Edward

Hi all,

So I have loooong since "retired" my 993 from track events to 100% pure daily commuting, but had never bothered to have the car re-aligned in these many years (car drives 100% straight, gets reasonable tire life, and corners great, so why spend the dough, right?). But I got to thinking since I am soon coming up toward replacing all four tires, and so am wondering if it would be worth popping the considerable dough for an alignment if it would get me better tire life.

What I have now:
Camber: front -1.2/rear -1.7
Tire mileage on Kumho MX: rear approx 15k miles/front approx 30K miles ...this over three sets of these MXs.

Thinking of reducing camber to around: front -.5/ rear -1
keeping the Toe the same.

Again, the car drives great, but I do notice a considerable difference in wear from the inside vs outside of each tire, and was thinking that going more conservative on the camber would even out the tire wear a bit and get me a few more miles. Thoughts, all?

Edward

e9stibi

Your alignment is not too aggressive. I would leave it alone and consider changing it as soon as the alignment "becomes off". you already mentioned that you got decent tire life.

trophy

That is excellent wear, I would leave well enough alone..... (maybe a little less camber in the rear, )

Inside wear is more related with Toe than it is Camber, and a combination of both (lots of toe and camber) is a recipe for short tire life.

ToSi

In addition to backing off camber / toe, you could try reducing the K-toe effect by installing stiffer bushings in the rear of the lower A-arms if you wanted to dig into it a bit deeper.

Significant toe-in is designed into the rear suspension during braking:


1) base 'static' toe per side = 15' seems high. this was reduced to 5' in the 996

2) braking @ a moderate 0.5g results in approx 8' additional toe for a total of 46' (0.77 deg). This increases to >1deg during max decel & is chewing up your tires!

The trade-off is a reduction of stability, probably no worse than an early car though.

Edward

OK, so it sounds like I really should just leave well enough alone. As I had stated, my tire mileage is pretty good on those MXs (not Sportcups-sticky by a long shot, but still pretty good on the street for "spirited" commuting ), and consistent over three sets of these things. And she drives great: rock steady going straight yet dives into corners crisply and remains neutral throughout ...unless you coax it, that is! Thanks for the feedback, all!

Edward