Crankbrothers Synthesis XCT 11 Carbon Wheels Roll Smoothly Between Trail and True XC [Review]

Crankbrothers Synthesis XCT 11 Carbon Wheelset

The final piece of “project don’t buy another bike” is a lightweight wheelset to accompany the feathery Thunder Burt tires and Whiskey carbon fork that chameleon my 130mm hardtail into a proper-ish gravel muncher. There are less expensive ways to drop wheel weight and at $2,400 the Crankbrothers Synthesis XCT 11 Carbon Wheelset is definitely a top-tier choice. Having loved the brand’s Synthesis Alloy I9 gravity set, I was confident the brand would do light right.

Crankbrothers has a more affordable Synthesis XCT Carbon Wheelset priced at $1,600 that uses CB-branded hubs with Sapim D-Lite spokes and the same rims.

Crankbrothers Synthesis XCT wheel specs

This “it goes to 11” version of these Synthesis XCT wheels pokes 32 of Sapim’s lightest CX-Ray spokes through the rear rim and 28 up front, in keeping with the system-approach of other new CB wheels. Each of the J-bend spokes is laced in a three-cross pattern, tensioned with black aluminum nipples at the far end. The CX-Ray spokes are some of the lightest on the market, and they go a long way toward cutting grams on this wheelset. The larger number of spokes out back give it a solid sprinty feel when you’re cranking out of the saddle, while the front end does provide a touch cozier compliance.

Attached to those nipples are a pair of symmetrical carbon circles; the front with a wider 26.5mm internal measurement and the rear is spaced at 24.5mm. The narrower profile is suited to all-throttle XC tire widths, with a tad more girth up front for added grip and a tinge more comfort. In practice, the rounder and narrower tire profile rolls billiard-smooth, leaving me to wonder if someone mounted a fan to my back. With a light set of tires, these wheels spin up laughably fast and feel appropriate for XC racing or lighter trail riding.

A shallower 19mm rim height likely adds to the comfortable feel for the Synthesis XCT 11 wheels, and they are a rightly pleasant set. A little lateral and radial flex tuned into the system helps the rims absorb gravel vibrations well, which is great for my use case. Grip with these rims is laughably better than the carbon XC circles we had just five years ago, as the new crop of carbon isn’t solely focused on stiffness like its predecessors were. While newer riders may not note a difference, those of us who owned carbon rims when they first came to market will deeply appreciate the way the Synthesis systems ride and provide grip.

At the center of this set, the Industry Nine Hydra hubs make for an excellent, if unnecessary, pairing. The super-tight engagement feels fantastic when you’re climbing technical steeps, but I don’t know how often I’ll be doing that with such an XC-focused wheel. For the smidge lower technicality of modern XC tracks, the Industry Nine 1/1 hub engagement would likely do just fine. For bikepacking and dirt road applications like mine, there’s no need for the level of perfection these hubs provide, but it’s a cool bonus if you have enough paper in your wallet.

I wouldn’t mount anything more aggressive than say a Schwalbe Racing Ralph or Maxxis Ardent on these rims. Not that they can’t take it, but these are speed wheels, and those are the slowest tires I would want to shroud them in. These carbon wheels are more than tough enough for any trail those treads were designed to handle. At the beginning of this test, the folks at CB said that these wheels are “a good bit more trail than XC” and they weren’t wrong. I’d line up for an XC race on these without hesitation, and point them into some fun rock gardens afterward. The rims include a lifetime warranty after all!

Setting the Synthesis XCT 11 wheels up tubeless was breezy, but the tape on the rear rim had to be redone. This happens kinda often. Glue in the tape can break free in transit, and it’s difficult to get it tight again. It might be better for wheel brands to send a roll of tape instead of pre-wrapping to avoid this issue. It’s never fun to get tires mounted only to find you need to remove and dry everything for fresh tape. Apart from that issue, the tubeless setup has held strong.

In summation

Crankbrothers Synthesis XCT 11 rear wheel

For bikes with less than 120mm of travel, where speed and efficiency take precedent over all else, these wheels are a sweet option. Speed is never cheap, and Crankbrothers Synthesis XCT 11 wheels aren’t either. If you’re able to pay for the fastest featherweight in the biz, a set of these should top the list of circular considerations.

Party laps

  • Lightweight and high performing
  • Maintaining narrower profile that some XC racers prefer
  • Tough build given their low weight

Pros and cons of the Crankbrothers Synthesis XCT 11 Wheelset.

Dirt naps

  • May be too narrow for some applications
  • No Superboost hub option