When it comes to mountain bike suspension tuning, there's a wide range in levels of interest and technical know-how. On one side you have the 'set it and forget it' crowd, riders who don't typically do much to their fork or shock after getting the initial settings dialed in, and then on the other side are the tech-geeks, those who could wax poetic for hours about shim stacks and suspension curves, and who leap at any opportunity to point out the difference between 'damping' and 'dampening'.
Neither side is better than the other, and even at the highest level of the sport you're just as likely to find racers who rarely touch their suspension settings as you are those who make minute tweaks almost every single run. It was with those facts in mind that RockShox decided to hold a tuning camp in Squamish and Whistler, BC, in order to demonstrate the steps for getting the most out of their Pike fork and Monarch DebonAir rear shock, two of the most common high end suspension elements currently on the market.
Volume Spacer Basics
Why Squamish? Well, in addition to being surrounded by some of the best riding in the world, it's home to Shawn 'The Wizard' Cruikshanks. His shop, Fluid Function, is located in small industrial park at the edge of town, and serves as a Canadian service center for SRAM products. Shawn is also the suspension guru entrusted with tuning the bikes of several SRAM sponsored athletes, including Brandon Semenuk. In short, if you need someone on hand to help get things dialed in, he's the guy to do it.
The purpose of the clinic wasn't to venture fully down the rabbit hole of suspension tuning, but to focus on the bigger picture, on the type of adjustments that are slightly more involved than turning a knob or flipping a lever, but still easily doable by anyone who can tell their left from right and turn a wrench. Adjusting the air chamber volume on either the Pike or Monarch DebonAir is a relatively simple procedure, but it can have a large influence on the way the suspension performs. In order to suss out the difference that altering the spacer configuration makes, we used the lift-served playground of Whistler Bike Park as our testing facility, repeating the same lap over and over again and changing settings between each run.
If you've purchased a bike equipped with a RockShox suspension fork recently, more than likely it came a couple red plastic spacers, which RockShox calls Bottomless Tokens
. Although they might look like pieces for a game of checkers, the tokens thread into the underside of the top cap, as well as to each other, and allow for the amount of ramp up the fork has at the end of its stroke to be adjusted. Look at the illustration above, and you can see the difference in air pressure in a fork without tokens versus one with two installed.
Suspension setup isn't an exact science, but rather one that's based partially on how a fork or shock feels on the trail. That's why taking back to back laps on the same track is the best way to compare different settings. The lap used for this session in the Whistler Bike Park was Angry Pirate → Del Boca Vista → A-Line, a run that includes a mix of twisty singletrack with a few rocky sections, and finishes with the high speed jumps that A-Line is famous for. Pike Bracket Testing
For my first lap, the fork (a 160mm Pike) was set the same way that I would usually run it on my home trails in order to set a baseline, something to compare the following runs against. Once the first of many runs down the mountain was complete, the one token that I normally have installed was removed in order to illustrate what one end of the range of settings felt like. The number of tokens a fork can accept varies depending on the amount of travel as well as the wheel size, but typically the less travel, the more tokens, because the ramp up needs to occur more quickly on a 80 or 100mm fork than it would on something with 150 or 160mm of travel.
Without any tokens installed, the fork felt more prone to diving, and it tended to get sucked into holes rather than staying in the middle portion of its travel. At slower speeds things felt relatively normal, but on bigger hits on rougher terrain it was clear that more progression at the end of the stroke would be helpful. After establishing what a token-free configuration felt like, it was time to install as many tokens as possible, in this case a total of four.
Running the Pike filled to the brim with tokens created much more feedback in my hands, especially when plowing through brake bumps or over rocky section of trail. The ride height was altered as well, due to the fact that the increased ramp up kept the fork positioned higher up in its travel. At times this height felt beneficial, allowing me to really drive the bike into turns, pushing into the front end as hard as I wanted, but at other moments it simply felt like it was overkill, creating a ride that was too harsh for my liking. With the two ends of the spectrum established, it was time to work downwards, removing a token after each lap until arriving at the setting that best suited my preferences. As it turned out, the setting I initially had (one token) was what I ended up settling on as my default configuration, but for days in the bike park or during a race when higher speeds than usual are the norm, I'd be inclined to put another token in to take advantage of the additional ramp up. Monarch Plus DebonAir Bracket Testing
What was the end result of all of this fiddling about with plastic tokens and rubber bands? Well, in addition to getting to ride the incredible trails in Squamish and Whistler, it provided a chance to experience the extremes when it comes to suspension setup. Even if it's unlikely that I'll ever use those settings, it's good to know what a fork with four tokens, or a shock with six spacers feels like out on the trail.
With the fork dialed in, it was time to start working on the rear shock, a Monarch Plus DebonAir. Once the air is removed from the shock, removing the rubber o-ring at the base of the outer air sleeve allows the sleeve to be slid off, and for the rubber band volume spacers to be added or removed. Unlike the fork, where one token makes a noticeable difference, it usually takes two or three rubber bands to make a difference in the shock's feel, as the above graphic illustrates.
Just like with the fork, after taking a run to set a baseline, it was time to install the maximum number of spacers, in this case a total of six. This caused the shock to feel like it was bouncing off obstacles, and it felt too firm in the rougher portions of the trail. On the smoother, jump filled section of the run the extra support was a benefit, providing a platform to push against and really pop off the lip of a jump.
Dropping down to three spacers in the shock ended up being the magic number, a setup that allowed the shock to track and grip well over roots and rocks, but with enough ramp up to keep from blowing through its travel. Of course, the number of bands required will depend on the bike's suspension design in addition to rider preference, since some designs are already inherently progressive and won't need as much progressiveness as a a bike with a more linear spring rate.
For riders that are interested in going a little bit further with their suspension setup, experimenting with different air chamber volumes is the logical next step, and it's easy enough that it can be performed trailside with minimal hassle other than toting along a few tools you wouldn't typically bring on a ride. Taking that extra bit of time to dial in a set up is well worth it, and can lead to an even more enjoyable time out on the trail.