[upstate650]

Originally Posted by SLGrassoPA

100 percent agree with you. I will say that summer tires are a bit harder than an all season, which may make your ride somewhat harsher. And a low profile (35) in the rear makes it harsher.

Don't know about the roads around you, but around here a 35 profile tire, even though it may look nice, is simply not practical as it will not even be close to comfortable.

Not trying to make any sweeping conclusions. Just stating my observation that the Adaptive M does absorb road imperfections very well, to the point of making the ride super comfy. However, with a staggered 19 inch summer set up (non run flat) with a 35 spec in the back, over rough roads, the adaptive would probably not make a ton of difference.

Wrong again. The 35 profile of a staggered 255 19” tire has the exact same sidewall height as the 40 profile of the 225 19” front, which is why they are approved for x drive. Please know what you are talking about before professing to be an expert.

[SLGrassoPA]

Thank you for your post.

Respectfully, I don't think I'm wrong, or as you say "wrong again."

Please allow me to disabuse the notion that a 35 and 40 aspect tire have the small exact sidewall. They do not.

Stated simply, the aspect is the amount of space from the ground to the bottom of the wheel, hence a 35 has less space when compared to a 40, and a 30 has even less space.

Obviously, an 18 inch tire is 18 inches and 19 inch tire is always 19 inches. The overall height of the tire is not what is at issue.

We are talking about the sidewall aspect ratio (something that is different than the overall height of the tire- which is 17, 18, 19, 20 depending on the tire.etc...)

The aspect ratio is the “height” of the sidewall, expressed as a percentage of the section width. In other words, a 35 will always have less rubber between the ground and the wheel when compared to a 40, and even more so when compared to a 45. Just look at a 35, 40 and 45 spec tire and you can see the difference with the naked eye. It's that obvious.

EXAMPLE:

The profile of 35 for instance is 35% of the width.

So let's use an 18 inch tire as an example, 225/40/18. This means the overall diameter is
40% of 225mm = 90mm.
The rim diameter is 18"x25.4mm= 457.2mm
Overall diameter of the tires are 90mm+457.2mm+90mm=637.2mm or 25.09

For F430 225/35/19
35% of 225=78.75mm
19" of rim diameter = 482.6mm
Overall diameter = 482.6mm+78.75mm+78.75mm=640.1mm or 25.2"

Anyway, the above is accurate. I'm not an expert.

If you think anything is wrong, please post and explain.

[TheMaxXHD]

Originally Posted by upstate650

Wrong again. The 35 profile of a staggered 255 19” tire has the exact same sidewall height as the 40 profile of the 225 19” front, which is why they are approved for x drive. Please know what you are talking about before professing to be an expert.

https://www.tacomaworld.com/tirecalc...0r19-255-35r19

Very similar, but not exact.

[SLGrassoPA]

Originally Posted by TheMaxXHD

https://www.tacomaworld.com/tirecalc...0r19-255-35r19

Very similar, but not exact.

Yes, correct. Similar, but definitely different. The trend, at least with higher end performance cars has been to go with less and less aspect ratio, with 20 inch tires with a 30 spec aspect are not uncommon these days. They look great, handle great, just not practical (or maybe I should say "comfortable") anywhere with less than perfect roads.

[upstate650]

Originally Posted by SLGrassoPA

Thank you for your post.

Respectfully, I don't think I'm wrong, or as you say "wrong again."

Please allow me to disabuse the notion that a 35 and 40 aspect tire have the small exact sidewall. They do not.

Stated simply, the aspect is the amount of space from the ground to the bottom of the wheel, hence a 35 has less space when compared to a 40, and a 30 has even less space.

Obviously, an 18 inch tire is 18 inches and 19 inch tire is always 19 inches. The overall height of the tire is not what is at issue.

We are talking about the sidewall aspect ratio (something that is different than the overall height of the tire- which is 17, 18, 19, 20 depending on the tire.etc...)

The aspect ratio is the “height” of the sidewall, expressed as a percentage of the section width. In other words, a 35 will always have less rubber between the ground and the wheel when compared to a 40, and even more so when compared to a 45. Just look at a 35, 40 and 45 spec tire and you can see the difference with the naked eye. It's that obvious.

EXAMPLE:

The profile of 35 for instance is 35% of the width.

So let's use an 18 inch tire as an example, 225/40/18. This means the overall diameter is
40% of 225mm = 90mm.
The rim diameter is 18"x25.4mm= 457.2mm
Overall diameter of the tires are 90mm+457.2mm+90mm=637.2mm or 25.09

For F430 225/35/19
35% of 225=78.75mm
19" of rim diameter = 482.6mm
Overall diameter = 482.6mm+78.75mm+78.75mm=640.1mm or 25.2"

Anyway, the above is accurate. I'm not an expert.

If you think anything is wrong, please post and explain.

Yes, technically off by 10th of an inch, or or 1/260th of the overall diameter. Sue me for my hyperbole.

You’re the one claiming the 26.1” diameter tire is acceptable, but the 26” tire is “low profile”. You’ve stated your opinion on adaptive suspension in every page on this board, and started your own thread about it. Give it a rest already.

[HighlandPete]

Originally Posted by SLGrassoPA

EXAMPLE:

The profile of 35 for instance is 35% of the width.

So let's use an 18 inch tire as an example, 225/40/18. This means the overall diameter is
40% of 225mm = 90mm.
The rim diameter is 18"x25.4mm= 457.2mm
Overall diameter of the tires are 90mm+457.2mm+90mm=637.2mm or 25.09

For F430 225/35/19
35% of 225=78.75mm
19" of rim diameter = 482.6mm
Overall diameter = 482.6mm+78.75mm+78.75mm=640.1mm or 25.2"

Anyway, the above is accurate. I'm not an expert.

If you think anything is wrong, please post and explain.

You are looking at a square set of wheels. Move to staggered and you go for a wider rear section (255) and get back to the same sidewall height.

Rim diameter is what is changing the sidewall height for BMW OE fitment.

[HighlandPete]

Originally Posted by SLGrassoPA

The trend, at least with higher end performance cars has been to go with less and less aspect ratio, with 20 inch tires with a 30 spec aspect are not uncommon these days. They look great, handle great, just not practical (or maybe I should say "comfortable") anywhere with less than perfect roads.

Now you are getting there, larger diameter rims with the lower aspect ratio, is where we get into different driving dynamics.

But the larger rim does not necessarily mean less comfort. It's the combination of rim weight, tire selection and suspension calibration.

Even in the 'RFT world' not all things are equal. There are situations where the 19" rim and tire, can be as comfortable, or even more comfortable than the 18".

[SLGrassoPA]

HighlandPete - bingo - absolutely correct. More width will, generally, increase overall size, and thus create a tire with a 35 and 40 aspect spec (percentage of selection width) being similar, although not the same. So basically, what upstate650 is saying is close to correct and he makes a good point.

It's just that in the real world, it seems that performance tires have less and less aspect spec, which generally (but not always) contributes to flats / blowouts / less ride comfort. Yes, a 19 " can possibly be more comfortable than an 18", although that's usually not the case as (it seems to me) the taller performance tires have not increased width as much as they have decreased sidewall aspect, resulting in tires that are ever increasingly close to the pavement. They look great, handle great, and make the car standout, but outside of the Autobahn or Florida or Arizona roads, how practical are they?

[HighlandPete]

Originally Posted by SLGrassoPA

Not trying to make any sweeping conclusions. Just stating my observation that the Adaptive M does absorb road imperfections very well, to the point of making the ride super comfy. However, with a staggered 19 inch summer set up (non run flat) with a 35 spec in the back, over rough roads, the adaptive would probably not make a ton of difference.

One of the problems with BMW, they typically run a high rear spring rate. That's a two edged sword, helps handling and running a loaded vehicle, but secondary ride is less comfortable. Now add large rims and a staggered set at that, and the added unsprung weight, particularly at the rear, makes it worse.

Now think 'adaptive' and run two 'base' damping modes. Let's assume BMW are currently following the previous system of the F3x models, we came to appreciate the Comfort setting was under-damped, the Sport setting over-damped, simply to work around the spring rate. What happens over broken road? Even with the adaptations within the variable damping we can get more jitter and bounce.

This is where in some conditions, passive M-Sport suspension will be better, firm but damping 'around' the spring rate.

[doublevanosrc]

Agreed, it's amazing how smooth the car drives even with run-flat tires. I have never thought about replacing the tires with OEM runflats again, but now I am considering it. The adaptive M suspension is a game changer, best thing I don't have to hear my wife bitch about bumpy ride.

Adaptive is a must!!

[tturedraider]

Originally Posted by upstate650

Wrong again. The 35 profile of a staggered 255 19” tire has the exact same sidewall height as the 40 profile of the 225 19” front, which is why they are approved for x drive. Please know what you are talking about before professing to be an expert.

Originally Posted by HighlandPete

You are looking at a square set of wheels. Move to staggered and you go for a wider rear section (255) and get back to the same sidewall height.

Rim diameter is what is changing the sidewall height for BMW OE fitment.

Bingo. These are the winners. 225/40 & 255/35 have exactly the same 3.5” tall sidewall.

[TheMaxXHD]

As far as RFTs go and comfort, I’m just chillin with my 225/45r18 square setup with adaptive suspension. Zero regrets of going with the smaller wheel size. Stiffer than my E90 (which was running 17RFTs), but not by much.

[Montaver]

Tire pressure also has a very significant affect on ride quality, the door suggestions are generally on the high side.

[HighlandPete]

Originally Posted by SLGrassoPA

They look great, handle great, and make the car standout, but outside of the Autobahn or Florida or Arizona roads, how practical are they?

I read a lot, discussed with BMW guys, and spend a lot of seat time in F10/11 models, to try and understand the dynamics of the different setups, and wheel performance, before I got my F11 back in 2012.

Passive M-sport (704) was just too firm for my typical driving and the roads I use. I tried different wheel sizes on the F10 with the base suspension. Different ride quality for sure. I didn't try 20" as my dealer had tried and removed them, because the chassis was ruined on anything but smooth surfaces.

I tried an F10 with Adaptive Drive on a 19" staggered set. VDC was going to be the answer, particularly as the F10/11 has 'three' base settings, the middle setting working perfectly around the spring rate for best adaptive damping. The F10 rear spring rate is, IMO, a bit too high, and that resulted in a bit more 'pitter-patter' from the road, than I expected. Sport setting meant it would fidget a bit on poor surfaces.

I was wanting an F11 wagon, so put together the spec', I understood would work best. I gained info' that the F10/11 was optimised on 18" wheels for Adaptive Drive. I didn't want staggered, as the rear wheels would be heavier and cause more rear jitter and interference. As the wagon has rear air springs, I'd not have a higher than needed spring rate. Air springs are a variable rate (due to self levelling) adjust according to the load in the car. With the feeling, "Got it... would it work?"

Absolutely, the best riding and handling F10/11 setup I'd driven. Just what I was after. I drive most of the time in the middle, 'Normal' mode. The chassis and ride is so balanced in the Normal adaptive mode. Use Sport when driving some of the better driving roads and it is a very composed and compliant ride, even on the RFTs.

I know I could possibly improve the comfort a bit with non run-flats, but using a 17" RFT in winter, I know the chassis softens on the 17". I sense with summer non run-flats, I'd be in Sport mode all the time to firm the chassis a bit. Or need to go up to a 19".

I went through the changes of tires and suspension in my E91 wagon, back in 2007, when RFTs were really "night and day" different to the typical UHP tire. Removing the RFTs, gave more comfort, but I had to change (improve) the damping, as it was too soft and handling wasn't good enough.

RFTs are different today, than back in the early E60/E90 days. But we seem to be more obsessed with bigger rims these days and lower profile tires. Scoring a home goal, IMO.

[HighlandPete]

Originally Posted by TheMaxXHD

As far as RFTs go and comfort, I’m just chillin with my 225/45r18 square setup with adaptive suspension. Zero regrets of going with the smaller wheel size. Stiffer than my E90 (which was running 17RFTs), but not by much.

I bought the same RFT again as a replacement, no regrets, felt like a softer tire.

My experience over many years with BMW, don't go low.

Here in the UK we have two load recommendations, a lower average load setting and a loaded setting. I find I need to be somewhere in between, for normal use. If we run RFTs, they need to be at the optimum setting to stop road interference and give the best ride. Too low and they will tram-line, a sign they are riding on the sidewalls.

Oops! wrong quote: Correct one below.

Originally Posted by Montaver

Tire pressure also has a very significant affect on ride quality, the door suggestions are generally on the high side.

[madpistol]

I had an M340i w/ non-adaptive. Now I have an M440i GC w/ adaptive. Both have run-flats. Here's my opinion.

GET THE ADAPTIVE SUSPENSION!!!!



Now to elaborate.

Had 18" 225 section wheels on M340i. The suspension was firm but not punishing. I could daily it, but I always wanted something more comfortable.

My M440i GC has the 19's w/ 245 front, 255 rear. With the adaptive suspension, it's night and day. Sport setting on the suspension feels about the same as the M340i. Comfort setting on the suspension feels sublime. The car is so comfortable and high-speed stable that I couldn't imagine a better suspension on a car at this price point. Obviously there are lots of cars out there with more cushy suspension setups, but the thing that really makes the M Adaptive Suspension so good is that you still feel fairly flat in corners. You go into a corner with a Camry, and the suspension rolls... not so in an M340i/M440i w/ adaptive suspension.

Best of both worlds. Get the adaptive suspension.

[rmedina]

Coming from a vette I'm good with the standard suspension. It is what it is.

[zazzau]

Originally Posted by madpistol

I had an M340i w/ non-adaptive. Now I have an M440i GC w/ adaptive. Both have run-flats. Here's my opinion.

GET THE ADAPTIVE SUSPENSION!!!!



Now to elaborate.

Had 18" 225 section wheels on M340i. The suspension was firm but not punishing. I could daily it, but I always wanted something more comfortable.

My M440i GC has the 19's w/ 245 front, 255 rear. With the adaptive suspension, it's night and day. Sport setting on the suspension feels about the same as the M340i. Comfort setting on the suspension feels sublime. The car is so comfortable and high-speed stable that I couldn't imagine a better suspension on a car at this price point. Obviously there are lots of cars out there with more cushy suspension setups, but the thing that really makes the M Adaptive Suspension so good is that you still feel fairly flat in corners. You go into a corner with a Camry, and the suspension rolls... not so in an M340i/M440i w/ adaptive suspension.

Best of both worlds. Get the adaptive suspension.

This thread is about G20 — and it goes back to my earlier point of apples to apples comparison. Experiences will vary widely across different chassis, wheel and tire size. So the conversation is only relevant where you have a baseline for like-kind comparisons.
I have driven a 5 series with Adaptive and sure it feels complaint but then the same experience doesn’t translate on my M340 staggered 19”.
So it’s all a matter of what you’re comparing with. Now that you know how it rides on M440i GC maybe try driving an M340i with the same EXACT setup.

[madpistol]

Originally Posted by zazzau

This thread is about G20 — and it goes back to my earlier point of apples to apples comparison. Experiences will vary widely across different chassis, wheel and tire size. So the conversation is only relevant where you have a baseline for like-kind comparisons.
I have driven a 5 series with Adaptive and sure it feels complaint but then the same experience doesn’t translate on my M340 staggered 19”.
So it’s all a matter of what you’re comparing with. Now that you know how it rides on M440i GC maybe try driving an M340i with the same EXACT setup.

You must have missed this part of my post.

Originally Posted by madpistol

Had 18" 225 section wheels on M340i. The suspension was firm but not punishing. I could daily it, but I always wanted something more comfortable.

Thus, my resounding recommendation to get the adaptive suspension. Believe it or not, I had 1+ year of experience with a G20 as my daily driver, so contrary to your belief, I do know what I'm talking about... and I would appreciate it if you accept my input at face value instead of questioning as to whether I'm qualified to share my experience.

[zazzau]

Originally Posted by madpistol

Thus, my resounding recommendation to get the adaptive suspension. Believe it or not, I had 1+ year of experience with a G20 as my daily driver, so contrary to your belief, I do know what I'm talking about.

I didn’t misread your comment. My point is you’re comparing a G20 with a completely different setup to M440i GC with a different wheel size.
I also never alluded in my comment that you don’t know what you’re talking about. I’m not doubting your experience; I’m just saying that these experiences are not the same across the board. There are other factors at play here. I’ve tested another exact G20 at the dealership with the same configuration as mine and the experience is the same. Story is completely different on a 5 series.

[madpistol]

Originally Posted by zazzau

I didn’t misread your comment. My point is you’re comparing a G20 with a completely different setup to M440i GC with a different wheel size.

And I'm also saying that the stock M sport non-adaptive suspension that I had on my M340i is too harsh, and that the adaptive suspension would fix that. This is easy to infer from my original message.

[zazzau]

Originally Posted by zazzau

I didn’t misread your comment. My point is you’re comparing a G20 with a completely different setup to M440i GC with a different wheel size.

Originally Posted by madpistol

And I'm also saying that the stock M sport non-adaptive suspension that I had on my M340i is too harsh, and that the adaptive suspension would fix that. This is easy to infer from my original message.

Go drive a G20 M340i with Adaptive and same staggered config and wheel size as your M440i GC before making that statement. I’m not doubting the experience on the M440i.