[S1verf0x49]

hi guys I need some assistance Pleaese, I changed my rear Michelin PSS for Pirelli PZ XL on the direction of Halfords, how ever my Michelin on the front are 88Y and my rear are 92y. Every time I put my foot down it’s all over the place, very unsteady and not handling well after 100mph any advice? I have booked to get my fronts in next week to match 92y Pirelli PZ XL on the front as well hoping that will solve the problem. Thanks

[IJO]

Not normally advisable to mix load ratings as the carcasses will be stiffer for the 92Ys.

If the wandering is still happening, have a 4 wheel alignment done (kwifit can do it).

[F20_M135i]

Different weights on a suspended mass (in rotation) = problematic feeling

[pochetemix]

That is normal behaviour. These cars are very affected by rear wheel changes, if you don't change the front wheels at the same time. Also, the DTC is probably acting more frequently. When you change the front wheels, the car will drive properly again.

It's not a matter of the different speed codes, as the M135i/M140i come standard with 88Y on the fronts and 92Y on the rears. Coded as OE BMW tyres (*) by Michelin.