To determine the correct spring rate please visit the Fox spring rate calculator page at the link below

Weight: 170g

The Schwalbe Black Jack Tyre is the new star of their Active Line

Weight: 243g

so it's actually a very light-weight way to get a much higher stack

Fox Enduro Knee Guards - L - Black Needs Images To determine the correct springThe Enduro Knee Guards are lightweight and breathable for maximum comfort as you rip along the trail. They allow full range of motion, thanks to a high stretch rear panel, and feature D3O inserts for impact protection that are removable for when you want to wash the fabric of the elbow sleeve. The abrasion resistant knee panel also brings some extra coverage should you take a digger. Minimal restrictions maximized benefits that's what you get with