WTB has been dabbling in carbon rims for the past year, but their first forays were designed for cross country riding or drop bar exploration. Their newest product is the Ci31 (carbon internal width 31mm) and is built for tackling technical terrain.

The rims have a 31mm internal diameter and a 39mm outer.

The rims have a 31mm internal diameter and a 39mm outer.​

The rims are TCS compatible and designed to pair with all tubeless tires designed to meet ETRTO standards. That means the tires should inflate tubeless with just a floor pump.

Drilling the spokes at an angle allows WTB to reduce stress at the nipple/rim interface.

Drilling the spokes at an angle allows WTB to reduce stress at the nipple-rim interface.​

Other features includes WTB's 4D drilling, which drills the spoke holes at an angle so that the nipples are aligned with the spokes under tension. This reduces binding and lateral movement at the nipple-rim interface to help improve durability and strength.


The WTB Ci31 comes in two sizes. The 27.5 rim weighs 455 grams, while the 29er weighs 490 grams. Retail for a rim is $600, which sounds like a bargain when you consider some other more well known carbon wheel maker's rims sell for nearly $1000.

For more info, Visit www.wtb.com.