Roval, Specialized’s house-brand wheel maker, has launched two new wheelsets: the Roval Alpinist CLX II and the Roval Rapide CLX II. To look at them, you’d be hard pressed to find any differences compared with the old wheels. But for close to two years, engineers at Roval have been working on the wheels to make them tubeless. The previous models of Alpinist CLX and Rapide CLX, which the pros were using in 2020 and 2021, were supposed to be tubeless. Instead, the company released them as tube-only clinchers. The top riders have been running the new wheels this season—at Paris-Roubaix, Flanders, Milan-San Remo, all the big races—with tubeless setups. For Roval, the hoops represent a lot of research and engineering to make them as safe and fast as possible.
Why the previous Roval Alpinist CLX and Roval Rapide CLX needed updating, or, Peter Sagan broke a wheel
“We pushed the previous generation of these wheels. We pushed them to the edge,” says Chris Wehan, category lead and senior product manager at Roval. “With Alpinist, in some cases, we went down to two layers of carbon on the sidewalls. You don’t have a lot of room for anything to go wrong with two layers.” Wehan adds he and his team wanted to get the wheels as light as possible and wanted them to have the best aerodynamic shapes, bringing things right to the edge. And they got close to the edge. A little too close.
“When you impact or hit something with a tubeless setup versus a tube-type setup there’s a different reaction that the wheel and tire have,” Wehan says. “We realized that in a tubeless configuration we were on the not-great-side of that edge. With the tube type, we were on the right side.”
With the Roval Alpinist CLX and Rapide CLX, the hoops passed all the necessary lab and safety tests for tube and tubeless. In December 2019, the Alpinist CLX failed a real-world test by Peter Sagan. The three-time world champion was running a tubeless configuration. He jumped a roundabout and hit the curb. Not only didn’t one of his wheels survive the impact, but the tire didn’t stay on the rim. The problem was not that a wheel broke: it was the way in which it broke. The way it failed, anyone but a supreme bike handler such as Sagan would likely have crashed. Roval couldn’t release those wheels as tubeless hoops. Tubed? Yes. The addition of an inner tube actually changed the wheel systems enough to get them on the right, and safe, side of Wehan’s cutting edge. Roval says the pros liked the new Roval Alpinist CLX and Rapide CLX wheels so much that they insisted on using them in 2020 and 2021, with tubes.
As the WorldTour riders rode their tubed wheels, Roval worked on making new hoops that were just as light or aero as what the pros were using, only tubeless, at safety standards that surpassed the minimum benchmarks. The development process involved beating the snot out of many sets of wheels.
Bashing wheels to build back better
When the team at Roval was testing the strength and safety of its wheels, it focused on two types of blows to the hoops: sharp-edge strikes and blunt strikes. The two strikes can be simulated in a lab with blunt or angled masses coming down on a wheel. Roval also tested wheels in one of its parking lots. Testers bolted a 76-mm steel bar to the concrete. The bar had load cells in vertical and horizontal positions. “We then used a super-glamorous piece of plywood, painted white, to change the height of the bump by raising or lowering the plywood,” Wehan says.
Then, riders of various sizes and with varying degrees of skill rode right at that parking-lot bump, and hit it. They kept their speed at a maximum of 32 km/h because things would get too sketchy for most riders beyond that. The testers measured the energy profiles of the hits. The biggest energy profile was generated by one of the smallest riders. He’s a pro with less fear of crashing than the other riders and with great bike-handling skills. Most riders would hesitate or pull up just a little bit as they approached the bump.
In the lab, Roval would bash its wheels with hits that ranged from 40 Joules (J) of energy to 70 J. In the parking lot, many riders hit the bump at about 30 J. What’s a 30 J hit feel like? “To give you some context, one 180-lb. [82 kg] rider’s biggest hit was 29 J,” Wehan says. “Afterward, he stopped and his heart rate was racing. He said it was one of the scariest things. Twenty-nine Joules is a big hit. Most of us would stop and wonder if all of our stuff was OK.”
Designing a wheel to break the right way
All the bashing and bumping gave Roval’s engineers the information they needed. They kept the same rim shapes as the previous Alpinist CLX and Rapide CLX wheels. The carbon layups did change quite a bit. There’s not necessarily more carbon, although the Alpinist does have a bit more material at the sidewalls. The magic, as Wehan puts it, is not only the increased strength of the wheels, but how they break, if they are actually brought to that point.
The “bad” way for a tubeless rim to break is close to its sides. If a crack appears, air rushes through it. That process could cause further damage and cause the tire to come off. Wehan and his team wanted to make sure that a rider could safely come to a stop, with the tire still on the wheel, even if the hoop was seriously busted. In order to achieve that, the failure would have to happen in the spoke bed. A crack in that area still allows the critical parts of the wheel to stay intact.
The previous generation of Alpinist and Rapide wheels, in a tubeless setup, would not survive a 70 J hit. The new wheels might. But whatever the result—crack or no crack—the tire will stay on, letting you roll to a stop. That’s all assuming that you were able to ride out that massive 70 J strike.
The argument for hooked rims
In the field of tubeless road tires, there’s the hookless and the hooked camps. The hookless folks, such as Cadex and Zipp, argue that a hookless rim (like the kind found on one of your car’s wheels) creates a better tire profile. It makes the tire and wheel more aerodynamic. A tire can run a maximum of 72.5 p.s.i. on a hookless rim. The hookless people say that low pressure gives the tire a wide and short contact patch for better rolling resistance. Also, a hookless rim can be lighter than a hooked rim because the former uses less material.
The new Roval Alpinist and Rapide wheels have hooked rims. “I know this might sound weird,” Wehan says, “but we’re really freakin’ proud of our moulded hooks. And we feel that the benefit of a simplified production isn’t there.” The Alpinist set of wheels is a light 1,250 g (1,265 g with tape and valves), so the hooks aren’t really adding much mass. (The previous Alpinist set is 1,248 g.)
What hooks do add, says Wehan, is flexibility in terms of tire choice and tire pressure. Some brands of hookless wheels can only run a small range of approved tires. Specialized would probably encourage you to use its own brand of treads, but you can easily run other tubeless-compatible tires. Also, you can run as much as 110 p.s.i. of pressure. The trend is toward running lower tire pressures, however, Wehan notes that many pros do like to use more than 72.5 p.s.i. If they want high pressure, well, that’s fine. The higher tire pressures can offer some protection to the wheels when they hit a bump hard.
Wehan also mentions that even though there are tight tolerances between the tires and the new wheels, the rims have been designed so that getting the treads on is slightly easier compared with the previous sets of wheels. You shouldn’t need a compressor to seat the tire beads.
Other features of the Roval Alpinist CLX II wheels
The rims of the Roval Alpinist CLX II wheels are 33-mm deep. They have internal rim widths of 21 mm. The front wheel has 21 DT Swiss Aerolite spokes laced to an LFD hub. The rear wheel has 24 spokes running to an LFD hub with DT Swiss EXP Internals and DT’s SINC ceramic bearings. The weight limit for the wheels is 125 kg (275 lb.).
Canadian pricing of the Roval Alpinist CLX II and Roval Rapide CLX II wheels
|Roval Alpinist CLX II front wheel||$1,500|
|Roval Alpinist CLX II rear wheel||$1,900|
|Roval Rapide CLX II front wheel||$1,500|
|Roval Rapide CLX II rear wheel||$1,900|
First impressions of the Roval Alpinist CLX II wheels
The Roval Alpinist CLX II wheels are strikingly light. Unless you are already running some flyweight hoops on your rig, your bike will feel noticeably different, in a good way, once you get the wheels on.
Wehan said it would be easier to get tires on these Alpinist wheels compared with the previous model. Easier is a relative term when it comes to tubeless wheels. With the front wheel, I was able to get the 26c Specialized S-Works Turbo tire on by hand. It was tough though. I couldn’t seat it with a regular pump, but a few blasts from a pump with an inflation chamber did the trick. For the rear wheel, I had to use a tire lever for some encouragement. I’d say it was a reasonable amount of labour. The rear tire seated with a few quick pumps from a regular floor pump.
As you can imagine, climbing with the Alpinist wheels is a joy. They are reactive and lightweight. On descents, they are equally capable. The tire profile they create may not be as round as a hookless setup, but I found the behaviour and traction of the tires quite good. These wheels are going to stay on my bike for some time—not just for some long-term impressions, but because I really want to keep riding them.