Better late than never, we've gotten our first Mavic Open Pro UST rims. Since we've built just one set so far and it will get ridden for the first time on Saturday, there isn't a whole lot to talk about yet but here are some first impressions.
First, they're unique looking. "ISM4D" milling creates a unique profile, which leaves more metal at the spoke holes and removes it between them. The theory on this is weight minimization without leaving the spoke holes liable to cracking. The profile's waviness extends to the brake track on rim brake models, which you'll either like, not like, or have no opinion on. Also unique among more modern rims, the Open Pro UST has eyelets. Mavic claims testing that shows eyelets provide a bunch of spoke hole strength benefits, so time will tell on that one.
Graphics are understated and, to me, good looking. Very in keeping with the previous generation of Open Pro. Everything is removable if you're a black black black black black type of person.
Width is 18.5 internal and 22 (max) external, and the depth is 25mm at the spoke holes. Claimed weight is 430g, which is actually somewhat more than the 409 to 415 range that we measured in ours. This will raise a lot of eyebrows, some to the good and some to the bad. For every "hooray, light!" there will be a skeptic that a rim so light can be durable. It's not a big rim, that's for sure. Stiffness through the build was quite good - actually surprisingly so - which we'll have to confirm on the road, but time will have to tell on durability.
We got one comment on our Facebook page that Open Pros set the standard for aerodynamic inefficiency, and have been the world's favorite wind tunnel punching dummy. An astute point, but the R-Sys is actually the wheel to use when you REALLY want yours to look good, and the Open Pro used, when it's used, is a 32 spoke wheel with straight gauge spokes. We know from our own testing that jumping from 20 bladed spokes to 32 straight gauge round spokes is going to be a pounding regardless of the rim use, and our testing came with thin gauge Laser spokes. Others have tested fatter, though not straight gauge, spokes and those show a much bigger loss than our tests with Lasers showed. The set here is 24/28, with CX Rays. My guess is that these aren't anyone's top choice for a TT, but my guess is also that they are no worse than the Shimano C24 which Tour Mag tested as down 13w to a Zipp 404. A gap, to be sure, but it may or may not matter to you.
Pricing is reasonable, at $99 retail per rim. Margins are short until you buy a quadrillion of them, so for those of you who've been pounded over the head with our pricing methodologies (which includes you, if you're reading this), you shouldn't be surprised when build prices are in line with builds using rims with slightly higher retail prices. We're getting builds up ASAP. Subscribe to our email at the bottom of this page and we'll let you know, or drop us a note with your preferred build specs and we'll work up a quote and timing for you.
I'm honestly reticent to swap out the Al33s that I've been riding all year, but I am excited to try them out. Big ride on them tomorrow, so we'll have an initial ride impression then. And actually since it's about 65* and bright sunshine out, a short shakedown lunch ride is in order right now!