19" vs 20" alloys (UK) going from M40i to 30D

Twickers · 09-20-2018, 05:04 AM

Hello everyone,

Having previously owned and rejected an M40i, I am just about to pull the trigger on a new BMW X3 30D M Sport which comes as standard with 19" tyres in the UK.

I sadly had to reject the M40i as it suffered from serious electrical issues. One thing I did find, and I appreciate perhaps the M40i wasn't ideal for me to start off with, was that it was overly firm on our poor UK roads. It had the standard 20" alloys.

I am now getting back into an X3 but this time into a slightly less highly strung and generally softer 30D.

I am interested in upgrading to the 20" alloys purely for cosmetic reasons and wondered if you felt that the 1" jump would be felt in the cabin when it comes to more pronounced unwanted road feel through the steering wheel, increased road noise and a noticeably bumpier ride?

In general I tend to have a slight bias towards comfort but I just wondered if in between my 2 choices there was going to be much in it? I really appreciate your help.

I would be really interested in hearing of anyone who may have tried both wheel sizes.

Best wishes to you all.

BMWGuySweden · 09-20-2018, 05:19 AM

If you favour comfort I would just stick with the 19"

strike4A · 09-20-2018, 05:43 AM

Did the M40i have Adapative Suspension? Mine does and in Comfort mode the ride is perfectly acceptable. I have 20" wheels.

For the most comfortable ride with a 30d M Sport then you can option "M Sport suspension deletion" at no extra cost.

nogren · 09-20-2018, 06:20 AM

I would say stick to 19" as well. I actually specced mine with 18", since I prefer the comfort, and actually like the design of those rims as well.

/n

Twickers · 09-20-2018, 06:22 AM

Quote:

Originally Posted by strike4A

Did the M40i have Adapative Suspension? Mine does and in Comfort mode the ride is perfectly acceptable. I have 20" wheels.

For the most comfortable ride with a 30d M Sport then you can option "M Sport suspension deletion" at no extra cost.

Hi, I did have the adaptive suspension on the M40 and have optioned it again on the 30D. Having now driven both cars with the adaptive suspension there is a pretty big difference between the two. The M40, although still perfectly comfortable, has a much stiffer feel to it.

strike4A · 09-20-2018, 06:50 AM

Quote:

Originally Posted by Twickers

Hi, I did have the adaptive suspension on the M40 and have optioned it again on the 30D. Having now driven both cars with the adaptive suspension there is a pretty big difference between the two. The M40, although still perfectly comfortable, has a much stiffer feel to it.

The M40i also has a stiffer anti-roll bar which helps to minimise body roll. A diesel engine is probably more suited to a softer ride though. Should be very comfortable with your suggested setup.

M3X3Z3 · 09-20-2018, 07:27 AM

I am currently getting out of an E82 135i into a G01 X3 30d primarily because i am tired of replacing pot holed rims and tyres every year and the roads in my area just deteriorate year on year.
So I took a 30d X-Line with 20" wheels for a test drive over a pre selected route that included a 100 metre stretch of very badly deteriorated and broken road. Prior to the test I had driven the 135i through that bad section at 30 km/h and the suspsnsion and tyres "banged" through it. The G01 on the other hand lightly thudded when driven over the same bad section at 60km/h. I and my wife were both extremely impressed with the suspension damping of the G01 and how quietly and comfortably it handled the bad road on 20" wheels.
I not suggesting abusing 20" wheels on bad roads except to say that their comfort level and resilience were adequate for the bad section even to the satisfaction of my wife who has a sensitive back when it comes to bad roads.
While I also drove a 30d and a 40i with 21" rims and the comfort level was quite good, I have since ordered a 30d with 20" wheels.
I would have preferred to go with 19" wheels purely for the higher tyre profile but declined because BMW only offers them in 7.5J.
I once had a 2006 X3 30d with 235 tyres on 7.5J rims and I found the rear end somewhat leary in fast corners. My 2010 X3 30d had 255 tyres on 9J rims out back and its handling was far superior to the 2006 X3 because of the wider tyres on wider rims out back

If your focus is mainly comfort then go with 19", if you want a balance between comfort and handling then I think 20" will be a good fit. Try get a test drive on a X3 with 20" and decide for yourself.

snakehips · 09-20-2018, 05:09 PM

Have you considered speccing non-RFT 20s? Those bring other challenges but should soften things up a little.

nxa · 09-20-2018, 06:55 PM

I have a 30d M Sport and in AU the 20” and adaptive dampers are standard on that config.

It is fine and on many roads can be very smooth *BUT* I have also had a few drives on 19” and they are much smoother on badly pot holed and inconsistently repaired side roads. These are all run flats.

So there is a difference.

09-20-2018, 05:04 AM	#1
Twickers Private 44 Rep 96 Posts Drives: X5 40i on the way Join Date: Apr 2018 Location: London iTrader: (0)	19" vs 20" alloys (UK) going from M40i to 30D Hello everyone, Having previously owned and rejected an M40i, I am just about to pull the trigger on a new BMW X3 30D M Sport which comes as standard with 19" tyres in the UK. I sadly had to reject the M40i as it suffered from serious electrical issues. One thing I did find, and I appreciate perhaps the M40i wasn't ideal for me to start off with, was that it was overly firm on our poor UK roads. It had the standard 20" alloys. I am now getting back into an X3 but this time into a slightly less highly strung and generally softer 30D. I am interested in upgrading to the 20" alloys purely for cosmetic reasons and wondered if you felt that the 1" jump would be felt in the cabin when it comes to more pronounced unwanted road feel through the steering wheel, increased road noise and a noticeably bumpier ride? In general I tend to have a slight bias towards comfort but I just wondered if in between my 2 choices there was going to be much in it? I really appreciate your help. I would be really interested in hearing of anyone who may have tried both wheel sizes. Best wishes to you all. Last edited by Twickers; 09-20-2018 at 05:22 AM..
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09-20-2018, 05:19 AM	#2
BMWGuySweden First Lieutenant 192 Rep 325 Posts Drives: X3 M40i Join Date: Mar 2018 Location: Sweden iTrader: (0)	If you favour comfort I would just stick with the 19"
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09-20-2018, 05:43 AM	#3
strike4A Captain 513 Rep 914 Posts Drives: X3 M40i LCI Tanzanite Blue II Join Date: Mar 2009 Location: Bucks iTrader: (1)	Did the M40i have Adapative Suspension? Mine does and in Comfort mode the ride is perfectly acceptable. I have 20" wheels. For the most comfortable ride with a 30d M Sport then you can option "M Sport suspension deletion" at no extra cost.
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09-20-2018, 06:20 AM	#4
nogren Captain 327 Rep 967 Posts Drives: G01 30d Join Date: Jun 2013 Location: Sweden iTrader: (0)	I would say stick to 19" as well. I actually specced mine with 18", since I prefer the comfort, and actually like the design of those rims as well. /n
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09-20-2018, 07:27 AM	#7
M3X3Z3 Private 26 Rep 81 Posts Drives: X3 3.0d G01 Join Date: Nov 2008 Location: RSA iTrader: (0)	I am currently getting out of an E82 135i into a G01 X3 30d primarily because i am tired of replacing pot holed rims and tyres every year and the roads in my area just deteriorate year on year. So I took a 30d X-Line with 20" wheels for a test drive over a pre selected route that included a 100 metre stretch of very badly deteriorated and broken road. Prior to the test I had driven the 135i through that bad section at 30 km/h and the suspsnsion and tyres "banged" through it. The G01 on the other hand lightly thudded when driven over the same bad section at 60km/h. I and my wife were both extremely impressed with the suspension damping of the G01 and how quietly and comfortably it handled the bad road on 20" wheels. I not suggesting abusing 20" wheels on bad roads except to say that their comfort level and resilience were adequate for the bad section even to the satisfaction of my wife who has a sensitive back when it comes to bad roads. While I also drove a 30d and a 40i with 21" rims and the comfort level was quite good, I have since ordered a 30d with 20" wheels. I would have preferred to go with 19" wheels purely for the higher tyre profile but declined because BMW only offers them in 7.5J. I once had a 2006 X3 30d with 235 tyres on 7.5J rims and I found the rear end somewhat leary in fast corners. My 2010 X3 30d had 255 tyres on 9J rims out back and its handling was far superior to the 2006 X3 because of the wider tyres on wider rims out back If your focus is mainly comfort then go with 19", if you want a balance between comfort and handling then I think 20" will be a good fit. Try get a test drive on a X3 with 20" and decide for yourself.
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09-20-2018, 05:09 PM	#8
snakehips Private First Class 52 Rep 153 Posts Drives: M40i Join Date: Apr 2018 Location: UK iTrader: (0)	Have you considered speccing non-RFT 20s? Those bring other challenges but should soften things up a little.
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09-20-2018, 06:55 PM	#9
nxa Second Lieutenant 112 Rep 200 Posts Drives: X3 G01 30d M Sport Join Date: Feb 2018 Location: Sydney iTrader: (0) Garage List 2018 BMW X3 30d [0.00]	I have a 30d M Sport and in AU the 20” and adaptive dampers are standard on that config. It is fine and on many roads can be very smooth BUT I have also had a few drives on 19” and they are much smoother on badly pot holed and inconsistently repaired side roads. These are all run flats. So there is a difference.
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