SAG TOOL
Mountain Bike Suspension Tool
I built this tool to assist in setting up the “Sag” on mountain bike suspension that uses a Coil-Over Rear Shock.
Tools/Skills- Solidworks, 3-D Printer
“Sag” is the amount that the rear-shock compresses when a properly outfitted rider sits on the bike.
The Sag Tool has a Measuring Contact (shown in gray) that slides along the length of the Tool.
There are gradated markings along the length of the tool to easily and accurately line up the Measuring Contact, and set the correct eye-to-eye measurement of the shock.
The contact points on the Tool are spherical steel surfaces, to assist in self-centering on the Shock Bolts.
The Lower Contact point is magnetic to assist with lining-up the Tool with the shock eyelet
An indexing feature is included to make certain the Measuring Contact stays put.
Measuring “Sag” on a bike equipped with an Air-Sprung Shock is typically simple, as most Air Shocks have an o-ring on the shaft that indicates the amount of shock travel.
Coil-Over Rear Shocks typically don’t have an o-ring, or any other method, to measure the amount of shock travel.
Normally, the only accurate method to measure travel on a Coil-Over Rear Shock is to measure the distance between the Shock eyelets.
This can be a difficult task to accurately execute without assistance, as the rider needs to be sitting on the bike to achieve proper “Sag”.
WHILE SEATED ON THE BIKE, SIMPLY LINE-UP THE SAG-TOOL WITH THE SHOCK EYELETS TO DETERMINE IF SHOCK ADJUSTMENT IS NECESSARY
WHILE SEATED ON THE BIKE, SIMPLY LINE-UP THE SAG-TOOL WITH THE SHOCK EYELETS TO DETERMINE IF SHOCK ADJUSTMENT IS NECESSARY
The Sag Tool allows the rider to set the proper Eye-to-Eye distance of the shock and the appropriate "Sag".
When the rider is seated on the bike, the Sag Tool is simply lined up with the Shock Eyelets to measure the “Sag”.