Tire Contact Patch and Vehicle Stability - Alignment
 

In a few days I'll participate in my 4th HPDE. It'll be my first in the BRZ (stock) and a RWD car (first 3 HPDEs were in AWD cars). I've completed the usual track-day prep (threads here were helpful to confirm what I have been doing).

I went to get an alignment at a local reputable shop that works on Subarus. The owners have years of track experience themselves in Subarus and they strongly recommended I stick with a stock alignment to learn how to drive the car before changing things up. This made sense and was my plan anyways, however, I had installed Eibach camber bolts up front to get negative camber because my previous experiences on track with street alignments was it killed the outer edges of of the front tires (though it probably tells me I'm over-driving) and felt like I was getting less grip through the turns.

In addition to learning the car with a stock alignment, they told me negative camber on the soft stock suspension and stock tires (215 width), I would experience instability under braking on the straights, as well as reduced friction with less tire contact on the road. They noted that negative camber would help in corners, it'd be negligible with stock wheels and tires, and it is safer to have stable braking into corners.

I do trust them and so far I can't fault what they've told me, but what are the thoughts of those with seat time? Especially if you've started off with a stock car and grown with it or kept it stock through the years. Thanks in advance for advice and stories!

I'll report back on my experiences after next weekend's track day...

They did you dirty, my car braked just fine with -3 degrees of camber on stock suspension, let me guess they want you to come back after you destroy your tires in two events? I'm on -4/-2.3 right now.

-1.5 degrees on all four corners would've been a good beginner alignment imho. Why did they toe in the right rear? Why do you have so much toe in on the front? Why isn't it even? Don't go back to that shop imho.

Edit: you'll survive the track day just fine with the current alignment if you don't have time/money, it just isn't ideal. Sorry, I think the car had a better alignment before you brought it to that shop, I'd rather hit the track with your before numbers than your finals.

I'm guessing that -1.5 "before" front camber was not really from alignment that was on car before, but rather measurements right after camberbolt install, and then they tuned to stock-like 0dg front camber. Rear .. i wonder if they just left it as is, as changes make little sense to me. What i also don't like - they added front toe-in. I'd rather see opposite, zero front toe and some toe-in rear, as twins are RWD, so it should stabilize a bit acceleration, especially out of corners.
Bit of worth very first trackday going with stock alignment to better feel it's deficiencies and have own experience/feel on what handling changes will subsequent future alignment changes will bring is not bad, but imho more so for beginner. Not sure it's that valued for one that already been to HPDE and already ripped tire outsides or felt understeer in past :)
As for optimum for track alignment .. camber, camber, camber. And more then what single front camberbolt set may bring (though even those -1.5dg are better then stock 0dg, obviously). I second from own experience that braking won't be that ill-affected with increased camber, yet it will help much with reducing camber wear of ripped on track tire outsides (-1.5 insufficiently though, imho one should start with -3front/-2.5 rear as starting point for more even on track wear & contact patch) and stock alignment understeer bias (again caused mostly by lack of front camber in stock alignment).
But mentioned 3 HPDE events before on other cars make me think that you don't participate that often overall. So if you do just one or two events per year, then maybe it's not worth to go for track specialized alignment (which i'd choose with at least 5 events) and worth compromising somewhere in-between. In such case I'd probably go for -2 front camber (& zero toe), and -1.5 rear camber (+0.1dg each rear wheel toe-in). If your camberbolts are for lower hole, worth reuse lower hole's stock 14mm bolt at top (16mm) hole, to get a bit more camber past probably around -1.5 maxed out camber of just single set of camberbolts.
P.S. Alignment aside .. worth to not forget about brakes. Stock brake pads and brake fluid are hardly track material, lol. It might be that you'll hit OE brake pad/fluid limits sooner then alignment deficiencies.

I would've rather had the before alignment.

I run about -2.5 front and -2 rear for camber and 0 toe. I'd say that I use a more mild alignment than many cars at the track.

Fuggin *morons*. This car needs as much negative camber up front as you can give it. Take it back and have them *maximize* negative camber up front. Take it to another shop if they won't. -1.5* is not nearly as much as you really want, and zero is fricking ABSURD for track duty and even street duty really...

Have them zero the front toe as well. Rear toe is fine where it is (near-zero).

I have no instability whatsoever under hard braking at the track with super-sticky Hoosier A7s on my car with -3.3* front camber. The idea that camber kills braking performance is an ancient trope that applies more to bias-ply tires. DAMN...

Yeah I'd say I'm pretty conservative with how I like to set up newbie's cars and that's...well...excessively conservative to the point where I don't like it at all. It's not good.

0 camber up front and a bunch of toe in is going to be annoying.

- Andrew

That will be the most stable 86 in the land...

Thanks for everyone's responses - and especially the civilized manner in which they were written and the amount of detail! :bow:
I wasn't going to keep the factory tires beyond the first track-day (and maybe an AutoX event) - so I'll still learn how the car drives with this setup - and I'll report back on my subjective impressions.

(I'll make individual responses below).

I appreciate the honesty and feedback. I should have questioned why it isn't even, but this was personally my first non-big box chain store I got an alignment at and the numbers were more even than what I'm used to seeing. Here I am learning...perhaps the hard way. In the back of my mind I had a feeling it might be a case of wanting to be able to charge for an additional alignment in the future - which most people in this thread seem to be echoing (to some extent). I'll know more soon. :thanks:

Yes the Before figures were camber bolts maxed out and nothing else touched. Wow thanks for all the details! I got this car so I can start to participate more. The consumables on cars I had previously were somewhat cost prohibitive and I learned over some time that I enjoy driving adequately powered cars fast, vs. fast cars slow or hitting insane top speeds (personal preference). The intent is for me to learn and sadly sometimes it means some wasted time and money, though forums like these help a lot.

I have better pads and fluids - STR600 and Hawk HP+ - for now. Again, want to be safe and get a baseline for me and the car. :lol:


Thank you - helpful data points and info. I have some experimentation to do and conversations to be had!


Appreciate your input, Andrew. I wish I had pushed back more at the shop, but I'm learning.

Prior to getting the camber bolts, pads, and brake fluid installed, I had run some 0-60 and 60-0 tests (as data points to keep for my car using a Dragy unit). After the install of everything (before alignment), I had to bed in the brakes and went to the same area I did my original bone stock tests at and in straight line braking something felt strange about the car's behavior. I could attribute this to different pads and how they were bedding in, but under hard braking the car did tend to pull left and right - felt less stable to me.

The stock pads vs. the new pads have no issues overcoming the max friction of the factory tires, and in the back of my mind this feeling which I replicated a few times kept me from debating with shop when he said the car can become squirmy under high-speed braking with narrow tires, stock suspension and more than factory negative camber. I'll know soon what's up...I was a bit surprised he went with 0 degrees though...would have thought -0.5 or something...but I'll get some seat time and have some first-hand experience!
:)

0 degrees front camber is there in stock alignment for twins. I somewhat guess he might have gone easy route simply sticking with OE suggested values (except extra toe-in in front, and zero toe rear).
It's not as if your car won't be driveable on track with closer to stock alignment. You may even can have your share of fun. Just that imho there will be lot of speed left on plate due alignment, as i predict understeer at lower speeds then car on very same tires should really be capable of, and there will also be less mileage to get from your tires due mostly worn if not ripped outer side and intact inside.
Then again, to some extent one may counter understeer with treshold braking, some throttle lift off and slight brake usage for mass/grip transfer to front, and just one track day probably won't wear your tires completely.

I would be more persistent on what you want.

This was my front left with -1.4° after two 30 minute sessions this past weekend. Definitely needs more than I what I had. I can't imagine having no camber.

My rears were stuck at -2.3° on RCE yellows and they wore a lot more evenly.


A few on here suggest 0 front toe and either 0 rear toe, or 1/15 total toe in.

I went with 1/15 toe in on the rear and that setup was pretty fantastic. The instructors that rode with me were impressed with the setup and how stable the car felt. I could easily rotate the car mid corner with the throttle.

Thank you! And that tire wear looks familiar to me and the Golf R with PS4S's I had before...:sigh:

Do you have any pictures of your tires after your last track day?

This will be my first ever track-day with the BRZ and RWD car. I'll have photos after this weekend.

Hopefully I won't get roasted for asking but...since there's a strong consensus that 0 camber is not good for track, absent the shop willing to redo my alignment for free (I haven't asked), I could add negative camber by adjusting the bolts myself. I know that'll impact toe too. Bad idea?