advice E85 tyre size front & rear

[lucky jim]

hi my z4 has 225 / 40/ 18 on the front & 225/35 /18 on the rear why is this what is the advantage what difference would it make if i ran a 40 profile front & back ?

 

[t-tony]

My rear tyres are 255/35x18 I would think yours at 225 should be 40 series all round. It's all about the rolling circumference.

Tony.

 

[lucky jim]

My rear tyres are 255/35x18 I would think yours at 225 should be 40 series all round. It's all about the rolling circumference.

Tony.

thanks for that tony you a right my rear tyres are 255 35 18 so that will give me same circumference but on a wider tyre that explains it