[fredfufufu]

I'm thinking about swapping P0 to PS4S* (ZTK) tires for the upcoming spring/summer. My car is a 22 M240ix with 792M wheels (non-ZTK so OEM tires are 225 front and 255 rear NRF P0).

I checked bmwtirecenters.com for PS4S* tires. I found PS4S BMW Original Tires (BSA) under two specs:

(first of all, hopefully these are the correct tires I'm looking for, if not, please point out)

Supposedly this is for non-ZTK OEM wheels:
225/40R19 | 93Y
255/35R19 | 96Y

And for OEM ZTK wheels:
245/35ZR19 | 93(Y)
255/35ZR19 | 96(Y)

Personally I'd like to go for the latter 245 front without changing wheels, for increasing front grip and better braking efficiency, and (hopefully) more lively rear movements.

I don't know too much about wheel specs and fitness for different tires. Would anyone recommend going for 245 front or should I stick with OEM tire sizes (aka 225 front) because of wheel differences?

[XC3LLR8]

Rim width range for 245 is 8-9.5". What rim width is your front wheel?

Running too wide of a tire for your wheel could result in sloppy turn-in and possibly more understeer.

[fredfufufu]

Originally Posted by XC3LLR8

Rim width range for 245 is 8-9.5". What rim width is your front wheel?

Running too wide of a tire for your wheel could result in sloppy turn-in and possibly more understeer.

I believe my front wheel is 8’’ , just on the edge according to the range you provided.

More details for anyone who might be interested:

My current setting: (non-ZTK package with non runflat)
225 front 8J X 19” ET27 -> I’m trying to do 245 front, same wheel
255 rear 8.5J X 19” ET40

The 245 front tire comes from ZTK package:
245 front 8.5J X 19” ET25
255 rear 9.5J X 19” ET35

[mmwwhats]

I’m in the same boat. I have 245 front and 255 rear winter tires used on my M2 that I’d like to now use on my non-ZTK M240. Would love confirmation that these fit.

[Roadwar]

Your front wheels are 8.0" and the rears are 8.5". 245/35/19 in front is fine on an 8.0 rim and is a good diameter match to keep the x drive system happy. I swapped out my stock Pirellis for Michelin Pilot Sport All Season 4s late last fall.

[Mike_H_]

Originally Posted by mmwwhats

I’m in the same boat. I have 245 front and 255 rear winter tires used on my M2 that I’d like to now use on my non-ZTK M240. Would love confirmation that these fit.

With x drive, the perfect set up would be same diameter front and rear, but within 1% is OK for BMW.

The reason for this is that size differential on AWD puts strain and wear and tear on the system.

I've found Bimmerpost threads (for other models) where owners who claimed they kept tire sizes within range had xdrive failure around 50k miles.

The standard tires for non-ZTK and ZTK is less than 1% (.8 of 1%)

This LINK is a tool that enables you to enter different tire sizes to ensure that you are within that 1% range.

Another consideration, as mentioned by XC3LLR8 earlier, is rim width.
Every tire has an "ideal" rim width but also a range that's acceptable.

The best guide for matching the ideal or acceptable rim width to a tire is Tire Rack, as they list that in the specifications for every tire.

[fredfufufu]

Anyone has any updates on the topic? any info will be much appreciated.

[danallxt]

Dunno if helpful, but a general rule is to match THREAD width to wheel width.
Another site i saw saying having TREAD width 90-100% of wheel width for best handling response. Keep in mind different tire manufactures and models of tires will have different tread widths for a given tire aspect ratio....not all tires of the same size will have identical tread widths. Tread width is NOT stated on the tire.

[TobyY]

I am in the same boat. I love how 792M looks ok the car but would also like a wider front tyre. Any update on this will be really appreciated ☺️

[Wasp_Factory]

Yes - you can run 245/35ZR19 on your existing 8" rim.

[TobyY]

Originally Posted by Wasp_Factory

Yes - you can run 245/35ZR19 on your existing 8" rim.

Thanks for the info. Would that also fit the xdrive system without any issue?

[Wasp_Factory]

Yes. You need to replicate the ZTK tyre sizing.

245/35/19 front and 255/35/19 rear - this is a 1.06% difference in rolling circumference, which technically is above the 1% that BMW apparently advise.

However, if you can, go for Michelin Pilot Sport 4S* which has some of the Cup2 compound - see link https://www.tyrereviews.com/Article/...t-OE-Tyres.htm

The key point of using the star rated BMW homologated tyre is that if you dig deep enough, you will allegedly find that the rolling circumference of the star marked tyre is very slightly different to the non star rated tyre, which brings the rolling radius within the 1%. Can't verify this myself, but if BMW specify it as OEM, you can't go far wrong.

Hope this helps.

[TobyY]

Just thinking about it today.
Does it solve the problem if I use 245 width both front and back? Then I don't have the xdrive compatibly issue?

[Wasp_Factory]

You could - 245s will be fine on an 8.5" rim at the rear, but why wouldn't you just go with 245/255 MPS4S* per my post above? Is it that you just want to be able to rotate the wheels?

[TobyY]

Originally Posted by Wasp_Factory

You could - 245s will be fine on an 8.5" rim at the rear, but why wouldn't you just go with 245/255 MPS4S* per my post above? Is it that you just want to be able to rotate the wheels?

Hard to get PS4S*. in Australia. Was just thinking about all the options I have. Thanks mate. Your reply is really helpful. I now know I have two options to change my tyres with 792M.

[M240iWhizz]

Originally Posted by Mike_H_

With x drive, the perfect set up would be same diameter front and rear, but within 1% is OK for BMW.

The reason for this is that size differential on AWD puts strain and wear and tear on the system.

I've found Bimmerpost threads (for other models) where owners who claimed they kept tire sizes within range had xdrive failure around 50k miles.

The standard tires for non-ZTK and ZTK is less than 1% (.8 of 1%)

This LINK is a tool that enables you to enter different tire sizes to ensure that you are within that 1% range.

Another consideration, as mentioned by XC3LLR8 earlier, is rim width.
Every tire has an "ideal" rim width but also a range that's acceptable.

The best guide for matching the ideal or acceptable rim width to a tire is Tire Rack, as they list that in the specifications for every tire.

This tool doesn't take into account rim width used so there's a margin of error. Does anyone know a tool that takes rim width and tire spec into account?

[ap2x]

Anyone know if I need 245/35ZR19 or 245/40ZR19 Michelin ps4s on my 19x8 OEM square wheel setup? Which aspect ratio is better or do both work? Looking to do a square setup

[BG42]

Originally Posted by ap2x

Anyone know if I need 245/35ZR19 or 245/40ZR19 Michelin ps4s on my 19x8 OEM square wheel setup? Which aspect ratio is better or do both work? Looking to do a square setup

run the 35 star tires.