Carbon clinchers have made huge strides in the past few years. We've seen them go from being pretty boat anchor heavy aluminum/carbon hybrids to being relatively heavy full carbon rims to impressively light and useful rims which have fully staked their claim in the grand scheme of things. We'd had a bunch of attractive carbon clincher rims come across our desks, and the 38mm struck us as an amazingly versatile basis for our first foray into the world of carbon clinchers. We got a couple of sets of rims, built them up, and have been doing our standard "go everywhere and aim for the potholes on the way" testing routine on them. The end result? Our new RFSC.
So, why carbon clinchers? First, they're aero. Not aero like a 50mm, or 58mm rim, but a very discernible bump in slippery factor from a 24-, 27-, or 30mm rim. Second, they're light. Our RFSC rims come in at about 400 grams. That's really light for an alloy box section rim, and just a few grams less than our 50mm tubular rims. Light. Third, they're stiff. These things JUMP when you push the pedal down. Fourth, well, they're clinchers. Changing flats is easy, you don't have to worry about sending your tires out to get sewn up, if you want to switch tires it's simple as, and you don't have to learn the whole deal with glue and all that jazz.
They're kind of like the ultimate incarnation of the go everywhere, do everything, light, fast, sexy alloy wheelset. They just needed to be made out of carbon to be fully realized.
One thing that people get sketched about with carbon wheels is braking. Using the included carbon-specific pads, the braking in dry conditions is indistinguishable from alloy rims. In wet, there's a little bit of brake lag - just like there is with alloy rims. Brake feel is actually just ducky - it's sure and positive and the brake tracks have an extremely straight and true finish on them so there's no pulsing at all. At all. Heat buildup has proven to be no more of an issue than it is with alloy rims. If you're going down some monster screaming descent, alternate front and back and don't ride the brakes - just like you'd do with alloy rims.
The brake tracks are pretty wide at just a shade over 22mm, and they pair awesomely with 25c tires (and for the record I will never buy a 23c clincher tire again - it's all 25s for me, they're the biz).
At $885, it's easy to find a set of alloy clinchers that cost hundreds more, weigh more, don't give you any aero benefit, and don't feel half as snappy. For a few bucks more (actually, quite a few - but we can't do anything about it), we'll be happy to have a Powertap built into them. Go ahead and train on them.
There's going to be a comment on this post pointing out the contradiction of me advocating training on carbon wheels. This is what's called a paradigm shift. When $885 buys you a set of wheels that will do everything wheels do demonstrably better than a set of alloy wheels that are a couple of hundred bucks more - yeah, I'm fully good with that. These are your desert island wheels.
Delivery is slated for late February, so you'll have them in plenty of time for Jeff Cup.
9 comments
Good question, Stephen. It's not so much that it's resilient, it's that it won't take the new curve anyway. As soon as the asymmetrical force of having one less spoke is removed, the rim will return to its original mold shape right away. All of the rims we've seen from our manufacturer pas the "do they lay perfectly flat in the first place" test with flying colors. I had a set of earlier generation carbon clinchers, and like many of this particular manufacturer's wheels of that generation, it popped spokes with some regularity. Before I really figured it out, I would lace a replacement spoke in and it would true right back up. When I got smart and replaced all the drive side spokes, it was perfectly true and also never popped another spoke. Also, carbon rims are generally stiff enough to get away without a spoke, at least for a short while.
Nice addition with the Carbon Clinchers. You might as well do at least some of your training with the equipment you plan to race. No naysayer comments here, but what about the 20/24 spoke pattern? If one breaks and the rim is deformed, does carbon have the resilient qualities like alloy to be trued back into shape without sacrificing the rim integrity?
JB – Simple price to performance. Lasers are the same weight, and have a tiny fraction less yield strength (which is much much higher than what you'd tension them to in a build – rims can only take so much tension), but they cost about 1/3 what CX Rays do. In the wind tunnel, CX Rays show about a 10 or 12 second per hour benefit over 14 gauge straight spokes (Lasers are 14-17-14). That wasn't enough for us to justify the cost increase across the board. In the wind tunnel, dropping your head 2 extra times costs way more. It's a measurable and quantifiable difference in the wind tunnel, it's just very small and in the real world (especially in road races where our wheels will see the majority of their service), it's too small a gain to justify. They're great spokes and they look hot, but the performance doesn't justify the extra $$. If you'd like a set built with CX Rays, we will happily do it. Building by hand here allows us the freedom to do that. ThanksDave
What was the reason to go with the Laser spokes vice the CX-Ray?
First, I wouldn't necessarily call it funky. Zipp uses a drive side cross/non-drive radial pattern across the board*, for example.The Powertap options will be 2x/2x laced, because you have to lace the non-drive of a Powertap hub with at least 2×. The non-drive side of a Powertap actually does some driving. For the non-Powertap ones, we were shown that we could get a higher non-drive tension with radial spoking. I still feel like the RFSW (50mm rims) ride better with 2x/2x lacing – radial spoking doesn't exactly encourage vertical compliance. The RFSC (38mm) rims are stiff in capital letters. The RFSW rims are stiff in ALL CAPS, bold, underlined, and in italics. The FSW (27mm alloy rim) might be a candidate for radial non-drive spoking. They ride really nicely as is, though, and we are guessing that a lot of people are going to do a LOT of miles on them. We also lace them up pretty hard, so there's plenty of tension on the non-drive no matter what. *Zipp uses that pattern across the board except on the 101s which they build for pro teams – see <http://velonews.competitor.com/2011/01/gallery/zipp-keeping-it-in-the-neighborhood_154336/attachment/img_7772-2>. My guess is that they build the particular wheels as they do for comfort and durability, as the average pro will probably put I don't know maybe 20,000 miles/year on them, maybe do as much maintenance as hitting them with a hose now and again (maybe), and expect them to be fairly comfortable.