How to Measure a Shock Absorber

Step 1: Remove the Shock Absorbers

Take out the shock absorbers from your 4WD before you begin measuring.

Step 2: Flex the Vehicle to Maximum Articulation

Flex your vehicle so one side is fully compressed and the opposite side is fully extended.

Hot Tip: If you don’t have access to a ramp, use an incline or even a forklift to achieve full flex.

Safety Warning: Only take measurements when the vehicle is stable and it is safe to work underneath.

Step 3: Measure the Compressed Side

On the compressed side, measure from the top shock mount on the chassis to the lower mount on the diff. This gives you the fully compressed (closed) length of the shock.

Note: The bump stop should be touching at this point.

Step 4: Measure the Extended Side

On the extended side, measure from the top shock mount on the chassis to the lower mount on the diff. This gives you the fully extended (open) length of the shock.

• Coil Spring Vehicles: Lower mount usually sits on the diff.
• Leaf Spring Vehicles: Lower mount usually sits on the diff or U-bolt plate.
• IFS Vehicles: Lower mount usually sits on the lower control arm.

Mount Types:

• Eye Mount – measure from the centre of the eye.
• Pin Mount – measure from the base of the pin where it fixes to the body.

Step 5: Record the Extended Shock Length

Pull the shock absorber out to its maximum length and record the figure. Ideally, this should match or come close to the extended measurement you took from the vehicle.

Step 6: Record the Compressed Shock Length

Compress the shock fully (by hand or using a strap) and record the closed length. Ideally, this should match or be slightly shorter than the compressed measurement from the vehicle.

Important Notice

• If a shock is too short, it will top out and may damage the top seal, causing leaks.
• If a shock is too long, it will bottom out, damaging the valving and reducing performance.
• IFS Vehicles: Lower mount usually sits on the lower control arm.

With both the open and closed measurements in hand, you’re ready to choose the correct shocks for your 4WD. Take your figures to a trusted suspension specialist like Superior Engineering and get set up with new shocks that are built to perform.