[alhsk]

Hi
My G30 factory tires size are:

Front
245/35R/20
Rear
275/30R/20

Can I change the sizes to following:

New front
245/40R/20
New rear
275/35R/20

Is this legal or BMW not recommending this?
I talked to my dealer he said it can damage on GearBox.

[Alscoob]

Originally Posted by alhsk

Hi
My G30 factory tires size are:

Front
245/35R/20
Rear
275/30R/20

Can I change the sizes to following:

New front
245/40R/20
New rear
275/35R/20

Is this legal or BMW not recommending this?
I talked to my dealer he said it can damage on GearBox.

Quite a few on here have done that exact swop and a very happy with it without issues. that 'change to' size give the front to rear tyres less percentage difference than the standard OEM size, so technicall is better.

Only issue is the wheels will be slightly larger so your speedo will be slightly out, but not much.

Look here and enter the sizes for % difference for both OEM & you option.
https://alloywheels.com/tyreCalculatorResults

Enter the sizes here and you'll see how they fit too...
https://www.willtheyfit.com/

Also it won't damage the gearbox, but x drive cars are sensitive to tyre sizes front to rear and need to be within 1% of each other

[G30M]

Originally Posted by Alscoob

Quite a few on here have done that exact swop and a very happy with it without issues. that 'change to' size give the front to rear tyres less percentage difference than the standard OEM size, so technicall is better.

Only issue is the wheels will be slightly larger so your speedo will be slightly out, but not much.

not sure if that size will clear the front suspension as there's very little gap with stock on mine?

re speedo my iDrive 7 cars self correct for tire size, i think it reads actual speed from GPS

[Alscoob]

alhsk Have a look here.... Post #9 fair discussion on the subject.

https://g30.bimmerpost.com/forums/sh....php?t=2072914