mtbdownhillshock

Fitting Maintenance Settings

FittingYour shock is supplied with mount kits to fi t your bike.Each mount kit consists of a needle bearing fi tted on a throu-gh-axle pin, which holds the spacer cups and fi ts the shock into the frame/swing-arm.If the frame is not compatible with the needle bearing kits, your shock may be supplied with standard mount kits.The mount kits are already fi tted to your shock on delivery. If, however, you need to replace the needle bearings, use the following procedure:Lightly grease the outer surface of the needle bearings. Put them in the shock, rounded edge down, fl at (numbered) edge up. Assemble using a press.

Base settings1. Spring PreloadSpring preload isn’t considered as an adjustment. It’s a base setting which is dictated by your weight. It aims to adjust the sag (negative travel) on the shock, which is the amount the shock compresses when you sit on the saddle. It’s measured as a percentage of the shock’s total travel, but can vary from one bike to another depending on the geometry. BOS’s recommended sag for most bikes is 30% minimum. NB: Don’t forget that sag is measured on the fl at, whereas when you’re riding the bike it’s at an angle which reduces the ‘dynamic’(moving) sag.The BOS Stoy is supplied with a spring to match your weight.The ideal preload giving 30-40% sag, should be between 0-4mm. If you exceed 4mm then a harder spring is strongly recommended. If you don’t get the sag, choose a softer spring.A spring which is too hard or with too much preload can negatively affect the shock’s hydraulic damping and reduce your bike’s performance.

2. Damping adjustmentsThe Stoy shock is a three-way type shock, which means there are three types of damping adjust-ment: rebound, low-speed compression and high-speed compression.Your shock’s base setting (internal) is designed for your bike’s geometry. We use three base settings which cover the majority of bikes on the market. If a different setting is necessary for a given bike, we will develop it especially.

The purpose of damping adjustments is to use all the shock’s travel without bottoming-out (or only rarely), to give grip to the rear wheel, but also to stop the bike stalling in holes, and fi nally to maintain a good position. Below are the base settings for your frame. Then it’s up to you to analyse its performance and adjust the settings to suit your riding style. Do this carefully and methodically, step by step. Only change one setting at a time and only by a few clicks. If it’s OK, note the setting and type of terrain. If you get confused with the settings, return to the base settings and start again.

A B

2.1 Low-Speed Compression (A)The low-speed compression affects the shock’s performance in compression over small bumps or through the beginning of the travel.It can be useful to make the low-speed harder (screw clockwise) on rolling terrain with big compressions and kickers.It can be useful to make the low-speed softer (screw anti-clockwise) on steep gradients.

2.2 High-Speed Compression (B)The high-speed compression acts mainly on harsh hits (jump landings, rough rutted sec-tions). It should be soft enough to get all the travel without bottoming-out. If, on a given track, you bottom-out a lot, make the high-speed compression harder. However, don’t get hung up on bottoming-out if you only do it once or twice during a run. You risk setting your shock for 3% of the course and losing effective-ness on the other 97%.If your shock doesn’t get full travel, soften the high-speed compression.

2.3 Rebound (C)The main factor in adjusting the rebound is the position of the bike. A downhill bike shouldn’t be ‘sat-down’ all the time, although the back does need to be fairly low. Playing with the rebound will allow you to keep this balance.If you feel like the back of the bike’s pushing you forward on a slope or when braking, increase the rebound (screw clockwise). It can be useful to accompany this adjustment (especially if the problem persists) by unscrewing the low-speed compression slightly.If, on the other hand, the bike seems too low at the back and/or the front end has a tendency to drift offl ine, reduce the rebound (screw anti-clockwise).

C

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MaintenanceCleaning:Clean your shock after every ride using a non-aggressive, non-alkaline cleaning product, leave to dry then spray with silicon spray and protective grease. Check it regularly and remove any dust/dirt from the bottom-out bumper.

Maintaining needle bearings:The needle bearings in the mount kits need regular maintenance. If you use a jet wash to clean your bike, take care not to direct it at the bearings and under no circumstances in the through-axle pins. Regularly take the shock off the bike, rotate the bearings a quarter turn and grease them (modera-tely) using bearing grease.

Periodic maintenance:In normal use (training and racing for a complete season), your Stoy shock only needs one service per year (oil change and replacement of wearing parts). This service can only be carried out by us or one of our authorised distributors.

2.4 Base adjustments corresponding to internal settingsThe Stoy shock is available in three internal settings covering the latest types of rear suspension. Below are the base adjustments for each setting. To optimize the adjustments in terms of your bike, riding style and terrain, always start from this number of clicks. If your shock has been sup-plied with a non-standard setting, refer to the information supplied on delivery.

Setting NumberNumber of clicks (anti-clockwise from fully closed)

LS compression HS compression ReboundST001 15 12 15ST002 18 18 15ST003 13 3 10ST004 12 15 12

Adjustments are always made by unscrewing anti-clockwise from a fully closed position.

!! NEVER attempt to alter the pressure in the shock’s reservoir. It never needs changing and the gas only acts to pressurize the hydraulic fl uid in order to avoid cavitation. Attempting to to modify the reservoir pressure will only result in shock failure.!