Thought I'd share my results since I hadn't heard of any issues like this before:

Mounted the following RE-01R's (for autoX) on the OE 18"s:
Front: 255/18 (18X8)
Rear: 265/18 (18X9)

I went with a wider front tire to dial out some of the understeer, but when the tires were mounted, the wider tire was having difficulty being seated properly (front OE tire is 235/18) and the TPMS was limiting the amount of air my tire installer could flow (more air was leaking out between the tire/rim than what he could input through the TPMS valve stem). He ended up having to remove the TPMS to get the tires to mount (a normal valve stem allowed much more air and easily allowed the tires to be mounted). He commented that this TPMS has the smallest opening by far compared to everything else he's seen and that most other TPMS would have worked w/out a problem.

*The tire installer is very experienced and works with tons of autoX and road racing guys...so he's accustomed to fitting super wider tires on narrow rims - fitting a 255 on a 8" rim isn't much of a stretch, which is why I was surprised that this occurred.


-this is for a '07 987 boxster

Interesting. I'm surprised you went with such a wide front tire. Let us know what you think of the setup.

I think you'll love the RE-01R's, I thought they were great tires.

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- Suneet


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I loved them! I did a Sat/Sun autoX event this past weekend...got 1st both days running in an indexed street tire class. I had autoX'd the boxster w/ the OE PS2's and felt that it tended to understeer while exiting some of the tighter autoX corners w/ throttle on - the bump in front tire width seemed to dial most of that out...the car feels much more neutral.

Understeer 08
Oversteer 08




*I normally run a BSP 350Z....it's been fun driving something else and seeing the difference - never thought I'd enjoy driving a boxster so much!

Your Front tyre should be maximum 245/18 with 275/18 on the rear....... Preserving the '30' rule

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Cheers Karel
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'Power is Nothing without Control..........'

I was aiming to change the handling characteristics...so I didn't want to preserve the 30mm stagger. (IIRC the guys running AS/SS in SCCA autoX run 245 or 255's R-comps on all 4 corners)

So would you also run 265/19 on the front with a 295/19 rear? (With a 9" front and 11" rear rim?)

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Current Cars:

2008 Orange - Limited Edition Boxster S
2004 Atlas Grey - Boxster S

Nick, I know you run a Boxster, but your reply defies competent logic.

The Tyres have to fit the available space, and the acknowledged best practice is as I have advised in my previous post.

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Cheers Karel
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'Power is Nothing without Control..........'

Where does this "30mm" stagger rule come from? I know that's the standard street setup on my 18"s but these cars are setup to drive with understeer on the street. On the track you want to close that gap, especially if you can't change the suspension at will. Getting a larger tire up front or softening the front end relative to the back helps tremendously. I can run a Hoosier R6 up front (225/45) and a 275/40 in back and still get nice bite and rotation control when the car is setup right. The track has a little to do with that as well. It's easier when there are low speed 90 degree corners (ie ECR). Note that the 225 R6 is wider than normal for a 255. I'm switching to the BFG R1 with 245/275 for a run at Barber in a couple of weeks and hope that will be a setup that works for me in the long run. I've run that size combo on victoracers that has worked well in the past. From what I see on the maps, there isn't a wealth of really HS turns there. A racer friend of mine has run 255/285 with no problems on a 986.

Now you have lost me.... the 9x19 and 11x19 is a well accepted size for the rims as long as the offsets are correctly calculated.

__________________
Current Cars:

2008 Orange - Limited Edition Boxster S
2004 Atlas Grey - Boxster S

Well, from what I have been told 255 is the widest you can go in the front without rubbing. So 285/255 or 295/255 is probably the best you're going to get as you go wider. As you know 305 with 11'' rears rubs unless you roll fenders; and you really wouldn't want to go that wide anyways.

Today was my first day of driving from 275/245 to 265/235... the 245/275 RE01R's look much beefier than the 235/265 Azenis RT615, and the wider rear contact patch definitely kept the rear more glued to the ground under heavy acceleration, so if your car has mods (I have AWE exhaust, EVO intake w/ desnork), I suggest running the 275/245 ratio for more control.

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- Suneet


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I am running 285/30/ZR18 rear and 245/40/ZR18 front (10 x 18 rear and 8.5 x 18 front), so this is 40 mm "stagger". Perfect handling with -2.6 camber up front, - 2.1 rear camber. No issues at all even though front diameter is 25.4" and rear is 25.0". I have been playing with pressure. Anyone else running BFG g-Force R1s who would like to share tire pressures? Mine are about 40 psi front hot and about 40.5 rear, though balanced front-rear is OK. I jhust added Tarret sway bars so this may change as I feel them out.

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Charles (arcticsilver)

MotorSport VOS, Mantis sump extension, Quaife TBD, GT3 lower control arms, PSS9s, Tarett sway bars, Softronic race plenum, Capristo exhaust, Hayden TransSaver Plus OC-1676 on power steering return line.

Yep I would agree 255 on the fronts would be pushing it too far. 235s way way easier to get the 245s