Syntace C33i Straight Carbon Wheelset - Review

wheel are low-inertia, straight-pull hubs, a fast-engagement star-ratchet freehub with a steel-reinforced cassette spline, and oversized high-load bearings and axles. C33i Straight Carbon wheels use 28, same-length spokes and are available in Boost or Syntace's zero-dish EVO6 spacing for 1400 Euro. Weight for the pair in 27.5 (tested) is 1580 grams and Syntace backs the wheelset with a ten-year warranty for manufacturing defects. Full specifications here.



Features and Construction

C33i rims: Syntace has been on the cutting edge of the wider rim movement, and they have learned a lot about the concept since the inception of their aluminum MX wheelsets five years ago. Short rim flanges free the tire to follow the terrain, while providing more support. Bead locking internal profiles that guide tubeless tires through the inflation process and efficient V-profile cross-sections that transfer loads without creating a non-compliant structure are a few gems.

Syntace included those lessons, and then took advantage of the carbon process to add some new features that were not possible or practical for aluminum construction. The rim flanges are double thickness for impact resistance, and, inside the rim, triangular cones are molded into the structure to reinforce the spoke entry points, which are correctly angled and tapered to fit Sapim Q-lock nipples. The new interface, says Syntace, is stronger than the spokes. The carbon used for the rims is engineered to be much more ductile, and thus can survive impacts, reportedly, far beyond those survivable by heavier aluminum rims. Finally, Syntace has reconfigured its hub-flange spacing to eliminate most spoke dish, which means all the spokes are the same length and nearly the same tension - an improvement that eliminated the need for the spoke offset of its original W-series rims. Going forward, all Syntace rims will be drilled symmetrically.



Straight MX hubs: Syntace is especially proud of its latest MX hubset. They incorporate straight-pull spokes, made for Syntace by Sapim. Syntace says that the smaller flange diameters help reduce fatigue and rotating mass. Internally, both the front and rear hubs use thin-wall oversized steel axles (20mm for the front and 17mm for the rear), and special triple-sealed high-load bearings, said to increase load-carrying capacity by 90 percent. Axle widths are Boost 110/148 and Syntace supports both conventional, centered-rim lacing and its EVO6, offset-rim lacing that is used on Liteville frames to maintain near-perfect spoke angles and improve the chain line. Both conventional hub caps and SRAM's Torque-Cap interfaces are also supported, and rear hubs support SRAM XD or Shimano cassettes.





At present, Syntace only offers the C33i wheels in the 27.5 size, but it shouldn't be a long wait for a 29-inch-wheel version. As mentioned, Syntace has an extensive in-house testing facility, in addition to a cadre of real-life test riders that they employ to vet out any flaws that may require design improvements before going to production. On that subject, Syntace offers a limited, ten-year warranty that covers manufacturing and material defects free for the first three years and at 50% of the MSRP thereafter for the years remaining.



Ride Report

Setup: Our C33i Straight Carbon wheelset was supplied with the Liteville 301 MK14 we reviewed earlier. Riding was shared between RC and fellow PB rest rider Harold Preston on various all-mountain and DH trails, most of which feature embedded granite rock, many square-edged impacts, and medium-height jumps and drops. Tires were Schwalbe Hans Dampf (rear) and Magic Mary (front) with pressures ranging from 20 to 26 psi and set up tubeless.

Technical performance: Removing and reinstalling tires requires a firm press with the edge of a shoe to unseat the bead from the C33i rim's raised locking ridge. The force was not as great as is required to free the bead from an Enve or the new Syncros carbon rims, which can be a tough job. Once the bead has been broken, tires can be removed or installed by hand. Inflation was uneventful using a floor pump and there was no need to remove the valve core to achieve maximum air flow. Throughout testing, which lasted approximately three months, neither of us burped air, cracked a rim or experienced a spoke failure. Spoke tension and rim runout remained consistent.

The faster engagement ratchet mechanism is an improvement from the previous W35 MX aluminum wheels I have been using for a number of years, and the growling sound they make is music to my ears. I had no need to adjust the bearing end-play, but I did anyway to check the feature. Finger pressure to rotate the Allen-clamp collar was all I needed to zero out the bearings and the hubs run so smoothly that I still spin the axles to experience it when I remove a wheel. The front hub was outfitted with oversize Torque Caps to interface with the RockShox fork dropouts. They hung up on the fork and typically required some shuffling to slide the wheel in accurately (no fault of Syntace, this is also an issue with SRAM's Torque Cap hubs).

Trail impressions: I rarely break wheels, but co-rider Harold Preston does. Neither of us were able to damage the C33i carbon rims in any way. The wheels are true within a millimeter, and there is no blistering on the tops of the rim flanges where sharp-edge rock strikes often leave their mark.

Ride quality is the talking point of these wheels. They are precise feeling in the turns, most likely due to their lateral stiffness and also for the secure footprint that the 33mm inner-width, low-flange design creates for the tire. Pressing the bike into a corner flares the tire's tread into the soil without any sensation of rolling or folding at pressures near 20 psi (Schwalbe 2.35" EVO casings). A number of wheels can make that claim, but few in the all-mountain class can boast the deft, lightweight feel that this 1580-gram wheelset delivers both while maneuvering, and when under power. Syntace has found the nexus point between a stupidly stiff build, and the twangy sound and feel of an overly lightweight build.


Pinkbike's Take:
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