Went to Firestone today because I have a slow leak in one of my tires.
The car is a 2002 Subaru Impreza TS with factory spec tires 195/60/R15.
Turns out the slow leak was due to a puncture in the sidewall of the
tire, so that tire is garbage. The tires are all about a year old and
have decent meat on them, but the tech said you can't just replace one
tire on an AWD car, you have to replace all 4 as a set, because the new
one will be some sixteenths of an inch larger than all the rest.
Of course he'd say that :D
Now, I understand the concept and theory of this- if all wheels are the
same circumference, they all rotate the same amount and internal
drivetrain components (center diff or viscous clutch) don't have to take
up the slack. But... I have a hard time believing that an amount
measured in sixteenths of an inch is significant. Surely a few pounds
of pressure off, or an unbalanced load (i.e., some fatass sitting in a
seat opposite some 80 pound child) would make just as much difference?
I declined to make any purchase at this time. I know I'll need to
replace that one tire, but I have another vehicle to drive for now. I
would like to replace the one tire only. Replacing all 4 is a bit