Extremely light, stiff and strong, these new Roval CLX 32 Disc wheels from Specialized are an enticing choice for 650B fans but the price is pretty damn high. Get past that if you can, though, and there's a lot to like.
The CLX 32 is an existing 700C wheelset in the Roval lineup. They actually launched at the Tour de France last year, with the 1,200g wheelset using a 32mm aero optimised rim designed for climbing and weight weenies. And now a 650B option is available.
The 650B size is proving increasingly popular with the growing gravel, adventure and allroad market. Smaller wheels allow bigger tyres which offer stacks of comfort and traction, ideal for smoothing really rough roads and, with the right tyres, tackling tough and technical terrain.
Like the 700C wheels on which they are based, these new 650B hoops have a 32mm deep rim shape with a 20.7mm internal width, designed to accommodate between 42 and 47mm tyre widths. They're also claimed to be more aero than the previous CLX 40 wheels despite being shallower. Not only is the all-carbon rim wide and light, it is also tubeless-ready, or 2Bliss in Specialized speak.
The carbon rims are laced to AFD2 aluminium hubs spinning on high-quality DT Swiss 240 internals with CeramicSpeed bearings, with 24 DT Aerocomp/Aerolite spokes and DT Swiss Pro Lock nipples bringing the rims and hubs together in a 2:1 lacing pattern. The nipples are external so adjustments are easy enough.
The Roval wheels come set up for 12mm thru-axles, which has quickly become the standard for all new disc-equipped road and gravel bikes. They are compatible with other axle configurations, it's just a simple case of swapping the end caps to suit.
The hubs use the increasingly common Centerlock disc rotor interface. It makes fitting and swapping disc rotors really easy, a boon if you're regularly swapping wheels onto different bikes. It's much less fiddly and slow than the previous six-bolt system.
The wheels arrive with branded wheel bags (nice touch), inside which are tubeless valves and plugs. Most companies provide some sort of rim tape to seal off the nipple holes, but Specialized doesn't, instead preferring to provide plastic plugs that snap into the holes. But golly they aren't half slow and fiddly to install. They do provide the necessary airtight chamber needed for successful tubeless installation, but I opted to use tubeless tape on the second rim and achieved a tubeless setup much more quickly. I'll stick to tubeless tape, thanks Specialized.
I paired the wheels with 42mm Specialized Sawtooth tyres and tubeless installation was mostly a breeze, though I did have to use a special tubeless track pump to get the tyres to puff up quickly onto the rim and the beads to snap loudly into place. The girth of the rims works very well with the wide tyres, helping to minimise the lightbulb effect you get when mounting wide tyres on narrow rims.
It's tricky to asses the supposed aerodynamic efficiency of these wind tunnel-developed wheels. The speeds involved in most of my 'adventure' riding is too low to really require every aero advantage, and a 42mm tyre isn't a good start if you're concerned with drag. When riding on the road I did notice they were not dramatically affected by strong crosswinds, so that's good.
Using the wheels on a couple of different bikes including my own Fairlight Secan and the most immediately noticeable benefit was the drop in weight. These wheels are seriously light. And boy do they feel just lovely when you're riding undulating and rolling terrain with lots of gradient changes. It seemingly takes no effort to get them up and spinning to cruising speed. And they love climbs too.
The stiffness of the carbon rim is apparent even with big volume, low-pressure tyres. There's an extra layer of crispness when steering the bike through tight and twisty trails dodging trees and roots on my local testing loops. There's no hint of vagueness at all. They corner sharply on loose ground or tarmac, and out-of-the-saddle efforts are met with very responsive feedback from the wheels.
With the 42mm tyres at 40-50psi, depending on the terrain, the comfort was superb. They soak up all the cracks, holes and ripples of distressed and poorly surfaces country lanes, and handle loose gravel tracks, rutted bridleways and rooty trails with aplomb.
The wide rims give a broad base for the tyres, which contributes to a very stable and predictable ride with no tyre squirm even at low pressures when bombing through corners.
They're tough, too. I've not gone out of my way to try to break them, but I have put them through some stern tests involving smashing down boulder-strewn gulleys and slamming into potholes, and the impact resistance of the carbon rims has been impressive. One time I smacked the rear rim into the edge of a rock I was pretty certain would result in both a flat tyre and cracked rim, but neither was the case.
The hubs run extremely smoothly, as you'd hope with the expensively upgraded CeramicSpeed bearings, but in all honesty it's difficult to say if they contribute any detectable benefit over regular bearings. The Shimano compatible freehub is reliable and quick to engage, and after quite a bit of use there's no sign of any damage when removing the cassette.
I've been really impressed with these wheels. They work well everywhere, being fast and light on the road and tough and sturdy off-road, with easy tubeless installation and that insanely low weight. They've also gone some way to convince me of the attraction of the 650B size for mixed surface riding.
But then there's the price... £1,850 is a serious amount of wedge. If you like the sound of these wheels but are put off by the high price, then you could check out the Reynolds ATR2 650b wheels (£1,299) previously tested here on road.cc. I'm also currently testing the Hunt 650b Adventure Carbon Disc Wheels, which are about half the price (£899), so should provide an interesting comparison.
If you're sold on these whatever the price, though, you'll love them.
Superlight and tough 650B carbon wheels but not so light on price
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road.cc test report
Make and model: Specialized Roval CLX 32 Disc 650B wheelset
Size tested: Rim Depth: 32mm Rim Width: 20.7mm internal
Tell us what the wheel is for and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about it?
Specialized says, "While the CLX 32 rim is the lightest and most aero in its category, there's much more to it than that. It's a durable, 2Bliss Ready, and wide-profiled carbon rim that's ready to take on any adventure.
Because of this, we developed the CLX 32 650b Disc wheelset. We wanted to create a super-light wheel that plays nice with big 650b tires-one that could also be used to take on anything from pavement to gravel to trails.
When you want to get rowdy, swap out the 700c wheels on your gravel bike with these wheels, mount up some 650bX~47c tires, and get ready for next-level capability; all while retaining excellent handing thanks to constant frame geometry and fork-trail.
And yes, while many opt to use mountain bike wheels for this application, there are clear advantages to choosing the CLX 32 650b Disc.
First off, while most mountain wheels have hubs that are convertible to various axle standards, not many are convertible to the 12mm road thru-axle standard. Secondly, mountain wheels often come with either a SRAM XD driver, a Shimano 11-speed mountain, or 10-speed road freehub, making them incompatible with contemporary 11-speed road cassettes. And lastly, most mountain wheels use standard six-bolt disc brake hubs, rather than the Center Lock hubs found on most road applications.
Finally, the 21mm internal rim width pairs well with 650b tires, delivering the tire profile that delivers confidence in the corners and great floatation in the rough stuff."
Tell us some more about the technical aspects of the wheel?
Rim type: Carbon clincher, 2Bliss-ready
Rim material: Carbon
Braking surface: Disc brake only
Rim depth: 32mm
Rim width: 20.7mm internal
Spoke pattern: One-cross/two-cross (2:1)
Spoke count: 24
Spoke type: DT Swiss Aerocomp (L)/Aerolite (R) T-head
Nipple type: DT Swiss Pro Lock hexagonal
Rear hub: Roval AFD2, Centerlock, CeramicSpeed bearings, DT Swiss 240 internals, 11-speed, quick-release or 142x12mm thru-axle end cap
Assembly method: Handbuilt
Extras: Roval padded wheelbag, Roval steel quick-release, Roval tubeless plugs and tubeless valve,142x12mm thru-axle and quick-release end caps
They're handmade and clearly to a high standard.
Superb performance with low weight and impressive stiffness and toughness.
I bashed and crashed them and they're still in one piece.
Oh hell they are light.
If you want very light carbon wheels with a wide rim and great durability, these offer all that, but there are cheaper options.
Did the wheels stay true? Any issues with spoke tension?
Yup, no wonkiness to speak of.
How easy did you find it to fit tyres?
Pretty straightforward getting tubeless tyres to seat and stay up.
How did the wheel extras (eg skewers and rim tape) perform?
I'd prefer rim tape to the tubeless plugs that came supplied with the wheels.
Tell us how the wheel performed overall when used for its designed purpose
For riding rough roads and off-road trails and terrain, these performed very well.
Tell us what you particularly liked about the wheel
The low weight.
Tell us what you particularly disliked about the wheel
The high price. And those tubeless plugs – I'm not a fan.
How does the price compare to that of similar products in the market, including ones recently tested on road.cc?
There are cheaper rivals, like the Reynolds ATR2 650b wheels for £1,299.
Did you enjoy using the wheel? Yes
Would you consider buying the wheel? Too pricey for me.
Would you recommend the wheel to a friend? Probably
Use this box to explain your overall score
Really nice wheels that provide near-flawless performance but you'll need deep pockets to look past the high price.
About the tester
I usually ride: My best bike is:
I've been riding for: 10-20 years I ride: Every day I would class myself as: Expert
I regularly do the following types of riding: road racing, time trialling, cyclo-cross, commuting, touring, mountain biking
David has worked on the road.cc tech team since July 2012. Previously he was editor of Bikemagic.com and before that staff writer at RCUK. He's a seasoned cyclist of all disciplines, from road to mountain biking, touring to cyclo-cross, he only wishes he had time to ride them all. He's mildly competitive, though he'll never admit it, and is a frequent road racer but is too lazy to do really well. He currently resides in the Cotswolds.