Ace suspension tuner Rick Gilmour takes us through how to set the sag on your bike.
Ace suspension tuner Rick Gilmour takes us through how to set the sag on your bike.
Setting Your Sag
by Rick Gilmour
Setting the rider sag is one of the most important things you can do as soon as you get your new bike, your suspension done or after you have changed the spring. This will help determine if you have the correct spring for your weight to balance the bike and get the most potential out of the suspension.
Firstly check your free sag or as I like to call it extended height. The bike need s to be on the stand with both wheels suspened in the air off the ground.
Measurement A.
Locate the bolt on the left side under the rear fender, measure from here to a visibal point at the back of the swingarm or the centre of the axle. This is measurement A.( Note: I like to add a little pressure with my toe under the rear wheel whilst taking this measurement to eliminate any slack or play in the bearings, generally 1mm is seen here.)
Measrement B.
Now take the bike off the stand, have the rider with gear sit in a neutral position in line with the foot pegs.
Its best to have a 3rd person present to hold the front of the bike steady and in line so the rider can keep both feet on the pegs.
Make sure that the rider is not holding a finger on the front brake or foot on the rear brake. This will throw your measurement off.
Once the rider is settled, push down on the rear suspension slowly and release letting the shock return. This will eliminate any friction ot sticky points generated by the shock seal and linkage bearings that can hold the shock up.
Measure again the same points as previous and you will get measurent B with the rider in place.
Subtract measurement B from measurement A and you will have your rider sag.
Generally aim for 100-105mm of sag on a full size bike depending on rider preference.
NOTE( turning the the lock ring clockwise will increase spring preload to a smaller rider sag number and vice versa)
Measurement C.
If you have had your suspension modified or springs changed by a reputable tuner, usually you are ok with correct spring rate. But when you buy a brand new bike you need to check measurement C which is STATIC SAG. Static sag is measured when the bike is under its own weight with no rider and you subtract measurement C from Measurement A. Generally 25-45mm range is ok.
If you have set your sag and then checked measurement C and it s less than 25mm a stiffer spring is required. If its more than 45mm a softer spring is required.
