[PNW2003]

I am looking at a 2018 440i xdrive and choosing between 19" 704M style wheels versus 18" 400M. The 19" wheels are an additional $900 on the build.

Since I don't know much about wheels, can anyone give me the pros and cons of making this decision? What is the difference, other than 1"?

Which one would you choose?

New to forum, thank you in advance.

[floydarogers]

Originally Posted by PNW2003

I am looking at a 2018 440i xdrive and choosing between 19" 704M style wheels versus 18" 400M. The 19" wheels are an additional $900 on the build.

Since I don't know much about wheels, can anyone give me the pros and cons of making this decision? What is the difference, other than 1"?

Which one would you choose?

New to forum, thank you in advance.

IMO, 18" is the limit for comfort, and is a better compromise between comfort and performance. Yeah, 19" may be a bit sportier, but at the cost of comfort, increased vulnerability to being bent by potholes, tires are more expensive. And if you want to put winter tires on them, you're pretty much limited to one or two, especially RFT's.

[PNW2003]

Originally Posted by floydarogers

IMO, 18" is the limit for comfort, and is a better compromise between comfort and performance. Yeah, 19" may be a bit sportier, but at the cost of comfort, increased vulnerability to being bent by potholes, tires are more expensive. And if you want to put winter tires on them, you're pretty much limited to one or two, especially RFT's.

Thank you, that's what I was looking for. I will likely need to drive this in Pacific Northwest weather. Sounds like the 18s will be better for me here.

[1QuikWS6]

I run 19's in the summer - 18's in the winter

Always good to have 2 wheel/tire sets so swap at seasons is quik/EZ

[MickAv8r]

Run 18's year round. Stock 18's are now my winter wheels. Then two sets of summer 18''s one with track tires, one set with PSS for daily driving.

[D_Frost]

Interestingly, I'm located in Washington and moved from 18's to 19's for other reasons. The difference in ride quality is not huge especially if you have adaptive suspension. In most cases, 19" wheels will weigh more than the 18" wheels (unless their construction is different - forged vs cast). More weight will impact MPG and handling (subjective as to +/-) as well.

[sygazelle]

Originally Posted by floydarogers

IMO, 18" is the limit for comfort, and is a better compromise between comfort and performance. Yeah, 19" may be a bit sportier, but at the cost of comfort, increased vulnerability to being bent by potholes, tires are more expensive. And if you want to put winter tires on them, you're pretty much limited to one or two, especially RFT's.

^^^^


I was going to write something but you summed it up perfectly.

[sygazelle]

Originally Posted by PNW2003

I am looking at a 2018 440i xdrive and choosing between 19" 704M style wheels versus 18" 400M. The 19" wheels are an additional $900 on the build.

Since I don't know much about wheels, can anyone give me the pros and cons of making this decision? What is the difference, other than 1"?

Which one would you choose?

New to forum, thank you in advance.

Welcome to the forum.

18's for the reasons mentioned in Post #2.

You didn't ask, but I'd also recommend a square setup over staggered. Staggered looks pretty cool I guess but it does nothing for the ride, the tires cost more, and you cannot rotate front to back if that's something you would ever want to do.

So, I'd go with an 18 square setup over anything else.

Good luck.

[TodmordenLad]

19" rims look better of course. I have them on my F31 in the UK, where road surfaces can be terrible. The solution is adaptive suspension, which transforms ride quality. I wouldn't buy a BMW without it

[Polo08816]

Originally Posted by MickAv8r

Run 18's year round. Stock 18's are now my winter wheels. Then two sets of summer 18''s one with track tires, one set with PSS for daily driving.

+1. Same here.

Originally Posted by TodmordenLad

19" rims look better of course. I have them on my F31 in the UK, where road surfaces can be terrible. The solution is adaptive suspension, which transforms ride quality. I wouldn't buy a BMW without it

BMW's adaptive suspension on the F3X platform is a not a solution, it's a costly band-aid for a user created problem. The best part of all this is that the user spent money to go from 18" to 19" and then had to spend even more money thinking an adaptive suspension would provide more comfort all in the name of subjective looks. BMW's adaptive suspension in the F3X platform is not the same as GM's MagneRide system which is capable of adjusting compression/dampening mid-bump.

[TodmordenLad]

Originally Posted by Polo08816

+1. Same here.

BMW's adaptive suspension on the F3X platform is a not a solution, it's a costly band-aid for a user created problem. The best part of all this is that the user spent money to go from 18" to 19" and then had to spend even more money thinking an adaptive suspension would provide more comfort all in the name of subjective looks. BMW's adaptive suspension in the F3X platform is not the same as GM's MagneRide system which is capable of adjusting compression/dampening mid-bump.

Well, we'll have to agree to differ.
I've driven 3 series with and without it and adaptive transforms the ride on 19"s on U.K. roads.

[sygazelle]

Originally Posted by Polo08816

+1. Same here.



BMW's adaptive suspension on the F3X platform is a not a solution, it's a costly band-aid for a user created problem. The best part of all this is that the user spent money to go from 18" to 19" and then had to spend even more money thinking an adaptive suspension would provide more comfort all in the name of subjective looks. BMW's adaptive suspension in the F3X platform is not the same as GM's MagneRide system which is capable of adjusting compression/dampening mid-bump.

You sound like somebody who doesn't have Adaptive Suspension. I have 18's and adaptive suspension is night and day difference from passive suspension on F30s with 18".

You say that BMW adaptive is not same as GM MagneRide which is true, but it's still darn good. Porsche engines are better than BMW engines too but that doesn't make BMW engines worthless.

[Polo08816]

Originally Posted by TodmordenLad

Well, we'll have to agree to differ.
I've driven 3 series with and without it and adaptive transforms the ride on 19"s on U.K. roads.

Originally Posted by sygazelle

You sound like somebody who doesn't have Adaptive Suspension. I have 18's and adaptive suspension is night and day difference from passive suspension on F30s with 18".

You say that BMW adaptive is not same as GM MagneRide which is true, but it's still darn good. Porsche engines are better than BMW engines too but that doesn't make BMW engines worthless.

Given 18" wheels and non-runflat tires, I don't see too much of a benefit to get the "Adaptive" Suspension over the passive 704 Suspension. Especially if you're going to replace your passive 704 Suspension with the M Performance Suspension kit or Ohlins Road & Track coilovers.

"Adaptive" suspension doesn't "fix" the insufficient spring rate of the 704 Suspension either.

[lkstaack]

Generally, larger wheels will facilitate better traction and look better. They are heavier, negatively affecting handling, cost more, and may have a harsher ride due to thinner sidewalls. Big brakes often require large wheels though. Some people initially opt for the smaller wheel, only to purchase larger wheels later when their preferences change.

[Polo08816]

Originally Posted by lkstaack

Generally, larger wheels will facilitate better traction and look better. They are heavier, negatively affecting handling, cost more, and may have a harsher ride due to thinner sidewalls. Big brakes often require large wheels though. Some people initially opt for the smaller wheel, only to purchase larger wheels later when their preferences change.

I'll fix this for you:

Originally Posted by lkstaack

Generally, larger wheels may look better. They are heavier, negatively affecting handling, cost more, and may have a harsher ride due to thinner sidewalls. Big brakes often require large wheels though. Some people initially opt for the smaller wheel, only to purchase larger wheels later when their preferences change.

The main reason to have a wheel larger than what is require to clear the brakes are mainly due to appearance. There's no functional improvement of a 19" wheel over a 18" in this case.

[alohasurftoad]

Originally Posted by PNW2003

I am looking at a 2018 440i xdrive and choosing between 19" 704M style wheels versus 18" 400M. The 19" wheels are an additional $900 on the build.

Which one would you choose?

although 18's would function better in the PNW, i find the 400M's "bleh".

i'm a function before fashion type but between your two choices, the 704M is nicer to look at everyday.

personally, i'd switch to aftermarket, but that's a whole 'nother can of worms.

[lkstaack]

Originally Posted by Polo08816

The main reason to have a wheel larger than what is require to clear the brakes are mainly due to appearance. There's no functional improvement of a 19" wheel over a 18" in this case.

Larger wheel allows for larger brakes and increased contact patch for better traction. Road and Track Tire Contact Patch In my case, most 18" wheels will not fit around my M Performance brakes.

[Polo08816]

Originally Posted by lkstaack

Larger wheel allows for larger brakes and increased contact patch for better traction. Road and Track Tire Contact Patch In my case, most 18" wheels will not fit around my M Performance brakes.

Larger wheels won't necessarily increase your contact patch for better traction. That contact patch is largely dependent on overall circumference of your tire and tire pressure. That's how it's explained in the link you've posted.

Anyways, my 18" APEX ARC-8 18x8.5 ET38 wheels clear my M Sport/M Performance Brakes with no issues.

[lkstaack]

Originally Posted by Polo08816

Larger wheels won't necessarily increase your contact patch for better traction. That contact patch is largely dependent on overall circumference of your tire and tire pressure. That's how it's explained in the link you've posted.

Anyways, my 18" APEX ARC-8 18x8.5 ET38 wheels clear my M Sport/M Performance Brakes with no issues.

OK, I concede your points. I mistakenly assumed that the tire circumference would increase with a larger wheel, but of course, its typical to decrease tire height to maintain stock circumference.

So, the only potential advantages of a larger wheel is stiffer sidewalls, and to clear brakes. Any potential advantage though could be offset by increasing the unsprung weight of the suspension (all variables being equal except size would mean the larger wheel will weigh more).

So I am intrigued by your Apex wheels. They are light and fit your M Performance brakes. Do you have the shallow or deep face? Do you run staggered? Did you have to get new TPS sensors?

[Polo08816]

Originally Posted by lkstaack

OK, I concede your points. I mistakenly assumed that the tire circumference would increase with a larger wheel, but of course, its typical to decrease tire height to maintain stock circumference.

So, the only potential advantages of a larger wheel is stiffer sidewalls, and to clear brakes. Any potential advantage though could be offset by increasing the unsprung weight of the suspension (all variables being equal except size would mean the larger wheel will weigh more).

So I am intrigued by your Apex wheels. They are light and fit your M Performance brakes. Do you have the shallow or deep face? Do you run staggered? Did you have to get new TPS sensors?

Correct. The advantage of insignificantly stiffer sidewalls over the significant increase in total un-sprung mass usually isn't worth it. The problem with trying to use an "adaptive" suspension to provide an acceptable level of ride comfort with large wheels and low profile tires is that it's not an effective strategy and it's technically challenging. Most adaptive suspensions barring the GM MagneRide system simply can't adjust/react fast enough for unpredictable imperfections in road surfaces such as potholes. Greater tire sidewall height is generally the best way to address ride comfort issues from unpredictable road imperfections.

I run a square setup with a 255/40/18 Michelin Pilot Super Sport all around. That way you can rotate the tires, keep wear even, and pro-long the tire life. With my M Performance LSD and tires, I have no complaints with regards to traction on a RWD car. I would not call the 18x8.5 APEX ARC-8 ET38 a "deep" face. I think you need to get into the low 30s or 20s for the offset to look concave.

I did have to buy new TPMS sensors because this was an additional set of wheels and tires. I use my staggered 400M wheels for my winter tire set.

[AustinA02]

Originally Posted by 1QuikWS6

I run 19's in the summer - 18's in the winter

Always good to have 2 wheel/tire sets so swap at seasons is quik/EZ

+1. Always the best decision IMO. Maybe you don't want winter/summer... maybe just change them when you feel like it

[ATs335Xi]

I bought 18's for all the performance benefits people have mentioned above. I will likely get 19's for the summer once my PSS' wear off and keep the 18s for the winter. This is subjective, but the 19s just look better on the F30 and I always have a little regret whenever I see another one around town with nice 19s. My life is not impacted by unnoticeable performance differences between the 18s and 19s and the improved appearance would increase my enjoyment of the car more than the nominal performance difference. Just my opinion though...