Fork Tuning

Note: Not all forks share the same adjustment characteristics, so please take a look at the forks to see what adjustment you have.

PRELOAD

This adjustment is always found on the top of the forks. Clockwise increases preload, counter clockwise decreases it. The adjusters are usually integrated into the fork cap and are sometimes differentiated by color. The preload adjuster may have adjustment lines machined into it so that you can compare to check that they are even.

Preload is initially used when setting SAG. Preload can be added if the rider experiences the forks “diving” under hard braking. A more accurate way of assessing “dive” is to attach a thin zip tie on the slider tube (make sure that it slides easily but is not sloppy), or place an appropriately sized rubber “o” ring on the tube that slides into the fork leg (using an O- ring will require one fork being removed).

The zip tie/O-ring will allow you to see how much of the fork travel you are using. If the zip tie/O-ring is firmly against the dust scraper or on an inverted fork, the axle casting, then the fork is bottoming out. In that case you need to add more preload, and then check the zip tie/O-ring again. If the zip tie/O-ring rests 5mm prior to the dust scraper or axle casting, this indicates that you are using almost all of the available travel.

REBOUND

The rebound adjuster is usually located in the center of the preload adjuster, and commonly requires a flat head screwdriver to be used for making adjustments (there are exceptions like Ohlins which require Allen wrenches). Sometimes the adjustments are measured in “clicks”, other times in degrees of turn. Usually OEM settings are in the middle of adjustment.

First, turn the rebound adjusters all the way in on both forks and write down how many turns/clicks there were. Then take the rebound adjustment all the way out on both forks so that you know how much total adjustment there is. With the adjustment all the way out, hold the front brake on to lock the wheel and then push down vigorously on the forks. As the forks begin their upstroke, let them move naturally and observe the action of the fork. The stroke may come back and then return into the downward motion once more, and may even return again on the upstroke (do not let go of the front brake while doing this!).

Then adjust the rebound all the way in on both forks, repeat the pumping action with the front brake fully engaged and observe the difference in the range of motion –the forks will rise back up slowly. What you are trying to achieve is the fork rising back almost to the top of the first rebound stroke and staying there. You will need to work the adjusters so that they are always the same on both legs until you have the rebound action set correctly.

COMPRESSION

These adjusters are usually found on the underside of the fork or close to the brake calipers at the bottom of the fork facing the rider. They commonly require a flat head screwdriver to be used for making adjustments (there are exceptions like Ohlins which require Allen wrenches). Sometimes the adjustments are measured in “clicks”, other times in degrees of turn. Usually OEM settings are in the middle of adjustment.

First, turn the compression adjusters all the way in on both forks and write down how many turns/clicks there were. Then take the compression adjustment all the way out on both forks so that you know how much total adjustment there is. With the adjustment all the way out, hold the front brake on to lock the wheel and then push down vigorously on the forks. You will be able to feel the way in which the forks move through the downward/compression stroke, which will be fairly easily (do not let go of the front brake while doing this!!).

Then adjust the compression all the way in on both forks, repeat the pumping action with the front brake fully engaged and observe/feel the difference in the range of motion –the forks will compress more quickly and will not travel as far on the compression stroke up. What you are trying to achieve is the compression stroke allowing the fork to move without restricting the amount of travel in the fork, which causes the sensation of “packing.” You will need to work the adjusters so that they are always the same on both legs until you have the compression action set correctly.