Product Test: Box Cusp Stem & X Handlebar

Box has quickly become a force to be reckoned with in the world of BMX, and therefore we were excited to get our hands on their new X handlebar and Cusp stem as soon as they became available. Box has also been working on a set of quad-piston mountain bike brakes and a 1×10 drivetrain that are aimed at com- peting with the Shimano XT market. That may seem like quite the standard to shoot for right off the bat, but we hope to be pleasantly surprised!

Carbon compliance: Manufacturers produce carbon fiber handlebars to create a lightweight cockpit that strikes a balance between stiffness and chatter absorption but with a lighter weight than aluminum.

Tech features:

Offered in three lengths—45, 55 and 65 millimeters—each of the Cusp stems are 3D-forged from 6061-T6 aluminum alloy. As is becoming standard for cockpit manufactur- ers, the clamps have a 35-millimeter diameter. With the clamping face being 50 millimeters wide, the clamping force is distributed over a large area, which is crucial when pairing it with carbon han- dlebars. While they aren’t offered in the widest range of colors, the stems can be purchased in red, blue, gunmetal or black-anodized finishes to match your bike’s color accents. They can be found at bike shops around the country and have a suggested retail price of $99.

The Box X handlebars complement the stem with a 35-millimeter diameter for decreased weight with the same amount of stiffness as a comparable 31.8-millimeter handlebar, even at the greater widths desired by downhill riders. They’re constructed from unidirectional carbon fiber to provide greater strength over the length of the handlebar. We tested the 800-millimeter downhill bars with 15 millimeters of rise, which cost $149, but there are five models ranging from $129–$149.

Right on the cusp: Box’s new Cusp stem grays the line between organic lines and a burly industrial appearance. Everybody has a different taste in stems, but did this one satisfy ours?

Field test results: 

Coming in at 168 grams, the 65-millimeter Cusp stem is middle of the road when it comes to weight. With the clamping face being 50 millimeters at the narrowest point, it’s certainly the widest stem in our quiver. Furthermore, we like how the widest point is where the bolts actually clamp. The design of many other stems has the bolts clamping at the narrowest point of the stem and leaves us wondering how much stress carbon can take in those areas. We were able to leave this worry behind with the Cusp stem. With the function of a stem being fairly straightforward, it’s the style of the stem that can be a make-or-break feature for some people. The Cusp stem looks at home on nearly any bike; it strikes a fine balance between organic lines and a blocky, industrial appearance. Our one criticism would be how few colors it comes in.   

To match our riding style and the enduro race bike we were testing the cockpit on, we wanted handlebars with a combination of a 770-millimeter width and 15-millimeter rise. Therefore, we tested the 15-millimeter-rise downhill model and cut the bars down to 770-millimeters after a few rides. The downhill model can be cut all the way down to 730-millimeters, although we suggest going with the trail model if you plan to make them that narrow. We tested the bars on some of the toughest trails in the Southern California area. Endless rocky descents strewn with hefty ledges and pinner chutes provided all the bone-rattling enjoyment one could ask for. The X handlebars offered a comfortable ride and ample stiffness but didn’t leave our arms or hands fatigued in any way. When it comes to a stiffness-to-comfort ratio, that’s about as good as it gets. The proprietary shape of the handlebar certainly stands out and caught the attention of every other rider on the shuttle, but it also made us nervous while riding. Traditional designs have smooth profiles that don’t have visual stress points. Whether it was reality or purely psychological, it was hard to keep from believing that the non-traditional shape had additional stress points. With the price of many carbon handlebars jumping over the $200 mark, it’s refreshing to have a company producing them for a few Andrew Jacksons less.

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