Tyre Size for Z4M Alloys on Standard Z4 3.0

[soundboy10]

Hi All,

I purchased some Z4M alloys at the end of last year, which came with the following tyres...

Front - 225/45 18
Rear - 255/40 18

...but it states in my manual etc that the appropriate tyres for 18" wheels on mine should be...

Front - 225/40 18
Rear - 255/35 18

Now i haven't had any issues at all with the current size, but just wondered when i need to change these, which is soon, should i go for what is suggested? And the second question is, i will more than likely be buying the rears a few months before the fronts, so if i go for the suggested rears of 255/35 18, is this going to throw everything off, as i don't have the recommended fronts??

I appreciate your responses

Neil

 

[Half Colin]

I am running those sizes (255/40 & 225/45 by 18) as winter tyres and the only real difference is the speedo reading because the tyre circumference is larger. The effect is to make the speedo read just about the actual speed rather than a few mph lower than actual. Some might say the ride is softer with the higher sidewalls but I haven't noticed any difference in ride or handling.

Personal choice but I would stick with OEM sizes for the car rather than the wheels.

 

[Dreamer]

Ive got regular size tyres (your second measurements) on my Z4M alloys. The lower profile looks much better

 

[Spud]

I used to have standard 3.0 tyres on my Z4M alloys on my old 3.0. Never had any issues, other than 1/2 tyre fitters saying they were a bit of work sometimes.

 

[Adamski]

I would go for the lower profile


Sent from my iPhone using Tapatalk

 

[maxman]

I have the std tyre set up on mine ie your second set of sizes.
The higher profile will alter your speedometer readings.

 

[soundboy10]

Thanks for your responses.

Looks like i should go for the suggested set of sizes, the second set in my first post. So back to my original post, can i mix the sizes, i.e have the suggested on the rear and on the bigger profile on the front...

Front - 225/45 18
Rear - 255/35 18

.. Just for a few months or so, until i need to replace the front ones??

Cheers

 

[aquazi]

advantages of the first measurements:
Came with the wheels - no cost
More dampening so a nicer ride

Disadvantages:
might rub on full lock up front
increased rolling radius so decreased acceleration

advantages of second measurements:
correct profile - so speedo more accurate (but then ironically the first size prob gives it closer to the gps anyway!)
look better

 

[Half Colin]

Thanks for your responses.

Looks like i should go for the suggested set of sizes, the second set in my first post. So back to my original post, can i mix the sizes, i.e have the suggested on the rear and on the bigger profile on the front...

Front - 225/45 18
Rear - 255/35 18

.. Just for a few months or so, until i need to replace the front ones??

Cheers

I don't think you'll have any problems whatsoever.

Another option to consider though is changing all 4 tyres together and then selling the fronts as used. You'll recoup some of the cost as well.

When I bought my Coupe it had nearly new runflats that I sold on for about half the price of a new set of Vredesteins.