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Syncros Untethers Flyweight Silverton SL Carbon Wheels

Two Year Development Process Results in Carbon Everything—Yep, Spokes Too

Carbon, so hot right now, carbon. Syncros released its high-end carbon Silverton SL wheelset during day one of the Sea Otter Classic. The wheels’ release concludes a two-year development process aimed wholeheartedly at domination within cross country and cross country race categories. The price tag reflects this. A Silverton SL wheelset will retail for $3,500 when available in September. Before you stop reading, note that Silverton 1.0 and Revelstoke 1.0 carbon wheels will retail for $1,700--so there’s still hope for those without limitless budgets.

For those willing to pay the price, there’s quite a lot going on and it’s certainly different. But before we get ahead of ourselves, the specs on the Silverton SL:

  • 1,250 grams
  • 29 inch
  • 26-millimeter-inner-rim width, 31-millimeter outer with a 35 millimeter depth
  • Hookless
  • 20 carbon spokes per wheel
  • 130 kilogram (286 pounds) maximum complete riding weight--bike, rider, gear
  • Boost
  • Center Lock
  • Tubeless
  • DT Swiss 190 internals
  • Carbon flanges, carbon shells

Everything about the Silverton development process focused on optimization. Syncros considered composite construction, wheels where we usually see a few pillar-like spokes versus traditional 28 to 32 hole J-bend and straightpull steel spokes and settled on somewhat of a hybrid of the two: 20 carbon spokes that at first glance appear normal.

One spoke goes from rim, across hub, to rim again eliminating a harsh angle at the hub flange that Syncros says would create a weak point for carbon.

Each carbon spoke goes continuously from rim across to rim again, wrapping around the carbon hub flange rather than intersecting with it. So, technically the Silverton SL is a 10 spoke wheel, though if you count around the rim, there are still 20 bonding points. According to Syncros, a continuous spoke prevents a harsh, bending point angle that would create a weak point. It also allows the fibers to be oriented in the same direction.

In order to ensure the wheels would still be laterally stiff, they overlap, creating five junctions per side of each wheel. They’re equidistant and create the effect of shorter, stiffer spokes. Think of them as a huge hub flange without the additionally filled, unnecessary space.

The five spoke overlaps just above the hub flange are designed to create the same effect as a massive hub flange without wasting unnecessary material and weight to create that huge flange.

On the rim’s surface, spokes pull from lateral locations. This creates the effect of a larger bracing angle while also preventing another harsh intersection that would jeopardize the strength of carbon spokes. For the rim width, thickness and depth, Syncros again focused intently on optimization, experimenting to find the sweet spot of weight to stiffness. They settled on 35 millimeters deep with a large cavity, offering the analogy of a large downtube--by creating a bigger tube, wall thickness can decrease while stiffness is maintained, ensuring it’s both light and stiff.

Smooth angles. A massive inner cavity allows for a thin wall that reduces weight while maintaining stiffness.

Manufacturing the wheels was quite a challenge. The first attempts required 34 pieces to make a wheel mold. Over development, Syncros was able to rein this in to eight pieces, a number they believe will allow for the attention to detail and quality necessary to create such a high-end product while still producing quantity.

Once the rim, spoke and flange are together, it’s time to squeeze in the carbon hub shells. In order to do so, the flanges need to move 2.5 millimeters per side. This further tensions the spokes.

Each hub flange moves out 2.5 millimeters to accommodate the carbon hub shell.

In determining spoke tension, Syncros also factored in tire pressure--it’s easy to forget that when inflating a tire, pressurization affects the wheel. When working with carbon spokes, everything needs to be ironed out from the start.

Carbon hub shell. Twenty grams.

On the Trail

I only had a very brief window to take the Silverton SL wheels out for a spin behind the expo mayhem and it was on the smooth, rolling, narrow singletrack found just beyond one of the ridge hugging camping areas. I rode them on a Scott Spark with Maxxis Aspen 29 x 2.25-inch tires over sunbaked clay and moderately sandy conditions. Hard with a chance of soft. What’d I think? Light.

Really, really light. I can’t think of a lighter wheelset I’ve ridden, including road wheels. They also feel stiff, which is quite perplexing considering they’re so light. It was an odd feeling for me--they spun up like something so light that I assumed they’d boomerang just in standing up hefting my weight from side to side, but they definitely didn’t. I wouldn’t go so far as to say they felt harsh, but I would say for an initial impression, it was definitely one of decisive power transfer--stiff but not harsh. Shaken but not stirred.

I rode the Spark locked out on the pavement up to the trail, zigzagging back and forth standing over the frame hunting for the twang feeling but I couldn’t find it. I also didn’t notice it while unlocked on the smooth singletrack. I’d love to take them into rocky conditions that hang onto wheels but sadly, there’s not much of that in the immediacy of Sea Otter--so, I can only report on initial thoughts pertaining to smooth conditions.

Width wise, they didn’t feel narrow, they didn’t feel wide and you’ll have to factor in that the majority of bikes we ride at Bike are trail or all-mountain bikes, arriving with wider rims so this admittedly does bias me a bit. That said, the Silverton SLs definitely felt wide enough to get the job done, and with less of a minimal racer tire on them, it’d be interesting to go do some proper trail riding.

Are they for everyone? At $3,500 they can’t be. But for somebody looking for the absolute utmost in carbon technology striking the seemingly unachievable balance of light weight without detriment to stiffness, then the Silverton SLs might be the ticket. A big ticket. Those appalled at that price and still wanting carbon could perhaps consider the Silverton 1.0 or wider Revelstoke 1.0, both with carbon rims but instead using a steel straightpull spoke construction and Syncros in-house hubs for $1,700.

Syncros Silverton SL carbon wheels are available September. More details available at Syncros’ website.