Suspension Services

One of the most critical things to proper suspension setup is making sure the sag is set correctly. This includes both the rider sag, and free sag. Below is a breakdows of measurements to ensure your setup is suited for you. We have also included a rough general chart for what your sag should be, but this again depends on you the rider and your situation.

Rider Sag

Measurement A

Place the bike on a stand, wheels un-weighted; measure from the left inside fender bolt to a point on the rear axle.

Measurement B

With the bike off the stand, have the rider stand on the footpegs in a nuetral position directly over the pegs. Have the rider use a wall or some structure to balance themselves by. Have someone measure the same two points as before.

Measurement A minus Measurement B

Too much rider sag indicates you must increase pre-load to the spring by turning the Spring / Pre-load Adjuster clockwise. (decreases rider sag measurement).
Too little rider sag indicates you must decrease pre-load to the spring by turning the Spring / Pre-load Adjuster counter clockwise. (increases rider sag measurement).

Rider Sag is a key factor in a proper suspension set-up. We recommend the measurements below. Remember these are only "General" recommendations. Different riding styles, tracks and manufacturer brands may vary these set-ups.

Reccomended Measurements

65cc 70-75mm
85-150cc Mini's 90-105mm
125 thru 650cc 100-110mm

Free Sag

Measurement C

With the bike off the stand and the rider off the bike; push down on the back end and let the bike come up by itself. Measure between the same two points as before.

Measurement A minus Measurement C (Generally 20 - 35mm)

If you set your rider sag and your free sag does not fall within the recommended range; a spring change may be needed.

HINT: Less than 20mm generally indicates a stiffer spring is needed and more than 35mm indicates a softer spring is needed.

NOTE: 1" = 25.4mm

Rider Information Form

If you are looking for Pro Motion Suspension to perform a service for you, we suggest filling out this rider information form to accompnay your suspension.

Download the form here.

Contact Us

For general questions or concerns please contact us using one of the following methods. If you are looking for information about shipping please see this Contact page.


Pro Motion Suspension (in Bent Lever Motorsports)
6707 NE 117th Ave Suite A-100
Vancouver, WA 98682
Phone: 360.260.5576
Email: Email Us Today!