In order to achieve the best ride possible with our air ride suspension products, the most important thing to do is to go through the sag setting process. This process will ensure there is enough air in the shocks to prevent bottoming out, as well as it will ensure there is not too much air resulting in a stiff ride with no top out clearance. Setting the sag will essentially make sure there is an adequate amount of air pressure in the shocks to achieve the effective "sweet spot".
With our air ride shocks on the 1989-2017 Softail models, we recommend 1" of total sag. This means the shocks are intended to be ridden at a length approximately 1" lower than the fully extended length when the rider or rider/passenger weight is on the bike.
To properly set your sag, you will want to follow the steps listed below:
1) Run the compressor to air the system up until the rear shocks stop raising the rear of the bike. Air the system up till it is hard enough that the rider does not compress the suspension when they sit down.
2) Have the rider sit their weight on the bike. Measure from a reference point on the fender to the top of the axle nut choose a place that will can be easily repeated (you'll need to measure again later)
3) Release air from the system, until the rear of the bike drops by 1". Remember when you release air, it is going to release much quicker than it will inflate, therefore, we recommend you just "tap" your release button on the handlebar control until the 1" drop is attained.
4) Once you have lowered the bike 1" have the rider give the seat a couple of good bounces and then sit.
5) Double check measurements to see if the bike is in the same spot as before the bounce.
6) Once the sag is set and you have achieved the 1" drop, the rider will need to go for a ride and make MINOR air pressure adjustments to "dial" in the ride.
7) After a test ride, if the rider feels it is too soft, hold the button is 2-3 second at a time to firm the system up until desired ride is achieved.
A tape measure isn't needed every time to set the sag. Once this process has been completed initially, the rider usually has an idea of where the "sweet spot" is providing the 1" of sag, and in the future will be able to adjust the air pressure "on the fly" to regain the desired ride quality.
The 1" of sag applies to two-up riding as well. If the sag has been previously set for a one-up riding configuration and the weight of a passenger has been added to the bike, the rider will need to add air pressure to the system to account for the added weight of the passenger on the bike, and once again achieve the 1" of sag. The process to set sag with a passenger is the same as steps 1-7 above, with both the rider and the passenger sitting on the bike.
Feel free to email firstname.lastname@example.org with any questions!