Crank Bros. Cobalt 3 Wheels

In 2008 when Crank Brothers first released its wheel range with their radically different twin-pair spoke design, they got a lot of people talking; unfortunately the off-the-shelf freehub they chose to fit had a roughly one in six failure rate, so the talk wasn’t particularly good. In 2010 the hubs (and spokes) were redesigned and things definitely improved, but wheel weights and rim width remained a little behind the mark for a premium wheelset. So, for 2014 the folks at Crank Brothers have totally redesigned the rim, and we’ve been riding the Cobalt 3s over the past few months to see if the last piece in their wheel puzzle can fall into place.

The Cobalt 3 is their top tier alloy XC wheel and it’s offered in 27.5 and 29-inch sizes. Our 27.5 wheelset came in exactly on spec at 1,650g (742g/908g) for a 100x15mm front and 142x12mm rear configuration. Front and rear end caps are included for the now old-style quick release system, and they can be swapped without the need for tools.

Crank Brothers lists this as an XC race wheelset, and as such the 1,650g weight is a little high compared to some other options available, especially if you’re looking at the upper half of the market; after all this is a $930 wheelset. That said, it’s about right for a general trail riding wheelset that can take day to day abuse.

With a 2mm increase in width, the new rims are acceptably wide at 21mm (measured internally). Shorter sidewalls are used to help resist pinch flats and rim damage, while the rim depth has been increased to present the spokes with wider bracing angles for better lateral rigidity. The rim surface is also shot peened to make them stronger and more resistant to cracking. Possibly the biggest benefit of the unique flange-mounted spokes is that the inner rim wall is solid and doesn’t require tape to make it airtight. Despite the lack of a removable core on the supplied valve, we had no problem mounting tubeless ready tyres with a floor pump.

The Cobalt’s certainly feel laterally stiff on the trail, and despite plenty of use on some particularly rocky trails, the rims have shrugged off all the impacts to remain dent free. We also had no burping issues with tyres at 23-25 psi, so the redesigned inner rim profile seems to work fine in both easing the beads into place and then holding them there. The 21-point freehub is at the slower end of the engagement spectrum. It’s fine for XC riding where power application through the pedals is fairly constant, and fewer ratchet points theoretically creates less drag when freewheeling, however for technical climbing there’s more lag in the pedalling response than we’d like.

Brothers Bling

The twin-pair spoke arrangement is what really sets Crank Brothers wheels apart from the rest; they’re instantly recognisable even from a distance. The 24 straight pull spokes are arranged in opposed pairs, with the spoke heads fitting through a small alloy barrel at the rim. Rather than being round, the head of each spoke is slightly flattened to sit against the rim, which stops them spinning during truing. Adjustments are done by turning the aluminium ‘nipple’ at the hub end, which as you can see is actually about the same length as the stubby stainless steel spoke. Apparently this arrangement was necessitated by the twin-pair design, which doesn’t leave enough room elsewhere for a spoke key to fit, but the long colour-anodised nipples also form a large part of the aesthetic of the wheels. Being specialised parts that you aren’t likely to find readily available at your local bike shop, it’s nice to see that all of the spokes and nipples are exactly the same length in both wheels; get yourself one or two spares and you’ll be pretty well covered.

After a dozen or so rides the rear wheel had developed a slight wobble; not enough to be in any way noticeable when riding, but enough to justify putting it in the truing stand—especially as we were curious about the truing process. We’re happy to report that truing the Cobalts was no more difficult than on any standard wheel. We did however notice the spoke heads had turned slightly against the rim flange; the fit is loose enough that they can spin around 45-degrees before they press hard up against the flange face.

While our small buckle trued up easily enough, we still have some ‘in principle’ issues with the twin-pair spoke design; particularly should you happen to get a significant buckle or flat spot in between the spokes. The paired arrangement means that there’s almost 15cm between ‘truing points’; double that of a traditional 24-spoke wheel, and almost three times what you’d find on a 32 spoke wheel, so it’s much harder to isolate a small area of the Cobalt’s rim for truing.

Overall we think Crank Brothers 2014 wheels are a big improvement over their previous offerings. They’re lighter, wider and stiffer than before, they aired-up easily without tubes, and the swappable hub end caps makes them far more versatile. The Cobalts are not really light enough to be a true XC race wheelset, and hub engagement is slower than we’d like for a set of general trail wheels, but despite our misgivings they’ve proven themselves to be tough enough to shrug off heavy everyday use. If you’re after wheels to add some unmistakable bling to your XC or trail bike the 2014 Cobalt wheels definitely have it in spades.

www.crankbrothers.com