There are more ways to get in trouble with the naming of this post than you could shake a stick at. Since I'm about to be a fun sponge anyhow, prattling on about stiffness and the like, I'll just play it safe.
We are often asked for recommendations on rims to go with a certain build, and have long had it in mind to do a survey of the rims we use in order to help people make the decision. Herewith, we present our first rim survey. This is also doubtless going to engender two responses which disagree with us: our subjective ratings are wrong, and we should sell rims that we don't. I'll give the only responses I can to both straight away. To the former, these judgments are our best assessments after a lot of experience with each one. We are happy to build with any of them (that's why we sell them), and all of the alloys are available from a lot of places besides November. We aren't trying to sell one thing over another here. To the latter, you just can't sell everything. We sell as broad a range of stuff as we can maintain expertise with, within our limits.
The Rail rims are included as much as a foil as anything else. They score well in a lot of regards, but you will notice that their finish and structure scores aren't quite as high as the HED rims. I've scored these on a curve: even though Rails build as round or rounder than HED alloys, carbon rims have the advantage of not having a joint. What I'm saying there is that a HED alloy is darn near at the limit of what an alloy rim can be, fit and finish-wise. And they charge for it. This isn't to say that there are carbon rims out there that are the carbon equivalent of what I find HED alloys to be - I've built several carbon rims and they have their strengths and weaknesses. All of the rims in this test score more than acceptably well in the subjective categories, otherwise we wouldn't sell them.
"Stiffness" is a relative score, as measured on our lateral deflection rig. No surprise that Rails are stiffest. To me, the Pacenti is the standout in this column. For its weight, it is very stiff - it approaches Rail stiffness, and Rails are the stiffest carbons we've tested (if you paid attention to our wind tunnel tests it should be obvious which ones that includes). The point of stiffness testing is primarily to indicate spoke count, but other factors come into play there. We still think 28 is the minimum for an acceptably stiff, strong, and durable alloy rear.
"Weight" is averaged across a large lot of each rim, expressed in grams/10 (a rim scoring 50 weighs 500 grams). This helps the chart make sense. Claimed weights are ignored in this chart.
"Tubeless" is subjective, 5 being "it's as easy or easier to install a tubeless on this as it is to install a tubed tire." All of the rims here have been used tubeless by us. Pacentis can offer an unholy challenge in mounting, the rest won't reliably inflate with a floor pump. That's the whole story there. The HEDS are tubular.
Width and depth measures should be self-explanatory. Again, the tubular HEDs don't show an inside width.
"Aero" is a relative score, as measured by us at A2 this summer. No external references are made - the 52 is the fastest of this bunch, so it gets maximum points. If we didn't test a rim at A2, it's not in here. Eyeball aerodynamics tests are worth no credit.
"Structure" is necessarily subjective. This is basically "how easily and reliably can this rim be built into a shining example of everything we think a wheel should be." As mentioned above, HED alloys do well here. Stan's and Pacenti are quite similar, and if you look at the serial #s in the rims I think an explanation is right there. The Grails seem to be a small bump up in structure - they are quite nice.
"Finish" is again obviously subjective. If I were Michael Kors (Katie used to make me watch "Runway"), I would express this as "how expensive would you guess each rim is, based on how it looks." Again, HEDs do well, but you don't find them at Payless either. The Kinlin's finish is a bit shiny, and it's graphically bereft. That's preferable to bad graphics, by far. We're working on a thing there.
This will be memorialized in a link from our custom builds page for reference, and if we feel the need to update it, we will baseline any updates to this post. We'll also follow with a brief write-up of each rim.