Adjust rear spring preload

Spring preload is how much the shock spring is already squeezed before you sit on the bike. More preload holds the rear higher under a heavy load (passenger, goods); less preload gives a softer feel with a light load. Preload does not make a worn damper work again. Many commuter shocks have a stepped collar at the bottom of the spring with several positions; for example the Hero Honda Splendor Plus rear shocks have a 5-step adjuster.

Safety

• Put the bike on its centre stand. Take weight off the rear wheel if the collar is hard to turn.
• On twin shocks, always set both sides to the same step. Different settings make the bike twist and handle badly.
• Keep fingers clear of the spring coils while turning the collar.

You need

• The C-spanner from the tool kit. A screwdriver used as a lever slips and cuts hands.

Steps

1. Find the adjuster: usually a stepped ring under the spring, with notches or numbered steps. Some shocks have a threaded collar with a locknut instead.
2. Note the current step on each shock.
3. Decide: higher step (more preload) for a passenger or load, or if the rear sits low or bottoms. Lower step for riding alone with no load, if the rear feels harsh and sits high.
4. Fit the C-spanner into the slot on the collar and turn it so the collar climbs to the next step. Move one step at a time.
5. Do the same on the other shock to exactly the same step.
6. Threaded collars: loosen the locknut, turn the collar the same number of turns on both sides, retighten the locknut.
7. Sit on the bike and bounce. Ride a short distance and judge the feel.
8. Write the setting down.

Check your work

• Both shocks on the same step.
• The rear does not hit its stops over normal bumps with your usual load.
• The headlight beam is not pointing too high with a load on the back. See Aim the headlight.

If it did not fix the problem

• Still bottoms at the highest step, or bounces: the spring is tired or the damper is worn. Check the rear shock absorbers.
• To set preload by measurement: Measure suspension sag.

Reference values