Rocky Mountain’s goal for the latest iteration of their famed Slayer bike line was to create a world class All-Mountain/Enduro/DH adventure cycle machine. Easy to pedal, light weight, and fantastic on the downhills. Did they meet these goals?
To achieve this, Rocky Mountain needed to design the latest Slayer from a clean slate. The engineers at Rocky Mountain chose a slightly modified four-bar platform for the suspension. The Slayer 70 uses Rocky Mountain’s SmoothLink™ suspension system, which is an extension of their ETS platform and is now used extensively throughout the Rocky Mountain bike lines.
The key features of the SmoothLink™ are minimal chain growth, for example a 140mm travel bike will have 9mm of chain growth, and a linear rising suspension rate. A benefit of this is that shock settings will be constant throughout the stroke and the suspension will have a limitless feel. The SmoothLink™ system puts the rear swing arm pivot 10mm above the rear axle, which allows the Average Chain Torque Line (ACTL) to follow more closely to the lower link of the system. Keeping these two lines closely in parallel allows the Instant Center of Rotation (ICR) of the suspension system to closely follow the ACTL, which means reduced pedal bob. But this isn’t the only design advancement that the new Slayer would receive. Rocky also noted that optimum pedaling power comes from having a correct seated position, so the StraightUp™ geometry was developed. This means that when the suspension is set to the correct sag, the seat tube angle will be around 73 degrees. At this angle you shouldn’t have to scoot up on the nose of your saddle when pedaling uphill. It will put your hips and legs in better alignment with cranks and pedals for optimal power. Obviously this geometry won’t make up for having weak legs, but it can make the chore of riding up hills more enjoyable and efficient.
Other cool tricks in the new frame include a two-piece bottom bracket that is hollowed out to save as much weight as possible, an e-type front derailleur that bolts onto the frame, tapered head tube for optimum strength to weight savings, and a pretty trick little chain device that helps keep your chain from completely dropping off the double rings up front. Oh yes, and that one guy, Wade Simmons, famous for doing stuff on bike or something like that, had a lot of input into how the bike handles and rides.