Reviewed: BLK TEC C1 tubular wheelset

MSRP: $2,700/pair
Advertised weight: 1,300 grams
Rim width: 25mm
Rim depth: 45mm
Spoke count: Front — 12 spokes; rear — six on non-drive side and 12 on drive side

While much of the cycling world is focused on the aero frame revolution — Kamm Tail designs, integrated everything, eliminating any and all round tube shapes — it’s often easy to forget how important wheels are to the overall effectiveness of a bike in sprints and on climbs. All that frame stiffness and aerodynamic advantage doesn’t mean much if the wheelset is flexy and aerodynamically clunky, keeping you from the most effective power transfer possible.

BLK TEC’s C1 wheels are about as far from flexy as a wheel can get. The 45mm-deep rim is bonded to bladed, solid carbon spokes that are in turn bonded straight to the carbon hub, for a mating that can be, at times, molar-rattling. But BLK TEC wasn’t after a compliant ride with these wheels; instead, the integrated hub, spoke, and rim carbon construction stiffens up the wheels to light the jets on the sprints and up the climbs. Tracking in high-speed corners is exceptional as a result of all that lateral stiffness, though like aero frames, aero-inspired wheels have their drawbacks. Just head out on a breezy day and you’ll know exactly what those weaknesses are.

Up the hill

It doesn’t take long to realize these wheels are a climber’s dream, and that’s exactly what BLK TEC set out to create. We put them on Bianchi’s Specialissima, a lightweight climber’s bike notable for both its prowess on ascents and its smooth, comfortable ride. The C1 wheels negated some of the Specialissima’s compliance, but complemented its climbing abilities, both as a result of the incredibly stiff design of the wheel. Out of the saddle, the C1 wheels waste no time hopping forward, which is a testament both to the wheel’s lateral rigidity and quick freehub engagement (a loud, cicada-symphony freewheel is the price you pay for that immediate engagement any time you’re coasting; according to BLK TEC, dropping some lube inside the hub assembly should quiet this a bit).

Down the hill

It also doesn’t take long to realize these wheels are a descender’s nightmare. At anything but a 0-degree yaw, the wind wreaks havoc on these wheels, particularly up front where the wide bladed spokes and deep rim create an unsteadiness that can be frightening at times. That’s unfortunate because the wheels do, in fact, track well through corners if there’s no wind at all. Can you think of the last time there was no wind on a fast descent? Ah, therein lies the problem.

One surprising takeaway was the much-better-than-average braking power. Whether this was the result of the Campagnolo BR-B0500x brake pads or the wheel’s brake track, or a combination of both, is hard to say, but even when it started to drizzle, braking was almost immediate and assertive.

On the flats

Straight-line speed is where the C1 wheels excel. According to BLK TEC, these wheels are designed primarily for climbing, though we found them to be equally exceptional in sprints. The wide 25mm rim helps provide an aerodynamic leading edge that works in conjunction with the 45mm rim depth to cut through the wind; this is especially important if you’re mating these wheels to an aero frame that essentially strives to do the same. So once you pick up speed on your sprint — and you’ll do that pretty quickly since these ultra-stiff wheels jump forward almost faster than you do — you’ll keep that speed.

In the garage

Yep, it was our first thought, too: Bonded carbon spokes can break, and what happens then? Is the wheel trashed? Not according to BLK TEC. The spokes can be replaced, though you’ll have to ship them back to the company for the job to be completed. Not exactly a convenient process, but to ensure the stiffness inherent in the design, it’s best to have the pros take care of it.

Truing is out of the question; there are no spoke nipples, and the spokes are fixed in place. After several hundred miles of riding, however, there seems to be no reason to true them anyway. They spin as straight as they did when they came out of the box. According to BLK TEC, they do have a crash replacement policy should your wheels get damaged beyond repair.

These are purpose-driven wheels, not all-round race wheels, mostly due to their skittishness while descending. Racers heading up into the mountains for the day will relish the incredible lateral stiffness of these wheels, as will sprinters on fast courses. In terms of versatility, though, the C1 wheels won’t stack up when the wind is blowing, and descending can be hair-raising in anything more than a light breeze. Get these if you’re trying to win the stage on an HC climb; leave them in the car if the breezy weather looks like it could ruin your day.