Vibrations induce stress in many area's of the vehicle. I wouldn't say it has zero effect on MPG, but it would have very little. Increased suspension wear and tire life would be a product of high tire vibration.
I would think that unbalanced tires would have only a very small effect on MPG, and that's exactly what this study found. Deliberately unbalanced tires reduced mileage by 0.50% This reduction is within the error margin of the test, so essentially no reduction can be claimed to have been found. Nothing earth shattering there.
A few days ago - in another thread - the issue of imbalance and fuel economy came up. I remembered that someone I worked with had calculated the effect imbalance would have on fuel economy and came up with a small number - small enough that other factors would totally overwhelm it and it might not be observable.
This study seems to confirm this.
It would have been nice to have done a laboratory experiment to control as many variables as possible. The myth of nitrogen inflation was pretty much destroyed when a lab test was done.
Consider most of the vibration problem is in highway speed and on highway most of the work is to overcome aerodynamic drag, the unbalance would have to be very big to cause fuel economy issue, much more of an annoyance to the drivers and passengers before it would to the wallet.
Originally Posted By: TomYoung
True or not, surely the impact to one's happiness and sanity is more the issue.
Probably more of this than anything. I could see the vibration effecting it in theory, but with so many variables It probably would be so minute you couldn't tell in the real life of driving.