Changing the Approach to Rear Suspension
How metric sizing could change everything
Photos by Adrian Marcoux
The bicycle industry has been under fire lately and, frankly, rightly so. It has been incredibly disorganized the last few seasons regarding the introduction of new “standards.” We’ve touched on standards a couple of times in the last year, and this debate has yet to be settled. From various bolt-circle diameters (BCDs), hub spacings, stem clamp sizes to shock mounting hardware, it is questionable whether these options actually hold any real advantages for riders.
On a recent trip to the North Shore of Vancouver, British Columbia, we were introduced to a new “standard” created to simplify suspension for riders without forcing frame designers to compromise on performance. We went into it with a tinge of skepticism, but came away with knowledge about a new system that may actually have some on-the-trail benefits for riders.
Shock sizing might not seem like a big deal, but it plays an important role in determining how your suspension rides. Shocks must fit in a compact area and pack in enough adjustments and damping performance to handle any trail situation. Modern geometries use aggressively sloping top tubes and higher bottom bracket heights that make shock placement even more complicated, especially on longer-travel bikes or smaller frame sizes.
The new “metric sizing” system refers to the two critical measurements necessary for shocks: the eye-to-eye length of the shock itself, which is the distance from the top and bottom mounts where the shock bolts to the frame, and the stroke, which is the distance the shock can compress.
With the current standard frame, designers use whatever eye-to-eye and stroke lengths they deem necessary to fit the shock in the frame to provide the needed clearance. SRAM’s metric sizing simplifies this process by establishing 18 sizes agreed upon by various suspension and frame manufacturers. RockShox currently produces over 50 different sizes, and this can be a huge headache for riders looking to make any changes to their shock choice.
This hasn’t been a project that RockShox engineers have kept to themselves; they have been in close communication with several other industry leaders to allow frame designers to better prepare for the change.
HOW TO MAKE IT FIT
Granted, you can’t just simply resize a shock, throw it in a frame and expect everything to go smoothly. RockShox has addressed this with two different mounting options that will take better advantage of the limited space provided. The focus of this system is a trunnion-style mount that mounts the linkage directly to the shock body. Trek has been using this design on its trailbikes, in particular the Fuel EX 29 that we tested back in our November 2015 issue, which we loved. The trunnion mount shortens the eye-to-eye length while allowing the shock to have the same (or longer) stroke. This style will be more widely used on horizontal shock mounts and will include bearings pressed in the linkage for reduced friction. Bikes that have vertical shock mounts will use a new bearing mount instead of a pin and DU bushing, which will greatly reduce the overall friction between the shock and linkage.
THE SUPER DELUXE
RockShox’s engineers spent all of this time and R&D just to unify the bike industry, and we commend them for that. For the last couple of years they have been working to bring riders a new set of shocks built around this concept, which takes a very complex system and simplifies it. The Super Deluxe provided a night-and-day comparison of how bearing mounts ride. The first day of riding in Vancouver was on a fleet of Transition Patrols using the current pin/DU bushing. After a long morning of riding, we switched our suspension to the new Super Deluxe with a trunnion mount. The difference between the two designs was drastic. Just setting the sag in the parking lot proved how much smoother the trunnion mount allowed the suspension to feel.
This wasn’t all because of the mounting system. The Super Deluxe uses more bushing overlap, which greatly decreases friction. The Open, Pedal and Firm settings were also more pronounced with the new damper.
DOWN THE TRAIL
Given the influx of proprietary technology that has cluttered the market, having a prominent company work in conjunction with other manufacturers to simplify things is a welcome relief. There are drawbacks, however. The shock is heavier and will only be available as original equipment on a few manufacturers’ bikes for now. It’s highly unlikely that this is something you will be able to adapt to your current rig. But don’t stress, RockShox is still planning to support its current mounting systems with replacement parts for as long as it needs to.
The bottom line is that RockShox is making a concerted effort to simplify a system that was too complex. The new mounting system will not be without its teething problems, especially since the current pin, reducer and DU bushing mounting system have been in place since the invention of the full-suspension bike; however, we see this not as a ploy on SRAM’s part to dig a little deeper into your wallet, but a plan to unify frame-makers with a system that’s easier to use for both manufacturers and the riders who buy their bikes. Can you call it a “standard”? Maybe not just yet. The system does show promise, though. We noticed the simplicity and improved ride feel in the first few pedal strokes. That’s something we can celebrate.
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