Scaling. How important is cross weight?

So new kart. And I’m scaling it currently. This a quick and dirty just to try and figure out where I’m at. Surface should be level but I haven’t got the level out yet to confirm. as I just wanted to see where I was at.

Does this tell you that anything is wrong? And where would you place weight based on this?

This is what I have been kicking around. But my cross is still terrible and front/rear is meh

Cross is fairly important and can be used as a tuning tool on occasion. Starting at 50/50 is the goal. If your seat is in the right spot and it’s still off that much I was start looking at chassis straightness or making sure nothing is accidentally offset.

Yep that’s what I was afraid of. Unfortunately I’m not going to be able to do a thing before the next race. I’m going to take a bunch of measurements tomorrow. See if I can figure out what it is. Maybe need to offset the seat more to the left possibly?

I have found a few setup issues that might have been causing it as well. Need to find someone with a chassis table. @DavinRS does HRE have one?

Honestly it could just be my scales too. Going to press forward and see what it does this weekend. If it’s not drivable then I’ll start going down the rabbit holes. Supposedly only 4 races on the chassis. And based on zero rub marks on the chassis I tend to believe it

Were the pressures set even?

Scales 100% level?

Pressures no. And level-ish. This was a quick and dirty to see where about I was. But it threw me off when my front left was heavier than right front.

I rechecked my seat measurements. And they are spot on to manufacturers recommendations. I’m going to rescale once I make sure we are squared away.

Did you have an appropriate fuel load in the kart? Other than that, were the weights actually mounted or just placed in roughly the right spots?

They were not mounted. I used that app to play around with placement. First pic was no weights. Second was with weights in about where I thought they would go.

This is weights installed. Front/rear a lot better. But cross still off. I might see if I can move the motor over another half an inch. That should help quite a bit.

What class and chassis is this? I agree that front/rear looks a lot better, but left to right is a little trickier to get correct.

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Scales being level and tire pressures being set correct can have a massive impact on corner weights.

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Everything needs to be dead level and square or you’ll drive yourself crazy.

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It’s been years since I’ve scaled a kart, but back when we did, our general rule of thumb was to have the fronts within 5lbs of each other, and the rears within 10lbs. As others have mentioned, really no point in scaling if they are not completely level, and tires are not set to equal pressures.

If you’re latest read out is an accurate representation of your corner weights, then you’re going to notice a pretty significant difference in how the kart turns left vs. right.

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Agreed with the sentiment that you’re really sort of wasting your time scaling if the scales aren’t set up properly.

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from the 1st set up.

Total 338.00
Front 41.42 %
Left 46.15 %
Cross 44.97 %
Left Front % 21.30%
Left Front lbs 72.00
Right Front % 20.12%
Right Front lbs 68.00
Left Rear % 24.85%
Left Rear lbs 83.99
Right Rear % 33.73%
Right Rear lbs 114.01
Front Cross lbs (4.00) Difference Right to Left
Front Cross % -5.87%
Rear Cross lbs 30.02 Difference Left To Right
Rear Cross % 26.33%
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I have pasted below your sessions. You have something up with the scales or you’ve got a chassis that is showing issues. Is the wheel centered? Seat bound up? Spindles at same ride height? Same ride height across axle? As many have mentioned, make sure you have air the same all around and scale must be level.

What scales are you using? High end as in intercomp, longacre or possibly bathroom or postal scales?

If you have a digital angle finder that is the best way to get level if you don’t have a high dollar level. Check out menards, lowes etc for one. Can place it on top of your level. Once scales are level you can also double check rear axle by placing on axle.

Session 1 – No weight LR is 84#
Session 2 – Proposed weight LR is 92#
Session 3 – Weight actually placed LR is 84#

If you truly placed 10# near where session 2 shows, that number should not be equal to session 1 with zero weight in the kart. I would like to assume you will see 7-8+ lbs min on the corner. Your RR went up 5# also. In theory with the weight added to LR and LF that RR number would have moved lower by a bit.

Just my .02. Hopefully we can all work to get you squared away.

no%20weight proposed%20weight actual%20weight%20added

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Yeah im going to take it to some proper scales and see where I am at.

I am not to familiar with your area but I would bet most kart shops out that way can help you out or a local racer. Maybe try asking on a local club page, regional series page or even the 206 racers page on FB. I’m sure someone would be more then willing to give a hand.

As a quick check turn the kart around and compare numbers.

Just for kicks - to see how things affect your corners

  • Move your head around and compare numbers
  • put a little steering lock in both directions and compare numbers
  • Shim between scale and tire 1/8" & 1/4" and compare numbers
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Scaling is truly something that can send you crazy…for a start the scale pads NEED to be all level wrt each other. This alone is a massive challenge as almost no one has a 100% level floor. Which brings me to shimming the scales somehow to get them level.

Believe me, I’ve lost quite a bit of hair doing this, if is incredibly difficult to do if you don’t have the right equipment. What is the right equipment? Scale leveller pads, the scales go on them and then you have 4 adjustable legs to get it perfect…problem is go search up the cost of these…its literally an arm and a leg!

I tried using coins to shim them but then they shift easily and it gets incredibly time consuming.

This is a topic that I have a keen interest on and would one day like to try with the right equipment to get a kart to scale close to perfect…to date I’ve not been able to achieve this.