Pc007

Hi guys

Just went with 18" turbo look wheels in me car, should i consider any special alignment? What alignment have you guys on your cars?

Thanks

uberlawyer

Changing tire or rim size should not require a new alignment.

nile13

Can you attempt to answer what an alignment actually does? If so, what effect would changing wheels have on an alignment and vice versa?

Pc007

I mean alignment as in toe, camber,etc.

What's the best one for 18" wheels on a 993?

Thanks

nine9six

Are you performing the alignment yourself, or are you taking it to a shop?

Assuming you are talking a 993...If to a shop, make sure they specialize in 993 alignment and have and know how to use a kinematic tool for rear toe.

nile13

See my question above?

Pc007

Nile 13, I really don't know, that's why I'm asking...for what I hear there are some guys changing alignment when they go higher and wider on wheels, I keep hearing good and bad about going from 17" to 18"....

Nine9six, thanks once more for that tip...yes it's a 993, I really don't know if they have that tool....what it consists of?

nile13

OK, understood. Then a bit of info, so you get a better picture.

The alignment adjusts suspension geometry via concentric bolts in control arms. Imagine wheels off the car. What's left is your brake rotors hanging on the hubs. Imagine turning a concentric bolt in suspension somewhere behind the brake rotor in such a way that the top of the rotor moves towards or away from the car's body (that is camber). Or that front of the rotor moves towards or away from the body (that is toe). Now you should have a mental picture that tells you that bolting any sized wheels or tires to these rotors will not at all change above-mentioned geometry. So... no, you don't have to change alignment when changing tires, wheels, tire/wheel sizes, etc.

No like everything else, this is ideal theory. If you tire is so fat that it's almost rubbing the inside bodywork or fender, you might have to consider changing alignment. But that should not be the case for a street car.

What you might be confusing things with is lowering the car. That actually changes suspension geometry and changes camber But that would be lowering the car via adjustable strut height. Even changing height via changing overall tire diameter would not change alignment.

Finally, 17" vs. 18" on a street car. It doesn't matter. It just doesn't. With 18s you will have smaller sidewall for the same overall diameter. Giving you stiffer ride if using the same model of tire as you would for 17". That might be a plus or a minus to you depending on your preferences. But, again, on a street car with unknown tires it doesn't matter and boils down to your aesthetic preference and availability of tires that you might want.

nile13

Here's a basic video explaining some alignment terms, btw:

Pc007

Thanks nile13, completely understood! So what's the normal alignment for a street use 993?

On my 964, I had major improvement by having a little negative camber in the front, the car does corners with more grip, it feels more safe...

With the 993, is there anything to consider on this subject, or stock is the way to go?

Thanks

nile13

Well, alignment is purely dependent on what you use the car for. Of course, adding more negative camber will give you more grip (to a point) in a turn (and, btw, reduce grip for acceleration and braking). It will also cause more tire wear on the outside edges.

So, depending on what you do with your car, you would want alignment corresponding to that. I think my 993 is mostly street alignment, which is probably somewhere between 0.5 and 1 degree of negative camber. For a more serious autocross use I'd go with 2-3 degrees. For track - probably somewhere in between (I have no idea)?

il pirata

You didn't say how long you have had the car,mileage, if you have ever done an alignment before, and if not, any records of pervious owners having an alignment performed.

In any case here is the factory specs for reference.

Pc007

Thanks nile13 and il pirata, the car has 60.000 miles, mainly street use, I don't think the car ever got an alignment correction, so when I change the wheels I was thinking of doing it...