Airmatic and alternate tire size
05-04-2017, 08:41 PM
#1
Member
Thread Starter
Airmatic and alternate tire size
It's new tire time for my 2012 S550 4Matic. The OEM size is 255/45/18. According to https://tiresize.com/tiresizes/255-45R18.htm size 285/40/18 is equivalent. I speculate the following impact:
1. MPG will go down. Can probably mitigate to some extent by running them a couple / few PSI higher.
2. Appearance will improve (IMO), riding a tad lower and with a fake-ish perception of a wider stance due to the wider treads.
3. Ride. This is where I get stuck. Although undoubtedly comfortable AND responsive to "spirited driving" (to be PC), I do find it quite balloony and bouncy in slow-to-normal speeds. On the alternate size, I anticipate the ride to get tighter due to the lower profile and even more so due to the higher PSI but I do not have the experience to factor in the airmatic compensation. I can hope that the car will only be more firm but I am not willing to risk it resembling an empty van. So what else is there to do but turn to the community?
Of course, thanks in advance.
PS For those who wonder, my tire of choice - if not THE tire of choice - is the ExtremeContact DWS 06. Had it on a A6 Quattro and could not find a fault, no matter the conditions.
1. MPG will go down. Can probably mitigate to some extent by running them a couple / few PSI higher.
2. Appearance will improve (IMO), riding a tad lower and with a fake-ish perception of a wider stance due to the wider treads.
3. Ride. This is where I get stuck. Although undoubtedly comfortable AND responsive to "spirited driving" (to be PC), I do find it quite balloony and bouncy in slow-to-normal speeds. On the alternate size, I anticipate the ride to get tighter due to the lower profile and even more so due to the higher PSI but I do not have the experience to factor in the airmatic compensation. I can hope that the car will only be more firm but I am not willing to risk it resembling an empty van. So what else is there to do but turn to the community?
Of course, thanks in advance.
PS For those who wonder, my tire of choice - if not THE tire of choice - is the ExtremeContact DWS 06. Had it on a A6 Quattro and could not find a fault, no matter the conditions.
05-05-2017, 02:42 PM
#2
MBWorld Fanatic!
Originally Posted by ClasseMiaMadra
It's new tire time for my 2012 S550 4Matic. The OEM size is 255/45/18. According to https://tiresize.com/tiresizes/255-45R18.htm size 285/40/18 is equivalent. I speculate the following impact:
1. MPG will go down. Can probably mitigate to some extent by running them a couple / few PSI higher.
2. Appearance will improve (IMO), riding a tad lower and with a fake-ish perception of a wider stance due to the wider treads.
3. Ride. This is where I get stuck. Although undoubtedly comfortable AND responsive to "spirited driving" (to be PC), I do find it quite balloony and bouncy in slow-to-normal speeds. On the alternate size, I anticipate the ride to get tighter due to the lower profile and even more so due to the higher PSI but I do not have the experience to factor in the airmatic compensation. I can hope that the car will only be more firm but I am not willing to risk it resembling an empty van. So what else is there to do but turn to the community?
Of course, thanks in advance.
PS For those who wonder, my tire of choice - if not THE tire of choice - is the ExtremeContact DWS 06. Had it on a A6 Quattro and could not find a fault, no matter the conditions.
1. MPG will go down. Can probably mitigate to some extent by running them a couple / few PSI higher.
2. Appearance will improve (IMO), riding a tad lower and with a fake-ish perception of a wider stance due to the wider treads.
3. Ride. This is where I get stuck. Although undoubtedly comfortable AND responsive to "spirited driving" (to be PC), I do find it quite balloony and bouncy in slow-to-normal speeds. On the alternate size, I anticipate the ride to get tighter due to the lower profile and even more so due to the higher PSI but I do not have the experience to factor in the airmatic compensation. I can hope that the car will only be more firm but I am not willing to risk it resembling an empty van. So what else is there to do but turn to the community?
Of course, thanks in advance.
PS For those who wonder, my tire of choice - if not THE tire of choice - is the ExtremeContact DWS 06. Had it on a A6 Quattro and could not find a fault, no matter the conditions.
255 *45 also = 114mm sidewall height. (Unless you count the extra 7/10ths of a mm)
They'll be equivalent in terms of rolling diameter but you're adding over an inch of width to the treadblock and the sidewalls are going to bulge like balloons on the OEM rims. Not sure how it'll handle or steer with an extra contact patch to push around, or how long the tires themselves will survive on the edges.
If you want to improve handling and firm up the ride, go to the OEM 19" (or 20") and put AirMatic in Sport. If that's not enough, go to a lower offset wheel or add spacers. If that's still not enough get a set of links and lower the car a bit.
No matter what you do the S on AirMatic is always going to be a bit of a barge. It's the trade off for the ride quality.
05-05-2017, 07:21 PM
#3
MBWorld Fanatic!
I have 20's and lowering links. Around town I tend to ride on comfort mode over all the rough roads, etc. On the freeway, I put it in sport mode for better control at speed. Still rides perfect to me, comfort is soft but when I am driving faster, sport mode firms it up nicely.
05-06-2017, 12:50 PM
#4
Member
Thread Starter
Thank you all for the valuable and informative replies. I think I will stay with the OEM size. I do want to entertain the idea of spacers though.
- Is this something as simple as fitting them in between the wheel and hub or is it a more involved process?
- Any recommendations on parts and sizes will also be helpful.
- Lastly, are there any drawbacks or caveats to using spacers?
Thank you
- Is this something as simple as fitting them in between the wheel and hub or is it a more involved process?
- Any recommendations on parts and sizes will also be helpful.
- Lastly, are there any drawbacks or caveats to using spacers?
Thank you
05-06-2017, 03:12 PM
#5
MBWorld Fanatic!
They're pretty straightforward. You select a thickness then buy new lug bolts that are longer than OEM as well. So if stock bolts are 56mm long and you add a 20mm spacer you'd want 76mm lug bolts. HR Trak Plus makes high quality spacers for MB applications.
As for negatives, they can cause vibrations. If I were you I'd want to go to at least a 19" wheel, and since I was buying wheels anyway, I'd choose a lower offset. That way I'd get the wider stance, better look and firmer handling without using spacers. 18's are undersized for the 221. Too much sidewall for such a heavy car which is why the handling is so squirrelly.
There are a ton of nice 19" replica wheels on EBay with 35mm offsets that would do the trick, for around $800 for a full set.
As for negatives, they can cause vibrations. If I were you I'd want to go to at least a 19" wheel, and since I was buying wheels anyway, I'd choose a lower offset. That way I'd get the wider stance, better look and firmer handling without using spacers. 18's are undersized for the 221. Too much sidewall for such a heavy car which is why the handling is so squirrelly.
There are a ton of nice 19" replica wheels on EBay with 35mm offsets that would do the trick, for around $800 for a full set.
Last edited by Mike5215; 05-06-2017 at 03:16 PM.
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