Originally Posted By: Char Baby
By statring out at 10/32nds of tread depth instead of 8/32nds, the rubber on the new Premire A/S, may over time, become too hard for Michelin's testing, causing less wet/dry, braking & cold weather traction as the tire ages, completely defeating Michelin's goals for this new Premire A/S tire.
Nothing wrong with a tire starting out with 8/32nds of tread depth if, the driver can get more miles out of each 1/32nd of tread as Michelin claims. And also, the owner/driver of these new tires, thaking the tire closer to it's full wearout rating.
IDK, what do you think?
However - some states require a certain amount of tread depth for an all-season (or even dedicated winter) tire to be driven in certain weather conditions without chains (or more precisely "traction control devices"). In California, that's 6/32". A tire with less tread depth to begin with will probably arrive sooner at this, even if it's meant to last longer through slower wear.
Suppose this tire is supposed to last about as long as competitors' tires that start with 10/32" down to the wear bars at 2/32", and the wear is roughly linear (I know - huge assumption) with reasonable rotation. For the 10/32" tire, it's going to spend about half its useful life above the 6/32" requirement. For the 8.5/32" tire it's going to spend about 39% of its useful life above this requirement.
A lot of dedicated winter tires start out at about 11/32" to 13/32" tread depth - probably with minimum required tread depth in mind. Of course they can get a little squishy because of the increased tread depth, but that's a matter of a tradeoff to meet winter requirements.