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Discussion Starter #1
It's really hard to find any real information about R8 staggered setups online.

From what I have found it looks like some people are concerned about potential strain on the viscous coupling - Is there any real evidence of this?

I've also read that even the potential impact on the viscous coupling can be mitigated as long as you keep within a 3% front-rear diameter ratio.

So all in all I'm after a bit of help. I'm looking for a new set of wheels and after all my deliberation, my wants are as follows:

  • 9" wide fronts, 12" wide rears - Really not happy with how my stocks don't fill the arches and I'm heading for an aggressive street LMS spec for my R8.
  • square side-wall tyres, preferably michelins
  • I've got my heart set on a set of Oz Superforgiatas for the LMS style
Which brings me to my conundrum. Oz 12" rears are only available in 20" on a 5x112 PCD. Now the easy option is to go 20" on the front but this wouldn't be very LMS! ha so before I take that easy way out I wanted to explore running 19's up front as I've always love the look of a staggered setup and you can't ignore that all F1 cars and I believe even the R8 LMS cars run larger diamters rears than fronts. So here's where I've got to:

My stock setup is:

Rim fronts: 8.5JJx19 ET42 Tyre: 245/35 Sidewall Height: 85.75mm Total diameter front: 654.1mm
Rim rears: 11JJx19 ET50 Tyre: 295/30 Sidewall Height: 88.50mm Total diameter front: 659.6mm
Front-rear diameter ratio: 0.991 (-0.9%)

Where I've got to with a potential Oz staggered setup:

Rim fronts: 9JJx19 ET40 Tyre: 245/35 Sidewall Height: 85.75mm Total diameter front: 654.1mm ET change: Gives me an extra 8.5mm width on the outside and 4mm on the inside
Rim rears: 12JJx20 ET41 Tyre: 325/25 Sidewall Height: 81.25mm Total diameter front: 670.5mm ET change: Gives me an extra 21mm width on the outside & 4mm on the inside
Front-rear diameter ratio: 0.975 (-2.5%)

So I've come to the conclusion that this proposed setup should not be a problem for the car. One of the official recommended stock setups is 235/35/19F & 305/30/19R which is 647.1mm F Diameter and 665.6mm R Diameter which is a Front-rear diameter ratio of 0.972 (-2.8%), which is more extreme than what I'm proposing above.

Unless, I'm missing something ha which I'm sure I am! If anyone has any experience or advice in this area then please let me know.

Oh and I also don't think the ET changes above would result in any rubbing do you guys agree?
 

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Your figures seem about right. I'm running the official setup that you use at the end (235/305) which as you say is about 2.8%. the 3% rule seems to be generally accepted as the max offset, so your 2.5% should be fine on that basis. Can't say about rubbing but from what I've read it would seem to be ok. There are a fair few that have changed to 20" all round and I think 325/25 has been used successfully.
 

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Hey brother. I would change on your new set up a 245/30/20. Because oem is a 35 profile with a 235 and 19 inch rim, bring down the profile to 30 since the wheel will now be a 20 instead of an oem 19 and you will be at 245 as well.
 

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Hey brother. I would change on your new set up a 245/30/20. Because oem is a 35 profile with a 235 and 19 inch rim, bring down the profile to 30 since the wheel will now be a 20 instead of an oem 19 and you will be at 245 as well.
He doesn't want 20" fronts he wants a staggered set up.
 

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I run staggered size 19” front and 20” rear.
They run basically stock diameters. So front is 235/35/19 and rear 305/25/20. Drives spot on and there is absolutely no issue, as you would expect given they are the right diameter. I think it’s the ideal setup IMHO as you get the “fill” of the rear arches with the 20s but the drive ability of the 19s on the front.

 

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Double Staggered look sgreat. You get the same "Tire Sidewall Size" visually. Otherwise, the rear sidewall looks taller than the front sidewall.
 

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I run staggered size 19” front and 20” rear.
They run basically stock diameters. So front is 235/35/19 and rear 305/25/20. Drives spot on and there is absolutely no issue, as you would expect given they are the right diameter. I think it’s the ideal setup IMHO as you get the “fill” of the rear arches with the 20s but the drive ability of the 19s on the front.

Is that rear 305/25 really agood setup? Ive heard having only 25 in height is to low making the wall of the tyres to weak. I know that normally when increasing the rims from 19" to 20" its normal to lower, Im just wondering if 25 in height is abit to low..?

If going 20" and choosing 245/30 & 295/30 will the % change be to big?

The gen2 20" is 245/30 & 305/30

You feeling any issues with only 305/25? You tested tracking it?
 

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Most people running 20” wheels on a MK1 r8 will have 25 profile rear tyres. I would imagine if 25 profile tyres were “too weak” the likes of Dunlop, pirelli, continental, Michelin etc would not sell them.
Bear in mind it’s a percentage of the width, so 25% of a 305 tyre is the same as say 30% of a 255 tyre
I run mine daily and will be tracking it soon with every confidence in the tyres.
I did run 30 profile on the rear, but then you have to run 40 profile on the front to match rolling diameters, which for me was too much tyre.

Jay
 

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The setup above looks "off" to my eyes. Sidewall on the front looks larger than the rear, which throws me seeing more rubber up front.

If going for an LMS look, I'd expect to see something more like the following pics with fatter rubber / sidewalls on the rear.

248092


248093


248094
 

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Most people running 20” wheels on a MK1 r8 will have 25 profile rear tyres. I would imagine if 25 profile tyres were “too weak” the likes of Dunlop, pirelli, continental, Michelin etc would not sell them.
Bear in mind it’s a percentage of the width, so 25% of a 305 tyre is the same as say 30% of a 255 tyre
I run mine daily and will be tracking it soon with every confidence in the tyres.
I did run 30 profile on the rear, but then you have to run 40 profile on the front to match rolling diameters, which for me was too much tyre.

Jay
No if going 30 profile on the rear, for a gen1, you would normally need to go profile 35 in the front, not 40.
 

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Discussion Starter #13
After doing more research I've found some more official stock setups which have an even more extreme F/R ratio:

245/35ZR19
295/35ZR19
which equals a total F/R difference ratio of 5%

245/30ZR20
305/30ZR20
which equals a total F/R difference ratio of 5.2%

I found these on: Audi R8 2013 - Wheel & Tire Sizes, PCD, Offset and Rims specs if you look under the European V10+

So for these to be stock settings, these must even be within a good tolerance for the differential. So I'd assume even going 6-7% is okay.

So where does this 2-3.3% come from that everyone suggests is the 'limit'? Or is this the limit for if your front diameters are bigger? Cos I notice that all the stock setups have larger rear diameters (which is what I would personally always go for).

Have audi ever published any official information about the quattro differential and its limits and sweet spots?
 

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I find it a bit odd that those sizes would be offered in Europe but no where else in the world. It might be wrong info. They also don't even show the standard fitments. I've never seen the rears offered in anything other than 30 profile, or the fronts in anything other than 35 profile. All official Audi literature (and most other sites) that I've seen, only offer 235/245-35 & 295/305-30 as options. All combinations of which fall within 3%.
I guess Ricky @ REPerformance might know official options and suggest other options.
The thing with the % difference front and rear is that a bigger change is not going to suddenly cause your diffs to explode, it's just going to increase wear and tear over time.
 

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I'm not sure that website really counts as a guide for 'official stock setups'. I'd be super wary of information like this found on the internet; not saying it's definitely wrong, but their disclaimer doesn't fill me with confidence. For something like this I'd be wanting manufacturer clarification or at least a reputable third party.
"This guide is accurate and is updated on a daily basis.
No warranties or guarantees are expressed or implied as to the accuracy of the information provided on this site."
 

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Zivtins those number are wrong and people are miss reading things.

Stock setup is 235/35/19 and 295/30/19
Note that’s 19” both front and rear.
Note that’s 35 profile on the front 30 profile on the rear.

If you run a 20” on the rear that needs to drop to 25 profile. Front stays the same

So to get stock circumferences with a staggered setup you need

Front -235/35/19
Rear - 305/25/20

Simple
 

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No if going 30 profile on the rear, for a gen1, you would normally need to go profile 35 in the front, not 40.
You are misreading this I think as we are talking staggered sizes 19/20.
I am right that If you went for a 30 profile on the rear on a 20” wheel (not a 19) you would need a 40 profile on the front on a 19” wheel to match.
 

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Discussion Starter #18
Yeah you're right @g60renshaw it is simple! Although my picky needs are what's making me explore more avenues as I wanted thicker rubber on the rear and seeing if there's any way I can do that in addition to having 19 fronts and 20 rears! ha

But it sounds like the 3% rule is pretty solid, and having a 20 rear with 19 front pretty much already uses up all that 3% difference (and a bit!) so doing this forces you to have thinner rubber on the rear.

All in all I either accept the thinner rubber on the rear or look for an alternative to the Oz wheels. I'm leaning more towards the latter. Thanks for your help guys!
 

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Yeah you're right @g60renshaw it is simple! Although my picky needs are what's making me explore more avenues as I wanted thicker rubber on the rear and seeing if there's any way I can do that in addition to having 19 fronts and 20 rears! ha

But it sounds like the 3% rule is pretty solid, and having a 20 rear with 19 front pretty much already uses up all that 3% difference (and a bit!) so doing this forces you to have thinner rubber on the rear.

All in all I either accept the thinner rubber on the rear or look for an alternative to the Oz wheels. I'm leaning more towards the latter. Thanks for your help guys!
I know you are wanting the Superforgiatas. These are the specs I’m running on mine and how they look. I decided to stay with 19” to make sure I cleared the CCB’s I’m putting on. You might get away with 18s if you want more rubber.

Not sure you really need the staggered setup. I’m with ez. Doesn’t look right with sidewall difference to my eyes at least.

My specs are:

OZ Racing Superforgiata wheels (black painted/silver lettering/CF
OZ Racing center caps)
19x9 ET29 (front) / 19x11 ET45 (rear)

Michelin Pilot Sport 4S tires
Front: 235/35 ZR19 (91Y) XL
Rear: 305/30 ZR19 (102Y) XL

Haven’t done spacers yet, but plan to.



249131


249132
 

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Discussion Starter #20
@ThunderDent Nice one cheers man! They do look so mega! My original problem I gave myself was wanting 12" rears! But OZ only do 12" rears in 20 rims, not 19! Hence why I started exploring the staggered setup.
All in all I think Ima stick with a non-staggered setup in the end, I prefer the thicker rubber look on the rears like yours and all the LMS cars!
Which leaves me with the beautiful Oz superforgiatas! But I'm also looking at some 18" options as this would really give me the look I want. Obviously depends if that's even possible with the CCB's!
 
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