george996

i found that the x74 front camber specification is -0.5 +/- 0.25 degrees. however, the x74 spring rate is stiffer than pss9's and the package includes stiffer sway bars. therefore, the car will lean less in a turn and will maintain more negative camber than pss9's. since i auto-x and am not concerned with even tire wear, i am running -0.75 degrees. for 100% street use i would probably run just a little negative camber like -0.1 to -0.25.

AudiOn19s

Can you tell me what the X74 spring rate is? Many of us tried very hard to find this info and were never able to come up with a value. There's no denying that the X74 is stiffer than PSS9 but that could all be in the damper.

Andy

LJpete

Why is everyone so afraid of negative camber? Increasing negative camber in many cases is good as it helps corning. With regards to tire wear negative camber and toe cause increase tire wear. Why not just go zero to and solve that issue. You'll also have a better handling car and crisper turn in.

I just think it's a bit funny that .5-1 degree of front camber is nothing, my first p car had well over 2 degrees but zero toe and had no adverse or accelerated wear. I ran -3.4 in the front end of my BMW and -2.4 in the rear (zero toe in the front and 1/8th toe rear) with no negative effect on tire wear. Wet traction was a different story. LOL

I come from the autocross side of the hobby but do a few track days a year and found the more aggressive setup is fantastic. It's kind of funny, but with my current car (stock), I'm not a fan of it's "street/factory" alignment as it's no where near as crisp as my first 996 (which was set up nicely). I can't wait to go back to my old cars settings. The only real negative with more aggressive setups in my experience, is the car can feel a bit darty on the street which requires a bit more focus to drive. I'm used to it but others may not be.

AudiOn19s

+1 Pete, Couldn't agree with you more. Even for a car that's 95% street why not improve the handling characteristics of the car all the time if you can.

-1.5 degrees all the way around (if you can get it at the front) is a great setup on street tires and a dream to drive. Keep front toe to a minimum and you won't know the difference in tire wear.

perryinva

George, thanks for the pics! Nice. X74 sways are the same as M030, which I've already installed. Stiffer sways mean less roll, which means more even distribution, so more negative camber makes sense. I don't understand why a stiffer spring rate "allows" more negative camber. Stiffer means less travel, I don't see the correlation, but I'm sure no expert. I didn't mean to imply I want a stock C2 street alignment, I was referring to an X74 alignment, which has a more performance lean to it. There is most definitely a more squirrelly feel to the front end with 0 camber, vs even a little neg camber, based on cars I have driven, just going straight, never mind cornering. I agree that -.5 - -1 is no big deal, and since you always eat the rears WAY before the fronts, this can allow easier justification to replace all 4 tires at the same time. Of course if you love the rubber you've got and can get a 2 rear for every front, then that may change. As long as -1 doesn't affect wet weather driving, then I see no reason not to do it, IMHO.

george996

I didn’t know you had m030 sway bars. Even so, I think the x74 spring rate is higher than the pss9’s based on driving both. However I am comparing pss9’s with stock sway bars to the x74 package. I didn’t explain my point clearly. When I wrote that a stiffer suspension will “maintain more negative camber” I meant to say the change in camber towards positive, due to body roll, will be less than a car with a softer suspension and more roll. Not that a stiffer suspension requires or allows for more negative camber adjustment. In other words, more negative camber is required to compensate for more body roll. Of course, the objective here is to optimize performance instead of tire wear.

Your point about replacing all 4 tires at once was my thinking too.

george996

Andy,

Unfortunately I do not know x74 spring rates. I do know from installing both, the x74 free length is shorter than the pss9's and compresses less from the weight of the vehicle.

perryinva

Yes, that makes a lot more sense...you will maintain that benefit of the negative camber in a corner instead of losing it to body roll from increased suspension travel. Also agree that I wouldn't optimizie for tire wear on a 911, but for the performance parameters that I want for my use of the car. It's not my dailey driver interstate car. Tires usually last longer than I want to based on my 4 -6k miles per year. Pretty much everyone agrees that the PSS9s will provide a more supple ride initially, which is that inital compression of the helper spring and inital load of the normal spring. As you probably know the M030 ARBs are ~25% stiffer rear and ~10% front...not much really, but it should help the understeer considerably. It yields noticeably less lean, and decreased understeer, but not anything eye-popping as far as I've been able to tell. Honestly, I expected more based on others posts.

george996

you raise another good point regarding ARB's. I feel my car has too much understeer and perhaps the m030 ARB's would help. I didn't notice the understeer as much before installing the pss9's but on the otherhand i didn't auto-x it then. I would be interested in your feedback after you install the pss9's.

perryinva

Well that would make sense. The old OEM struts yield more suspensionmovement & body roll, which has the effect of pre-loading the ARBs. The much stiffer springs and compression of the PSS9s reduce same, so the old ARBs act softer. This would definitely be more noticeable when autoxing because of the constant sharp radius reversals.

maci911

mine is 25inch all around ....and front lip also 5.75inch from ground....anything lower will probably compromise the ride.........

perryinva

You front lip is 5.75 from ground? Are you sure? Mine is about 8", stock front bumper and struts at 26 1/2" all around. I know the turbo bumper has less protrusion (flatter nose) and is lower, I just never realized it was that much more. Dang!

maci911

sorry my mistake front lip to ground 5inch,fenders to ground 25inch all around with full tank gas.......................

perryinva

Wow! When I install my PSS9s in June, I'm planning on dropping 3/4 to 7/8", which would get me to about 7" or so, which is as low as I can get and still have 1/4" to clear on my steep driveway. You must hit everything!

george996

I ordered C4S rear ARB (20.7 mm, same as GT3) and will let you know how it works in a few days.