9. Increased preload can make up for a weak spring

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“Spring rate is spring rate, and adding preload is just storing energy in a spring,” notes Sorbo. Let’s define our terms: spring rate is how strong a spring is, namely how much weight it can hold up over a given distance. One common way to measure spring rate is inch-pounds or what weight is required to compress the spring one inch. So, a 100-lb spring is compressed one inch by a 100-lb weight. For every additional 100 lbs, the spring gets one inch shorter.

When you crank preload into your bike, you’re storing energy in the spring. If you preload a 100-lb spring one inch, then placing less than 100 lb on top of the spring will not compress the spring more. So, it doesn’t move anymore until you add more than 100 lb of load to it. Placing 200 lb on it will compress the spring an additional inch.

If you were to instantly remove the 200 lbs, the spring would only decompress an inch, but it would do so with the force of a spring compressed two inches. When viewed from the perspective of motorcycle suspension, the bike with too much preload in an attempt to make up for a weak spring will bounce back more over the same-sized bump because it has more energy stored in it, which can cause the bike to wobble.