[Docbentley]

My car is a daily driver, typically about 2500 miles per month. Currently have Michelin Pilot SS on car and they have been really good. However, the rears are going to need replacement soon (about 12k on them now). My question is what would be the effect of running 255x40x19 on the rear instead of the 265? I don't track the car and most miles are highway. The idea behind this is that it looks like Goodyear has F1 asymetric allweather tires the correct size for the front and the 255 size for the rear. These tires have a much longer treadlife projection that the Michelin.
?????

 

[Brian C in Az]

For street use, you won't notice any difference in dry performance unless you are an aggressive driver that corners like a bank robber's getaway car.

You will get better wet grip and better fuel economy with a tire that is less wide.

I like the Yokohama Advan Sport for street use, I have them on 18" wheels. They grip very well in the wet. They offer very good dry performance. They are totally quiet and very smooth riding and long lasting.

 

[sjfehr]

Running narrower rear tires is going to negatively impact the shape of the contact patch and change the balance of the car making it more prone to oversteer. You'll probably never notice until you take an intersection or curve a little too fast and the *** starts sliding and PSM kicks in to save you.

The other problem you're going to run into is that tread life and grip tend to be mutually exclusive: tires grip well by using softer rubber that wears faster, and wear longer by using harder rubber that doesn't grip as well. And all seasons make it worse with lots of skinny blocks and siping that are awful awful in nice weather. The double-whammy of narrower harder tires may give you problems and you do NOT want to put summer tires on the front and all-seasons on the rear! If you want to keep the fronts, maybe do MPS4 or Conti ECS in the rear which are better tires than MPSS, but similar enough to MPSS you're unlikely to get nasty surprises in different weather conditions.

 

[Docbentley]

I really like the Michelins on the car now. However, the rears are fast coming to replacement time and colder weather is just around the corner. I don't need winter tires, seldom have snow and ice, and I wouldn't drive in it anyway. Many times when leaving for my 50 mile drive to work the temp is in the mid 30s to low 40s and the summer tires just don't work. When making the drive home in the early afternoon, the temps have usually come up to the high 50s or above. This is why I want an all season tire. Since my initial post, I've talked w/Jim at tirerack and will probably be getting the Michelin Pilot Sport A/S 3+ for front and rear in 225x40 and 255x40 for the 19" wheels. These will hopefully last a good bit longer than the SS or PS4s.
Thanks for your replies.