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
pnichols wrote:
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.
Pnichols: My formal education in this area and 40+ years engine tuning experience would disagree with most of what you've written so there is no sense in us hashing this over anymore between us. I'm not a good debater...
Only thing I wanted to find out is what size wheel people were using (other than 16.5).
Don: I live on the eastern side of the Flint Hills here in Kansas. We have a lot of long straight road but quite a bit of hill climbing too. Since most of my future destinations are going to be mountain climbing in the east I am going to stick with a smaller diameter tire to help with mechanical advantage on the climbs. The minor loss in fuel economy (if any) will be acceptable when it comes to climbing those hills.
