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by James Huang
May 16, 2017
Photography by James Huang
TECH NEWS BROUGHT TO YOU BY BIKEEXCHANGE
Roval — the in-house wheel brand of industry powerhouse Specialized — recently revamped its road wheel lineup, and the new CLX 32 Disc sure seems to tick all the boxes. It’s light, wide, aero, tubeless-compatible, and competitively priced. But is it really the unicorn it appears to be on paper? Almost, says US technical editor James Huang — almost.
Roval has come a long way since Specialized first purchased the historic French brand in 2005. Although those early models were perfectly ok, they were hardly remarkable, and goofy features like the star-shaped spoke flanges on the forgettable Fusee Star model always seemed more like marketing hype than functional benefits.
Nevertheless, much has happened at Roval in the twelve years since, and the latest range shows the rewards of persistence. Perhaps no other model in the collection demonstrates this better than the CLX 32 Disc carbon clincher wheelset, with an enticing spec sheet that includes a 1,350g claimed weight (610g front; 740g rear), a progressive 20.7mm internal width, a versatile 32mm depth, proven DT Swiss freehub internals and DT Swiss Aerolite bladed stainless steel spokes, swappable hub caps to fit various dropout configurations, tubeless compatibility, CeramicSpeed hybrid ceramic bearings, two-to-one spoke lacing for more balanced tensions between left and right sides, and even externally located spoke nipples for easier servicing.
Roval’s industrial designers have done an excellent job of making a disc-compatible hub easy on the eyes.
According to Roval, aerodynamic performance of the 28.1mm-wide external profile is on par with competitors’ wheels that are twice as deep, and the company’s industrial designers deserve props for crafting what are easily some of the best-looking disc-compatible hub shells on the market. Roval has even put its own spin on sealing the rim for tubeless use, forgoing traditional tape for individually sealed, snap-in plastic plugs.
Retail pricing is competitive for what is offered, too. Official retail figures come in at US$2,400 / AU$3,800 / £1,870 / €2,200 per set, and included in the cost is a nice pair of wheel bags, quick-release and thru-axle end caps, a pair of quick-release skewers, the aforementioned tubeless rim plugs, and lightweight aluminum tubeless valve stems.
So what’s not to like?
For the most part, Roval has stayed true to what the CLX 32 Disc offers on paper.
Roval’s aerodynamic efficiency claims are tricky to verify on the road, if for no other reason than the fact that few wheel companies use test protocols that are directly comparable. Nevertheless, the CLX 32 Disc’s crosswind stability is very obviously exceptional, with even strong and unpredictable gusts doing little to knock them off-line. Readers accustomed to criticizing anything and everything that comes out of Specialized’s Morgan Hill headquarters may quickly dismiss this as needlessly effusive praise, but truth be told, these are some of the most confidence-inspiring mid-section wheels I’ve used in blustery conditions.
How much does Roval benefit from having easy access to Specialized’s in-house wind tunnel? It’s hard to say, but it certainly doesn’t hurt. Crosswind stability of the Roval CLX 32 Disc is among the best I’ve used.
Build quality is very good, too, with eight months of regular use on both paved and unpaved surfaces — including blindly hammering dirt potholes at the Boulder Roubaix — doing nothing to knock things out of true. Even when tweaking is eventually required, the process is made easier with the externally located spoke nipples and firmly anchored straight-pull spoke heads that resist spinning at the hub flange.
As is usually the case as compared to a more traditional 13-15mm-wide rim, the CLX 32 Disc’s generous internal rim width effectively broadens the footprint of any tire that’s installed for improved drive, cornering, and braking traction. A Specialized S-Works Turbo measures 26mm across when inflated to 100psi on a Shimano Dura-Ace rim (15mm internal width), but gains a full 2mm on the Roval rim at the same pressure. Other tires I tried saw similar increases in size, and so long as you keep the actual tire width below 28mm or so, there should be minimal degradation in aerodynamic performance.
The wider tire bed provides improved casing support, too, allowing both traditional and higher-volume tires to be reliably run with lower pressures for a smoother ride and increased grip without the vagueness that often comes with the same pressure decreases on a more traditionally narrow rim profile.
Road tubeless technology has definitely gotten better in recent years, but it still has a ways to go before it’s as convenient as standard tubed setups.
Weight-wise, the CLX 32 Disc’s performance on the scales is better than claimed. The complete set comes in at an outstanding 1,314g (592g front, 722g rear) with a Shimano/SRAM freehub body, 12mm thru-axle end caps, and without rim plugs or valve stems — 36g less than expected. Not surprisingly, the CLX 32 Discs feel plenty light on the road — especially on steep climbs — and despite the feathery weight, front and rear wheel stiffness was more than adequate for confidently aggressive cornering when road conditions allowed.
The CeramicSpeed brand name normally carries with it quite a lot of respect, but that unfortunately didn’t stop the front hub bearings from feeling very rough at the end of my test period, despite the wheels seeing very little water in the arid Colorado climate. Things felt much better out back, however, and while I personally find DT Swiss’s 18-tooth freehub mechanism to engage too slowly for my tastes, the thoroughly battle-tested star ratchet design bodes well for long-term durability. Users that demand faster engagement can easily upgrade to 36- or 56-tooth ratchet for about a hundred bucks and five minutes of work.
While the hub’s shape may have been crafted by Roval, the rear freehub internals come courtesy of DT Swiss and its well-proven star ratchet mechanism. The 20-degree engagement speed is slow by mountain bike or cyclocross standards, but it’s perfectly fine for road use while also producing less friction while coasting than the company’s finer-toothed options.
As disappointing as the premature front hub bearing wear was, an even bigger disappointment on the CLX 32 Disc wheelset is its tubeless capability — after all, bearings can be easily replaced, but a less-than-ideal rim bed shape is with you forever.
Instead of using tape to make the rim airtight, Roval uses individually sealed plastic snap-in plugs to close off each spoke hole — an idea that Velocity originally touted as a weight-savings measure on its rims more than ten years ago. The plugs themselves do their job just fine in terms of keeping air from bleeding into the rim cavity, but the lumpy external profile they produce is stubbornly resistant to create an initial seal with tubeless tire beads. Even with Specialized tires, a good compressor, and removing the valve cores (which allows air to pass faster through the valve stem), tubeless setups are far more frustrating than they should be.
Making matters worse is the fact that the plugs offer no weight advantage whatsoever. I weighed a full set of plugs at 14g, whereas the requisite length of tape to seal the rim came in slightly lighter at 12g. Granted, riders who prefer to go a little more conservative with two layers of tape instead of the single one I used will roughly double that figure, but that’s a small price to pay when the alternative is barely functional at all.
Worse yet, those little tubeless plugs turn a smooth internal rim profile into a lumpy that’s stubbornly resistant to create an initial seal, even when using Specialized tubeless tires and a compressor. A standard taped setup (at left) is far less maddening to set up, although still more frustrating than it needs to be.
Roval road product manager Stewart Thompson didn’t refute any of my tubeless issues, but he insisted said there are potentially some other issues — at least on the rim-brake version — that nevertheless still justify the plugs for some users.
“[The plugs] are a holdover from the mountain bike wheels we had done, where we were trying to save weight of the rim strip, especially when you get to a really wide rim,” he said. “In this case on the road, there’s not much weight savings going to tape, but one of the reasons we stuck to plugs in our design was because we had some concerns with tape in its durability under braking heat on rim-brake wheels. We saw in some of our initial testing that the adhesive on tape would separate from the tape, and we’d get tape moving out of place and air leakage. So had some concerns with safety on carbon rims. Obviously, that’s not a concern with disc brake wheels, so we feel 100% letting people run tape like you had done. I’m not going to hide from the fact that they’re more difficult, and that [setup] is most likely going to require a compressor.”
The CLX 32 Disc’s healthy rim width and disc compatibility will invariably draw the attention of cyclocross racers, but those tubeless woes unfortunately keep me from recommending these for that application. Even if you’re able to get tires to seat and seal, Roval hasn’t incorporated any kind of shaping in the rim bed to lock the tire bead in place. The beads of nearly every tire I used with the CLX 32 Disc fell back into the center of the rim when the tire was deflated, which can complicate adding sealant and doesn’t lend much confidence for low-pressure setups.
In fairness, I didn’t fall victim to any tires peeling off the rim while hard cornering during my test period, but that’s likely due more to the slightly higher pressures used on the road. In that environment, I had little cause for concern.
Riders who aren’t interested in tubeless tires can obviously ignore that aspect of this review, but given the growing popularity of that category — not to mention to increasing number of truly excellent tubeless-compatible tires flooding the market — it would be an oversight on my part to ignore it completely.
Roval road wheels were largely forgettable a decade ago, but the company has made dramatic advances over the past few years that bring its offerings well inline with other top models.
Mid-section wheels like the 32mm-deep Roval CLX 32 Disc don’t draw as much attention as their deeper-profile brethren. When properly done, though, they seem nearly as fast in a straight line while being much easier to handle in windy conditions.
As is becoming increasingly common these days, the Roval CLX 32 Disc rims are notably wide with very blunted curves at the spoke bed.
Can a disc-compatible hub be pretty? Judging by the ones used on Roval’s CLX 32 Disc, many would say yes.
While the front wheel uses a crossed spoke lacing pattern only on the disc side, the rear wheel uses it on both.
The DT Swiss Aerolite bladed stainless steel spokes are thankfully paired with externally located aluminum nipples for easier servicing when needed.
The Roval CLX 32 Disc wheelset may be tubeless-compatible, but without any sort of mechanism to physically lock the bead in place once it’s seated, it wouldn’t be my first choice for a low-pressure cyclocross setup despite a generous internal width that would otherwise be ideally suited for higher-volume knobby tires. When the tire is deflated, the beads fall back down into the center channel of the rim.
The included aluminum tubeless valve stems are well thought-out, with big knurled collars that are easy to tighten by hand, a smooth section on the body that spares pump head seals from excessive wear, and removable cores that let you rapidly blast air into the tire for faster seating.
Roval originally provided these airtight spoke hole plugs for its mountain bike wheels, where they offered some weight advantage over standard tape. That advantage goes away completely on a narrower road rim, however.
The machined aluminum DT Swiss freehub body is relatively lightweight, but also prone to scarring from cassette cogs. It’d be nice some steel reinforcements similar to what American Classic (and others) now offer.