Review: WTB Ci31 Carbon Rims

In Issue #111 of Singletrack Magazine, Wil delivered us his review of the WTB Ci31 carbon wheels

A bit over a year ago, WTB introduced its first carbon fibre rim. Called the Ci24, with a 24mm internal width, tubeless compatibility, and a lightweight construction, the Ci24 is targeted at cross-country and trail riders.

WTB offers two carbon rims; the Ci24, and the Ci31.

As trail riders and enduro racers demand wider rims and fatter tyres though, WTB has answered those needs by adding its second carbon rim option; the Ci31. With an internal rim width of (you guessed it!) 31mm, the Ci31 joins the range as a burlier option for harder hitting riders.

With a 31mm internal rim width, the Ci31s are designed for fat rubber.

Like all WTB rims, the Ci31s are only sold on their own. They have a claimed weight of 455g, and are also available in a 29in diameter (490g). They feature 32 spoke holes, which are moulded into the rim rather than drilled, a la ENVE.

Our rims were handbuilt to a set of Industry Nine hubs.

Of course, rims are a little useless on their own. Conveniently for us, the Ci31s arrived laced to a set of Industry Nine Torch hubs with 32 J-bend spokes per wheel in a 3x lacing pattern. That’s a build that’ll please mechanics, as will the externally adjustable nipples and easily replaceable tubeless rim tape. The complete weight for our test hoops came out at 1,725g for the pair.

Buzzy 120pt engagement out back.

Thanks to the TCS profile, tyre installation and inflation proved to be a doddle on a variety of different tyres we tested the rims with. Those included a 2.3in WTB Vigilante, 2.5in Maxxis Minion DHF, and 2.35in Schwalbe Nobby Nic tyres. Pumping up each tyre resulted in a satisfying ‘snap!’ as the beads locked in place.

The Ci31s were mostly paired to a set of Maxxis Minion Wide Trail tyres.

According to WTB, most of the extra mass in the Ci31 has gone into reinforcing the spoke holes further, while beefing up the base of the bead hooks to increase the rim’s resilience to blunt impacts. Despite this, the Ci31 still comes with a 102kg rider weight limit. WTB recommends heavier riders consider alloy rims.

With all tyres tested on the Ci31 rims, tubeless inflation was achievable with a floor pump.

Like a good quality carbon wheelset, the Ci31s offer a snappy and responsive feel at the pedals. Compared to alloy hoops, they offer more crisp acceleration and the ability to change trajectory without hesitation. Their stiffness is both good and bad, however. In back-to-back testing with comparable alloy wheels set up with identical tyres and air pressure, there was noticeably more buzz coming through to the grips and saddle. The stiff build of the Ci31s mean they do transmit more trail feedback, and unless you’re taking charge when launching the front wheel into a rock garden, the lack of flex means you get pinballed more easily.

The Ci31 rims are mega stiff, and offer laser-like steering precision for your bike.

With the exception of the Bouwmeester Tammar and the Stan’s Bravo, most carbon rims can exhibit this kind of harshness, and especially those with a full 32-spoke build and a deep profile like the Ci31s. Then again, bigger and more aggressive riders will appreciate the ‘direct’ feel of the Ci31 rims, with their laser-like accuracy offering precise trail-ninja manoeuvres.

On rougher terrain, there’s a lot of feedback through the stiff carbon rims.

Oh, and did I mention the Ci31s were tough? Despite our aggravated attempts, we couldn’t put either wheel out of true, let alone come close to breaking one. They are absolutely bulletproof.

With thick carbon fibre sidewalls, the Ci31 rims are super tough.

Overall

A strong, stiff and high-quality carbon rim that’s ideal for 2.3-2.6in wide tyres. For aggressive riders who frequent alpine terrain, or for those who spend too much time truing their alloy wheels, the Ci31s are tough rims that are built to eat rocks for breakfast.