Haha my bad, OK, I've had the tires for about 14k miles, stock tire size for 04 aero coupe (staggered 245/45R, 225/45F). They're Achilles ATR Sports with treadwear rating of 400.

The static alignment is important because how your alignment sits still on the ground is not how your alignment sits while going 55mph. Basically you want to account for the fact that its gonna pick up a little positive cam while driving down the freeway. This is how Nissan comes up with the "stock" numbers.

The caster issue is kind of similar. Caster is how your wheel sits inside the well. The easiest way to think about caster is to relate it to a shopping carts front wheels (or casters). There is almost never a setting for caster from the factory on any car. Its directly related to how true the frame is and how true the parts connecting the suspension to the frame are. So I realized my caster was off and the guy said the only way to fix it is to "tweak" the frame. Ha!! That wasn't happening, so I know the only thing connecting the suspension to the frame is my compression rod bushings. Of course, they were basically deflated. (This was before I lowered my car BTW). I changed them to polyurethane because poly is much harder than rubber but still soft enough to not be metal on metal. So with that fixed it retrued the steering suspension, tightened it up so there's no loose wiggle and fixed my caster (which is part of the reason for uneven and accelerated tire wear).

And lastly, no, I'm not stock I'm lowered on eibach pro kit, poly bushings in the LCA and comp rods, spc rear camber arms and toe bolts and kinetix v2 upper control arms in front.

 

Any reason you went with the Kinetix upper front arms instead of the other brands offered? Is it because you prefer the bushings within them? I'm lowered on Konig Sport shocks and Eibach Pro springs right now on my '07 G35 Sedan. My alignment numbers are currently -2.7 rear, -1.5 front. I thought about simply getting the SPC rear camber kit to fix that excessive negative camber back there, but I've pondered leaving the front untouched. If you guys were to have a -1.5 front camber, what would yall say the geometry of the G35 Sedan likes, balance wise for the rear. Do our cars normally handle better with more negative camber in the rear when lowered? For Miata ppl, stock alignments have more negative camber in the rear, but when we lower them with performance coilovers, we prefer more negative camber up front (with the spread being .3 to .5 more negative camber up front than the rear)! I'm just curious if maybe the autocrossing crowd might have found the Sedan to act similarly. What's the best spread between front and rear when these cars are lowered?

 

The kinetix have the most adjustability of any UCA (+/- 3 degrees) and its a set it and forget it application. Once you get the camber dialed in it can not move from that position until you move it. Its just a great design. And the replacement ball joints are only $27.

 

Thanks for the super fast response. It looks like if I installed the Kinetix on my own, I'd have to set them to the correct length before going to the alignment shop, right? It appears the adjustment requires it to be disconnected from the wheel spindle. How did your alignment guy go about adjusting these while the weight of the wheels were on the rack? Or was it a back and forth process? It looks like the adjustment end rotates and then a locking nut used to tighten it up.

I was recommended these http://www.importpartspro.com/spcfradcaar21.html
...but the Kinetix are less expensive, especially if the ball joint is easily serviceable. Any reason one would go with the SPC UCA's?

 

The SPC are a really good product, definitely. They are easier to adjust and I've heard of alignment techs not wanting to work on the kinetix, but my guy had no problem. Basically I compared it to my OEM arm when they were both off the vehicle, I knew I wanted the ball joint out a little bit and I just eyeballed it before I took it in. Turned out I was only off by one thread on the right and I got it perfect on the left.

Now, yes, you have to disconnect it, but each full turn (one thread) is .3 degrees of camber (negative going in, positive coming out). That being known, you can adjust it accordingly with only one adjustment. For instance if I'm at -1.7, and I want -0.8 I know I need to extend the ball joint by 3 turns. Simple as that.

 

I noticed the front left is seemingly always +.1 camber off from the right when I see lowered ride alignment numbers, but I think they aren't sitting in the driver's seat when the tech is adjusting. -1.5 for front left, -1.6 for front right... that's what I actually have for mine with no driver when the alignment was being done.

I am so used to running up to -2.7 front, -2.3 rear (on my Miata), part of me is saying -1.5 or -1.6 is no big deal, and some retailers of suspension components say the same thing. However, I'm wondering if the camber targets most achieve are mostly for saving the tires. I would like to see what ppl think about street performance alignments.

 

You're right, my left is 0.9 and right is 0.8.

Mine used to be -2.0L and -1.9R up front and I'll tell you right now, the difference is night and day. I was riding on 2" of the inside of the wheel and now I'm on the whole thing. The car is much more comfortable over rough roads now. Or hitting things like speed bumps. I still have a little negative cam to account for static and turning, but the car feels like a much more quality machine now.

 

i'll chime in with this tidbit.

the alignment tech at infiniti told me a small amount of mismatched camber left to right is desirable. he didn't elaborate, but said it like it was a wise piece of wisdom he accumulated over the years. he has been doing infiniti alignments at the dealer for a good number of years, so since he wasn't really trying to sell me anything, i guess I have to believe him. and my car rides and drives great. i do like your theory about how it might accommodate the difference in driver weight which isn't present on the alignment machine stage.

one would think that running a lot of negative cam on either the front or rear would hurt straight line drive-ability, even in a lowered car. lowering SHOULD just lower the center of gravity of the ride, and NOT affect the suspension geometry once everything is dialed in. of course, real world is not ideal world and everyone's driving needs and styles aren't the same.

also, if you think about it, tire wear is a good indication of a properly aligned vehicle for the roads you drive on regularly. if you always go around in left hand circles (on a track), the best alignment for you will be much different than the one that works for 90% straight line driving.

any type of setting that devotes energy to scrubbing rubber off the tire is going to reduce fuel economy and generate heat. anything that puts you up on the edge of the tire is going to:

1. reduce the contact patch of the tire resulting in lowered co-efficient of friction when going straight
2: this MAY increase fuel economy but at the expense of braking distances, especially in panic situations when you need every square inch of contact patch for stopping.
3. may increase tire noise. tread patterns are computer designed and optimized for flat contact patches.
4. increase the tendency to tram-line or follow grooves in the pavement (squirrely or jittery on the interstate)
5. lead to increased tire replacement frequency.
6. possibly lead to lower fuel economy due to the car always being in dynamic tension in everyday driving (competes with 1 above but likely adds to increased friction/heat, thus cancelling out the narrower contact patch effect)
7. is going to wear your subframe suspension components prematurely because the car is always up on the side of the tire and the suspension wasn't designed to hold the car in this unnatural position.

so, if the costs are acceptable to you, set it up for your needs. in my case, the car is a regular driver and i don't track it, so i am going for best all around driving experience and lowest cost of ownership.

 

Lower ultimate cost of ownership would definitely be to get aftermarket parts and align properly rather than to try to get the best you can out of stock parts. This is due strictly to the tire parts on the conversation. My last tires I got 29k miles out of with all stock setup. My tires now are at 15k and I fully expect to get 45-50k out of em. Granted their treadwear rating is slightly higher, but still that's a significant number of extra miles that I won't have to buy tires. Almost 2:1.