[anketp]

Hello folks,

It's time to change the rims on my daily driver F36 430i Xdrive GC and would like to use the opportunity to switch from the factory staggered (225/40R19 front & 255/35R19 rear) to square setup with all seasons.

I read on multiple threads that 18" are recommended for this switch. How do I go about figuring out what size I should go for (or will fit) a square setup?

Thanks.

[johnung]

You can run a square setup with 18” or 19”, it doesn’t matter. 18” will be more comfortable with the cushioning of more sidewall and less prone to tire/wheel damage from potholes.

Below is the process that I followed along with the advice of Alohasurftoad

Start with the actual tire size and model that you want to run. That will lead you to the wheel width. And finally the offset ranges that will fit and possibly spacer sizes to make fine adjustments. Getting the car aligned is important too.

Square 255’s fit well. Some guys have managed 265’s but that can cut it close unless all variables are perfect.

I wanted 255 in the summer Michelin Pilot Sport 4S. 255/40-18 matches the 26.0” stock diameter of the 225/45-18 runflats. The MPS4S is more oval in shape/profile so an 8.5” wide wheel looks like a perfect fit with the sidewall. If I had chosen a more square profile tire like the All Season Continental DWS06+, then a 9” width wheel might look better.

So my tires would be MPS4S 255/40-18 and the wheels would be 18x8.5”. So what about the offset?

Wheels with custom offsets are incredibly expensive. So it’s a matter of going through many many wheel choices to see what look you like and what offsets they are made in.

Wheels have a huge price range depending on their quality, strength and weight. There are different manufacturing methods to attain these qualities.

For 18x8.5”, a common offset made is ET35. The front wheel well on my F30 can just fit an ET42 without rubbing against the suspension strut, but that would certainly look recessed into the wheel well. That’s okay because spacers can always be used to pull the wheel out a bit.

ET32 or ET30 might just fit without hitting the fender lip (also depending on whether the car is lowered and exactly what the alignment settings are.) But ET30/ET32 would leave no room for adjustment because spacers only make wheels poke out more from the wheel well.

After considering maybe 100 wheels my favorite were the APEX VS-5RS. For the 18x8.5” the only offset in my range was ET40 which was fine. These wheels look incredible, are super strong forged and are super light at only 17.2 lbs each. In fact this wheel/tire setup saves almost 10 lbs per corner, huge reduction in rotational mass that provides improved acceleration, braking, handling and gas mileage. It’s simply less work to spin, stop and control a much lighter wheel & tire.

I ended up measuring with a drop string to perfectly align the tire sidewall flush with the fender lip. It took 3mm spacers in front and 5mm spacers in the rear. Turner Big Pad spacers were by far the best because they match the pad size of the APEX wheels (and my winter BMW 400M wheels). Photos attached.

Hope this helps!

[A2_Matt]

Hi, I'm in process of switching out the OEM 19" staggered summer wheels/tires on my 2019 430i x-drive Gran Coupe to 18" square setup.

Decided to go with Enkei Raijin 18x8.5 et38 wheels (ordered today). Likely putting 225/45R18 rubber on them, something all season, likely from Costco or Belle Tire. Open to suggestions.

The wheels:
https://enkei.com/shop/wheels/tuning/raijin/

From my perspective a relatively classic look, good quality product at a reasonable price. And they fit. That helps a lot.

[A2_Matt]

Hi, I'm in process of switching out the OEM 19" staggered summer wheels/tires on my 2019 430i x-drive Gran Coupe to 18" square setup.

Decided to go with Enkei Raijin 18x8.5 et38 wheels (ordered today). Likely putting 225/45R18 rubber on them, something all season, likely from Costco or Belle Tire. Open to suggestions.

The wheels:
https://enkei.com/shop/wheels/tuning/raijin/

From my perspective a relatively classic look, good quality product at a reasonable price. And they fit. That helps a lot.

[oem.plus_440gc]

A2_Matt I have Continental DWS 06+ all season tires and I really like them. No complaints in dry or wet conditions. I don't track the car, but for spirited back road driving they're great. Haven't had too much experience with them in the snow yet (pretty dry winter last year here in NJ), but they have good reviews.

Not sure if you'll be able to get them at Costco or Belle Tire, but you could always order from Tire Rack and have them delivered to an install shop in your area.

[oz3n]

Originally Posted by johnung

You can run a square setup with 18” or 19”, it doesn’t matter. 18” will be more comfortable with the cushioning of more sidewall and less prone to tire/wheel damage from potholes.

Below is the process that I followed along with the advice of Alohasurftoad

Start with the actual tire size and model that you want to run. That will lead you to the wheel width. And finally the offset ranges that will fit and possibly spacer sizes to make fine adjustments. Getting the car aligned is important too.

Square 255’s fit well. Some guys have managed 265’s but that can cut it close unless all variables are perfect.

I wanted 255 in the summer Michelin Pilot Sport 4S. 255/40-18 matches the 26.0” stock diameter of the 225/45-18 runflats. The MPS4S is more oval in shape/profile so an 8.5” wide wheel looks like a perfect fit with the sidewall. If I had chosen a more square profile tire like the All Season Continental DWS06+, then a 9” width wheel might look better.

So my tires would be MPS4S 255/40-18 and the wheels would be 18x8.5”. So what about the offset?

Wheels with custom offsets are incredibly expensive. So it’s a matter of going through many many wheel choices to see what look you like and what offsets they are made in.

Wheels have a huge price range depending on their quality, strength and weight. There are different manufacturing methods to attain these qualities.

For 18x8.5”, a common offset made is ET35. The front wheel well on my F30 can just fit an ET42 without rubbing against the suspension strut, but that would certainly look recessed into the wheel well. That’s okay because spacers can always be used to pull the wheel out a bit.

ET32 or ET30 might just fit without hitting the fender lip (also depending on whether the car is lowered and exactly what the alignment settings are.) But ET30/ET32 would leave no room for adjustment because spacers only make wheels poke out more from the wheel well.

After considering maybe 100 wheels my favorite were the APEX VS-5RS. For the 18x8.5” the only offset in my range was ET40 which was fine. These wheels look incredible, are super strong forged and are super light at only 17.2 lbs each. In fact this wheel/tire setup saves almost 10 lbs per corner, huge reduction in rotational mass that provides improved acceleration, braking, handling and gas mileage. It’s simply less work to spin, stop and control a much lighter wheel & tire.

I ended up measuring with a drop string to perfectly align the tire sidewall flush with the fender lip. It took 3mm spacers in front and 5mm spacers in the rear. Turner Big Pad spacers were by far the best because they match the pad size of the APEX wheels (and my winter BMW 400M wheels). Photos attached.

Hope this helps!

Hi there on the forum i have seen that you run 400m wheels as winter wheels i want to do the same could not figure out the tire size i need. can you help? i have the 8inch onthe front and 8.5 at the back as it comes out of the factory.

[danb1979]

The 18" 397s and 405Ms are what I run (405Ms for my summer wheels and 397s for my winter wheels)

IIRC these are the dedicated winter wheel options for all F3x cars; and would run 225/45/18 tyres all round for RWD and xDrive

My F31 is RWD, so I run 235/45/18s all round as they offer a straighter sidewall/better rim protection etc - but no good with xDrive IIRC

If you want 400Ms, you just need x4 18x8s (ie x4 front wheels)

To give you an idea:

Summer 405Ms:



Winter 397s:

[johnung]

Originally Posted by oz3n

Hi there on the forum i have seen that you run 400m wheels as winter wheels i want to do the same could not figure out the tire size i need. can you help? i have the 8inch onthe front and 8.5 at the back as it comes out of the factory.

If I had staggered 400M wheels, I would just use the same stock tire size for winter tires, Front 225/45-18 and Rear 255/40-18.

[anketp]

johnung, thank you for your insight.

I am finalizing on the following to replace front 225/40 R19 8Jx19 ET36, rear 255/35 R19 8.5Jx19 ET47:

• MICHELIN Pilot Sport AS 4 245/40ZR19 98Y XL BSW
• Square Enkei Raijin 19x8.5 +38

Other ones I am considering are Enkei TY5 19x8.5 +38 or Touren TR60 3260 19x8.5 +40.

Anyone see any reasons those will not spec out?

[johnung]

Originally Posted by anketp

johnung, thank you for your insight.

I am finalizing on the following to replace front 225/40 R19 8Jx19 ET36, rear 255/35 R19 8.5Jx19 ET47:

MICHELIN Pilot Sport AS 4 245/40ZR19 98Y XL BSW
Square Enkei Raijin 19x8.5 +38


Other ones I am considering are Enkei TY5 19x8.5 +38 or Touren TR60 3260 19x8.5 +40.

Anyone see any reasons those will not spec out?

I will defer to Alohasurftoad
As resident wheel/tire guru, he may have insights to off

[alohasurftoad]

Originally Posted by johnung

I will defer to Alohasurftoad
As resident wheel/tire guru, he may have insights to off

lol...you know the same as i do already @johnung

members in the links below have 245/40/19 on 8.5" @ ET35. it will work at ET38 and should work at ET40 but will tops will be close to the spring perch.
https://f30.bimmerpost.com/forums/sh...35&postcount=3
https://f30.bimmerpost.com/forums/sh...78&postcount=4
https://f30.bimmerpost.com/forums/sh...12&postcount=4

OEM=26"...245/40/19(26.7") while these taller tires will reduce the x-drive gap, it also raises the total vehicle height 0.35" and changes your gearing at the pavement slightly. they will ride more comfortably and have better impact protection but reduced turn in sharpness.

i find the taller sidewall too bulky and it makes 19" diameter look smaller. personally, i'd use 235/40/19(26.4") unlowered or 255/35/19(26.0") if mildly lowered, instead, but 245/40/19 will work if that's what you desire.

[anketp]

Thanks for the insight, alohasurftoad. I am not set on 245 so I will look at 235/40/19 instead.