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      05-06-2013, 07:08 PM   #1
Artsee
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Keep front camber bias on square setup?

I noticed that people run a at least .5 deg more of camber up front vs the rear on staggered wheel/tire combos.

I know the macpherson setup up front has very little if any dynamic camber, where the rear has quite a bit.

I am running a square WHEEL setup consisting of 18x9 et45 Front and Rear, however I am running 255's out back vs 245's up front.

Does anyone recommend I run square camber with this setup for street/track use? Also, I am running a 10mm spacer front vs a 5mm spacer rear. And lastly, my camber is maxed out with GC plates and coil overs at -2.3 deg.

Any ideas?

Last edited by Artsee; 05-07-2013 at 01:22 AM.
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      05-06-2013, 07:59 PM   #2
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1 degree more -ve camber up front is very typical for track use. There is no reason to change this for a square wheel and/or tire setup.
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      05-07-2013, 01:15 AM   #3
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Quote:
Originally Posted by fe1rx View Post
1 degree more -ve camber up front is very typical for track use. There is no reason to change this for a square wheel and/or tire setup.
Since a standard staggered setup (many people run 225/265 setups) would have a bigger contact patch and consequently much more grip in the rear, additional front camber helps the car rotate.

With a square setup or something close to it, I'd imagine that less front to rear camber variance is needed to have balanced characteristics.

Anyone run a square setup and frequent the track?
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      05-07-2013, 02:00 AM   #4
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Front/rear camber "balance" doesn't exist - at least as far as I understand. Front/rear camber differential also has nothing to do with tire sizes.

I know I'm being obvious here, but I have to point out that the rear and front tires perform different tasks. The rears have to put the power down as well as possible and provide the best possible contact patch. The rears also don't turn ('doh) and thus there camber range both static and dynamic vary much less throughout the suspension travel, compared to the front.

The fronts don't have to provide the best possible traction in a straight line, they have to provide the best traction and responsiveness in corners - i.e. when the car is loaded asymmetrically and the center of balance is shifting to the outsides.

Long story short, you need different camber settings front->back since the tires perform different tasks.

I'm currently running -3 / -2 btw. with square 255 tires for racing and 235/255 for the street all without problems.

And just for fun, here's a random F1 picture showing the camber differental in F1 cars:

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      05-07-2013, 09:28 AM   #5
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Quote:
Originally Posted by int2str View Post
Front/rear camber "balance" doesn't exist - at least as far as I understand. Front/rear camber differential also has nothing to do with tire sizes.

I know I'm being obvious here, but I have to point out that the rear and front tires perform different tasks. The rears have to put the power down as well as possible and provide the best possible contact patch. The rears also don't turn ('doh) and thus there camber range both static and dynamic vary much less throughout the suspension travel, compared to the front.

The fronts don't have to provide the best possible traction in a straight line, they have to provide the best traction and responsiveness in corners - i.e. when the car is loaded asymmetrically and the center of balance is shifting to the outsides.

Long story short, you need different camber settings front->back since the tires perform different tasks.

I'm currently running -3 / -2 btw. with square 255 tires for racing and 235/255 for the street all without problems.

And just for fun, here's a random F1 picture showing the camber differental in F1 cars:

Thank you for the thorough reply.

Although this makes sense to a certain extent, I would say that an F1 car is not a good example. An F1 car has a tremendous amount of downforce over the rear wheels to keep the contact patch as flat as possible in all conditions. If the car had minimal camber up front, it would be practically impossible to turn.

Also, you mention that the rear is subject to less camber change compared to the front. I disagree with this as well, as this is dependent on the type of suspension--this especially applies here with MacPherson front vs multi link rear.

That being said, your reply got me thinking...since the rear is subject to more camber under compression and the goal is to keep the contact patch as flat as possible to maximize grip (particularly on the driven wheels in a car with short wheelbase), less camber is needed in the rear vs the front, which has practically zero camber change even under load.
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      05-07-2013, 10:09 AM   #6
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Quote:
Originally Posted by Artsee View Post

Also, you mention that the rear is subject to less camber change compared to the front. I disagree with this as well, as this is dependent on the type of suspension--this especially applies here with MacPherson front vs multi link rear.
It also depends on the magnitude of compression. Front suspension tends to roll more, or compress more. Thus, making camber comparatively more important.

One other little tidbit...upping the width of the tire does not increase contact patch area, it alters contact patch shape. And, while a discussion on slipangles, etc. isn't warranted, a wider, shorter (front to back) shape is more advantageous for lateral loading then a narrower, longer shape.

Contact patch area is a product of the cars weight, and tire pressure only (assuming things like relatively similar sidewall strengths across tire sizes, thus permitting them to be ignored).

Contact patch area * PSI better equal the weight of your car, regardless of tire size...or you've just invented a flying car.
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      05-07-2013, 10:37 AM   #7
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I'm running 255 front and 265 rear on my e90. I have no additional camber in front and track the car. I'd definitely recommend a little extra camber. It's much better than stock with the almost square setup but you can see from the wear that some xtra would help. Dinan has a fixed offset plate that adds just a little extra camber. I put these on my 1 along with a 235 front and 245 rear tire setup. I haven't tracked the car yet but gauging from what I've seen on the street the camber offset from the Dinan plates will be perfect. I'll know for sure next month when I go to the track for the first time with the 1.
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      05-07-2013, 12:37 PM   #8
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You can also knock out the camber alignment pin on the struts and slide the bolts as far inward as possible for some free negative camber, i did this on mine. I'm waiting for it to be aligned but i'm hoping it'll full -1 in front with lowering springs and the pin out.
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      05-07-2013, 02:06 PM   #9
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Anyone ever looked into swapping left and right stock tophats?

It would be unlikely, but with an E46 M3, for example, you can get around -2.5 to -3.5 up front by swapping the top hats side to side, in addition to some added caster.

Pathetic that you can't even get a full degree on the stock setup.
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      05-07-2013, 03:07 PM   #10
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Thanks for all the replies.

BTW, I am not running a stock suspension. I have GC Coilovers with koni yellows topped with GC race camber plates. The front camber is maxed out with GC plates at -2.3 deg. Looks like I will need the M3 LCA's after all.
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      05-07-2013, 03:38 PM   #11
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Quote:
Originally Posted by PrematureApex View Post
Anyone ever looked into swapping left and right stock tophats?

It would be unlikely, but with an E46 M3, for example, you can get around -2.5 to -3.5 up front by swapping the top hats side to side, in addition to some added caster.

Pathetic that you can't even get a full degree on the stock setup.
I don't think the stock strut mounts on our cars are side specific. Meaning you can swap side to side without any effect. So, no go in gaining camber that way.
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      05-07-2013, 03:39 PM   #12
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Quote:
Originally Posted by Artsee View Post
Thanks for all the replies.

BTW, I am not running a stock suspension. I have GC Coilovers with koni yellows topped with GC race camber plates. The front camber is maxed out with GC plates at -2.3 deg. Looks like I will need the M3 LCA's after all.
Maybe look into street plates? You can gain more camber with those compared to race plates. I'm at -2.1* and still have about a degree to go.
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      05-07-2013, 05:45 PM   #13
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Man, GC plates max out at 2.X?

Jesus, what is it with this car?
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      05-07-2013, 08:17 PM   #14
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Quote:
Originally Posted by r0nd3L View Post
I don't think the stock strut mounts on our cars are side specific. Meaning you can swap side to side without any effect. So, no go in gaining camber that way.
Correct, the strut mounts are identical, hence the alignment pin is on the left on both sides of the car.

To answer an earlier question, I run square 225 Z11's on the street and track. -2/-1.5 on the street, -3/-1.5 on the track, GC street plates, OE M-sport springs, struts and bars, M3 rear bushings, M3 front arms. 225s fit properly on the OE wheels. I would go wider if I changed the wheels, but will definitely stay square.

The factor limiting front camber on this setup is interference between the OE springs with the strut tower. They will hit at something over -3 degrees. Smaller race springs would give you more available travel. My street setting has a bit of toe in. Shifting to the track setting results in a bit of toe out.
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      05-09-2013, 06:13 PM   #15
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Quote:
Originally Posted by fe1rx View Post
1 degree more -ve camber up front is very typical for track use. There is no reason to change this for a square wheel and/or tire setup.
+1
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