American Classic owner Bill Shook says that, apart from some dings, they have never had of one of their Wide Lightning rims fail. Despite this, he was still determined to better his design and created this Carbonator wheelset. The carbon rim comes with a fifteen gram weight penalty over its alloy brethren, but Bill wanted to over-build in order to improve upon the performance and reliability of the Wide Lightning. The new rim has a 26mm internal width and a hookless rim wall that measures 3mm thick, while the bead seat slopes downwards from the centre of the rim to help with burp security - the bead will actually tighten as it is pushed or pulled inwards.
The hubs have a number of interesting features and a trio of patents. First is the freehub body that has three steel inserts to prevent steel cassette carriers biting in to the softer alloy, which might not be a new idea but is a smart one. The second is the two cut outs through the sleeve that spaces the inner bearing races. This makes the sleeve behave like a leaf spring that will absorb pressure when preloading the bearings, giving them less rolling resistance, and it will self adjust as the bearings wear. Inside the freehub there are six pawls that are engaged using a patented timing plate rather than springs - the pawls only move when prompted to engage, which reduces rolling resistance. With standard springs and pawls they are constantly being pushed in to the ratchet teeth, and there is also a very small difference in the timing as each pawl engages, with the timing plate this happens at exactly the same time. Shook says that this creates the strongest system on the market.
The Carbonator wheelset weighs in at 1,595 grams (27.5"
) and costs $1,799 USD. All the usual options are available, and Boost hubs with a difference are on the way. Cecile and Cedric Ravanel will be out to prove this wheelset on the EWS circuit in 2015, riding for the newly formed Commencal/Vallnord Racing Team.
American Classic have taken a slightly different approach to other manufacturers jumping on the Boost bandwagon. While other brands simply moving front hub flanges outwards 5mm on each side, Shook have added extra 10mm of width to the non-drive side axle, and the flange width hasn't changed from their regular hubs.This makes for a symmetrical wheel build, which they say is more beneficial in terms of strength and weight than a wider base to the spoke triangle. A symmetrical wheel will have equal spoke tension rather than one side having a higher tension and therefore less pressure on the spokes and eyelets, and the possibility of building a slightly lighter rim. The same theory is applied to the rear hub which adds 6mm to the non-drive side between the flanges and disc mount, not quite achieving symmetry, but close.
Bill didn't seem to be a fan of the new Boost standard, and says he only produced these hubs to give his customers the option. He feels that the industry isn't thinking outside of the box, and suggests the main reason for Boost is to move the chain line further outboard, to give clearance for wider tyres and shorter chainstays, not to create wider hub and stronger wheel. He's a fan of Cannondale's F-Si cross-country race machine which uses an offset rear end to achieve the same effect. The F-Si has some of the shortest 29er chainstays on market with suitable rear wheel clearance and chain line. "We didn't need the Boost standard in this ever-changing industry, and could have simply used non-symmetrical rear ends to achieve the same results,
" he said.
Until now, the only options for RS-1 owners were SRAM and DT Swiss wheelsets. This hub has bigger axle and clamping area then competitors for even more stiffness. The sides of the axle are also smooth instead of serrated, and Shook says that with the design of the RS-1 the serrated edges can cause the bolt-thru axle to work itself loose as the 'teeth' dig in to the alloy fork dropout, which shouldn't be an issue with smooth sides.
This is an example of the valves that are supplied with all American Classic wheelsets. They use two different sized o-rings at the base of the valve, a configuration that means that the valve seal is created against the flat surface of the rim instead of sealing against the edge of the valve hole. This is said to provide more surface area to give a better seal that's less likely to break when adjusting the valve or using a pump.