Ideal tyre size staggered set up for Z4??

[mybmmer318]

Hi..currently on stock set up..225/45/17 all round for my z4 2.5 and thinking of upgrading the rim size to 18 wheelers and going for staggered set up.. any advise which is a more ideal set up which i can use? I have tried using the tyre calculator and the best upgrade size they gave me is 255/35/18. Wondering is this set up suitable? But i don't think the 255/35/18 can fit the frount as i am afraid that it will rub against the fender during turing..Any z4 owners can advise what is the ideal size to use for the frount if i were to use 255/35/18 for the rears and it will not affect too much of the speedometer difference compare to stock and most impt the safety of the vehicle.

Help appreciated...

 

[louis]

Re: Ideal tyre size staggered set up for Z4??

oem 18" staggered set up is 225/40/18 for front and 255/35/18 rear.

 

[mybmmer318]

Re: Ideal tyre size staggered set up for Z4??

oem 18" staggered set up is 225/40/18 for front and 255/35/18 rear.

Hi, thks for e info..oh btw what is the ideal offset and rim width to select when going for the 18' wheelers in order to fit in the 255 rear tyres?Do i need spacers for the rear as well? Thanks..

 

[louis]

Re: Ideal tyre size staggered set up for Z4??

again using oem specs as reference, you'll need 8.5j width for the rears and an offset of around +40. i think you can try to go as far out as +34 on the rears if you're not lowered.

hopefully TripleM can chime in... he's the wheels and offset guru.

 

[TripleM]

Re: Ideal tyre size staggered set up for Z4??

Hello mybimmer318

Like louis has mentioned before, the ideal staggered set up is 225/40/18 Front and 255/35/18 Rear and this is from BMW factory specs. And this set up was fitted on 8JJ +47 front and 8.5JJ +50 rear ( rims 108 model )

That set up is perfectly fine for street driving but in my experience, you can make the handling and look even better but going a bit more aggressive set up.

Factory set up will make the look of the wheels a bit more sunken inside the wheel arches. To make it more flushed without sacrificing increased stress on the axles and wheel bearings, what u can do is to get a set of rims that increase in both widths and at the same time, reduce the offsets to a smaller number ( more negative technically speaking )

So, I'd got with offsets +39 to +42 with 8.5JJ rims in the front AND +40 to +42 with 9.5JJ rims in the rear. If u use +42 in the front, u can slap on 245 or even 255 tires and dial in about -2degree camber to avoid rubbing. If u go with +39, I think u should max out with 235 profile.

But again why would u want to put 255 in the front on 8.5JJ which isnt optimal?
For 8.5JJ u should go 225/40/18 to be optimal or at most 235/40/18

Now it's easier said than done. As I said, I'd lv to hv those offsets n widths but in the end, I settled with +39 8.5JJ front and +39 9.5JJ rear. The results? Superb handling and look. The rims I used were Prodrive GC-07E. Tire sizes for street driving was 225/40/18 and 255/35/18 but for track day use, I used 225/40/18 and 265/30/18 on semi slick tires. No rubbing whatsoever, cambers were dialled at -2.5 front and back, the car was lowered.

If u want to check out the ride, pm the new owner nick-named 33 and see it for yourself.

To recap:
Choose rims with 8.5JJ and offset range : +39 to +42 for the Front
and 9.5JJ and offset range +39 to +42 as well for the Rear

If u prefer with 8JJ and 9JJ then get +40 all rounds. Oz Ultraleggera has such set up.

Gd Luck

Jack

 

[mybmmer318]

Re: Ideal tyre size staggered set up for Z4??

Hello mybimmer318

Like louis has mentioned before, the ideal staggered set up is 225/40/18 Front and 255/35/18 Rear and this is from BMW factory specs. And this set up was fitted on 8JJ +47 front and 8.5JJ +50 rear ( rims 108 model )

That set up is perfectly fine for street driving but in my experience, you can make the handling and look even better but going a bit more aggressive set up.

Factory set up will make the look of the wheels a bit more sunken inside the wheel arches. To make it more flushed without sacrificing increased stress on the axles and wheel bearings, what u can do is to get a set of rims that increase in both widths and at the same time, reduce the offsets to a smaller number ( more negative technically speaking )

So, I'd got with offsets +39 to +42 with 8.5JJ rims in the front AND +40 to +42 with 9.5JJ rims in the rear. If u use +42 in the front, u can slap on 245 or even 255 tires and dial in about -2degree camber to avoid rubbing. If u go with +39, I think u should max out with 235 profile.

But again why would u want to put 255 in the front on 8.5JJ which isnt optimal?
For 8.5JJ u should go 225/40/18 to be optimal or at most 235/40/18

Now it's easier said than done. As I said, I'd lv to hv those offsets n widths but in the end, I settled with +39 8.5JJ front and +39 9.5JJ rear. The results? Superb handling and look. The rims I used were Prodrive GC-07E. Tire sizes for street driving was 225/40/18 and 255/35/18 but for track day use, I used 225/40/18 and 265/30/18 on semi slick tires. No rubbing whatsoever, cambers were dialled at -2.5 front and back, the car was lowered.

If u want to check out the ride, pm the new owner nick-named 33 and see it for yourself.

To recap:
Choose rims with 8.5JJ and offset range : +39 to +42 for the Front
and 9.5JJ and offset range +39 to +42 as well for the Rear

If u prefer with 8JJ and 9JJ then get +40 all rounds. Oz Ultraleggera has such set up.

Gd Luck

Jack

Wow...indeed e tyres and rims guru...ok..will take your advise and go for e above set up...i might be using koni adjustable shocks and combine it with stock springs..Appreciated alot...

 

[TripleM]

Re: Ideal tyre size staggered set up for Z4??

no worries
gd luck n happy modding