Rear Suspension Set-Up
Setting Rider Sag
- Check the shock for smooth action and check the heim joints, and/or linkage bearings for excessive stiction and binding.
- Put the bike on a stand that allows the suspension to fully extend. Measure from the axle center vertically to a point on the chassis. The seat bolt, fender bolt, or a mark on the fender make good reference points. Record this measurement as L1.
- With the bike off of the stand and the rider aboard in a normal seating position, bounce up and down on the suspension several times then allow it settle to a resting position. Again measure from the axle center to a point on the chassis and record this as L2.
- Subtract L2 from L1. Rider/Race Sag = L1 – L2
- Tighten or loosen the spring pre-load adjustment collars to obtain proper sag. For dirt bikes, this measurement should be 30% to 33% of the total travel. Example: 12″ travel x .33%=4″ sag. Linkless KTM models have 13.2″ of travel and the sag should be 105-110mm.
Measuring Free Sag
Using the same measurement points as used for the rider sag, measure the rear suspension sag with no rider aboard. Lift and press on the suspension several times to establish a consistent resting point. The free sag should be 5% to 10% of the total travel. On 12″ travel suspension the measurement should be 15mm to 30mm. Linkless KTMS should be 25mm to 40mm.
Determining Correct Shock Spring Rate
Once the correct rider sag has been set, the amount of free sag will indicate if the spring rate is correct. If the free sag is less than recommended, you need a stiffer spring. If the free sag is more than recommended, you need a softer spring.
Too much front/rear tire pressure causes deflection and harshness which creates instability on rocky, rooty trails. We recommend 10 to 12 lbs for 2 strokes and 12-13lbs for 4 strokes. These pressures will NOT increase flats but will increase pleasure and safety. We highly recommend the TUbliss system which allows lower pressures, more traction and increased stability and comfort.
Front Fork & Wheel Installation
Improper installation of the front wheel and axle and/or over-torqueing the triple clamp bolts can cause the forks to bind and harsh/stiff action. Most lower triple clamp bolts should be torqued to 14-15ft. lbs and most upper triple clamp bolts should be torqued to 17-18ft. lbs. Consult your service manual for the correct torque setting.
Install the front wheel, slide in the axle and tighten the nut/bolt, leave the axle pinch bolts loose, remove the bike from the stand, lock the front brake and depress the front suspension several times to center the fork legs on the axle. Next, tighten the axle pinch bolts to the O.E.M. specification and you are done.