[ozinaldo]

Originally Posted by LotusBoy

Hi Tom, hi OZ ! A friend of mine, let's call him "R", runs PSS's on his 1M, front and rears. He's one size more than stock: 255/35/19 and 275/35/19. No rubbing at the rear ! No issues at all, just more grip.
But... I wouldn't recommend increasing the aft size much more, if you don't increase the front size as well.
Let us imagine you put 245/35 in front and 295/30 aft. Aft grip is increased, so you get better traction when accelerating. Forward grip is not increased, so you get understeer the rest of the time, altering the balance of the car...
So I think it's nice for the looks, but bad for the driving !!

You are right there LotusBoy, I am aware of the principle. Still I believe in the case of 1M it might be less pronounced since the PSS extra grip should help the fronts as well and because the car's rear will be more settled and predictable it might not end with that bad understeer. I feel like M3 and 1M are quite different cars in terms of their power delivery and traction characteristics so 1M needs wider and stickier tires at the rear vs a stock M3 imo.

In fact I am contacting a few 1M and M3 owners who keep the fronts stock while getting wider at the rear like 295s and they all seem to be happy with the result so I may give it a try and if I feel that it is not working, not a big issue for me since I keep the stock PS2 set almost unused, as my reserve and I can use them if and when needed and just sell the wider new rears in the market.

Still again, the reason why I am not decided yet on this is simple; I am quite happy with the stock sizes since the added grip of PSS is more than enough for me..for now.

In fact, if we go with the book, I could go and try 275/30 19 front and 295/30 19 rear set which would be perfectly proportional upgrade and if 255/35 can fit at the front so should 275/30. I assume there won't be a hint of understeer with that one but will the car react as agile as it is now?