[Tigers] Gas milage with different tires?

[wsamouce]

Hey guys,

I am thinking about a bigger rear tire to save me some $$ when driving 1600
miles to TE/AE United 2010.  The Sumitomo's I have (195/60R13) are 22.4 in
diameter and 935 revs per mile.   If I go to the 205/60R13, they are 22.8 in
diameter and 914 revs per mile.  I am trying to figure out if the gas
savings would offset the $170 cost of the tires with mounting.

I just can't get my head around the math to figure it out.  I am currently
running 3600 RPM at 78 MPH (3.07 gear).  I plan on running the same speed,
with cruise control, all the way to Maine.  The larger tire would allow me
to run at 3535 RPM for the same speed. 

TIA!

Duke
B382002037