Performance Alignment

[tarmac and beer]

I have 20k miles on my 07 MS3 and the stock tires were due for replacement come the California winter, ie rainy season. Unfortunately a nasty roadside screw ended the life of one of my tires so my plans are accelerated. I have the new 215/45/18 Yoko Advan AD08 on the way

I need alignment recommendations for really fun street driving with an eye towards making these very expensive tires last 15k miles. I've searched and not found much help.

Here is what I'm thinking:

Front
camber = 1.5deg
toe out = 1/16 total
caster = 3.5deg

Rear
camber = 1.25deg
0 toe

Any experts out there?

 

[Nliiitend1]

Well, your camber (and front caster) isn't really independently adjustable with the stock hardware, so the most you can ask for is that they try to muscle it to the point at which it's even on both sides.

Your toe settings there look pretty good for tire wear, and that little bit of toe out in the front will make your turn-in a bit more crisp than with the stock recommendation of slight toe in.

Looks good to me!

 

[meicalnissyen]

Well, your camber (and front caster) isn't really independently adjustable with the stock hardware, so the most you can ask for is that they try to muscle it to the point at which it's even on both sides.

Your toe settings there look pretty good for tire wear, and that little bit of toe out in the front will make your turn-in a bit more crisp than with the stock recommendation of slight toe in.

Looks good to me!

+1

 

[Rubasu]

the only thing i can recommend is have them even out the front cross camber if it is out by having them shift the front crossmember to even it out and stand both wheels up even...

 

[Nliiitend1]

There is actually a little bit of wiggle room in the bolt holes for the front strut top mounts...

 

[bacarl]

... and that little bit of toe out in the front will make your turn-in a bit more crisp than with the stock recommendation of slight toe in.

Ok, here's a silly question I've always wondered about, and this is wandering off topic so I apologize, but it ought to generate good discussion. Toe-out is supposed to help with response/turn-in. But if you think about it, it seems like loading up a toed-out outside wheel in a turn would slow down response, right? Since the loaded wheel must pass through center before it can direct the car into a corner. Am I thinking about something wrong? Is there some black magic involved?

edit: think about it this way. Typically bump steer is set by the manufacturer to increase toe-out through jounce travel, in order to tend to understeer. So if toe-out bumpsteer understeers, why does static toe-out speed up turn in?

 

[Nliiitend1]

Ok, here's a silly question I've always wondered about, and this is wandering off topic so I apologize, but it ought to generate good discussion. Toe-out is supposed to help with response/turn-in. But if you think about it, it seems like loading up a toed-out outside wheel in a turn would slow down response, right? Since the loaded wheel must pass through center before it can direct the car into a corner. Am I thinking about something wrong? Is there some black magic involved?

edit: think about it this way. Typically bump steer is set by the manufacturer to increase toe-out through jounce travel, in order to tend to understeer. So if toe-out bumpsteer understeers, why does static toe-out speed up turn in?

I think you're putting too much stock into the "weight-transfer/loading" part of the equation, especially since "turn-in" really only applies to that split-second that you're initiating a turn (before the load has really been transferred). The static toe angles have less of an effect on the car's dynamics once the car is already in the turn (because of the weight-transfer that you mentioned).

When you have static toe out, the inside tire will attempt to turn a tighter circle when turning than the outside tire, which it needs to do anyway. Basically, the tires aren't fighting each other for that split-second the way they would be if the wheels had static toe in.

Does that make sense?

 

[bacarl]

Yep it sure does. I was thinking along those lines too... The wheels turn, then your weight transfer happens, then the tire gets loaded up after the wheel has turned through center.

I hadn't thought about the tighter inside line, either -- that makes sense also.

 

[ericrapp]

Being a new person to above 130mph, lets say i have little interest in autocross and am looking at stability and straight tracking at these speeds. Suggestions on toe in front. Neutral? I will have camber adjustment also once i have sorted some structural strengthening issues. Thanks, sorry to jack if i have

 

[Nliiitend1]

Being a new person to above 130mph, lets say i have little interest in autocross and am looking at stability and straight tracking at these speeds. Suggestions on toe in front. Neutral? I will have camber adjustment also once i have sorted some structural strengthening issues. Thanks, sorry to jack if i have

Actually, moving towards zero front toe might reduce straight-line, high speed stability. You must remember that we're talking about "static" settings here, and that these settings shift under dynamic conditions (cornering, braking, acceleration, etc.). Zero front toe makes the front/steering feel too "numb" for my tastes. Running a slight amount of toe actually makes the car run straight.

 

[ericrapp]

Toe in? I understand what you are saying a little and i have read up on setups and the theories But without actually making my adjustments i have not remembered enough. i was hoping for personal experience on these cars. I will get a chance to play with this stuff more next year. i am still collecting the pieces that will allow me a range of adjustment. thank you for your advice and i appreciate your opinions. I have some engineers from work attemting to strengthen up the front towers while allowing for full camber adjustment and they may take awhile. Thank you for your help

 

[Nliiitend1]

Well I run about 1/16th TOTAL toe OUT in the front on my car, and I find it to be a great compromise between tire wear, turn-in feel, and stability at speed. My car will follow ruts a bit, but when I'm on the track I'm always holding the wheel firmly enough that it isn't ever a problem.

 

[specvspeedfreak]

im running 1/16 total toe out in the front as well.. rears are at 0... and i don't like it.. this is the third time i have gone toe out for street driving w/ my cars.. Where i live now it sucks. I just don't reccomend them it at all for mostly street even if you are a very spirited driver. 0 toe is enough.

btw.. my high speed stability sucks as well.. i might just end up getting mazdaspeed coilovers and toss my koni/h&r setup

 

[Nliiitend1]

What specifically don't you like about having your toe set slightly out?? (dunno)

What kind of wheel/tire combo are you running??

 

[specvspeedfreak]

the twitchyness... The roads here suck though... It follows an crown in the road..and any slight imperfection it'll pull the car hard in either direction< but thats what you get.. i don't think its worth it for street driver though.. its annoying and makes you look like a drunk driver at times lol

im running 235/40/18 on a 7.5inch wheel... azenis 615 <also not what you'd call a forgiving tire ..also around -2.0 camber all the way around

 

[Nliiitend1]

Yeah, toe out will tend to make the car follow ruts/crowns a bit more (an effect that is exacerbated by wider/lower offset tires/wheels) but I've never found 1/16" to be so much that it becomes a problem. Of course, with your -2 degrees camber up front (I've only got ~1.5 or maybe a little more) it will make it a little more noticeable. Like I said, with 235/40/18 Kumho XS (even stiffer sidewalls than the Azenis) tires and 8" wide et50 wheels, I find it pretty tolerable.

On a side note - Why are you running so much camber in the rear? I'm assuming you've got camber correction hardware since it's even all around...

 

[specvspeedfreak]

Yeah, toe out will tend to make the car follow ruts/crowns a bit more (an effect that is exacerbated by wider/lower offset tires/wheels) but I've never found 1/16" to be so much that it becomes a problem. Of course, with your -2 degrees camber up front (I've only got ~1.5 or maybe a little more) it will make it a little more noticeable. Like I said, with 235/40/18 Kumho XS (even stiffer sidewalls than the Azenis) tires and 8" wide et50 wheels, I find it pretty tolerable.

On a side note - Why are you running so much camber in the rear? I'm assuming you've got camber correction hardware since it's even all around...

i don't actually. the rears i think have just a tad more neg. camber than the fronts do but they are very close. Its just the way the the camber settled after the springs.... I am fine with it.. Why do you ask?... you don't like that much camber for the rear?

 

[ericrapp]

I am glad you guys have moved to the issue of neg camber. I am using Cobb springs and was able to get factory specs at the garage when alignment was done. And asked them to favor to the negative side front and rear as much as they could. I am very pleased with the way the rear tracks now. But the coilovers i have will change all that. I have some rear endlinks coming and then the rear adjustable camber arms are next on the list. I will install the rears first and bring them in close to what Cobb height does to the geometry. And it is easy compared to the problems up front. But i have much to learn and more pieces to purchase before i install the coilers.

 

[Nliiitend1]

i don't actually. the rears i think have just a tad more neg. camber than the fronts do but they are very close. Its just the way the the camber settled after the springs.... I am fine with it.. Why do you ask?... you don't like that much camber for the rear?

Ah.

Typically I like to run less negative camber in the rear than the front, given the option.

The general rule that worked well on my Focuses was to have the rear set to about 2/3 of where the front was, and tinker from there. The more negative camber you have in the rear relative to the front, the more likely the car is to understeer, and vice versa.

 

[ericrapp]

i would think it depends on the lateral loading, for how much negative camber is effective, in the regard to understeer to oversteer. i know that more neg makes the car harder to drive straight, from a little exp. regardless of toe set up. isnt the focus suspension similar to the Mazda3 design in the rear at least?