Dirt Bike Suspension Tuning

Setting the sag is one of the most important setup aspects for the overall handling and performance of your bike. The sag affects your ride height, steering, and handling. Properly tuned suspension will put your machine at its top performance. You can adjust the sag for the rear shock as well as the front forks. And it's something you can either do yourself or have an expert help you. The two most common measures of sag are race sag and static sag. To calculate sag you need three measurements in millimeters:

• Unloaded: Place your bike on a stand and measure the distance from the axle to a fixed point like the fender or side panel
• Loaded without rider: Place your bike on the ground and measure the distance from the axle to the same fixed point as measurement 1
• Loaded with rider: Place your bike on the ground, sit on it, and measure the distance from the axle to the same fixed point as the other measurements

These three measurements should be taken with the gas tank full, and all other fluids filled so your suspension is tuned for the correct bike weight. You should also sit on the bike wearing your riding gear, including your helmet, to get accurate measurements.

Race sag can be calculated as unloaded subtract loaded with rider.

Static sag can be calculated as unloaded subtract loaded without rider.

A good rule of thumb for proper sag adjustment is as follows:

Suspension	% of available travel
Front Static	14%
Front Race	25%
Rear Static	11%
Rear Race	34%

Adjust the race sag first, and always refer to your owners manual to verify proper specs. Also, it can be helpful to adjust your suspension for whatever terrain you are riding on. Softer terrain can often justify firmer suspension, while hard terrian may warrant softer suspension.

Different size bikes have different suspension settings, and if you don't want to do the math to figure out the correct level of sag the table below shows the typically reccomended setting for different size dirt bikes:

	50 - 65 cc	85 - 100 cc	125 - 450 cc
Race Sag	70mm	80 - 90mm	102 - 105mm
Static Sag	25 - 35mm	25 - 35mm	30 - 40mm

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