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
PappyChris wrote:
Wasn't my intention to debate tire sizes.
A simple vacuum gauge can make my point.
I will be using a tire in diameter close to what was originally recommended on a 16" wheel and spend my time working on the VE of the engine to increase fuel economy of my flying brick.
Well Chris,
In our group there is probably more engineering development going on than there is at most of the rest of the RV industry. The bad news for you is that in spite of changes of engine, going to both port and throttle body, rear end ratios, the standard line is that these coaches will get 8~10 mpg depending on how you drive and if you tow.....
Engines very from the Olds 403 (the 455 was a common OE) to the Cadillac 500 and GMC 8.1. Rear end (actually a final drive) can be anyplace between 3.07 (OE) and 3.77 and performance may improve, but mpg doesn't.
Most are still open loop carburetor engines with both points and HEI, many now have knock controlled TBI, and they can do 10+ a lot of the time, but it can't be counted on.
Several have installed diesels. Those do a little better, but not enough to pay for the conversion.
My advise? Tune it up and enjoy it. The more you drive it to interesting places and events, the less the fuel cost will bother you.
Matt
