well..its all in opinion......i bought 13,14,15 sunstAR front, and two different size rears and spent a day just f&%king around and eneded up sticking with the 14/40...it just felt good..lol and allot of guys run that setup..just mess around with it. I have a track in my back yard that we keep groomed. my buddy has a few bobcats for his landscaping business.. so i ride on fairly dry dirt and well maintained. if you ride in a bunch of mud then you may want 20's or 22's...all in what your into, ya know.but to get back to your post..a stock chain length will certainly work for those gear setups..been there ,done that !!!