The limit of realisticness on the GenIII stops at a 2.6"...honestly...if you go lower...its just overkill IMO. Anything lower than that is just one of those..."just because I can" things. Also, like the GenV...it stops at the 2.8"...proven time and time again the GenV takes too much power off of the crank to MAKE power when going lower than the 2.8".