Join Date: Sep 2011
Thanked 264 Times in 203 Posts
Highest gear without bogging excessively.
For just cruising on level ground at those speed 6th may indeed be too much - but give it a try. Obviously if you need to accelerate you have to click down a couple, but chugging along on flat ground at 1500 RPMs (or whatever) should be doable.
Given a chance, open it up occasionally. Engines don't like extended running at low RPMs for the most part, and will build-up deposits in the combustion chamber. That can lead to detonation. Bogging (high load/low RPMs) can cause detonation as well. Detonation will cause engine damage eventually.
Running a strong fuel system cleaner once per season is a good idea.