[blackcolor]

Hi, I'm a newbie ,

May I know if the stock of the 3gt tire size was 225/50/18 & 255/45/18......

But unfortunately, I want to change the tire to the michelin pss which don't have this size.

So, can I make change to 225/45/18 & 255/40/18 ???

Except the car will be lower and the real speed will slower than the meter shown......

Is it safe ? Any risk or effect ?

Thanks a lot !

[blackcolor]

Please help !

[reprod]

It will affect your speedometer and will increase the appearance of gap in the wheel well. I would recommend just getting some 19s for your 3GT, run some proper tire sizes and have those as your dedicated summer set.

[.BMW.]

Do you have OEM staggered style 400 wheels on your F34?

3 Series GT has slightly different rear wheel width and offset compared to the other 3 and 4 Series models.

OEM F34 staggered:
F: 8x18" ET34, 225/50-18
R: 9x18" ET42, 255/45-18

Do you have xDrive?
If not I would recommend the following tire setup:
F: 245/45-18, 1% shorter than OEM
R: 265/45-18, 1% taller than OEM

Michelin PSS are available in both tire sizes listed above and they will fit very nice on 8" and 9" wide wheels.

If you have xDrive you can choose a square 245/45-18 setup.

Shorter tires (as 225/45-18 and 255/40-18) will look undersized in the huge wheel housings of the F34.

[blackcolor]

Thanks for all your advices ,

I'm not driving xdrive, actually I'm more concern about the safety than the "outlook" !

I know it will have a big gap between the tire and fender, anyway, I might have to go for 19" wheel and change to the 225/45/19 & 255/40/19 pss tire will be more safe. (As I know this is same with the 3gt 19" stock wheel size)

Btw, anyone know what's the offset of the 3gt 19" wheel ?

Thank you so much !

[.BMW.]

F: 8x19" ET30
R: 9x19" ET42

[blackcolor]

Originally Posted by ss0803

F: 8x19" ET30
R: 9x19" ET42

Thanks so much

[blackcolor]

Sorry for one more question .....

What if I change the rear tire from 255/45/18 (stock size) to 245/45/18 ??

Is this change more safe and compatible ?

Thank you !

[.BMW.]

225/50 front and 245/45 rear will work aswell (since your GT is RWD).

[blackcolor]

Originally Posted by ss0803

225/50 front and 245/45 rear will work aswell (since your GT is RWD).

Btw, the rear wheel is 18x9J , and if I changed from 255/45 to 245/45, is it ok ?

And anythings I have to alert ?

Thanks !

[.BMW.]

No problem, the rear tires will just look slightly more stretched and the speedometer will show 1% higher speed than actual.

[Keyless]

235/50/r18 will also be Ok.

[.BMW.]

I wouldn't recommend 235/50-18 as rear tires.

The rear 9" wide wheels are not within recommendation for 235/50-18 tires.
235/50-18, has 7.5" as recommended rim width and 6.5-8.5" allowed

245/45-18 on the other hand are within spec.
245/45-18, has 8" as recommended rim width and 7.5-9.5" allowed

[Keyless]

Strange.

As I wrote in a another tread, my dealer change to non RF yesterday.
They change to 235/50/18.

[.BMW.]

Originally Posted by Keyless

Strange.

As I wrote in a another tread, my dealer change to non RF yesterday.
They change to 235/50/18.

On staggered 18" with 8" rim width front and 9" rear?

235/50 all around will fit fine on square 8x18" wheels.

M Sport 3 Series GT comes stock with staggered 18", the other lines comes with square setup.

[blackcolor]

Thanks for your all replies....

Sorry about that I didn't say it clearly!

Actually my car is 3gt m sport, stock size is come with...

The wheel size is "18x8J front & 18x9J rear"

and the tire size is "225/50/18 & 255/45/18"

And due to the PSS tire doesn't got the 255/45/18, only have the 245/45/18....

So, I just want to know is it compatible ? I also want to make sure will it be safe and what I have to alert on after this change !?

Thanks !

Stock - 225/50/18 18x8J front + 255/45/18 18x9J rear

After - 225/50/18 18x8J front + 245/45/18 18x9J rear

[Keyless]

Originally Posted by ss0803

On staggered 18" with 8" rim width front and 9" rear?

235/50 all around will fit fine on square 8x18" wheels.

M Sport 3 Series GT comes stock with staggered 18", the other lines comes with square setup.

I have not M-Sport and I have a square setup. And yes I guess it is 8x18".

[.BMW.]

Originally Posted by blackcolor

So, I just want to know is it compatible ? I also want to make sure will it be safe and what I have to alert on after this change !?

Thanks !

Stock - 225/50/18 18x8J front + 255/45/18 18x9J rear

After - 225/50/18 18x8J front + 245/45/18 18x9J rear

Yes it is safe, both front and rear will fit fine with only slightly stretched tires!

Originally Posted by Keyless

I have not M-Sport and I have a square setup. And yes I guess it is 8x18".

Then everything is clear, 235/50-18 will fit perfect on your square wheels!

[liveevil]

Currently have the staggered 400m setup on my 3gt rwd 225/50/18 front and 255/45/18 rear. Choices are lacking for the sizes especially the front and seems more expensive as well compared to the more common and wider tyres.

Would 245/45/18 front and 265/45/18 rear rub, as I have the m sport suspension?

Or would changing the front to 235/50/18 and keeping the rear, 255/45/18 work?

[.BMW.]

Both 235/50 front and 255/45 rear or the 245/265 combo will fit fine.

Personally I would have chosen the 245/265 setup since I like the beefy tire look, but that is up to personal taste.

With the 245/265 combo it's important that your car is RWD (not xDrive) since the front and rear diameter differs too much for the AWD system.

[liveevil]

Thanks. It is rwd and I think the 245/265 tyres selections are a lot wider.

[liveevil]

Just an update, I changed to Pzero tyres. 245/45/18 front and 255/45/18 rear on the stock 400m and M sport suspension.

Huge improvement in comfort over my stock csc5 run flats.