mlawrence

I recently discovered exteme wear on the interior edge almost to the steel belts on the original Dunlop Run Flats on my '08 SC430. The dealership is telling me the the front tires (which were rotated 4000 miles ago and the car has only 9800 miles) are showing normal wear due to the fact that the "camber" (?) is intentionally misaligned to improve handling, thus the increased wear on the interior side of the front tires. This does not compute. Has anyone heard of this or understand? I'm definitely getting rid of the Run Flats. I've read all the Forum points on that issue but not the intentional misalignment.

antigeek

My service manager said the same thing to me, but I believe it was the rear wheels. I'll pull my last alignment figures -- that'll show what's considered spec.

I didn't like seeing that wear pattern myself, but be (unfortunately) assured that it's not the run-flats that are the only tires that do that.

And just to throw in my $0.02M, if you haven't decided on your next set of tires, filter the online reviews with the following information:
some positive reviews are from people who switched from run-flats.
Yes, they're better, but they may not be good for long.
In my case, the Pirelli P-Zero Neros were a good buy, had great reviews, and gave me lousy traction in very short order.

Harold57

That sounds a little fishy to me, of course I have an '02 not an '08 so that may be the difference. I got about 18k miles on the Bridgestone (R040 or R050, I can't remember) RF and I'm at about 14k+ miles on the Pirelli P-Zero M+S RF (I forget the full model name) and neither had any uneven wear.

The issues that I had were that the Bridgestones started tracking grooves in the road real bad near the end of their lives and the Pirellis just started making a bunch of road noise (service guys said that is because the tread has started cupping).

JohnnyCake

Since you put a question mark by camber, let's start there. Camber is tilt of the tire when viewed from the front. Zero or neutral camber means that the wheel is perpendicular to the ground. On a flat and straight road, that's great. But most roads are not flat and straight. They are arched to permit water run-off and, of course, have turns.

Accordingly, most manufacturers design cars to have "positive" camber (we talking less than one degree), meaning that the top of the wheel is tilted outward from the car and the bottom of the wheel slopes in, permitting better contact with the sloped road. However, the weight and springing of the car usually counteracts positive camber so that the tires actually run level.

But slight negative camber helps cornering. When you go around a corner, have you noticed how the car rolls to the outside? The tires do also. Slight negative camber permits better contact with the road during turns for the outside tire. The outside tire is the one which carries more load during turns. So for best cornering, negative camber is placed on all four wheels, even though the negative camber will reduce grip on the inside wheel, relative to neutral.

I come from a NASCAR background. With the exception of road courses, tracks involve all left turns. So if you decide to enter your SC in the Daytona 500, you'd want to set positive camber for the driver's side wheels and negative camber for the passenger's side wheels. No compromise is necessary since there are no right hand turns.

Proper camber is so slight that I doubt you'd really show a huge difference in tire wear.

Anyway, this is my rudementary understanding of camber, fwiw. I could be wrong but that is how I learned it.

Habious

I had the same issue with my front tires (Dunlop 5000 RFT's). They wore out in only about 10K miles (insides of the fronts wore out).

I replaced all 4 with Michelin Pilot A/S; I'm at around 30K miles on those, and they still have tread left.

If you do a search on the SC430 forum for "camber kit" (including the quotes), you'll find several threads talking about some kind of solution for this.

The most promising appears to be this thread right here - Post #4 has a picture of the worn front-tire that probably looks very familiar.

antigeek

Crap. From Johnny's info (and thx for that, BTW), it believe my service manager was referring to toe. That would explain inner tire wear as well.

Below are my specs from last November, and the spec range of each.
I'll leave their definition and significance to the experts.
(all numbers in degrees - apologies for the format)


FRONT LEFT / RIGHT / SPEC RANGE
Camber -0.5 / -0.6 / -1.3 to 0.2
Caster 7.8 / 7.9 / 7.2 to 8.7
Toe 0.07 / 0.06 / -0.03 to 0.18
SAI 9.0 / 9.5 / 8.4 to 9.9
Included Angle 8.5 / 8.8 / 7.1 to 10.1

FRONT ACTUAL / SPEC RANGE
Cross Camber 0.1 / -0.5 to 0.5
Cross Caster -0.1 / -0.5 to 0.5
Cross SAI -0.5 / -0.5 to 0.5
Total Toe 0.14 / -0.05 to 0.35

REAR LEFT / RIGHT / SPEC RANGE
Camber -1.6 / -1.5 / -1.7 to -0.7
Toe 0.07 / 0.08 / -0.03 to 0.17

REAR ACTUAL / SPEC RANGE
Cross Camber -0.1 / -0.5 to 0.5
Total Toe 0.15 / -0.07 to 0.33
Thrust Angle 0.00 / no spec (probably 0)