It's not just Nokian. I've seen this phenomenon on various tire brands. Although most of what I've seen I attributed to passenger car tires installed on a Vanagon. In other words, not rated for the weight.

BenT
sent from my electronic leash

> On Nov 20, 2014, at 5:24 PM, Michael Hart <mjhart853@GMAIL.COM> wrote:
> 
> 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 They have been replaced by Nokian (pro-rated rate) now, apparently a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')