help with junior driver setup (scaling)

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dirttrax

New member
I'm looking for good starting numbers to scale my 6yr sons rage champ car to. I haven't set it on scales yet but will this evening. Right now he gets in and through the turn good but blows the tires off and spins out alot on exit. We are running pinks and blues. The Kart Is A Early 2000,S Rage Sr CHAMP Fitted For A junior. He runs a stock clone motor with a weenie pipe. Any help would really be appreciated. Thanks
 
Contact Jeff at Rage, Usually the spin out on exit problem at that age is tight ( push ) on entry he has to put to much wheel in it when it grabs it goes snap loose and they spin, watch his hands for amount of steering input, If it's not tight in then maybe to much rear stagger.

Good Luck !!
 
I did that a lot on my 1st day of karting. Thing is, I learned pretty fast, and the fact that I was 25 years old when I started probably helped. I would think a six-year-old would have a little more trouble at it. Perhaps dad is expecting a little too much,..............you think? I can imagine it takes a lot of patience getting started with a six-year-old.

It could be that the kart does not have the proper corner weights. Scaling will tell you if it's right or not. Are you paying somebody else to scale the kart? Do you have a good idea of what those scale readings should be? What type of scales will you be using? Not that they need to be the very best, 4 bathroom scales are used by a lot of people and they seem to work out okay. Doing it that way is easy with the proper software.

Be aware that corner weights are important, but there are other things just as important. Stagger, cambers, castor, wheelbase, tire pressures and compounds, all important.
 
Thanks guys. I am a long time dirt racer (street and modifieds) so I understand scaling . But I am new to carts. I own a set of Longacre scales. Here are the numbers it was raced ar last weekend.

Total 247
Lf 63. Rf 44. Lr62. Rr77
Cross 42.8
Left 51.0
Rear 56.7

Lf camber +.25
Lf caster +7.5
Rf camber -2
Rf caster +12

Front track width 41.5
Rear track width 39.0
Toe in is 0
Air is 5 lefts idea 6rightside
Maxxis pinks and blues prepped but unsure of duro.
Stock clone with aluminum flywheel, 390 carb and weenie pipe.

I know in most dirttrack cars the left and cross are to low. My question is what a starting point for him? Or is there something else I need to change with these numbers. He's 6 yes but not new to driving just first time in this kart and didn't have time to scale last week before race. I cut the throttle in half and he would still spin out coming off. Thanks for any input.
 
dirttrax said:
Thanks guys. I am a long time dirt racer (street and modifieds) so I understand scaling . But I am new to carts. I own a set of Longacre scales. Here are the numbers it was raced ar last weekend.

Total 247
Lf 63. Rf 44. Lr62. Rr77
Cross 42.8
Left 51.0
Rear 56.7

Lf camber +.25
Lf caster +7.5
Rf camber -2
Rf caster +12

Front track width 41.5
Rear track width 39.0
Toe in is 0
Air is 5 lefts idea 6rightside
Maxxis pinks and blues prepped but unsure of duro.
Stock clone with aluminum flywheel, 390 carb and weenie pipe.

I know in most dirttrack cars the left and cross are to low. My question is what a starting point for him? Or is there something else I need to change with these numbers. He's 6 yes but not new to driving just first time in this kart and didn't have time to scale last week before race. I cut the throttle in half and he would still spin out coming off. Thanks for any input.
Click to expand...

I'll be first to tell ya I'm NO champ guy, but know some of your numbers are off, Increase Nose to 45.5 % which would = lower rear % to 54.5 %, Increase left to 54 %, Increase cross to 51 %, Increase RF camber to 2.5 Neg, I would bet the spin off is to much wheel in because of low nose % then it snaps loose and spins on him, you don't mention Staggers I would think 1 3/8 " to 1 1/2 " front, and Rear is track dependent 1/5 th mile 1 " rear, smaller 1 1/8 " to 1 1/4 " rear, wipe the tires for BITE, I'm not saying this is the Idea set-up but it will be better for ya, I would still look up number for Jeff at Rage and contact him.

Good Luck !!
 
Thanks a bunch. I did email jeff waiting for responce.
I belive you guys are right on. He looked fine to me getting in but when he spun it was all of a sudden. So snapping loose sounds like our problem. I'm gonna start scaling again this eve after work.
 
I don't scale champs but that looks like an awful lot of caster and caster split, especially for a Jr racer. Also that's a very narrow rear track for that front track (that will definitely cause a snap loose center off)
 
I'm gonna change the caster to lf 9 rf 10
What should the track width split be? I keep hearing 39 1/4 rear but the front can only go 1/2 in.
 
Also just to make sure I'm correct. How exactly do you measure track width? I was told from outer wear line to outer wear line, is this correct
 
dirttrax said:
Also just to make sure I'm correct. How exactly do you measure track width? I was told from outer wear line to outer wear line, is this correct
Click to expand...
I'm assuming you mean outer wear line between the front and back straights. Nothing wrong with that, just be consistent.

When I lay out tracks in my CAD/CAM program, to estimate a theoretical stagger,
I use the left rear track simply because it's more convenient and not subject to rear tread width variances.

Not that there are many variances in rear tread width. A fact that has dumbfounded me for years. Coming from Sprint racing, a lot of things dumbfound me. The fact that nobody wants to try something different dumbfounds me even more.
 
dirttrax said:
Also just to make sure I'm correct. How exactly do you measure track width? I was told from outer wear line to outer wear line, is this correct
Click to expand...


Yes the Kating world measures it from outside of tire patch to outside of tire patch, front set it narrow just so your wheel has clearance with the spindle, Rear put inside edge of wheel 1/8 " off cassette hanger, and put LR 3/4 " off that will get it stable for now once he's up to speed then you might be able to move LR in some.

Good Luck !!
 
Race promoter I was told to measure from outer wear line on rr to outer wear line on lr. Is that correct. Or maybe a better question would be...I keep getting told my rear track needs to be 39-1/4 how do i measure that? Right now with the way I measured it, it looks like lr is in 2 inches farther than it should be according to body lines. The rr is as close the cassette frame as it can get
 
dirttrax said:
Race promoter I was told to measure from outer wear line on rr to outer wear line on lr. Is that correct. Or maybe a better question would be...I keep getting told my rear track needs to be 39-1/4 how do i measure that? Right now with the way I measured it, it looks like lr is in 2 inches farther than it should be according to body lines. The rr is as close the cassette frame as it can get
Click to expand...

Just set the LR inside wheel when it on studs 3/4 " to 7/8 " from cassette frame and don't worry about what it measures, but yes that should be correct clear outer edge ( Tire patch ) of rear tire to clear out edge ( Tire patch ) is where to measure, but that should not have you LR wheel out 2 " if that's the case that's big part of your snap loose problem for sure.

Good Luck !!
 
I don't know that I would go to a 1 degree split. I'd probably start at 10 and 7. I think 12 is too much for a rookie.

I'd close the front track to as close as possible. Set the RR about hand width off the rear hanger, then check the relationship of the right side tires. Which tire is out more?

Just as a numbers thing. If you can get the front end to 41", I'd set the rear at 39.75 or 40. The closer you get the tracking the more stable the kart will be. Stability does not equal speed but it does equal control.
 
This is where I would be:

10.7 Castor

-2.25 RF
+0.5 LF

45.0 Nose
54.0 Left
54.0 Cross

Front tires in as far as they will go (should be about 39.5" Track Width on the front this way)

RR - 1/4" off the frame rail
LR - Out as far as you need to be to meet 39.5" (same as front)

This may or not be a "fast" setup, but thats not the goal. The goal is to make the kart comfortable as he gains experience.
 
You guys are great. Sorry for all the nube questions but I got one more. I'll do the 10 7 caster but are you saying 7 lf 10 rf ? Just want to clarify thanks
 
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