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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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