Scaling Kart

Mike Robertson · Posted: Tue Jul 20, 2004 10:18 pm Post subject: Scaling Kart

I need some help with my kart.

I have been pushing pretty bad and finally got some scales to check my kart. With full gear on, scales level, gas in tank, tires at same pressure and tires only 1/16" different in circumfrence. This is the readings I got.

LF 65 RF 88

LR 105 RR 96

How do I go about getting the right balance?

Mike

Michael Polizzi · Joined: 18 Jul 2001 Posts: 1565

Did you check to make sure the front spindles were parallel with the rear axle?
Toe in equal on each side (if any)
Double check front spindle spacers are equal top and bottom.
Check rear axle is equally set for height in the chassis.
Which tires were 1/16" bigger? If its the RF or LR swap the one with the largest discrepancy to other side and re-scale.

Front to back balance is OK but diagonally your off 10%

Re-scale if any of the above needs correcting.

If the above all checks out.

Move one washer or spacer from top of the RF down to raise the spindle.
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Michael Polizzi
Full Bore Karting LLC
KartRaiser.com - The Original Mobile winch powered kart lift - New design!

Mike Robertson · Posted: Wed Jul 21, 2004 9:01 pm Post subject:

Thanks Mike, I'll try that and let you know how it works out.

Mike

Peter Stolper · Joined: 04 Jun 2004 Posts: 130

sorry wrong button............Carry on!
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Mike Robertson · Posted: Sun Jul 25, 2004 7:12 pm Post subject:

Mike,

OK, Front spindles are parallel with real axle. I'm in a Tony Kart and I can't see any way to change the toe.

Spacers were equal, and rear was equal height. RF and RR are 1/16" biger than LF and LR.

I took a spacer out of the RF and put it on the bottom. Then rescaled. It was a little closer, but still out. So I took the spacer out of the bottom of the LF and put it on the top. Then rescaled.

LF 75 RF 75

LR 105 LR 95

Didn't have time to try anything else, and went to the track.

Well, I was real tight. Hopping a lot. It was a race day, so we couldn't try too many things, tried air pressure adjustments. Took front bar out, put back in and added rear bar. Then tried putting front wheels out one spacer. Nothing seemed to help.

Any other suggestions?

Mike

Michael Polizzi · Joined: 18 Jul 2001 Posts: 1565

The tie rods adjust the toe in/out, loosen nuts and turn rods to lenghthen or shorten.

What year and make of Tonykart? and class are your running?

If there have been some heat cycles done to the tires you can swap the fronts to get the smaller tire on the RF which will also reduce RF and LR weight.

Do you have any weight you can move on the kart from LR to RR?

What is the rear track width? front width?

If all else fails: Go back to origional front end.
The part I left out was some times when running the same track constantly with more Left or right turns, the chassis will take a set. You can relieve this by putting a cinder block under the low front tire (higher weight), have someone hold down or stand on the rear bumper and then push down on the floating front corner to re set it.
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Michael Polizzi
Full Bore Karting LLC
KartRaiser.com - The Original Mobile winch powered kart lift - New design!

Michael Polizzi · Joined: 18 Jul 2001 Posts: 1565

All the above said.

Try loosening side Nerf bars. make sure you have rubber washers between floor pan and chassis mounts Wink

I made that mistake with my '02 Mitox125 and nearly broke my ribs, front and back ends were hopping Shocked

_________________
Michael Polizzi
Full Bore Karting LLC
KartRaiser.com - The Original Mobile winch powered kart lift - New design!

Chris Parks · Posted: Mon Jul 26, 2004 5:36 am Post subject:

I have never scaled a kart but am curious about the whole thing. Do you guys scale it with and without the driver and if not why not.
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understeer happens on road courses and usually is pronounced with a British accent. Push happens on ovals and usually is pronounced through a wad of chew. Other than that, I don't think there's a difference - Jim Derrig

Chris

Ed Watts · Posted: Mon Jul 26, 2004 6:10 am Post subject:

Scale it with driver suited and sitting in driving position. It is the most important tuning parameter you need to get a base setting for. Mine is 42% F 58% R.
Racing is all about controlling weight transfer.

Chris Parks · Posted: Mon Jul 26, 2004 5:42 pm Post subject:

Ed Watts · Posted: Tue Jul 27, 2004 4:08 am Post subject:

Chris Parks · Posted: Tue Jul 27, 2004 7:11 am Post subject:

Larry Andrews · Posted: Tue Jul 27, 2004 9:34 am Post subject:

Perhaps there are multiple ways to achieve the same goal?

As my friend from the Netherlands says, "there are many ways to kill the cat." Shocked

Gary Lawson · Joined: 21 Aug 2001 Posts: 542

You always need a starting point. I am a person that always uses my scales at the track but don't necessarily need them because I have used them so much I no what does what and how much. It is also an easy way to detect a bent chassis. Anyone ever had a kart that was loose one direction and tight in the other? If you put it on the scales you would know why. They are not a necessity but are very useful when you know what you are doing. I will say it is much more useful for the fine-tuning needed in the lower HP classes. Karting is about controlling weight transfer, but it is also good to know where the weight is to begin with. You will also see patterns develop in your tuning so you don't have to start from square one all the time.

Gary Lawson

Liav Barshishat · Joined: 25 Jun 2004 Posts: 32

what type of scales do you guys use? I've seen scales that go for about $1,000, does anyone use regular scales? If so, how good do they work?