to much body roll

[iluvdrt]

-2.0 degrees negative camber in a 98 lego GT would eat tires faster than the store could ship them. the max factory limit for specs is -0.7 front and -1.6 rear. I do daily drive this car. I want my tires to last 45-55k.

 

I still disagree with your theory on lowering car. By what your saying, if it were true, than raising the car would improve the handling instead of lowering it. (am I getting that right?) Why would lowering my car with a set of STi struts be a bad thing. the way I see it is:

 

the higher a vehicle is the wider it must be in order to be stable. On the flip side the lower it is, the wider it doesnt have to be. If you take a wide and tall vehicle, than lower it, you now have a low and wide vehicle. That will have less body roll,and better steering responce, with better handeling. With a lower car there are less forces being excerted on the suspension and body during a corner, than on a higher vehicle. Lower cars perform and handle better than higher ones.

[jamal]

-2.0 degrees negative camber in a 98 lego GT would eat tires faster than the store could ship them. the max factory limit for specs is -0.7 front and -1.6 rear. I do daily drive this car. I want my tires to last 45-55k.

 

I still disagree with your theory on lowering car. By what your saying, if it were true, than raising the car would improve the handling instead of lowering it. (am I getting that right?) Why would lowering my car with a set of STi struts be a bad thing. the way I see it is:

 

the higher a vehicle is the wider it must be in order to be stable. On the flip side the lower it is, the wider it doesnt have to be. If you take a wide and tall vehicle, than lower it, you now have a low and wide vehicle. That will have less body roll,and better steering responce, with better handeling. With a lower car there are less forces being excerted on the suspension and body during a corner, than on a higher vehicle. Lower cars perform and handle better than higher ones.

 

-2 degrees of front camber won't go through tires if you go around corners with any frequency. Plus you've got -1.5 in the rear. Generally you want a little more negative camber up front than in the rear. My tires wear completely evenly by the way.

 

It's not "my theory" on lowering the car. It's what happens to the tire and suspension geometry as it goes through it's travel. Here is a diagram of the camber curve on an STi, which is close enough to other cars to be applicable:

 

 

As the control arms move away from horizontal in either direction, the balljoint moves closer toward the center of the car on it's arc of travel, which increases positive camber. You can see from the curve that at stock height, you'll gain negative camber, to a point, on the outside wheels in a corner which will improve grip.

 

If you lower the car, you're giving yourself less travel before the camber goes positive. This is just what happens with a MacPhearson setup. Wishbone and multi link suspensions can be designed to have a much better camber curve, but a macphearson setup is easier to package, durable, and has a good amount of travel.

 

Body roll isn't a function of height, it's a caused by the moment arm exerted over the distance between the roll center and the center of gravity. The roll center [axis] is the point [axis] that the car tries to roll around. The lateral force due to cornering is exerted through the center of gravity. So the distance between them multiplied by the cornering force is the roll torque. As the suspension compresses the roll center moves down, away from the center of gravity, which increases the roll moment.

[jamal]

Oh, I forgot to mention the most important thing: Tires.

 

Tires are what make you stop and turn. You can have a $15,000 coilover setup, and it's still going to handle like crap if you put junk all-seasons on it. A tire that grips is softer and will not last as long. A tire that lasts 50k miles is going to be pretty hard and not grip too well.

 

I'm on my 3rd set of RE92s in as many years. They last about 10k miles for me. I've done quite a bit of work to my suspension, and now the tires are the weak link. Next spring I'm going to put down the money for a good set of performance summer tires.

[subeerex]

I have way to much body roll in my wagon. It causes some nasty understeer. Aside from struts (which Ill get into in a minute), what is available (fits) my wagon to help. It is a 98 GT Limited BTW.

 

What Ive done so far is replace the struts . Fronts recieved new WRX struts and springs, the rear has recieved New STi struts and springs( not the inverted ones). could the differant combo cause this?

-----------------------

Don't know much about "swaps" for your car but I Have an '02 WRX wagon to which I swapped the sedan's (thicker/bigger) rear sway bar and there's a considerable amount of difference. It's a bit stiffer and as a matter of fact, the swap was a freebie cause I found a "take-off" from someone that had done a bigger up-grade:brow: . I also added strut bars (front and rear) from Whiteline and I'm happy with the results (everyone's driving style differs).

Do some research on swaps...sometimes it's a lot more affordable than after-market up-grades.

[Ranger83]

-2 degrees of front camber won't go through tires if you go around corners with any frequency. Plus you've got -1.5 in the rear. Generally you want a little more negative camber up front than in the rear. My tires wear completely evenly by the way.

I had -2 degrees on my old autocross Scirocco. It ate up the tires in a major way.

 

I have way to much body roll in my wagon. It causes some nasty understeer. Aside from struts (which Ill get into in a minute), what is available (fits) my wagon to help. It is a 98 GT Limited BTW.

 

 

This is a whole lot of money to be putting into a car that can't easily accomodate a bigger footprint or more power. The H6 and turbo Legacys and Outbacks use the VTD drive system that minimizes understeer. Even after the suspension changes you're still going to have a drive system that understeers by default.

 

Personally I'd put on good tires and call it done. these mods are going to put you in a street modified autocross class, where you;ll be eaten alive.

[jamal]

then you didn't have 0 toe. And um, I would expect tires on an auto-x car to not last long.

 

I, along with many others, have 2 degrees or more front negative camber without uneven wear. I suppose if I didn't drive down windy roads fairly often I would get a little extra wear on the insides.

 

When I only had -0.7, I had extra wear on the outsides of my front tires.

[Ranger83]

then you didn't have 0 toe.

Oh, that must have been it!

 

Or, not.

 

then you didn't have 0 toe. And um, I would expect tires on an auto-x car to not last long.

Unless they came to the autocross in your trunk....

 

I'd be really leery of going beyond -1 degree if you drive a lot.

[Virrdog]

Oh, that must have been it!

 

Or, not.

 

I'd be really leery of going beyond -1 degree if you drive a lot.

So you are going on your own singular, personal experience with a non-Subaru car to make a blanket statement about all Subarus...

 

There are many, many, many an auto-x'er here in Ohio that run over 1 degree of camber up to 2 above up front on the car they drive everyday and there is not exceptional wear with just camber. Toe on the other hand will eat a tire alive. How do you know you did not have any toe on your auto-x car? (Just so we know its not you guessing )

 

The overwhelming evidence says that camber will not eat up a tire on a Subaru. People that have a bad experience with one set of tires or don't realize adding camber also changes the toe do not nullify the truthfullness of the statement. Me personally, I chew tires up when I don't have enough camber.

[jamal]

Turn In Concepts, a vendor/suspension expert on nasioc, is running 3.4 degrees of front negative camber on their project car/daily driver.

 

They say that with regular rotation they had about an extra 1/32 of wear on the inside of the tread at the end of the tire life.

[cookie]

It really depends on what you want to do with your car, and maybe how old you are.

I'm running stock settings on my Subaru, a little lower tire profile, WRX rear sway bar, 15% stiffer struts. It is far nicer than a stock Forester of the same vintage and handles very well in corners. Testing showed 50 50 breakaway in parking lot stuff. The car gave me 70,000 miles on the last set of tires. I know that I could get a little better handling by lowering and increaseing camber, but I'll guarantee you I won't get 70,000 miles out of the tires.

On my BMW M Roadster I am currently running Bilstiens, big sways, and 1 degree of camber. If I am lucky I'll get 25,000 miles out of the current set of SO3s at $1,000 a set. BMW owners constantly complain about the factory setting rear camber at a rate good for a racetrack (3% on many models), and they eat tires for lunch.

If you want more camber and faster time at the track be prepared to sacrifice some tire wear.

[iluvdrt]

I dont auto cross my car, I dont need that much negatiive camber, I was just looking for a more stable ride.

 

I wasnt aware that with subys as the suspension travels it turn the cabmer positive with compression. Most cars do the opposite...wierd.

 

anyway here is my alignment printout. I did the the alignment on a hunter alignment machine at work.

 

As far as tires go, I am currently running Yokohama Avid V4s "V" rated..they are OK.