Cornering Balancing... :)

Hey Guys,

I wanted to get your input on the importance of corner balancing. I’m pretty sure I’m going to get an overwhelming “hell yes” answer from this bunch.

Just as a precaution, I’d like to state that I understand the theory and benefits of the practice and I’m all for it, so please try not to flame. I was curious in terms of a daily driver or a mountain/ canyon car if the benefits could be dramatically felt, as well as, the if it’s worth the time and equipment investment.

I’m trying to convince my mech. that it’s a good investment and that he should offer this services at the shop (once again, I’m in Korea so corner balancing is something that is not well known)

Also any recommendation on scale brands? I see Longarc ads all the time in GRM, I was wondering if they’re up par in terms of quality.

Thanks Guys!

How dramatically it can be felt depends on how bad it is to start with. Honestly, if your coil over perches are close to even side to side, you're in pretty good shape.

The easiest way to notice it is often under braking. The light corners (usually the front one) will lock up first every time.

Longacres have served us well at Flyin' Miata for about a decade. I'd happily buy another set.

I own my own 4 wheel scales and I do use them to corner weigh my race car. They key part of that last sentence is "race car"! Unless you have adjustable spring perches at all 4 wheels I see no reason to go through the trouble. If you do scale a car and can adjust the corner weights you will see/feel a difference. The results are not always measureable via lap times but certainly the ability to put the car at the limit and hold it there more consistently is one result that I found. Also better tire wear or more equal tire wear.

On a street car I just don't see the point unless the car has been modified to the point that the car's original balance has been changed to a point that it doesn't feel comfortable to drive at the limit. Most cars are nose heavy; other then mid-engine or rear engine ones so moving any weight to the rear/trunk area will help any car.

On one front engine/rear drive racecar I moved the engine rearward, the front sub-frame forward and added light weight engine parts all to reduce the F/R weight balance. It made a difference that was measureable but I wouldn't do this on a street only car, not worth the cost and work.

I spend most on my chassis set up time aligning the car. I have found more time via setting the alignment to fit each track I run at then playing around with corner weights. I have worked with a number of Lemons race teams and I have found that a good alignment does wonders for these cars. I have made adjustments that were sometimes questioned by the team but I always say "drive it, see how it feels". A car that feels good and is consistent makes the driver more confident. A confident driver will be a fast driver.

BTY I own a set of Intercomp scales.

You can get surprisingly close by setting ride heights at each corner of the chassis. Be sure to remember to simulate your weight in the drivers seat when you do so.

I used Intercomp scales on my old car but I know lots of people have used longacres without issue as well.

An old drag racing guy I knew used to shim the sway bars on his FWD street cars/drag cars to jack the weight around and increase traction.

So even on a street car, it can be very helpful, especially in a peg-legged turbocharged FWD car.

CarRacer wrote: You can get surprisingly close by setting ride heights at each corner of the chassis. Be sure to remember to simulate your weight in the drivers seat when you do so.

What are you using to measure out the corner heights? Some people say to use the lip of the fender as reference point? Some say to make sure the perches measurements are the same?

Every time I use the latter method, the ride is uneven it seems. I'm using fully threaded bodies so the height is changed by turning the lower mount and does not effect preload.

If you are going to run adjustable spring perches on a street car, you should corner weight the car. I have a set of old school scales that I use. Set the desired ride height, corner weight, align(see article on string aligning). Repeat after every spring change. Make sure there is a driver in the seat or at least something close in weight, and at least a half a tank of fuel.

It's possible to have a level car with the corner weights completely jacked up. For example, if you raise the perches on opposite corners the car will stay level, but that diagonal will pick up a bunch of weight. That's why I mentioned even perch heights side to side. Once you've got them close, level the car. That's good enough for most street cars.

Preload is not a thing. The spring will compress the same amount with the weight of the car on it regardless of preload until you get into boundary conditions where the amount of preload is larger than the corner weight. If you have shocks with adjustable length bodies, then you also want those matched side to side to get the corner weights in the ballpark.

Adjustable length bodies are mostly a way to use a generic shock insert in multiple applications. You lose overall shaft travel by doing do.

If you don't have adjustable perches or some sort of height adjustment on each corner, then corner weighting isn't really possible.

what about equalizing the PSI in the tires and then setting the car down on 4 clean sheets of paper? Measure the areas of the resulting 'tire imprint', then adjust to make the tire imprints equal side to side? (PSI * Square inches = pounds)

I've never actually tried this, but the idea seems incredibly grassroots.

I used to get very close on corner weighting my VW GTI autocrosser/DD by measuring the distance from the top of the front knuckles to the spring platform. The rears were measured for the distance between the perch and the lower shock bolt.When it later became my ITB race car I could jack weight around by counting turns of the perches. My best time was set with my FR/RF set to 52% (the track had more, and faster right hand turns.

rcutclif wrote: what about equalizing the PSI in the tires and then setting the car down on 4 clean sheets of paper? Measure the areas of the resulting 'tire imprint', then adjust to make the tire imprints equal side to side? (PSI * Square inches = pounds) I've never actually tried this, but the idea seems incredibly grassroots.

Ive done this, it works well but i used clean cardboard instead of paper. The only thing is its really time consuming.

echoechoecho wrote:

rcutclif wrote: what about equalizing the PSI in the tires and then setting the car down on 4 clean sheets of paper? Measure the areas of the resulting 'tire imprint', then adjust to make the tire imprints equal side to side? (PSI * Square inches = pounds) I've never actually tried this, but the idea seems incredibly grassroots.

Ive done this, it works well but i used clean cardboard instead of paper. The only thing is its really time consuming.

AWESOME!!! I'm gonna have to try it.

Another thought. What about setting the car down on a known area (as long as it is smaller than the contact patch, like a small brick) and measuring the resulting PSI?

Unless you're a BTTW driver, a street car used as a track car, etc. does just fine with proper alignment and tire pressure adjustments. Or that's been my experience.

About using tire area - it would work best if you had no sidewall construction. Set the car up on a set of inner tubes, for example. It'll work best on soft, high profile tires. Otherwise, you'll find the structure of the tire takes too much of the load.

I tried playing around with tire prints versus pressure a while back and on some tires, you can just about run them flat before there's a change.

Keith Tanner wrote: About using tire area - it would work best if you had no sidewall construction. Set the car up on a set of inner tubes, for example. It'll work best on soft, high profile tires. Otherwise, you'll find the structure of the tire takes too much of the load. I tried playing around with tire prints versus pressure a while back and on some tires, you can just about run them flat before there's a change.

I was thinking about this too. Now I'm thinking about how to make a scale using basically a very small inner tube or bladder and just reading it in PSI.

But then you run into problems of the scale actually squishing down and now your car is no longer level.

SO!

Then I thought about putting a bottle jack under each wheel and measuring the PSI readout with that. Basically it would work like this:

• Set the car on the 4 bottle jacks (would have to make something stable so the wheel/tire can sit on the jack).
• jack each up so the car is up in the air, and make sure it is level in the air (or that each wheel is the same distance from the floor if you have a level floor to start).
• read the pressure of the fluid in each jack.

If the 4 bottle jacks are the same, the area is constant so you can get your percentages straight from the pressure. Otherwise, it should be pretty easy and accurate to measure the area of the bottle jack piston and then translate to weight.

HA! DONE!

Then I start to wonder if all this work is worth it or if I should just find someone who has scales I can borrow...