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Old 01-04-2006, 08:00 PM   #1
Scott Farmer
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Default The merits of Corner Balancing?

I did a search, but couldn't find a concensus opinion on the benefits of corner balancing. What are the benefits of corner balancing for either autocross or open track usage?

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Old 01-04-2006, 08:06 PM   #2
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If
a) You want to win or care about winning
or
b) its free or almost free
dooo it

Otherwise, don't spend mega bucks on it.

-Tom
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Old 01-05-2006, 12:17 AM   #3
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Quote:
Originally Posted by trhoppe
If
a) You want to win or care about winning
or
b) its free or almost free
dooo it

Otherwise, don't spend mega bucks on it.

-Tom
a= Check

b= Check

So I am good to go. I am at 50/50 cross.
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Old 01-05-2006, 12:33 AM   #4
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how do you do it?
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Old 01-05-2006, 12:39 AM   #5
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GO to a shop that can do it, or know a friend who works at one.
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Old 01-05-2006, 12:40 AM   #6
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maybe I should have asked exactly what is it? I have a general idea, but only from listening to a few people mention it....
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Old 01-05-2006, 12:42 AM   #7
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With coilovers you can adjust the ride height, which tranfers the weight of the car. It is ideal to have a 50/50 cross weight, so the car is balanced well. It helps through cornering to have a well balanced car.

Am I right Tom?
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Old 01-05-2006, 12:49 AM   #8
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by cross wiehgt do you mean front to back or side to side? Or both? I was watching a show about the 350z and they said the optimum weight balance was like 55/45 (rear/front) so when you were braking the car would shift to a 50/50 weight balance? I have no clue about any of this so forgive my ignorance....

Last edited by Phil Jr.; 01-05-2006 at 01:05 AM.
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Old 01-05-2006, 12:53 AM   #9
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I am still learning myself, so Tom, or one of the other autox/track guys, may need to chime in to correct me if I am wrong.

Well you can balance it for both, but I believe it is ideal to have it side/side. IF what you mentioned above is correct then you would want it 45/55 cause under brakign the weight tranfers forward. Plus you have to remember that that is for a RWD car, and ours are AWD, I am sure there are some difference in how to balance them.
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Old 01-05-2006, 01:36 AM   #10
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Since a Subaru will never be 50/50...What is importane is the "Cross Weight". Basically, the combined weight of opposing corners should be close to equal. I don't have the numbers exactly in front of me, but when mine was done it came out very close where
LF + RR = RF + LR.

So for example (hypothetical #'s) the Right front(RF) weights 1050, the left rear weighs 920 (LR) and the Left front (LF) weighs 1045 and Right Rear (RR) weighs 925. The cross weights are both the same at #1970 You want that cross weight to be as close to 50/50 as possible.

Also, just for info, my car has a 57%/ 43% Front/ Rear weight balance.And, Like you guys said above, this transfer of weight is achieved by adjusting the coilover suspension to transfer load from corner to corner.
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Old 01-05-2006, 02:25 AM   #11
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Quote:
Originally Posted by lagnwagn
Since a Subaru will never be 50/50...What is importane is the "Cross Weight". Basically, the combined weight of opposing corners should be close to equal. I don't have the numbers exactly in front of me, but when mine was done it came out very close where
LF + RR = RF + LR.

So for example (hypothetical #'s) the Right front(RF) weights 1050, the left rear weighs 920 (LR) and the Left front (LF) weighs 1045 and Right Rear (RR) weighs 925. The cross weights are both the same at #1970 You want that cross weight to be as close to 50/50 as possible.

Also, just for info, my car has a 57%/ 43% Front/ Rear weight balance.And, Like you guys said above, this transfer of weight is achieved by adjusting the coilover suspension to transfer load from corner to corner.
12345
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Old 01-05-2006, 09:00 AM   #12
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Quote:
Originally Posted by Crash477
I am still learning myself, so Tom, or one of the other autox/track guys, may need to chime in to correct me if I am wrong.

Well you can balance it for both, but I believe it is ideal to have it side/side. IF what you mentioned above is correct then you would want it 45/55 cause under brakign the weight tranfers forward. Plus you have to remember that that is for a RWD car, and ours are AWD, I am sure there are some difference in how to balance them.

Adjusting the coil-over spring seats will not change the front / rear or left right / percentages, that can only be done by actually moving or removing mass in the car.

It is possible to have the car sitting level, but the cross weight way off.

If there's more cross weight LR and RF, the car will want to understeer more turning left, and understeer less (or oversteer more) turning right, vice versa for more cross weight on RR and LF.

In most cases you'll want the car to behave the same turning left and right.

In some road race situations, I have intentionally put cross weight in the car at tracks where the corners were predominantly tight in one direction, and fast in the other, to make the car rotate better turning right, and more stable for a fast left hand bend.
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Old 01-05-2006, 10:14 AM   #13
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Old 01-05-2006, 10:53 AM   #14
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Default

Aaron beat me to it.

That is a great article.

Like M.Hurst says, changing a corners ride height will change only the cross weights.
It will also change the alignment.

So the process will have you setting the ride height roughly, then the alignment, setting corner weights, then re-setting alignment, re-setting corner weights, etc. until the law of diminishing returns tells you that you are done.
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Old 01-06-2006, 03:27 AM   #15
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Quote:
Originally Posted by Aaron B
Wow, awesome article. Thanks for the link.
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Old 01-06-2006, 08:26 AM   #16
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A more simple explanation is that cornerbalancing ensures consistent contact patch pressure (and thus adhesion) at each tire.

As weight transfers in a corner, contact patch pressure goes up on the outside tires and decreases on the inside tires, and does so at each corner in a fashion that can be described (if you graphed it) by a sort of modified parabolic curve.

Cornerbalancing ensures that the tires have similar enough pressure ramp curves that transitional handling is consistent in both directions and under both braking and acceleration. It also helps to eliminate directionally inconsistent understeer or oversteer conditions caused by inconsistent contact patch adhesion on one or more corners.

In short, it can both A) increase grip and B) make the car much more consistent and predictable during handling maneuvers, allowing the driver to push the car harder while retaining control.

Hope this helps.
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Old 01-06-2006, 01:39 PM   #17
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so corner balancing should be done with the driver in the car right? Or the weight of the driver should be compensated for,correct?
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Old 01-06-2006, 02:30 PM   #18
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Correct.
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Old 01-06-2006, 02:45 PM   #19
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Quote:
Originally Posted by Phil Jr.
so corner balancing should be done with the driver in the car right? Or the weight of the driver should be compensated for,correct?
If you want to get real crazy you would corner weight with the same wieghts as when you compete (spare tire, gas level, driver, passenger, etc) weight near the center line of the car will have less of an effect on the balance. ei, the car will likely be close to 50/50 with or with out the spare tire, but a driver will make a noticable difference.

Personally, I could care less if my car were balanced. At this point there are far more things to optimize that will actually improve my times. Of course, every little bit helps, and for classes with limited mods / adjustability you might as well do it so long as its cheap.
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Old 01-06-2006, 03:24 PM   #20
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What prices have you guys paid (assuming you don't know anyone at a shop that can perform this task- i.e. full price) for your corner-balancing work?

I'd be interested to know how + when the alignment would best be set when performing this procedure.
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Old 01-06-2006, 04:03 PM   #21
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The vehicle should be aligned following the cornerbalancing, to whatever spec is appropriate depending on your particular vehicle setup and type of motorsport.
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Old 01-06-2006, 05:25 PM   #22
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Quote:
Originally Posted by javid
Of course, every little bit helps, and for classes with limited mods / adjustability you might as well do it so long as its cheap.
How are you going to cross-weight without height adjustment, though?

By the time you get everything set up to align, adjust and test-fit wheels and tires, corner weighting seems like a worthwhile step to me. I spent four or five hours noodling around with all the settings on the alignment rack last season, and the corner balancing only took another 45 minutes or so.

Finding a set of scales is probably the biggest problem to overcome.
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Old 01-06-2006, 07:08 PM   #23
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Adjusting your corner weights is a big step from simply thrashing your car at the track to the bestof your ability. You can indeed alter the weight percentages from front to rear, although to a very small degree.

One of the big things missed here is that if you have sway bar(s) fitted, they'd need to have threaded/adjustable links to remove any binding or undesired cross weight.

Lots of talk about how adding or buying parts are more important than playing with corner weights--that's fine, but when one is done buying all of those things, and in a road racing/auto X environment, the only thing to make those additions work are the 4 little tires sitting on the ground.

I've watched countless people put a zillion hp under the hood, go to a track, and end up treating it like nothing more than a collection of mini drag strips while coasting around the turns--pretty lame.

Since the question was about handling and not power, I'd suggest you look up your local SCCA chapter, find a race prep shop that can answer some questions and possibly help.

Making any car go fast in a straight line is easy. Making it go fast while turning left and right isn't---getting your car properly balanced, and then beginning to tweak that balance to what suits your driving style the best is a smart move. Getting your car to work best with those 4 little tires is a great call.
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Old 01-06-2006, 08:24 PM   #24
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Quote:
Originally Posted by javid
If you want to get real crazy you would corner weight with the same wieghts as when you compete (spare tire, gas level, driver, passenger, etc) weight near the center line of the car will have less of an effect on the balance. ei, the car will likely be close to 50/50 with or with out the spare tire, but a driver will make a noticable difference.
I had mine balanced with no spare, jack, mats, and with me in it. In Autox trim pretty much
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Old 01-07-2006, 10:46 AM   #25
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Quote:
Originally Posted by MPME
One of the big things missed here is that if you have sway bar(s) fitted, they'd need to have threaded/adjustable links to remove any binding or undesired cross weight.

Very important point often lost when people start cornerweighting their cars. If you have adjustable endlinks, one usually cornerweights the car with the swaybar disconnected. Once you get that set, you reconnect the bar and adjust the endlinks accordingly so that there is no pretention on the bar.

Another way to visualize what cornerweighting is, is imagine a table or barstool with four legs. If one of the legs us uneven or the ground is uneven the stool or table wobbles. By adjusting the little caster under the leg or shoving some coasters under it, you get even weight distrubution and no more wobbling. Same basic idea for a car. One adjusts the coilover height till there is even distribution across the corners.
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