SUPERMOTO TECH - SPRINGS AND PRELOAD

Springs and Preload: Preload is quite literally, the amount your springs are compressed when installed. By measuring the difference in length of the spring before you put it on (free length), and the length of the spring as it sits on the shock (installed length) you can determine the preload. Some specs will call for a certain amount of preload. Otherwise you can use the sag to determine the appropriate amount of preload.

If we have set up your suspension for you, we will have recommended a spring for you and a window of adjustment with the preload. Preload is necessary to hold the bike up in the position the designer had in mind when he planned it in the first place. If the springs have been chosen correctly, they should yield our baseline sag numbers, while maintaining some static sag. As mentioned earlier we like to see around twenty five to thirty percent of the wheel stroke as sag, with five to ten percent of the stroke as static sag.

Preload is often used as a tuning variable, but like with anything it is important to avoid going to extremes. It is not uncommon to find preload used to band-aid other conditions.

A common problem includes the use of too much preload to band-aid an under sprung or under damped fork. The problem that then arises is that the bike is held high up in the stroke all the time, adversely affecting weight transfer, and sometimes steering. The bike will also tend to want to quickly pop up in front when the brake is released. This is very problematic for effective trail braking.

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