This week we have enlisted the help of suspension guru Arthur Gaillot of Suspension Therapy in North Vancouver. Arthur offers suspension setup for mountain bikes so that riders can get the most from their machines.
Having the correct suspension setup is paramount for optimizing performance. A bicycle, no matter how high end it is, will only perform to a very small percentage of its capabilities out of the box. Setting up your suspension is something that is actually pretty straightforward, but is also easy to make a mess of. The following is simple approach to establishing a solid base setting for suspension. Think of it as a set-up that is ideal for 90 percent of the time. As a rider you will become so familiar with how your bike works that way that it will come naturally to compensate for the last 10 percent. Obviously drastically different conditions and terrain will require a different set-up, but don't make the mistake to think that every ride requires a change in settings. You are doing this once, so that you can enjoy riding a well set-up bike after!
Refresh yourself on last week's glossary of suspension terms to help you through this.
People often rush to setting up the sag, or even worse, just fiddling with dials. There are a few steps before you can get that far.
1. First things first. Are your suspension components within the recommended service interval? As a rule of thumb, 30-50 hours for a basic service (fork lowers and/or air sleeve service on shock; 100 hours or yearly for complete service on fork lowers, air or coil assembly, damper; air sleeve and damper).
2. Eyes up. Look for worn seals, wear on the stanchions or suspension shaft. Clean the unit of dirt, dust and grit.
2. Sag to be set with dampers fully off or open. Once that is done start with baseline damper settings for the fork and shock. (Refer to manufacturers recommendations, both bike and suspension unit manufacturer.)
3. Set the sag (read on for more).
4. Go ride. Riding will help fine-tune damper settings, spring rates/ air pressures. The fork will usually need to be set-up with slightly less sag (firmer) than the shock. The shock will run more sag than the fork and be set up to rebound proportionally slower than the front fork. Keep track of your settings, and make one incremental change at a time to really get a feel for what is being affected.
5. The human factor: Be objective with yourself. If you are having an off day, or if the trails that were dry for months just got rained on overnight, it is likely not the best time to be assessing what is right or wrong. Pick a ride on a trail you know offers some variety, when you are not pressed for time, and preferably on your own. Your riding buddies likely won't be patient while you're getting your bike dialed!
You will need the following equipment:
– A clean bike
– You and the riding gear you wear and carry with you
– A friend
– Measuring device (ruler, tape measurer)
– Find a flat surface adjacent to a wall taller than shoulder height. Ensure there is enough room for the rider to stand on bike, elbow against the wall.
– Wear the riding gear that you use most of the time. Your riding pack should contain the gear and amount of water you usually carry.
– Dampers (rebound and compression) all the way off, fully open.
– With your bike in the stand and the fork and shock fully extended, measure the amount of exposed stanchion (top of seal to bottom of lower crown) and the eye-to-eye length of the shock (from center of one mounting bolt to the other). These measurements will be used in the following equation to measure sag:
Total length - (stroke x sag percent) = stanchion length or shock length under sag
Example for a 150-millimeter fork with 153 millimeters of exposed stanchion, and a desired sag of 25 percent:
153 - (150 x 25 percent) = 116 millimeters
Example for a 200 millimeter (length) x 57 millimeter (stroke) shock, and a desired sag of 27 percent:
200 - (57 x 27 percent) = 185 millimeters
1. Hop on your bike (feet on pedals, hands on grips), elbow resting against the wall, pedals level (your usual forward foot forward). Adopt your usual riding position, with as a guideline the neutral stance (shoulders and chest over the headset cap, bend at the elbows, knees not locked out, but well extended). You will notice that the neutral position on a bicycle is quite forward.
2. When you are stabilized, remove your fingers from the brake levers and wrap them around your grips.
3. Compress your bike by applying pressure into your pedals, through your hips. The idea here is to activate both your fork and shock to break through the slight friction in the initial stroke.
4. At this point, you might have to rotate your pedals backwards to re-align your cranks in a level position.
5. Maintain the neutral stance described above, looking 10 feet ahead of you.
6. The second person will now measure the length of the shock and fork:
a.For the shock, measure the eye to eye length = center of mounting bolt to center of mounting bolt.
b.For the fork, measure the amount of exposed stanchion = top of dust seal to bottom of lower crown.
7. If the shock sags too much, pump it up a little. Too little sag, release some air using the shock pump air release valve, not directly from the shock. For air suspension 5psi increments are ideal. Repeat the above procedure until you get the required sag. For a coil shock, add preload to the spring (maximum two full turns for Fox and RockShox, maximum four full turns for Cane Creek). If you need more sag than the spring will allow with this amount of preload, go up a spring rate, if you need less sag than with ½ a turn of preload, you need the spring under.
Setting rebound damping
You want to have rebound set so that it returns without getting bogged down on repeated hits, but not so fast that it loses traction and skips. Start off with the rebound damper in the middle of its range. Take your bike for a spin in the parking lot and compress the suspension forcefully. The fork needs to rebound a little quicker than the shock. As a rule, too much rebound will make the suspension feel harsh and un-compliant, too little rebound will feel like the bike doesn't stay put in corners and lacks control in the rough. This can only be figured out on the trail. Add one or remove one click at a time to either slow down or speed up the fork or shock. Generally, more aggressive riders need more rebound (slower return). As well, rough, rocky, rooty terrain with heavy compressions requires more rebound. Smoother, loose over hard pack conditions require less rebound to maintain traction. Work out what feels best in the conditions you ride in. If you want to go faster on your bike then get out the timing poles and do some science testing. Again, putting settings on paper helps to keep track.
Setting compression damping
Low-speed compression controls the force on the suspension under pedaling, braking and weight shifts. You want just enough of this so that it counters brake dive and doesn't squirm in corners, and not so much that your bike skips under braking and doesn't hold a line. The common misconception is that low-speed compression comes into play when going slow. When hucking off a drop at speed, your low-speed compression is part of what controls the absorption of your landing.
High-speed compression refers to how much travel is used when the shock has to deal with a hard compression (G-out) or square edge impact (roots, rocks) at speed. Too little high speed and the bike will squirm or bottom-out, too much high speed and the shock doesn't use enough of its travel, will ping on roots and rocks and not allow the rear end to stay settled under heavy compressions (corners, G-outs).
The terms low and high speed refer to the speed at which the damper shaft moves, not necessarily the speed at which the bike is going.
Compression damping can be hard to get right. The best technique again is to start with the dial right in the middle of its adjustment range. Go riding while trying to focus on when the bike feels harsh. It's a case of trial and error and does require some patience. Remember that sag must be correctly set first. One can't mask the effects of the other.
Going the full pro route and tuning the shock
This is something that very few people really need to do. Many bike manufacturers work closely with suspension manufactures to make their bike work as best as it can stock. However, for certain combinations of suspension designs/tunes/riders/terrain, tuning the internals of a suspension unit can be useful. However, this should only be done by someone who knows what they are doing and executed by professional suspension technicians at an approved suspension service center.
Suspension manufacturers often publish guidelines for damper setting ranges, spring rates/air pressures for a given rider weight and fork or frameset. These guidelines, however, apply to a damper in isolation (fork or shock only), not to a whole bicycle. Fork height, geometry, suspension design and characteristics, front-end height, bar width, stem length, rider measurements, rider ability and weight bias, fork and rear shock parameters, terrain, all need to be considered when performing a complete suspension set-up. Having your suspension set up by a professional will ensure you get the most out of your bike, minimize unnecessary fiddling and provide peace of mind that your bike is helping you become a better rider.
Thanks to Arthur and Suspension Therapy