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
When going down the road, the work to overcome wind resistance is not related to the diameter of the tires and/or what mechanical gear the engine is in.
A vacuum gage will read the same for the same RV on the same stretch of road, at the same speed, in the same mechanical gear, and under otherwise identical conditions - one time with a smaller diameter tire, the second time with a larger diameter tire. The only difference should be slightly better gas mileage with the larger diameter tire due to less friction and (maybe) less heat loss in the engine at lower RPMs.
A vacuum gage will read the same for the same RV on the same stretch of road, at the same speed, in the same mechanical gear, and under otherwise identical conditions - one time with a smaller diameter tire, the second time with a larger diameter tire. The only difference should be slightly better gas mileage with the larger diameter tire due to less friction and (maybe) less heat loss in the engine at lower RPMs.
