and decisive "get 52s." As we've known for a long time, and had proved in the wind tunnel last summer, 52s are easier to handle than other wheels of their depth/speed class. Between the two, the choice is obvious.