If you have Nokian tires, please check them.
My 3 year old Nokian Hakka C 205/70R15 tires had horrible cracks on the
inner sidewalls.
Quarter inch wide cracks running most of the way around the circumference
of the tire, the tire wires sticking out.
Just 30k miles and absolutely no signs of damage on the outer sidewalls.
All four tires were affected.
They have been replaced by Nokian (pro-rated rate) now, apparently a
manufacturing defect.
Very scary to find this after a 70mph freeway trip back from the sierra.
You will only see the damage by looking under your van or removing the
wheels (I was changing brake pads when I found this).....
I'd be interested to hear from you (pmail) if you have a similar experience.
I did find other reports on thesamba.

Michael Hart
Palo Alto, CA
'87 2WD Westfalia ('T3WESTY')