A6 C6 - downsizing to 18" OEM wheels - use 245/45 R18 tires
05-21-2015, 11:09 AM
#1
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A6 C6 - downsizing to 18" OEM wheels - use 245/45 R18 tires
Hi Guys
My question is regarding 2009 Audi A6 3.2L Quattro (it’s 2009 but production of 2008 so it’s the pre-facelift) with factory installed 255/35R19 tires and 8.5jx19 ET48 wheels. The car also has option 1BE which is the sport suspension.
I just bought the car last week and I must change the tires because they are in terrible condition. The original owner said he had difficulty finding this tire size and upon searching at the main traders, I also didn’t find it. I also think the wheels might have some defects because there is vibration and noise above 100 km/h. Roads here also have many pot holes or horizontal lines so the ride isn’t really nice with such a heavy car and low profile tires. I am currently driving an A4 B8 with standard suspension ad 225/55R16 tires and to be honest I don’t feel the “comfort” of the A6 at all !
For that, I will buy new 18” wheels as the 18” tires is commonly available here for BMW and Mercedes Sedans. My current wheel is 4f0601025BA with ET48. I bought the wheel 4F0601025AL (which is 8.5j ET46).
The tire size available widely here is 245x45 R18, because it is used on the 5-series. The car catalog indicates that at 18”, the tire size is 245x40 or 255x40. I made some calculations and came up with the following :-
The outer tire diameter of my 255x35R19 : 661.1mm
The outer tire diameter incase of 245x40R18 : 653.2mm (less) - not available
The outer tire diameter incase of 255x40R18 : 661.2mm (exact match) - not available
The outer tire diameter incase of 245x45R18 : 677.7mm (little more) - available easily
My questions are :-
A- Has anyone tried the 245x45R18? Would it fit? Do you have pictures?
B- Is there a concern about rubbing? The addition in diameter is 677.7 – 661.1 = 16.6mm
C- Will I be at risk to damage anything in the suspension or struts by using such a profile (45)? since I am changing the "unsprung mass"
D- What are the differences between the sport suspension and the standard one? Because I am suspecting the A6 must be much more comfortable than this !!
My question is regarding 2009 Audi A6 3.2L Quattro (it’s 2009 but production of 2008 so it’s the pre-facelift) with factory installed 255/35R19 tires and 8.5jx19 ET48 wheels. The car also has option 1BE which is the sport suspension.
I just bought the car last week and I must change the tires because they are in terrible condition. The original owner said he had difficulty finding this tire size and upon searching at the main traders, I also didn’t find it. I also think the wheels might have some defects because there is vibration and noise above 100 km/h. Roads here also have many pot holes or horizontal lines so the ride isn’t really nice with such a heavy car and low profile tires. I am currently driving an A4 B8 with standard suspension ad 225/55R16 tires and to be honest I don’t feel the “comfort” of the A6 at all !
For that, I will buy new 18” wheels as the 18” tires is commonly available here for BMW and Mercedes Sedans. My current wheel is 4f0601025BA with ET48. I bought the wheel 4F0601025AL (which is 8.5j ET46).
The tire size available widely here is 245x45 R18, because it is used on the 5-series. The car catalog indicates that at 18”, the tire size is 245x40 or 255x40. I made some calculations and came up with the following :-
The outer tire diameter of my 255x35R19 : 661.1mm
The outer tire diameter incase of 245x40R18 : 653.2mm (less) - not available
The outer tire diameter incase of 255x40R18 : 661.2mm (exact match) - not available
The outer tire diameter incase of 245x45R18 : 677.7mm (little more) - available easily
My questions are :-
A- Has anyone tried the 245x45R18? Would it fit? Do you have pictures?
B- Is there a concern about rubbing? The addition in diameter is 677.7 – 661.1 = 16.6mm
C- Will I be at risk to damage anything in the suspension or struts by using such a profile (45)? since I am changing the "unsprung mass"
D- What are the differences between the sport suspension and the standard one? Because I am suspecting the A6 must be much more comfortable than this !!
05-21-2015, 11:41 AM
#2
Hi Guys
My question is regarding 2009 Audi A6 3.2L Quattro (it’s 2009 but production of 2008 so it’s the pre-facelift) with factory installed 255/35R19 tires and 8.5jx19 ET48 wheels. The car also has option 1BE which is the sport suspension.
I just bought the car last week and I must change the tires because they are in terrible condition. The original owner said he had difficulty finding this tire size and upon searching at the main traders, I also didn’t find it. I also think the wheels might have some defects because there is vibration and noise above 100 km/h. Roads here also have many pot holes or horizontal lines so the ride isn’t really nice with such a heavy car and low profile tires. I am currently driving an A4 B8 with standard suspension ad 225/55R16 tires and to be honest I don’t feel the “comfort” of the A6 at all !
For that, I will buy new 18” wheels as the 18” tires is commonly available here for BMW and Mercedes Sedans. My current wheel is 4f0601025BA with ET48. I bought the wheel 4F0601025AL (which is 8.5j ET46).
The tire size available widely here is 245x45 R18, because it is used on the 5-series. The car catalog indicates that at 18”, the tire size is 245x40 or 255x40. I made some calculations and came up with the following :-
The outer tire diameter of my 255x35R19 : 661.1mm
The outer tire diameter incase of 245x40R18 : 653.2mm (less) - not available
The outer tire diameter incase of 255x40R18 : 661.2mm (exact match) - not available
The outer tire diameter incase of 245x45R18 : 677.7mm (little more) - available easily
My questions are :-
A- Has anyone tried the 245x45R18? Would it fit? Do you have pictures?
B- Is there a concern about rubbing? The addition in diameter is 677.7 – 661.1 = 16.6mm
C- Will I be at risk to damage anything in the suspension or struts by using such a profile (45)? since I am changing the "unsprung mass"
D- What are the differences between the sport suspension and the standard one? Because I am suspecting the A6 must be much more comfortable than this !!
My question is regarding 2009 Audi A6 3.2L Quattro (it’s 2009 but production of 2008 so it’s the pre-facelift) with factory installed 255/35R19 tires and 8.5jx19 ET48 wheels. The car also has option 1BE which is the sport suspension.
I just bought the car last week and I must change the tires because they are in terrible condition. The original owner said he had difficulty finding this tire size and upon searching at the main traders, I also didn’t find it. I also think the wheels might have some defects because there is vibration and noise above 100 km/h. Roads here also have many pot holes or horizontal lines so the ride isn’t really nice with such a heavy car and low profile tires. I am currently driving an A4 B8 with standard suspension ad 225/55R16 tires and to be honest I don’t feel the “comfort” of the A6 at all !
For that, I will buy new 18” wheels as the 18” tires is commonly available here for BMW and Mercedes Sedans. My current wheel is 4f0601025BA with ET48. I bought the wheel 4F0601025AL (which is 8.5j ET46).
The tire size available widely here is 245x45 R18, because it is used on the 5-series. The car catalog indicates that at 18”, the tire size is 245x40 or 255x40. I made some calculations and came up with the following :-
The outer tire diameter of my 255x35R19 : 661.1mm
The outer tire diameter incase of 245x40R18 : 653.2mm (less) - not available
The outer tire diameter incase of 255x40R18 : 661.2mm (exact match) - not available
The outer tire diameter incase of 245x45R18 : 677.7mm (little more) - available easily
My questions are :-
A- Has anyone tried the 245x45R18? Would it fit? Do you have pictures?
B- Is there a concern about rubbing? The addition in diameter is 677.7 – 661.1 = 16.6mm
C- Will I be at risk to damage anything in the suspension or struts by using such a profile (45)? since I am changing the "unsprung mass"
D- What are the differences between the sport suspension and the standard one? Because I am suspecting the A6 must be much more comfortable than this !!
A - they will fit just fine, they will be slightly larger, but will fit in the wheel well fine
B - no issue with rubbing since your offset is 46mm, there are people running far more aggressive offset (i.e. ET29) and are doing fine.
C - nope...the main issue you want to be aware of is that your tires are actually rated for the weight of the vehicle
D - the sport suspension sits slightly lower than regular, by 20mm.
BTW, noticed that you had already asked the very same question a few days ago here: A6 C6 - downsizing to 18" OEM wheels - use 245/45 R18 tires
05-21-2015, 11:41 AM
#3
AudiWorld Super User
I don't know about the rubbing and clearance issues. That could be an expensive experiment if you guess wrong.
I'm in the USA and I believe the 18" tire would be a 245/40-18 with a 97Y (or H) XL rating. That's what my Owner's Manual shows.
I hope you are not disappointed with the lack of improvement in ride quality. Our '06 estate is the firmest riding (harshest over poor surfaces) car I've experienced in a long while. Our road surfaces are very poor and we have the original 17" wheels.
I'm in the USA and I believe the 18" tire would be a 245/40-18 with a 97Y (or H) XL rating. That's what my Owner's Manual shows.
I hope you are not disappointed with the lack of improvement in ride quality. Our '06 estate is the firmest riding (harshest over poor surfaces) car I've experienced in a long while. Our road surfaces are very poor and we have the original 17" wheels.
05-21-2015, 11:55 AM
#4
feel free to use the following to figure out details regarding differences in tires sizes and how it'll impact your speedo and odometer: https://www.tacomaworld.com/tirecalc
05-21-2015, 11:58 AM
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Dear uberwgn, thanks for that. I guess I will get even worse ride because I have lowered suspension?
Dear raj99, thanks for your answer, yes I did and still concerted.
My question about rubbing isn't "horizontally", I am afraid tub vertically? because the O.D. of the tyre has increased. what's your say on that?
Strange thing is that in the catalog, Audi says 255/40R18 (only for S6), and the wheel I am getting when you look at its description it says (for 10 cyl only).
Do you think wheel/tyre size has any relations with the shockabsorber or the suspension (for that, they only include it on the S6)? DoesAudi consider any relations between wheels and suspension when they build a caror you can change the wheel of your car like you want? (because I see on thespecs that they say this wheel is “ONLY FOR 10 CYLINDER”, and some times itsays “ONLY FOR WINTER”).<o
></o>
Dear raj99, thanks for your answer, yes I did and still concerted.
My question about rubbing isn't "horizontally", I am afraid tub vertically? because the O.D. of the tyre has increased. what's your say on that?
Strange thing is that in the catalog, Audi says 255/40R18 (only for S6), and the wheel I am getting when you look at its description it says (for 10 cyl only).
Do you think wheel/tyre size has any relations with the shockabsorber or the suspension (for that, they only include it on the S6)? DoesAudi consider any relations between wheels and suspension when they build a caror you can change the wheel of your car like you want? (because I see on thespecs that they say this wheel is “ONLY FOR 10 CYLINDER”, and some times itsays “ONLY FOR WINTER”).<o
></o>
05-21-2015, 12:27 PM
#6
Dear uberwgn, thanks for that. I guess I will get even worse ride because I have lowered suspension?
Dear raj99, thanks for your answer, yes I did and still concerted.
My question about rubbing isn't "horizontally", I am afraid tub vertically? because the O.D. of the tyre has increased. what's your say on that?
Strange thing is that in the catalog, Audi says 255/40R18 (only for S6), and the wheel I am getting when you look at its description it says (for 10 cyl only).
Do you think wheel/tyre size has any relations with the shockabsorber or the suspension (for that, they only include it on the S6)? DoesAudi consider any relations between wheels and suspension when they build a caror you can change the wheel of your car like you want? (because I see on thespecs that they say this wheel is “ONLY FOR 10 CYLINDER”, and some times itsays “ONLY FOR WINTER”).<o></o>
Dear raj99, thanks for your answer, yes I did and still concerted.
My question about rubbing isn't "horizontally", I am afraid tub vertically? because the O.D. of the tyre has increased. what's your say on that?
Strange thing is that in the catalog, Audi says 255/40R18 (only for S6), and the wheel I am getting when you look at its description it says (for 10 cyl only).
Do you think wheel/tyre size has any relations with the shockabsorber or the suspension (for that, they only include it on the S6)? DoesAudi consider any relations between wheels and suspension when they build a caror you can change the wheel of your car like you want? (because I see on thespecs that they say this wheel is “ONLY FOR 10 CYLINDER”, and some times itsays “ONLY FOR WINTER”).<o
></o>That will fit just fine within your wheel well and there are people who've done EXACTLY what you are thinking of doing see the following and leverage the SEARCH function:
https://www.audiworld.com/forums/a6-...5-18s-2607442/
Audi is a manufacturer and wants to limit risk and mitigate and issues with litigation...all manufactures create tolerances with offset and with wheel well clearances. That is why typical C6 wheels are ET45, but on your own you can go more than ET30! Audi doesn't want to 'push' things and they leave such tolerances 'vertically' as well. Good luck and welcome to the forum.
05-21-2015, 12:46 PM
#7
AudiWorld Senior Member
I'm running stock 245/40-18 xl load here in Sweden Europe.. My car is also a 3.2l with sport chassie.. No Problem 👍.. Even the roads are awful where I live..
Cheers /H
Cheers /H
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