Michelin HydroEdge Tyre Replacement: Sidewall Dry Rot

Our '04 Prius is nowadays almost entirely driven by my wife, so it was a surprise to me yesterday to find the steering was quite a bit stiffer than I am used to. I first figured it was a low tyre pressure, but instead only found significant sidewall weathering. A local Toyota dealership also thought the weathering was the cause of the hardened steering and warned that the tyres were not safe, so today I went to Costco to buy new tyres.

The old tyres are Michelin Hydroedges bought 10/2008, now with about 75k miles on them. The tyres tech agreed that the wear was a manufacturing defect rather than just cosmetic, and then to my surprise determined the residual value based on treadwear remaining rather than age, there by returning me 6/11ths of the original cost. No fuss, no hassle. Costco also did not charge me installation or tyre warranty for the new tyres, and they even prorated the tax. Hard to believe, eh ?

I'm willing to accept that the premature wear is at least partly a matter of my dry climate and the car living outside, so I decided to break my habit of buying very high treadwear rated tyres in favor of a LRR 65k mile tyre with (relatively) good snow performance and chose the Bridgestone Ecopia 422. That tyre is $90 at Costco before installation etc, but as part of the warranty swap my car drove away with four new shoes for the quite remarkable price of $155. Parenthetically, I chalk up the outstanding 5 mm tread wear over 75k miles to rotation every 10k miles and inflation to sidewall maximum, but I at least have to wonder if the early sidewall weathering is an unintended adverse effect of running high pressures. I really have no idea if Michelin tyres have more sidewall wear than other manufacturers, although I did find it interesting that the tech had a Michelin supplied card to assess warranty eligibility.

Steering is back to normal, and Michelin and Costco have given me the best customer service I can hope for.

Pretty damn awesome.

P.s., I posted this thread in the G3 forum on purpose, since the topic is not gen specific and I figured most Prius on the road these days are G3. Any moderator unhappy with my choice is welcome to move the thread.