[Solid67]

I've been on the fence about getting new rims, but I've decided to stick with my stock M405 7.5Jx19f + 8Jx19r rims. I want to upgrade my run-flats to Michellin PS4S. My question is what is the biggest tire I can fit if I go with a square setup and what is the biggest tire I can fit if I stick with a staggered setup?

[Solid67]

Damn no one knows?

[dradernh]

Originally Posted by Solid67

I've been on the fence about getting new rims, but I've decided to stick with my stock M405 7.5Jx19f + 8Jx19r rims. I want to upgrade my run-flats to Michellin PS4S. My question is what is the biggest tire I can fit if I go with a square setup and what is the biggest tire I can fit if I stick with a staggered setup?

1) 225/35-19

2) 225/35-19 F; 245/30-19 R

Source: https://www.tirerack.com/tires/tires...ggered%20Tires

[Solid67]

Originally Posted by dradernh

1) 225/35-19

2) 225/35-19 F; 245/30-19 R

Source: https://www.tirerack.com/tires/tires...ggered%20Tires

Lol I already know the stock tire sizes. What I'm asking is if I wanted to stay with my stock rims (which I have given the dimensions) in a square setup what is the biggest tire I could run all around. If I decided to stick with a staggered setup, what are the biggest tires I could run?

[Solid67]

Originally Posted by dradernh

1) 225/35-19

2) 225/35-19 F; 245/30-19 R

Source: https://www.tirerack.com/tires/tires...ggered%20Tires

Ahh I see what you did. My bad, okay so 225 would be the biggest for a square setup. I guess I need to get rims lol.

[dradernh]

Originally Posted by Solid67

Ahh I see what you did. My bad, okay so 225 would be the biggest for a square setup. I guess I need to get rims lol.

Yeah, no worries – this car is not ideal for square setups, and that's putting it mildly.

Look in my sig to see what I did to get square tire widths in the tire I wanted. But hey, I did manage to keep the OEM aspect ratios!

The subject has been discussed many times on this forum. IIRC, the sweet spot for many owners has been an 8-inch wide wheel with an offset of around +42 to +45. If you went with 17X8 you'd run a 245/40-17; with an 18X8, a 245/35-18; and with a 19X8, 245/30-19. How it looks, handles potholes, and is generally responsive to steering inputs seem to be the dividing lines on what owners choose. Just my 2¢.

I recommend looking for threads on the subject and querying/PM'ing other owners to find out what they did to make it work for them. For example, were spacers required in front, did they have to roll their fenders at all, had their cars been lowered (possibly making other mods necessary before they could fit their new wheels & tires), etc.

It's been my impression that owners wanting/needing 255 and wider tires have had to make mods to the car to accommodate the wider combination of wheels and tires.

[Solid67]

Originally Posted by dradernh

Yeah, no worries – this car is not ideal for square setups, and that's putting it mildly.

Look in my sig to see what I did to get square tire widths in the tire I wanted. But hey, I did manage to keep the OEM aspect ratios!

The subject has been discussed many times on this forum. IIRC, the sweet spot for many owners has been an 8-inch wide wheel with an offset of around +42 to +45. If you went with 17X8 you'd run a 245/40-17; with an 18X8, a 245/35-18; and with a 19X8, 245/30-19. How it looks, handles potholes, and is generally responsive to steering inputs seem to be the dividing lines on what owners choose. Just my 2¢.

I recommend looking for threads on the subject and querying/PM'ing other owners to find out what they did to make it work for them. For example, were spacers required in front, did they have to roll their fenders at all, had their cars been lowered (possibly making other mods necessary before they could fit their new wheels & tires), etc.

It's been my impression that owners wanting/needing 255 and wider tires have had to make mods to the car to accommodate the wider combination of wheels and tires.

Hey man that sounds like a plan. I realize its hard to give definite answers on something like this because each person's setup is different given the mods they have or don't have.

Offtopic but how are you liking the Al Subframe Bushings? Do you feel like its a worthy upgrade and does it add any additional nvh?

[Solid67]

I just got an email from Apex Racing

Good afternoon Shabib,

Thank you for reaching out in regards to your BMW M240i. Currently, our only 2-Series applicable wheel size in our ARC-8R Forged wheel design is going to be the 18x8.5" ET35. Here is some additional information regarding a square setup for that particular wheel:

Front & Rear: 18x8.5" ET35 with 225/40-18 tires
Popular fitment.
Typically a direct fit. Certain compounds that run wider-than-average may require front negative camber.
235/40-18 tires can be a direct fit, but we strongly suggest dialing in front and rear negative camber to prevent rubbing. Amount of camber varies depending on tire brand and ride height.
245/35-18 tires require at least 1.5 degrees of front negative camber, and 1.8 degrees of rear negative camber depending on tire brand and suspension setup.
255/35-18 tires require at least 2.2 degrees of front negative camber and 1.8 degrees of rear negative camber depending on tire brand and suspension setup.

Typically, the widest tire you can run with these wheels without any additional modifications to the car is going to be a 225/40-18 or a 235/40-18. You can run a 245/35-18 or a 255/35-18 as a wider alternative, but typically some negative camber will have to be dialed-in to alleviate any rubbing that might occur.

[dradernh]

Originally Posted by Solid67

...how are you liking the Al Subframe Bushings? Do you feel like its a worthy upgrade and does it add any additional nvh?

They've not added NVH of note to me. I had them installed because an LSD was going in at the same time. I wouldn't have installed one without the other and saw them as a natural pair of components to be installed together. The purpose of the bushings was to further increase the car's ability to transfer power to the ground due to less flex in the rear subframe. They haven't made the car any less pleasant to drive.