Wheel size upgrade.
My (new/old) 79 Holiday Rambler 27 is still sitting on 16.5 bias ply tires (all 6 less than a year old). I intend to budget for 6 radial tires to replace them (better ride and improve fuel economy). ...
Forum Discussion
pianotuna wrote:
In the 8000 miles I've driven since the change I've averaged about 10.5 mpg. Before it was 10 or less.
Don ... is your 28.5 foot Class C on the Ford E450 V10 chassis?
If it is, as you're well aware that 10.5 miles per gallon after going to larger diameter tires is outstanding for that engine/chassis combination and you've made my point on what making your gearing a bit taller can do if you take it easy on the gas pedal after you do it.
Good point on you're reduced rolling friction also being a contributor. Are your 235 tires Michelin's newer M&S2 line? Michelin mentions their M&S2 tires (NOT their old M&S line) as being "Green X" rated due to lower rolling friction.
FWIW, I've ran 3 diameters over stock on my 4X4 offroad GMC pickup for years for excellent gas mileage (if I kept my foot out of it) and terrific ground clearance. The pickup's RPM was around 1700-1800 when cruising on the highway - right down there where diesel cruise RPMs run.
