The stock KLX230S (Street Model) front spring is a progressive two-stage spring that increases from .35 to .50 kg/mm.  While this sounds like a positive thing, this means that the front end goes from very soft to very hard extremely fast.  Not what you are looking for if you do any type of off-road riding.  We recommend a straight rate spring for consistency and confidence in the front tire. Spring rates are available in .48, or .52 kg/mm.  Easy to install.  Just lift the bike to unload the suspension, remove the front fork caps, remove and replace the spring, and re-assemble.  Its that easy.