Originally Posted by swamp2
.... It also does sounds quite fishy that tread wear decreases but grip stays constant (again after about mid life). Lastly when does the plateau end does it simply hit a vertical "brick wall" right at the wear bar or is it right at cording? It must come down at some point and even get below the grip when just broken in. If it drops in the way he described then it must come down sharply, like going over a cliff.
There does seem a logical conflict between admitting that as you approach the wear bars there is a reduction in the tyre wear rate but no change in grip...suggesting that its a function of the tyres reduced ability to heat up I suppose is plausible , but not totally convincing.
I guess I could be a victim of "selective memory"...by coincidence the tyres on my M3s could have been wearing out as we entered into winter and the reduced traction was a function of reduced temperatures rather than an overall reduction in tyre grip.
As I noted before, a few years ago I had already discussed this apparent phenomenon with Michelin so convinced I was of its repeatability...now I'm begining to doubt myself.
As far as how grip changes as you pass the wear bars, we didn't really get into that. Here the weather in winter is such that running your tyres below the wear bars is not sensible and will get you into serious trouble if stopped by the police...each tyre below 1.6mm will get you 3 points on your licence - 12 points = lost licence.