Scales not reading cross properly

Ratistiss

Member
Just got my scales back from intercomp. All of them read the same when a weight is put on them one at a time. My scale stand reads dead nuts in every direction. Both my karts were scaled recently at other places and I have the numbers, which match my scales dead on for left and front weight. My cross though is reading about 10% below what is should be, which seems like a rather drastic amount since both karts have only ran once since being scaled. Any thoughts?
 
Rotate the kart 180* if the numbers on each individual wheel match the previous #'s . You gotta go with it .
10% does seem like a high error margin .
 
I see you said the scales are level in every direction. Make sure that includes diagonally. Also make sure your scales don't rock on the stand. Set your air pressure and verify the camber and caster settings. I also like to lift the front end on and off the scales to verify they repeat.

Are you scaling with the same set of tires on?

10% difference is huge. Are you seeing this on both karts? I can see a bit of difference, especially if it's a kid, based on body position, fuel level, different wheel offset, etc. If you don't find anything to be a "smoking gun" I'd be suspect that the initial scale numbers weren't correct.
 
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Figure your cross out manually with the weights the scales give you...take left rear weight and right front weight add them together then divide that number by total weight ...see if its the same as scales say cross weight is
 
Both my karts were scaled recently at other places and I have the numbers, which match my scales dead on for left and front weight.
If your scales have the exact weight at >>>each<<< wheel as the other place you had the karts scaled, then what the other place told you for cross was "WRONG" or there was a miss understanding.
Cross is a calculation based on weight on the wheels and if the individual wheel weights were the same on your scale as the "other" place, the "OTHER" place gave you wrong information for cross.

If wheel weights are the same then cross will be the "SAME". period end of discussion. maybe???? ... :)

I can't believe your scales are doing the calculating wrong. >>>> do you? that's the only way you can have the error if the other places scales were correct. When's the last time you saw a hand held calculator give you the wrong answer?
answer: never
... and the fancy dan comp scales will do the calculating correctly too.
They may not weight correctly but they will calculate correctly.
Same weights= same answer
different answer and somebody's scale didn't weight correctly butt you said they read the same. ?????
The scale can read incorrectly but it's "STILL" going to pass on what it read incorrectly to be calculated, NOT SOMETHING DIFFERENT.

... MAYBE ???? ... :)
 
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If your scales have the exact weight at >>>each<<< wheel as the other place you had the karts scaled, then what the other place told you for cross was "WRONG" or there was a miss understanding.
Cross is a calculation based on weight on the wheels and if the individual wheel weights were the same on your scale as the "other" place, the "OTHER" place gave you wrong information for cross.

If wheel weights are the same then cross will be the "SAME". period end of discussion. maybe???? ... :)

I can't believe your scales are doing the calculating wrong. >>>> do you? that's the only way you can have the error if the other places scales were correct. When's the last time you saw a hand held calculator give you the wrong answer?
answer: never
... and the fancy dan comp scales will do the calculating correctly too.
They may not weight correctly but they will calculate correctly.
Same weights= same answer
different answer and somebody's scale didn't weight correctly butt you said they read the same. ?????
The scale can read incorrectly but it's "STILL" going to pass on what it read incorrectly to be calculated, NOT SOMETHING DIFFERENT.

... MAYBE ???? ... :)
Your never is my once just saying
 
Turning my LR pad 90 degrees brought up my cross percentage by 4 on one kart and 6 on the other kart. So I inspected the pad a little more and it does not look level, so I am starting to think that may be playing into it.
 

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Just got my scales back from intercomp. All of them read the same when a weight is put on them one at a time. My scale stand reads dead nuts in every direction. Both my karts were scaled recently at other places and I have the numbers, which match my scales dead on for left and front weight. My cross though is reading about 10% below what is should be, which seems like a rather drastic amount since both karts have only ran once since being scaled. Any thoughts?
since they are just back from intercomp . you gotta think they are right .
Funny we had this issue , at home numbers didn't match at track . cross was off . turned out the shims we used to level had some spring in them. Plywood was warped . it setteled in when the kart and driver got in vs just the stands when leveling . Only 2-3 % not 10%.
Driver pointed it out . i was too stuborn to listen .
I would suspect the scale setup at either location .
In the end you have to go with your setup . its a comparison / change relationship anyway .
 
Provided there calibrated, Easy test stand on each Pad individually and check, IF there reading different it's the blocking either under the pad if not using a stand is not consistent, If using a scale stand it's the blocking under the stand legs not being consistent, adjust until they all read the same or extremely close, then take total weight and individual weights and simply do the math, the scales could just not be calculating the numbers correctly.
 
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I've seen some big swings in a new chassis we have race-to-race. The chassis is flexing. Scaled out, went out and raced. Didn't hit anything. Set him on the scale before the next race and the cross was up 6% :oops: Checked the camber. Adjusted it slightly. Didn't help me get the cross down. Ultimately everything checked out and we started moving washers on the front and had good results the next time out.

Perfectly level is a good start. Also keep the things you can control constant. If you don't have to take down the scales or move them then leave them in place. Mark the floor, the scale table, and the scale pads to line everything up the same each time. I also keep a set of tires for scaling out and set air and stagger before scaling out. I make my kids empty their pockets and put their helmet on before getting on the scale. That is a nuance, point is I try to do it the same each time.

flattop1 made a great point above. I would set the scales on a concrete slab rather than a raised floor with joists for reliable results. Also keep in mind the numbers on the scale are just a reference. Once the kart starts rolling and lateral force is applied the numbers change.
 
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