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-   D3 - Wheels and Tyres (https://forum.a8parts.co.uk/forumdisplay.php?f=51)
-   -   21" Alloys on Staggerd Fitment. Will they work? (https://forum.a8parts.co.uk/showthread.php?t=10720)

LordHefner 25th October 2015 04:30 AM

21" Alloys on Staggerd Fitment. Will they work?
 
Hi Guys,

Well the old girl is going in for a new coat at the beginning of the week after next and thought she would like some new shoes to go with her new look to make her look fantastic. :love:

What I have found are:-
Fronts:- 21" x 8.5J with 255/30/21
Rears:- 21" x 10J with 295/30/21

My Audi's an A8 D3 Quattro Sport and would love to have these on my car as thing it would just make it awesome so first of will they fit, and secondly will it full lock and then finally can I move it without upsetting the Quattro system?

I assume that the tyre rolling circumferences on the fronts and the rears must be somewhere close, but does anyone have a means of finding out whether they are matching each other and also how close these are to my current 18's that I have fitted on my A8 at the moment (factory wheels)

Regards,

Mark.

Architex_mA8tey 25th October 2015 05:29 AM

Quote:

Originally Posted by LordHefner (Post 101262)
Hi Guys,

Well the old girl is going in for a new coat at the beginning of the week after next and thought she would like some new shoes to go with her new look to make her look fantastic. :love:

What I have found are:-
Fronts:- 21" x 8.5J with 255/30/21
Rears:- 21" x 10J with 295/30/21

My Audi's an A8 D3 Quattro Sport and would love to have these on my car as thing it would just make it awesome so first of will they fit, and secondly will it full lock and then finally can I move it without upsetting the Quattro system?

I assume that the tyre rolling circumferences on the fronts and the rears must be somewhere close, but does anyone have a means of finding out whether they are matching each other and also how close these are to my current 18's that I have fitted on my A8 at the moment (factory wheels)

Regards,

Mark.

Hi Mark
As you have suggested you will need to ensure that the front and rear rolling radius's are as close as possible. I run 21" staggered wheels on my D2 and the fronts are 255 30 21 on 9" wheels but the rears are 295 25 21 on 10.5 wheels and I think your rears will need to be 25 profile rather than 30 to give the same close rolling circumference. Size wise the 21's will fit ok under D3 arches but you need to check the offset to see how the wheels sit in the arches and how far they come out towards the arch +++

Architex_mA8tey 25th October 2015 05:37 AM

1 Attachment(s)
As you can see the front to rear difference is 0.81% and you are Looking for the difference to be less than 1% to make sure that you don't get quattro issues due to differing rolling circumference you would therefore need to change the back tyres to 25 profile instead of 30 to achieve this. +++

http://forum.a8parts.co.uk/attachmen...4&d=1445751414

Architex_mA8tey 25th October 2015 05:48 AM

1 Attachment(s)
This graphic shows the difference if you don't change the rear tyres to 25 profile - over 3.3% difference which would throw up quattro faults where the car is thinking that the rear and front wheels are rotating at different speeds and assume that they are slipping etc.

If you can tell me the ET on the existing wheels you have and then the ET on each of the front and rear new wheels then it will be possible to see how changing them affects how the new wheels line up in or out towards the arch

http://forum.a8parts.co.uk/attachmen...5&d=1445752067

LordHefner 26th October 2015 08:54 AM

Thanks very much for that buddy! I did think after owning a Mitsubishi Evo 9 tuned to 448 bhp that these 4wd trains are a bit temperamental and needed to some how be similar but was sure that I read on this forum of the use of the staggered fitment wheels otherwise I would of simply ignores the sales advert assuming that they were on sale for BMW's and other large Arched Merc etc...

However the 25 profile with the 30 profile, does that not look strange with the thinner tyre wall at the back? Have you got a side on image of your car that you could post up please, it would be great to see how the two different profiles look on the same car. +++

As a second option though I've managed to find just 2 alloy wheels for sale minus matching centre caps but these are 10.0J x 21" (2 of) so I could have the option of buying these and then sell off the two alloys from my set that are 8.5j's (I assume that is what the owner of the two spare alloys has done) That was I would have four alloys at 10.0J x 21" and then it's just a case of buying two more tyres in the same 295/30/21 profile so that the car is the same all around. :cool:

Would the latter set up fit the car then, the 4 units of 295/30/21's and still get full lock on the steering? :Confused:

Regards,

Mark.

ainarssems 26th October 2015 11:34 AM

Quote:

However the 25 profile with the 30 profile, does that not look strange with the thinner tyre wall at the back?
It will not look thinner.

25 and 30 are % of the width so 30 % of 255 =6.75 cm, 25% of 295 =7.375cm so it will actually be 6mm higher sidewall at the back.

HPsauce 26th October 2015 11:50 AM

Odd calculator you're using Ainars.... :tuttut:
76.5mm and 73.75mm respectively so less than 3mm in it but fronts very slightly deeper..

ainarssems 26th October 2015 12:05 PM

My bad, guess just mistyped swapping 6 and 7 other way round and then just looked back to what already typed when comparing. So yes rear will be lower sidewall but just by 2.75mm.

Architex_mA8tey 26th October 2015 01:45 PM

3 Attachment(s)
heres a side view - and as others have said, its a percentage of the width so thats why it doesnt look odd. my car also has coilovers at the front so the front is much more lowered to try and get rid of the huge arch gap you often get at the front with D2's

LordHefner 5th December 2015 08:17 PM

Right guys, the car is back from the body shop, full respray and wow is all I can say, I've had many new cars, but not seen anything quite like this before. However I've got the lowering links waiting to go on but still needing to get these 21's sorted anyone got any fresh ideas?

Regards

Mark


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