Motocross

What are the parts of a shock?

Spring - A spring sits on the outside of the shock body. The spring provides constant resistance to keep the shock from collapsing in and staying there.

Shock shaft - The shaft provides a point for the shock to mount to the suspension arm. The shaft is often made from stainless steel or is coated to provide a super-smooth finish.  Inside the shock body, the shaft attaches to a piston.  Piston - The piston is a round piece that is attached to the shock shaft. 

Piston - The circular shaped piece that attached to the top of the shock shaft.  Usually has two holes that will vary in size...depending on the piston number.

Damping Fluid - Shock fluid fills the reservoir inside of the shock body.

Shock body - The body provides an internal reservoir for damping fluid.

Seals - Seals are o-rings that keep the shock oil inside the shock body while also keeping dirt and debris out.

Shock Collars - Shock collars are adjusted on the shock bodies to determine the amount of pre-load on the shock springs.  This in turn helps set the vehicle's ride height.

Shock Cap - A shock cap keeps shock oil inside the shock body and provides a mounting point for the shock.

How do I know when my shocks need to be rebuilt?
When a lot of debris is located where the shock shaft enters the body.  If there is oil on the outside of the shock.  When compressing the shock it has no resistance...which means no dampening. 

How do I rebuild my shocks?
Rebuilding your shocks can be easy by following these few simple steps.

Step #1 - Remove the shocks from you vehicle.

Step #2 - Remove the springs. 

Step #3 - Brush off any debris that is on the outside of the shock body.  An old toothbrush works great.

Step #4 - Remove the shock cap or cartridge (bottom loading shocks).

Step #5 - Remove the shock mount located on the bottom of the shock shaft.

Step #6 - Remove O-rings.  For Associated shocks insert the shock building tool into the bottom of the shock body at an angle and push out the retaining clip.  Remove all pieces and throw away old o-rings.  For Losi shocks just buy a new shock cartridge.

Step #7 - Spray out the shock body with motor cleaner.  Use a Q-tip to get out all the debris and excess oil.  Allow time for the motor spray to evaporate.  Hint: Don't get motor spray on any new o-rings.  This will cause them to leak.

Step #8 - Reassemble the shock.  For associated use the shock rebuild tool.  The parts go on like this...retaining clip...small while spacer...o-ring...large white spacer...o-ring...small white spacer.  If you are also replacing the white parts in an Associated shock make sure their are no burrs on the pieces.  For Losi shocks rebuild the cartridge like this...cartridge body...o-ring...center spacer...o-ring...cartridge cap.  Hint: Don't forget to use green slim on the o-rings.  This will cause the o-rings to be lubricated...making the shock smoother...and less likely to leak.

Step #9 - Apply a drop of oil to the threads of the shock shaft and insert it in to the shock body or cartridge.  The shaft should slide through easily.  If not then realign the parts in the shock body.  Forcing the shaft through will damage the o-rings.

Step #10 - Once the shaft is re-inserted attach the shock mount to the bottom of the shock shaft.

Step #11 - Now you are ready to fill you shocks with new oil.

Step #12 - When you refill you shocks make sure you get the air bubbles out by moving the the shaft up and down, be careful not to fully expose the piston above the shock body.  Refill shock body and apply cap or cartridge.  Associated shocks should compress with a little effort and rebound about 1/4 to 1/2 of a inch.  If the shock has trouble compressing then there is to much oil...if it doesn't rebound then there is not enough oil.  Try to have all your shocks rebound the same distance.

What do the different sizes of pistons do?
Smaller the pistons will cause your car to sit higher

Does the temperature outside affect shock oil?
Yes, if you practice at 8:00a.m. and its 70degrees out and your car is dialed. Then you run your first qualifier at 12:00p.m. and the temperature is at 95 degrees, suddenly your car feels unstable and unpredictable. You should try changing the weight of your shock oil by 5wt and your car will back to being dialed. This is something that you want to play with to get a good feel so you know when to increase or decrease your oil and how much to do it by.

What do the different colors of springs mean?
The different color of spring represents a different firmness or softness.  Experimenting with different springs will drastically effect how your car handles as well as jumps and lands.  Refer to the chart below for the different types of springs.