Track Tac

Scaling ?

paulkish

paulkish

old fart
I read scale numbers often on here. We never scaled very often but I just had a thought on it.

When ever I'm at a track everyone always seems to setup their scales the same way. Other then squaring up, leveling the scales and calibrating and zeroing the scales, is there anything else you do to make sure your numbers are right?

I just thought of doing this to ensure your scales were right.

Put the kart on the scales after making sure all is ok and take a reading. Then put your kart on the scales facing the other direction and see if front weight matches up to what rear weight was and if left side now matches up to what right side was.

I think it should, but never thought about trying it the few times we scaled and I'm just curious if the numbers would match. ... I'd bet they don't match, probably come close but won't match up exactly. ... :)
 
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Thebmodman88 said:
Other than making sure they get calibrated every year or two not much I can think of.
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I'm not arguing with you I just thought of this while reading your post. The scales can be perfectly calibrated, but if your leveling is not perfect, couldn't you still be off?

Might this be a way to prove how you did your leveling was ok?

I don't see another way to check to see if how you do your leveling is right or not. I guess that leads me to ask, how do you know you leveled up everything ok? I assume a long level is used going between scales in all directions. Proly never mind on this whole thread, because now thunkin and writing, that seems good enough. ... :)
 
Level doesn't make as much difference as most people think. The largest thing about being level is to ensure that all four pads have weight on them. Leveling everything helps with this a lot. Consistency and repeatability are essential in any weighing operation. When we level the pads, we maintain that consistent foundation. Modern load cell pads can also work themselves loose with usage and handling, so if you have a pad that doesn't want to maintain a stable zero condition, it is a good idea to check the bolts and alignment of said pad.
 
Leveling is HUGHLY important! If one scale pad is just 1/16" inch higher than the others the result is the same as going down 1/16 (or one washer) with a spindle which could be 2-3% cross weight. For left/right or front/rear it doesn't matter that much, but for cross (which is the main purpose of scaling) it does.

Spinning the kart will tell you if the scales are measuring weight correctly, but not that they are level. If one scale is high (lets say the RF) and you rotate the kart, now the LR is on that high scale and your wedge will still read the same (but be wrong).

Uneven scales can work if you keep them that way and set your numbers consistently around them. But when someone says "try 55% cross"- Their 55% will not be your 55%.

I use a 4' digital level and make sure all 4 pads are within .01 degree level of each other. I don't think a bubble level is good enough for this.
 
Rotating the kart will let you know if you scales are not level, I've try it. You can't just look at the cross reading. If your of scale is high it will also give you a false nose and left reading. You will see the readings will be different when you rotate the kart.
 
I have never seen a thin washer (1/16") change cross 2-3% before, usually the thin washers are close to 1-1 1/2% and the thick washers are 2-3% on our karts. Leveling the scales is probably the most important part of scaling that there is, if the scales aren't 100% level you might as well not even use them in my opinion because your readings are not going to be consistent unless you set the scales up that exact same way every time, which would be hard to do and by the time you do that you could have just made them 100% level to begin with. Just my opinion on the topic
 
One item I would add for at track setup would be ensuring you have a solid foundation. You can spend all the time you want leveling your scales to only have them sink into the ground and then you could be chasing the wrong problem and don't recognize it.
 
I like to place a shop towel down on the scales to keep my tires from sticking to them and picking them up when moving kart ... Just a tip
 
MikeleoneCT said:
Leveling is HUGHLY important! If one scale pad is just 1/16" inch higher than the others the result is the same as going down 1/16 (or one washer) with a spindle which could be 2-3% cross weight. For left/right or front/rear it doesn't matter that much, but for cross (which is the main purpose of scaling) it does.

Spinning the kart will tell you if the scales are measuring weight correctly, but not that they are level. If one scale is high (lets say the RF) and you rotate the kart, now the LR is on that high scale and your wedge will still read the same (but be wrong).

Uneven scales can work if you keep them that way and set your numbers consistently around them. But when someone says "try 55% cross"- Their 55% will not be your 55%.

I use a 4' digital level and make sure all 4 pads are within .01 degree level of each other. I don't think a bubble level is good enough for this.
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A bubble level is fine, as long as its a good level
 
XXX#40 said:
A bubble level is fine, as long as its a good level
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+1.

We found a quality 6' level, which makes leveling and repeatability real easy. It gets even easier since we have the shop floor marked for the scale stand feet, so it's usually just a quick check to assure there have been no unintended changes. We store the pads in a heavy duty tote box, separated by thick plywood squares a little larger than each pad, so on those rare times when we scale at the track, we can put those under the scale stand feet for a stable, no sink into the ground foundation.
 
I would think the best thimg to do is scale at home on a solid surface and then when you get to the track use air pressure and prep to fine tune the kart ?
 
Christopher.norman said:
I would think the best thimg to do is scale at home on a solid surface and then when you get to the track use air pressure and prep to fine tune the kart ?
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You'll probably have to use a little more than just air pressure and prep at the track, but yes, that's the approach we feel is best. The last time we scaled at the track was about 2004, but we have set ours up at the track once in awhile to help those in dire need - not everyone can do what is best all the time, and we will try to help those in a bind when we can.
 
I was at Eldora for a Kings Royal race and there was some guy who had several Indy Car engineers working on his sprint car. These guys had it on scales and all kinds of strings and levels and lasers hooked up to the car. Karl Kinser walked by and asked..."what you boys doin?" One of the engineers said...."we're getting the chassis right!" Karl said, "you do realize these things aren't on the ground half the time don't you!" I think the same is for karts....they do flex when they are on the track, and they don't flex the same every time in every turn. I see guys putting their karts on scales every time they come off the track. If you have to scale every time you come off the track, you've got other problems.
 
harrym said:
I see guys putting their karts on scales every time they come off the track. If you have to scale every time you come off the track, you've got other problems.
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They could just be checking their overall weight (vs cross etc.). We have to make weight after each non-practice session (on race days).
 
If they're that close to min weight, they still have potential problems; they really need to leave enough of a cushion (2-3 lbs after fuel is burned off during that session is about as low asyou should risk) that making weight is not an issue. And we assume they regard the track's scale as the last word, not their scales.
 
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