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Old 03-26-2006, 09:08 AM   #31
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A example of this would be the assoc TC3 when the factory drivers started milling out the center rib on the car so they could get the battery closer to the centerline of the chassis to balance the car better without having to add a lot of balast.....
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Old 03-26-2006, 09:12 AM   #32
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Quote:
Originally Posted by lookinco
okay, after reading the thread and some other old thread, here is my understanding.

Bascailly, there are two ways to balance a chassis, one is with 4 scales, and the other way is to use the hudy tool or something similar under the middle of the chassis.

I believe both of the above way works but they achieve different things.

First with the hudy tool way, I believe this is how you distribute the weight of the chassis evenly left and right. In order for the chassis to be balanced perfectly on the hudy tool, the Center of gravity of the chassis must be right in the middle or else the chassis would fall on either left or right side. This way of balancing have nothing to do with the suspension and is simply balancing the weight distribution.

Now with the 4 scale ways, this is how you balance the car based on corner weights, which means how much weight the car is putting on each wheel. This is the part where you adjust your suspension until the corner weights are equal. I believe this is not a perfect way to truly balance a chassis. Even though people would argue that if the corner weights are all the same on all 4 wheels then the chassis must be balanced. However I believe that even if you have an unbalanced chassis to start with (one side heavier then the other), you could still adjust the suspension to compensate and achieve same corner weights on all 4 wheels. The car might have perfect equal corner weights when you put it on the scale sitting there. However, when you are running the car, weight transfer from the left to right, right to left, front to back etc..........and I beleive this is where there would be problems if you have a chassis that is one side heavier then the others. One side would transfer more weight to the other side and cause handling issues.

That's why I believe that BEFORE you balance your car on 4 scales, you should make sure your weight distribution of the chassis is balanced first. Then you could use the 4 scale to make sure your suspension is setup correctly to achieve equal corner weights on all 4 wheels.

I have no scientific prove of what i said above, it's just strictly what I believe. Please correct me if I am wrong.
You're pretty much dead on with this. I don't even use the scales anymore. I balance the chassis to make sure the weight is properly distributed and then put setup wheels on it (they won't have the deflection that tires will that could make this a little more difficult) and put it on a perfectly flat, level setup board and check the tweak by lifting one end of the car. On our car we have a notch in the center of the shock tower just for that. As long as the droop is exact on both sides and the chassis is straight, when you lift one end of the chassis, both tires should lift off the ground at the same time. Theoretically, if the chassis is balanced, the droop is equal on both sides, and there's no binding in the suspension, you should be able to have your preload collars at exactly the same position on both sides. But because of the slight variances in springs, you may need to adjust them slightly to get the car just right.
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Old 03-26-2006, 09:15 AM   #33
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basicly on a touring car if you have a well balanced chassis(unsprung) and your ride heights are set the same and your tires are all the same circumfrance then by using scales or a tweak station you fine tune it by adjusting out any chassis tweak or making up any differance in spring lenths to get your sprung weight equal on all four corners.
Pretty much what Jon said...........
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Old 03-26-2006, 03:14 PM   #34
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Quote:
Originally Posted by Jon Kerr
You're pretty much dead on with this. I don't even use the scales anymore. I balance the chassis to make sure the weight is properly distributed and then put setup wheels on it (they won't have the deflection that tires will that could make this a little more difficult) and put it on a perfectly flat, level setup board and check the tweak by lifting one end of the car. On our car we have a notch in the center of the shock tower just for that. As long as the droop is exact on both sides and the chassis is straight, when you lift one end of the chassis, both tires should lift off the ground at the same time. Theoretically, if the chassis is balanced, the droop is equal on both sides, and there's no binding in the suspension, you should be able to have your preload collars at exactly the same position on both sides. But because of the slight variances in springs, you may need to adjust them slightly to get the car just right.
Jon, unless something has changes on the Mi2 EC, the original Mi2 does not have any centerline holes so how are you balancing the car?

Other car chassis also don't have any centerline holes.

In the past, I have measured the chassis at four points using a very percise measuring table and snap a line down the center crossing my four measuring points in the center and then using a 1/16 drill bit made my centerline holes as far out on each end of the chassis as possible.

Is there a another way to measure without the centerline holes?
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Old 03-26-2006, 11:28 PM   #35
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The car has the center notches on the underside of the shock towers. I take a string and run it from the front to the back and string it up. Then use a bullseye bubble level on top of the top deck to tell if it's balanced or not.
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Old 04-13-2006, 06:50 PM   #36
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Ok I just changed over to a wardspeed chassis TC3 and can't get it to balance out right here are the numbers.

RR 374 339 LR

RF 365 310 LF


The ride hight is set at 5 mm front and back.
Any thoughts
B
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Old 04-14-2006, 04:55 PM   #37
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Rockdog. This FTTC4 has perfect balance and is a legal weight. Ballast was added to make it so.
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Balancing a chassis-fttc%24-ballast.jpg  
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Old 04-15-2006, 06:30 AM   #38
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But almost 90 grams worth sounds like alot.
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Old 04-15-2006, 10:28 AM   #39
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You can reduce this weight by mounting the electronics as close to the right edge of the car as practical. The battery is heavy. The way that you find your ballast weight is to weight the car and subtract from 53 ounces which is the roar legal weight. The top drivers at our track do this for club racing just to even the playing field and prevent any complaints. Notice there is also a transponder practice weight which is about .8 ounces. He balanced the weight on this car by using two knife points in the center front and back and picking up the car to see if it lifted even. He balanced front to back weight based on years of experience with several cars, a few of which we had put on the scales. I checked this car on the scales and it was very good. A little excess weight in the back (just like on my car) and very even side to side on corner weights.

Last edited by John Stranahan; 04-15-2006 at 04:43 PM.
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