cruiser

This Saturday I had alignment done on my FD for the upcoming trackday on Sunday.

I am running Eibachs and 17" Enkei wheels, 8x17 ET38 235/40/17 front and 9x17 ET38 255/40/17 in the rear.

EDIT: I must add that I run Bridgestone Potenza RE540 with extremely hard sidewall (which may not require that much negative camber then).

I had them set alignment to following:

FRONT REAR
camber -1.5° -1.3°
toe-in 1/8" 1/8"

caster 6°
thrust angle 0°

Today I picked up the fronts that a friend of mine took home in his car and was shocked to see the front tyre wear. I have only done about 60miles on the track and all the thread on inner part of the tyre (about 3" wide) is gone (was previously 2-3mm).

I have to say that my front toe-in is even a bit higher then 1/8" because I miscalculated the conversion to degrees (the alignment shop has only degrees for settings).

Then on the web I read that excessive inward tyre wear is caused by too much toe-out but I may have too much toe-in, which should cause excessive tyre-wear at outer edges of the tyres.

So whats going on here ?

Anyone knows how much you need to turn the toe setting nuts to come from 1/8" down to 1/16" setting ? (I dont want to pay another $50 for changing only this).

Thanks,
Tadej

DamonB

Toe will wear tires much more quickly than camber. As for toe in wearing the outside and toe out the inside that is only true if camber is zero. As soon as you put negative camber in the car the inner side is always going to wear no matter which way the toe is. With negative camber the outer edge of the tire doesn't see the pavement until you're cornering.

With even great amounts of negative camber the tire still rolls freely down the road, there is just more pressure on one side of the contact patch. With toe in or toe out the tire literally scrubs on the pavement because the tire is never pointed in the path it is actually traveling. Combine that with negative camber which will scrub the inner portion of the contact patch even more and that's what you're seeing. If the toe was excessive then it certainly will eat tires very quickly. Toe will always cause more wear than camber.

If you told the alignment shop to set at 1/8" of toe in and they didn't do it (regardless of their knowledge of degrees, etc) I would insist they correct the toe settings. I think the tires will be your problem as I can't imagine anybody will pay money of any sort for tires that have been on the track.

cruiser

Big thanks Damon, that makes sense and should be the problem

And no, I havent told them to set it to inches, they may not even know how much an inch is, lol. This is central Europe

Do you maybe know how much you need to adjust the nut to get the toe-in under 1/16" ?

I cannot afford that much tyre-wear as the tyres will only last me 2 events, lol
Or should I just go back and have it done properly ?

rynberg

Go back and get it done properly, you don't even know where the toe is at now to make an adjustment. I'm surprised the alignment place would work with degrees of toe instead of a linear measurement....otherwise, just tell them 2-3 mm toe-in.

maxcooper

Degrees doesn't change with wheel/tire diameter.

-Max

rynberg

Hah, good point.

cruiser

Ok... I guess I need to have it done again. Cheaper then destroying good tyres

I'll get it down under 1/16" and maybe some smaller amount of front camber.