[radman76]

Hi all,

My car is a 428i M-Sport F36. I just got a screw that punctured my rear RFT this week. Some tradesmen left screws on the ground in front of my garage after they done some work! The screw is quite big so I think it will be difficult to repair the tyre. I am thinking of using this opportunity to change from RFT to non-RFT.

Currently the front tyres are: 225-40-19, and the rear tyres are 255-35-19.
I have the BMW M-sport wheels style "442".

I am planning to replace with
Michelin PSS, 245-40-19 for both front and back tyres.

Can you please let me know if this is ok? I understand the new tyres will have a 2% larger diameter and therefore the speedometer will be out by 2%. I am ok with that.

Apart from the speedometer, are there anything I need to be worried about? Will the front tyres become too wide and large and rub the car? The reason to choose a narrower and higher profile tyre for the back is so that I can have a bit more comfort and compliant with the ride due to using the car to transport baby and children. I don't use this car for racing and don't corner fast due kids in the car. Also I thought it would be good to standardise all 4 tyres to the same size, so I can rotate them every 10,000kms. I will also be purchasing a Slime pack and tyre inflator and keep it in the boot.

Please let me know your opinion and thoughts on this, especially if you had experiencing of moving to this size tyres for front and back.

Thanks and appreciate your help.

Radman

[alohasurftoad]

442m specs are 19x8 ET36 front, 19x8.5 ET47 rear

245/40/19 will fit on both 8" and 8.5", however if you try to put the rear rim up front, @ET47 a 245/40/19 will contact the spring perch.

You will only be able to rotate side-to-side, if using non-directional tyres.

[thejeremyman9]

The other thing i would note is that MPSS is a retired tire. You should get the newer generation PS4S that replaces it, otherwise, you could find yourself unable to get a replcement tire should something happen.

[radman76]

Thanks all for your comments.

Thanks alohasurftoad about front/rear rotation limitations. I will forget the idea of rotation given these tyres are also uni-direction.

Thanks thejeremyman9 about the end-of-sale for MPSS. Good point, if I have another punctured tyre 1 year down the track, I won't be able to get a replacement.

Having done more research, the Goodyear Eagle F1 Asymmetric 5 looks like a good tyre relative the the Michelin PS4s. In Australia, they sell the Goodyear about $70 USD cheaper per tyre, which is a lot of money.

The Goodyear doesn't come in 225/40/19 size though. So I am thinking of the using the following size:

Front - 235/35/19 (2% smaller diameter)
Rear - 255/35/19 (same as current size)

With the front tyre 10mm wider than existing, I assume it will still stay well within the front fender and not stick out? Also, with the tyre 15mm smaller in diameter, I am hoping it won't make the gap in the wheel well look big.

Or should I go with 245/35/19 for the front? I just don't want the tyres to stick out on the side.

thanks

Radman

[alohasurftoad]

yes, you should do 245/35/19 front, 255/35/19 rear. here is a member with a 340i that has swapped the fronts from 225/40/19 to 245/35/19, with 255/35/19 rear, on his 442M. when you increase the front grip, it will reduce understeer and your handling through high speed turns will be much improved.