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How important is getting all 4 corners of the car perfectly balanced?

How important is getting all 4 corners of the car perfectly balanced?

Old 04-03-2015, 10:54 AM
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Default How important is getting all 4 corners of the car perfectly balanced?

Ok. So late last year I bought a SkyRC Corner Weight System (see pic) which is a great way to measure weight on each tire. However I discovered that it is very rare to have a perfectly balanced car (same weight on all 4 tires). I tried moving electronics around and adding some Lead and Tungsten weights to my chassis to get close to perfect balance, but it still does not come anywhere close to a balanced car. My corner weights vary from 5g to 30g from corner to corner.



Open question: How important is having a (near) perfect balanced car?
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Old 04-03-2015, 10:58 AM
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I also saw this video which helps (a little) understand the importance of balance...

+ YouTube Video
ERROR: If you can see this, then YouTube is down or you don't have Flash installed.
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Old 04-03-2015, 11:09 AM
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I put my car on pins to get the left/right balance correct but do not use scales. I'll also rock the chassis on the setup board to compress one end of the car to check the spring preloads are close. IMO you want more weight on the rear of the car, especially for high grip so I never worry about making f/r 50/50.

Also with scales you should try to make sure you put the same scale on each corner every time, they might read different so if you swap them you will be pulling hairs out trying to figure out what changed
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Old 04-03-2015, 11:26 AM
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For me, using scales is more of a tool to check tweak.

When I assemble my car for a race day or even just a run I make sure the chassis is straight with my setup blocks and piece of granite tile I use as a setup board. Then I do something which might be unusual, I flip the car over on the tile and check to see if there is a tweak when the car is sitting on my shock towers, and if the chassis is straight it likely will be near perfect. If that's all good I will put my setup wheels on the car and check for even ride height all around, which it should be if I have the correct preload on all four springs.

THEN, if I want to be really pedantic, I get out my four cheapo $7 each digital scales I got from Harbor Freight. If the car is straight in all other respects it will be pretty close, sometimes I hit it right on the nose and have almost no crossweight. This step is mostly unnecessary, as I found that as long as both the main chassis plate and shock towers are FLAT and the ride height is even as well, the car will drive true and have equal performance in left and right turns, which is the important part.
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Old 04-03-2015, 11:28 AM
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Thanks Mike. Also, have you ever added weights to your chassis to get the balance closer to 50/50?
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Old 04-03-2015, 11:43 AM
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Originally Posted by wwddww34 View Post
Thanks Mike. Also, have you ever added weights to your chassis to get the balance closer to 50/50?
Yes, my cars I need to add weight to the electronics side to balance the car. I added 20g roughly to balance it. Works out since I need to add about 20g anyway to make weight. Most people will likely need weight on the electronics side, especially in stock since batteries are so heavy now
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Old 04-03-2015, 11:46 AM
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I agree with Gee. Just put it on the pins and make sure the left to right is balanced. Ive never used the scales and think it would just become a pain in the ass trying to get all the scales correct.
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Old 04-03-2015, 11:50 AM
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The SkyRC corner weight scales are not all that entirely accurate. Me and a buddy of mines had issues with ours. I guess you get what you pay for.
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Old 04-03-2015, 12:10 PM
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When I do a "fresh" build, BEFORE I install electrics, I'll use TWO identical batteries, one on each side. Then I'll completely setup the car with camber, caster, ride height and droop with the two batteries ( a little bit of double stick tape ensures they won't move ). Then I'll ensure tweak is accurate via a number of methods ( visually, as Mike mentioned above ) , tweak board, and including a sanity check with 4 corner scales. Then after I install electrics with the needed weight to balance the car on pins I'll double check tweak and ride height and lastly droop.

You can get a car balanced left to right with pins, but the cross weight ( mass, not pre load ) can still be off due to the electronics being a different shape and position compared to the one piece monolith a battery is. So using two batteries makes sure this isn't happening. Good quality corner scales can show you that the cross weight is off, but it could also be a tweak from unequal spring pre-load.

The use of two batteries before installing ALL electronics ( including servo ) ensures that your static weight is equally balanced and any tweak is due to spring preload being off. If it isn't then you know to look for missing shims, bent parts or that camber and caster aren't set properly... ( oh yeah, shock length too )

Then you can add weights to the electrics side ( usually ) to balance the car on pins. Then recheck everything to see where added weight should go, forward or back on the electronics side. I usually use tungsten under the receiver or esc.

p.s. setup wheels are a must when using corner scales !!!

Hope that helps,

Jake D.

Last edited by Magnet Top; 04-03-2015 at 12:32 PM.
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Old 04-03-2015, 12:54 PM
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Thanks Jake! I didn't even think about using aluminum setup wheels instead of my rubber tires. I'll bet that the setup wheels will make the corner measurements more consistent.
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Old 04-03-2015, 01:06 PM
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Unfortunately the heavy motor in the rear of a touring car makes it impossible to achieve a symmetrical left/right rear balance. So in the end you have to work with damper preload...
I have the Zeppin Racing Digital Tweaker Scale Elite and found for myself that if the above written is reality then the precise work with my Hudy Quick Tweak Station does the work with a tolerance of +/- 5 grams.

For the initial build and positioning of the electronics I like the scales. At the track a tweak station will do the job very well.

A good balance is in my opinion very important for a good consistent behaving car. I check it after every impact or touch with a wall or fellow racer.
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Old 04-04-2015, 12:12 AM
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I had the SkyRC corner weight system and ended up selling it. To me it created more problems than solving any.

And if I tapped on any of the wheels the weight would change some grams and ind the end it was like chasing a "ghost".
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Old 04-04-2015, 05:12 AM
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Well guys, I think that after you do all the above mentioned work with the setup board and pins, you'll need to use four scales for crossweight check(within 10g), but you'll need to take the car off the scales from time to time and work the suspension before remeasuring the crossweights. When the readings get consistent, then you install the body and check again... If the readings stay consistent, then you're ready to race...
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Old 04-04-2015, 02:23 PM
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Originally Posted by Salkin View Post
I had the SkyRC corner weight system and ended up selling it. To me it created more problems than solving any.

And if I tapped on any of the wheels the weight would change some grams and ind the end it was like chasing a "ghost".
The only way to get consistency with those types of scales is to use hard setup wheels and even better, lock the shocks to take out the spring.

Too hard.
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Old 04-04-2015, 02:35 PM
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Also remove the sway bars.
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