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First Ride: Crankbrothers Carbon Synthesis Wheels

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The carbon wheel system is available in a few different configurations. There is a standard hub with 17 degrees of engagement, and a fancy hub with Project 321 internals and 2.5 degrees of engagement. All of the wheelsets have Sapim spokes, with the higher end E11 wheels coming with Sapim's CX-Ray in the front and CX-Sprint in the rear. There is also a rim-only option for those wanting to build up their own sets.The XCT and Enduro wheels both have a standard hub option for $1,699 USD/EUR or the Project 321 hub and higher end spokes for a cool $700 USD/EUR upcharge. The DH wheels are only offered in the high-end build and sell for $2,399. The rims in both wheelsets are the same and can be purchased by themselves for $699 each. The Enduro wheelset is available for purchase now and the DH/XCT wheelsets will arrive in late 2018.

BackgroundThe design and development of the Synthesis took Crankbrothers several years; it's not an evolution of their previous wheelsets but a completely new approach and philosophy on wheel systems.
carbon specifically, for a couple of decades, spending time at Reynolds, then at Enve. He was the first person to make a carbon clincher wheel and a carbon mountain bike wheel, among other things.Shears admits that joining on with Crankbrothers initially wasn't an idea that he nor many people he knows and trusted would consider the best move - their track record for wheels hasn't been stellar. He worked with them as a consultant for about 18 months, and then as the pressure built for him to come on full time he came up with a wishlist that included quite a few asks, including having a new development center in Utah - SR56. SR56 is used for designing and developing carbon and Selle Royal brands.

With the two minds together, they decided that if they were going to bring another carbon wheel to market, they needed to do something completely different than what was currently available.

Crankbrothers Synthesis Wheels are BornThe philosophy behind the new guard at Crankbrothers is to develop products that actually improve the ride experience, not just something to bring another product to market...commendable this day in age when at times it seems there's often a new standard just to be different. The team developed a number of wheelsets, some very compliant and some very stiff, and then put them under a variety of test riders. Shears claims that they ended up getting a mixed bag of feedback on each set. Some were too stiff, some were not stiff enough. Mellow developed compliant wheels, Shears made stiff wheels. After some frustration with the results of those tests, they started to mix and match the compliant and stiff wheels. At this point, the team found that everyone agreed on one mix...something Shears says he hasn't seen before in 20 years of wheel development. The result was a more compliant front wheel with a stiffer rear wheel.It's a pretty simple concept: more compliance to let the front wheel find its way, and then more stiffness in the back wheel to help the bike track well. An analogy that was made was how most riders run a little less pressure in their front tire than the rear. If the front wheel is too stiff, it won't flex and hold the trail. Rather, it will skip around and ride poorly. Conversely, the rear wheel has to be stiff to manage larger hits and power through impacts with more force. With the idea of a more compliant front wheel and stiffer rear wheel figured out, the SR56 team could now start the development process.

Across the board in the Synthesis wheel system, the front wheel is more compliant than the rear. It has a reduced spoke count, a lighter gauge spoke, and a lower spoke tension. The rim itself is slightly lighter and the inner rim width is slightly wider - this is to match up with running a slightly wider tire up front and allow the tire to have a rounder profile. The rear wheel has a higher spoke count with a higher spoke tension, and the rear rim has a slightly narrower inner width to sharpen up the tire profile for cornering. The rear rim wall is thicker to handle higher impacts. Crankbrothers claim is that this builds a super tough and durable wheelset but one that has a compliant ride quality.

Front/Rear Rim Comparison Chart


Durability and a Controlled Failure Mode The rims have been under the bikes of the Unno World Cup DH team for some time now. The SR56 engineers claim they are happy with the results, especially from the rock-laden tracks in Losinj and Mont Sainte Anne as the wheels were in more of an R&D phase rather than a final and refined product at that point.Everything can eventually break, but the well-known fact that carbon wheels can fail catastrophically is a contentious issue that a lot of riders are rightfully concerned about. Shears says he's been obsessive about the way carbon fails and how to manage catastrophic failure ever since he worked to make the first Edge/Enve wheels. Synthesis' ultra-thick carbon sections have some trade secrets hidden inside them that can't be duplicated by traditional thin-wall tubular-section types. The resin system used in the carbon is a special high-impact formula, while the layup schedule is tailored to disperse impact events. Nobody is talking about specifics here, but similar materials and layups are used to protect drivers in F-1 race cars, where catastrophic carbon failure is not an option. Those materials require additional thickness to disperse energy - a feature the new rim profile incorporates. Shears says that they're not the absolute lightest out there, but they fail with a propagation type failure...more like an aluminum wheel. You'll get a deterioration before a complete failure. He claims that if people are developing carbon wheels, then they have a responsibility to manage the failure of carbon wheels and make it safe and controlled. I won't argue with that.

Synthesis E 11 Specs:



Performance and Ride Impressions

I have quite a few days on the Synthesis E 11 wheels on a smorgasbord of terrain ranging from long steep fire road climbs with chunky and extra-rocky descents to more mellow undulating trail loops. The wheels are set up on my Specialized Enduro 29 test bike. The E 11 wheelset has the Project 321 hub internals with 2.5-degrees of engagement and magnetic pawls. 28 Sapim CX-Ray spokes in the front and 32 Sapim CX-Sprint spokes in the back. The front wheel has an inner rim width of 31.5mm and the back is 29.5mm.
propagation failure is appealing to me, and I would imagine that other riders are into that as well - especially given there's a lifetime warranty as long as you're riding the bike, not running over your wheels with a car.I'll continue to put miles on the Synthesis wheels to see how they hold up at home in North Carolina, especially through the fall season as leaves blanket rocks that have taken many a wheel in the past. We'll do an update once we have more time on them, as I'm sure anyone who's dropping that kind of money on a wheelset will appreciate a long-term test.
bigquotes So, did Crankbrothers reinvent the wheel? I wouldn't go that far, but they certainly have a unique product on the market, one that's different than anything they've produced in the past - and that's a really good thing. The Synthesis wheels do offer a high-quality ride in a complete package. Knowing they are engineered to fail in a way that is safe, and also have a lifetime warranty, suggests your body and wallet will be better protected. My initial impression is that they've created a serious contender in the sacred circle of high-end carbon wheels. If that's what you're after, their ride quality is certainly better than many I've ridden.Daniel Sapp