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Old 07-20-2009, 02:40 PM   #16
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place car in hand like pizza dough, then find the balance point with index finger and....

Whalla! Car is balanced!
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Old 07-21-2009, 01:29 AM   #17
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Originally Posted by Cpt.America View Post
Sorry I didn't see this reply here. My tray was about the same weight as yours, and I ended up drilling all of the holes out, to about 4 times their initial size to get the car balanced (the holes are about as big as a dime). How much you have to drill them will completely depend on what electronics you are running, so go slowly. It doesnt matter what lipo I am using... it matters which one YOU are using. You have to drill, measure, drill, measure. . . etc.. I think I drilled and checked weight 20 times. I used a dremil and it made short work of the manutech tray. Once its 50/50, weigh your car to see how far under 1500g you still are, and add that weight BACK to the car, right down the middle. Don't forget that the body and body clips add up as well, so you don't want your car to be 1500 with no body... you will be over by quite a bit once the shell goes back on.
Thanks.

I tried using the manutech tray and balancing it again but i was no were near the 1500 mark. Much higher almost 1580.(With perfect side to side balance. Not sure what im doing differently but oh well

I ended up using the lighter tray i had and placed most of the weight in the centre and it was much better. I bettered my best lap time by .3 of a lap. But that was with a different setup and better motor. (SP 4.0 to a x11 4.0) For those wondering. I managed to outqualify the other two modified cars i was running against, which i have never done before.

Once again Thanks for all your help.
And thanks to everyone else that gave me advice

Antoni
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Old 07-21-2009, 01:10 PM   #18
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Best way to balance in my opinion is to first adjust left and weight bias by balancing on some pegs. After this is done, measure the wheel loads on each wheel using 4 scales. Adjust the crossweight to equal 50/50. This is different than getting the load equal on opposite wheels.

For sake of simplicity, lets assume we have a car that can balance on two pegs. However, when it is measured on scales, it is LF 395, RF 405, LR 505, RR 495. The crossweight is figured up by adding LF+RR=CWL (ex. left front + right rear = crossweightleft) and RF+LR=CWR;
395+495=890CWL, 405+505=910CWR. So it appears that the LF&RR Crossweight is 20 grams lighter than the RF&LR crossweight. This means under acceleration the car will probably veer right and under heavy braking the car will veer left due to the increased traction and wheel loading @ CWR over CWL.

The way to remedy this is to adjust all four shock preloads. The amount of turns of the shock collar must be the same for each front shock and the same for the rear. So in this case, we'll adjust the front by one turn and the rear by two turns just as an example. Because CWL is less than CWR, we must add preload to CWL and take some away from CWR. Adjust LF by adding one turn of shock preload and adjust RF by taking away one turn of shock preload. For the rear, adjust LR by taking away two turns of shock preload, and adjust RR by adding two turns of shock preload.

Re-measure the wheel loads and see how close we came to a 50/50 balance. Remember, we can achieve a 50/50 balance even if left and right front and left and right rear wheel loads are different. However, when this happens, this means the car isn't balanced left and right, but the crossweight is right and it should handle decent.

Usually it takes several adjustments to get the crossweight balance to be 50/50.

Sometimes it is beneficial to bias crossweight or left-to-right weight to take advantage of a particular track. If you are on an oval, bias the weight to the left of the car, and bias the crossweight to CWL.

Shown below is an oval offroad XXX-T with a custom made tweak scale I made. You can find more information about that in my signature. Sorry I don't have a picture of my touring car on the tweak station, but it works the same.

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Old 07-21-2009, 01:23 PM   #19
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I bought 4 scales in the past and then promptly sold 2 of them haha. Nearly impossible to get a good reading without tinkering with the preloads late into the night. I figured getting to bed earlier would help me on race day more
I just balance left to right or front to back now and correct spring collar tweak on a MIP tweak station.
As an example look at the difference in preloads Mattnin had to dial in to get the 4 scales to balance

just my $.2
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Old 07-21-2009, 01:49 PM   #20
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That XXX-T in the picture had a tweaked chassis and it was my first ever "balanced" vehicle. I took this picture about an hour after I made that tweak board, and I still had a lot to learn. I really should show updated pictures of my balanced vehicles, it is not like that at all. I now know that if preloads are that much off, the chassis must be tweaked or there is a broken or loose parts which is more valuable information.

Using the 4-scales method, I can tell if a part is broken on the car. A friend of mine had me balance his car, and after about 5 attempts, I was getting nowhere, the preloads looked like shown in the picture, awful. I told him his chassis must tweaked and to check all the screws or look for broken parts. We ended up finding out he had a broken plate underneath the shock tower.

The math can become complicated, that is true. But I made a program using a TI-92 calculator that calculates up everything for me in seconds so I am no longer fiddling with a paper and pencil. This program is written simple and I believe can be adapted character-to-character into earlier TI calculators, and if you are decent at programming, you can get the idea and make your own program. If anyone is interested, I'll share my program with them. Also, there is another valuable program on the Apple I-phone, I forget the name of it but it can also calculate crossweights too.

Yes, this is a very involved method to getting your car set up right, but you will hear from some racing greats that this is the best way. In full scale racing, 4-scale setups are essential.
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Old 07-21-2009, 01:58 PM   #21
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Quote:
Originally Posted by MikeR View Post
I bought 4 scales in the past and then promptly sold 2 of them haha. Nearly impossible to get a good reading without tinkering with the preloads late into the night. I figured getting to bed earlier would help me on race day more
I just balance left to right or front to back now and correct spring collar tweak on a MIP tweak station.
As an example look at the difference in preloads Mattnin had to dial in to get the 4 scales to balance

just my $.2
Is it true to always have an equal preload L and R...meaning same amount of turns on the collar? I am asking because I just finished reading the Hudy setup manual and it mentioned that equal preload is important.
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