Geometry settings
 

Does anyone have the geometry settings (camber and track) for track/fast road on BC BR coilovers?

Hi I would also like to find this out as just finished fitting bcs yesterday!!!

What tires are you running and is inside tire life a concern for you?

I've got toyo proxies t1r. These will be replaced with something more track focused when they are ready. Tyre life not too important within reason.

If u don't mind me jumping in on ur thread?

I have 18 inch yoko prada spec 2 and personally don't want to be changing tyres too often as manly used for my partner to drive work then fun at the weekend:thumb:

I'll jump in as Arnie hasn't come back yet...he's really the best chap to speak and will prolly add something

Below is a fast road geo print out for a classic. The set-up works very well. There is a fair amount of toe-in (front & rear) which can feel slightly disconnected at slowish straight ahead driving, but comes alive when pushing on and is what I use on my classics.

Note the amount of castor which is a fair bit for a classic (you want as much as possible). This was achieved with an ALK. If your Impreza is a New Age you will have this amount of castor anyway (see Arnie's tips for getting more castor below)

Note: Toe settings and measurements for both below are toe-IN

https://lh3.googleusercontent.com/-5...2520struts.jpg

Here is a New Age print out with more castor. The camber is a little excessive and perhaps one and three quarter degrees may be better, but toe-in is the same

https://lh3.googleusercontent.com/-2.../alignment.jpg

That new age setting looks good but is this more of a track day set up?
I was after a fast road set up.

Would u keep the toe and camber settings the same and just adjust reduce the camber to achieve this??

Thanks

Nice one thanks :)

Can't help but think using that toe setup day to day your going to go through tyres quickly.

Subscribed

Me too...

Cheers Bonesetter! Good stuff there.

Bonesetter's camber and toe settings, front and rear for the Classic are great for "fast road". Though I personally prefer a bit of toe-in in the rear, rather than toe out. Basically, as the rear suspension compresses on a GC and GD chassis, the wheels toe-out. If you already have static toe out then under compression (when cornering), your outside wheel will have even more toe out and make it very tail happy and less stable. So under roll compression I like to have the outside rear wheel be at zero toe, so that necessitates a bit of toe-in static.

The settings posted for the WRX would actually make a decent track setting, depending on the tires. Typical semi slick tires like A048s, R888's like a minimum of -2.5 deg camber up front (depending on how stiff you suspension is and how wide the tire is). Its a good starting point, though I've seen it go as high as -4 on some people's cars. As a rule of thumb for track or aggressive road use ;) , I usually go about .5 deg less camber in the rear than in the front if you want the rear to be a bit more active. So if you have -2.5 up front, set the rear at -2. In the end, you'll have to take tire temps at the track to really optimize that alignment. If you want a more stable rear end (say for the road), then go equal on rear camber to front or about .25 more in the rear.

Caster is really important on the GC/GD chassis. Basically you can't have enough. So do whatever you can to get more. it makes a huge difference in front end grip. So ALK or Caster bush, rotated camber plates, etc. For you BC guys with camber plates, ideally I would look into rotating (and flipping) your camber plates so you can get more caster and camber. They would look like this:

http://i36.photobucket.com/albums/e1...h/DSCF1018.jpg

Here's a good thread about it: http://forums.nasioc.com/forums/show....php?t=1896023

If you have alu wishbones, I would do the "free caster mod" as well. Basically you flip the rear pin around and you get about .5 deg more caster that way for free!

Here's an interesting method to get even more!

http://forums.nasioc.com/forums/show....php?t=1900666

Here you can see how the pin normally sits:

Attachment 56139

torque specs:

Attachment 56140

With the pin flipped 180 deg and he added a plate for even more caster:

Attachment 56141

As far as toe and tire wear goes, its completely dependent on usage. I've had -2.5 camber and 3mm toe out and got even tire wear, but I drove like a bat out of hell. When I was driving like a granny on that setting, I started to wear the insides. Backed off my camber to -1.5 and zero toe and got even tire wear in granny mode. Then started driving like a crazy man again and got outside edge tire wear! lol Its all about compromise for your given driving conditions/needs.

You can use Bonesetters Classic geometry specs up top for a newage too. Caster will be different but the specs you want to change toe and camber, you can use his Classic settings for a GD/GG for fast road.

Note that rear camber is not adjustable without camber bolts with most struts. However, the BCs and KW's are, I believe slotted a bit in the rear. So that means there is a degree of adjustability by loosening the bolts and pulling the tire out or shoving it in. Make sure you alignment guy knows that.

Would this set up be good on a type r with tein coil s also I got no adjustable top mounts is this a prob . Would I get away with standard adjustable camber bolts on rear to?

Thanks very much Arnie for taking the time posting. Pretty comprehensive :thumb:

For the record, my toe measurement recordings on the print outs above are indeed toe-in (not toe-out)

In fact, that reminded me of a Total Impreza feature on Impreza four wheel alignment with Peter Cambridge (who to remind everyone is Prodrive's (now former) chassis development engineer, who also worked on the P1's chassis development. I was struggling with set-up a while ago on my V4 Type R (non dccd) and found the article valuable.

I was particularly taken with Peter Cambridge's rear toe-in (see below): a fairly hefty 0°15' per wheel. I experimented with these settings and ran the full .15', but personally found the rear a little leery (only on the absolute extremes it has to be said, and on one high speed occasion when the rear almost came round on a 'yumpy' off camber bend, when suspension compression was reduced to what must have been almost none (increasing toe-in?) )

Since then (and many, many alignments later) I have settled on the 'classic' chart I posted above which although giving a slightly woolly feel at slow speed, esp when tyres are cold, is absolutely spot on for fast B-road hooning :D

Final thought... for now. While alignment is critical for a well performing chassis, and looking back I went to great lengths proving everything to myself, not to mention the expense, I found my car's handling and indeed overall enjoyment, was synergised with good tyres. They made one of the most singular biggest improvements, and as a friend commented after their maiden outing, the difference 'totally sorted' the car

https://lh6.googleusercontent.com/-A...52520small.jpg

https://lh5.googleusercontent.com/-V...52520small.jpg

Bonesetter - ah, missed that on your settings, in regards to the toe being "in". Was a bit late. ;) Cool article, btw. But you are absolutely right in regards to tires. They will always be the single most important part of the handling equation. They are everything and are the cornerstone of the setup. Ideally, one should buy the best tires you can afford.

With that said, sometimes budgets and personal circumstances don't allow for running something like Michelin Pilot Super Sports on a daily basis! My last working and living arrangement forced me to commute 5 hours a day, 2/3's of which were gorgeous, windy mountain canyon roads on very abrasive tarmac. I went through a set of Kumho SPT tires in 4000 miles. Completely even tread wear and I rarely drove hard enough to hear the tires chirp. Unfortunately I did that mileage in about a month. I put on a set of quality Michelin Pilot Sports and got maybe another 1000 miles out of it. But the cost, almost triple over the cheapy Kumho's just did not justify the added performance and somewhat better mileage. While I did that job, I just bought the cheapest crap chinese tires that I could find as they lasted almost as long as the Michelins. Didn't grip much at all but, at that point, I just needed some rolling stock! Anyway, my point being sometimes, one doesn't need the "ultimate" in grip and handling out of their tires. Sometimes its just as fun only being able to pull .75g's on a turn rather than 1.5g's! Admittedly, all this fiddling with fine tuning alignments, damping, ARB settings, etc. etc. seems a bit silly when you're rolling on crap tires. But I suppose there is something to be said about optimizing your setup for what you have and just enjoy the overall driving experience. You might not be cornering as fast as the guy on Pilot Cups but I think you'll still have a smile on your face doing it.

I guess for me that is one of the joys of suspension tuning (over engine tuning), you can enjoy the performance improvement at any speed. Whether you're blasting at 160 kph through the highlands or 30 kph in a roundabout. That feeling of precision, tactility and sublime handling is something you get every time you step into the car.

Anyway, sorry about the bla, bla, bla! :)

sonic93 - These settings are a good starting basis. Regardless if you are on P1 suspension, BCs or TEINs. They will, ideally, need to be fine tuned to your particular car if you really want to optimize things for ultimate grip and performance. But as a starting point, you will be very happy with the above settings Bonesetter posted. As far as how you can achieve these settings, it will depend a bit on your car's setup. The front camber bolt will net you about -1.3 to -1.5 depending on how much you tug and loosen things to get there. For the rear camber you'll most likely need camber bolts. If your car is low, you'll probably be sitting at around -1.75 to -2 in the rear. This will necessitate some camber bolts to dial some of that camber back.

Sorry to hijack this a little - re the comment about twisting the camber plates on the coilovers - mine are installed the same way as this:
http://i15.photobucket.com/albums/a3...x/102_2156.jpg

I'd have thought doing what's advised in that article would result in your front wheels not running truly straight - I'd certainly be more than a little worried about running them in this fashion!
Has anyone outside the states been brave enough to do this?!

I reckon I'd be happy with between -1.6 and -1.75 for my daily driver!

Your toe settings are what determine if your front wheels are straight or not.

Your camber plates are set to a standard position.

In order to properly gain caster and camber you would need to remove the tophats and switch them, left to right and then rotate them. Then you can have the possibility of adding caster and camber simultaneously.

You'll be able to easily attain your desired camber setting (while maximizing caster) by maxing out your camber bolt and setting your plates. Personally, I'd do the camber plate flip and swap and push the plates back as far as it can to gain max caster. Then I would tweek the camber bolt till you get the camber level you want to have. You may have to back off the top hat a bit to get more or less (camber).

interesting reading ive just finished fitting my bc`s on sunday and have also fitted as in pic above anyone going to try rotating camber plate ?

Interesting - thanks for the information.
Given that I'm unlikely to ever track the car in the immediate future, would you say that this modification is probably overkill for the majority of us?

I'm just wondering whether you'll get sufficient adjustment out of the top mounts?
Thanks for the lessons - learning here :) :thumb:

alot useful/helpful info here. I have BC's on my Newage, so having had a loooong read I am going to follow bonesetters recommendation and use this setup.

https://lh3.googleusercontent.com/-2.../alignment.jpg

I have kept the standard 17 inch alloys which are running on Toyo Proxies P1 but have noticed wear on the inside tyre wall. Am I correct in saying getting the cars geometry setup in the way set out by bonesetter will help this and the driving stability.

There's many ways to skin a cat :) but the way I set-up that new age JDM worked brilliantly. If you went for something along those lines I really don't think you would go far wrong.

Your geo pic link doesn't work btw

Edit: Ooopps, was thinking of another thread - this one, but yes, new age geo print out above stands good

BonesetterArnie1

Here are my Newage STI alignment settings. Whats your take on these settings done a year ago. I will get the geo done real soon but value both your input.

http://www.flickr.com/photos/7683311...in/photostream

Only other suspension mods are the BC coilovers which I dont have the spring ratings for.

Cheers guys

Honestly, he just adjusted your toe. didn't touch your camber settings AT ALL. They are more or less the same as when you drove in. And the camber settings are pretty much doggie doo doo as they are.

ahh I see, apparently speaking to the sales manager at the time the alignment guy who himself owns a supped up Evo was supposed to be the top alignment man there. Yeah right...what a joke he dont no jack.

Cheers Arnie

Here's a thought for all those playing with ride heights and alignments,

Geometry.

Have you noticed that the standard car has a feeling on cornering that when it rolls it pushes the rear corner down? That fitting a bigger RARB reduces this, and that lowering the car makes it feel weird at first?

All this is linked to the magic thing called roll centre.

Basically, look at a picture of a scooby from the front. Superimpose the suspension on your picture. Draw at 90 degrees from the top mount inwards and along the bottom arm from the balljoint through the inner pivot and continue until the extended line crosses the upper one.

Now draw back to the centre of the tyre contact patch. Where the line crosses the centreline of the car, strictly the other line from the other suspension unit coming past intersects, that is your instantaneous roll centre.

The roll moment is the distance from this point to the centre of gravity.

On a Subaru, the rear transverse arms are much longer than the fronts. Both ends have very upright struts ( A VERY good thing thank you, Mr Ford Mondeo designers)

The roll centres are highish and the Cenre of gravity low. Thus with relatively weak springs the Impreza has supple suspension and low roll moments.

That feeling of rolling and sinking at the back? the rear roll centre is lower than the front. Hence the car pivots on an imaginary axis higher at the front than the back.

However, with travel of the suspension, it should (in theory) change less for changes in ride height at the back. My car feels strange now as I've lowered it 30mm at the front and the roll centre has plummeted. The axis has changed and now it pitches the outer front down when cornering.....

Time to lift it back up methinks....Can't afford the RC adjustment kit right now.

Sorry to jump on this but following a post on my MOT failure (both front and rear offside tyres bald on the inside) I have been told my camber is probably wank, I dont do track days and I am really just looking for some settings where I can get a set of tyres to last more than a year as I had to replace all 4 last year fro the same thing, any advice woul dbe great

Had the car in at lunch for a alignment. It's a little bit fiddly and tight in to adjust in the rear so we only had time for the rear and toe at the front. But we will take the front next week I hope.

Here is the result. The second picture is the alignment last year before all the modifications.

The camber in the rear is a little bit to much compared to what I had planed. The left side had -1.9 when we begun so we only adjusted the right side to match. I will adjust the camber at the front o about -2.1 - -2.2. But I have a nice increase in caster after my modifications. Last year i only had 2.9 as you can see and now I got about 5. I will get a little bit more after next times alignment because I've flipped the camber plates to adjust the camber and caster at the same time.


What do you think about my thoughts??

Translation of the words to english =)

aktuellt - current
före - before
fram - front
bak - rear
vänster - left
höger - right

http://img.tapatalk.com/02419546-2dcd-c065.jpg


http://img.tapatalk.com/02419546-2ddd-fdd7.jpg

You can rotate the BC top mounts to gain more caster. When I was using BC's a few years ago I rotated mine and machined the slots out a bit to allow them to move completely to the mas travel allowed by the strut top and had just over 5 deg of static caster. Easy way to gain caster even just by rotating them, you los a bit of camber adjustment but if there is not enough at the top this can be gained using camber bolts.

Attachment 56147

very interesting ready, subscribed so i can find it again :)

i just didnt know how complicated suspension could be. ive read most of the threads about camber castor and ride height.

i have BC coilovers with various whiteline goodies

ive not been on track with this set up yet.

i will be getting my geometry set up in a week or so, from reading other threads would the best set up be camber -2 at the front -2.5 at the rear, castor as much as poss. with slight toe in at the rear. my ride height with my track tyres is 335 front and 345 back.

i will be doing around 2k road miles a year(very few motorway miles) and a fair few trackdays (money premitting)

is the camber to harsh for the amount of road miles i will be doing?

thanks for any help

dazzer