champ kart push center off

4

4palsracing

Member
ran at possum kingdom a couple weeks ago and the kart would enter the turn flawlessly all the way to the center then pick up a terrible push center off here are my numbers advice would be greatly appreciated!
44 nose
59 left
58 cross
1.5 front stagger
1 rear stagger
.5lf & 2.5rf camber
caster is factory setting parallel with frame and rf is forward lead position

saw a lot of karts that looked to be on much lower cross.
 
I Was just thinking about the push and read what paulkish is saying in the Thread: 3 holes on left front spindle, I believe what he is explaning there would help you a bunch.
 
Several different answers listed and I think there could be some truth to each of them. :)

First, it's not a flat kart -- most champs don't like big cross numbers...get your cross down lower.
Definitely need more nose weight if you're on a stock class engine.
Not sure about the thread that Paul Kish refers to....If he's talking about increasing ackerman -- I doubt that is your issue at corner exit (it helps moreso on corner entry.)
Left side might be high and RF camber low, but then again we don't have enough info to make that conclusion.


We don't know anything about how much bite was in the track - or your prep program. This could be a simple tire problem that is seen as no front grip at corner exit (don't know.)

I think you stated that the RF L block is forward (longer right side wheelbase) - that could be making your problems worse as well as it takes too long for the weight to transfer to the RF. That lead can help on high bite, but again, was the track biting hard - we don't know.

Lot of good shots in the dark answers thrown out there -- like I said, probably all of them have some merit to them.


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The track was biting hard, and was very fast for this time of year.
Wouldnt lower left, adding camber and lower cross was good suggestions.
Nose, well that depend on what champ.
Most likely tires are the issue, what duro were they at?
 
Same here cross little high, but check that left rear tire compared to right rear on duro, if left rear was to soft the champ will push, along with to much cross.
 
BRE said:
Same here cross little high, but check that left rear tire compared to right rear on duro, if left rear was to soft the champ will push, along with to much cross.
Click to expand...

The LR relationship to the RR once again comes down to what kart. We finished side by side with Donnie Nall and took 3rd in 1 of the champ races and the duro was the same.
 
Moving the LR out a bit could be enough to free it up as well.
If it was biting up hard like Earl is saying, it's probably not a left side weight issue or the RF lead.

I still tend to think it's a little light in the nose. I'm thinking too high on cross still as well. Those two will make even a slight push "on throttle" even worse.

Have you checked all your normal alignment, air pressures, etc (stuff that too we often take for granted)?

It could be fixed with glue in the tires. That's the approach that most take anymore. If it's as bad as you say -- I'd say there a bigger balance issue with the chassis.
 
As most will probably tell you, I'm kind of a simpleton. Occam's razor; his law says; all else being equal, the simplest explanation tends to be the right one.
There is more to it, but that's the essence of it.
So, on that basis, I think, if a kart is pushing there's too much rear bite for the amount of front bite. The other side of that; if the read is loose, there's too much front bite for the amount of rear bite. My approach would be, if the rear is loose, find a way to get more rear bite. If the kart is pushing, find a way to get more front bite.
And know that, as you experiment, trying to find the right balance between the front and rear, you're really learning a lot. Give a man a meal and he may be content for a day, teach him how to grow that food, and he eats for a lifetime. Or something like that. lol
In Sprint racing we play a lot with tread width. LTO racing is quite a bit different with a lot more setup options. Find out what those options are, play around with them, learn what does what with your kart, your driving and your track. There are books out there that explained how an LTO kart works, buy one, read it, a lot. You went to school to learn to read and write, right? This is the same thing.
Comments compliments criticisms and questions always welcome.
 
thanks everyone haven't checked on the thread here in a few days so I'll try and answer everyones questions on tires they were punching 42-44 on the duro with the lr at 48+or- 1 and grip was excellent so I don't see tires being the issue. balance however is a great concern and all of us seem to strongly agree that cross was way too high, and at one point we added two washers of cross and that is what made the kart nearly fly off the track coming out of 2 & 4 that bein said the extra washers put us right at 59% cross, and that was the last run for the kart that day. so before we put the kart back in the trailer I took seven washers of cross out. haven't been back on the scales yet but this should definitely put its cross in the low 50% range. now we have to be much closer on cross but then I say what about nose weight and why are they recommending such low nose weight (right at 44%) when every other major kart manufacturer out there are saying there karts should be in the 46-47%+ on nose weight. it sucks we made the wrong move at one point but it was a for sure sign we should have decreased cross. kart was lined up with accutoe advanced so it wasn't anything crazy wrong with alignment. Thanks again to everyone for all the advice just a little rusty after not working on setup for a few years
 
This is from paulkish, I hope he don't mind me copying over here.

Grip is usually associated with weight on a tire. We talk about balancing grip front to rear and balancing it across the back. And most of the concern about balancing weight across the back is about lost rpm apex out. What's neglected and not talked about is balancing weight across the front. This is LTO and tires do a specific job all around the track. We don't concern ourselves being able to balance things because we need to turn both left and right. Instead it's about using each tire for specific needs around the track. You also don't just have one cross on a LTO racer. You have RF/LR cross, but you also have a LF/RR cross which comes into play, again during how you specifically need to use your tires around the track.

We've hashed out often about how to set camber gain etc. at the RF to get needed use out of the RF entering and to the apex. There's also been a lot of explanation on how the RF settings effect holding rpm's up, especially apex off. But now all of a sudden there seems to be a realization about how the LF is turned, can effect rpm's apex off. Well, which is it, the RF or LF that so critically effects rpm's? Back to basics, at least my basics. The only reason you lost rpm's in the first place was you were tight coming off. Tight in the meaning of two or more tires were fighting each other for control of direction.

I'll try to net it out. Up to the apex things were great because you got needed weight to the RF via the RF/LR cross while decelerating and maintaining speed to and through an extended apex. Next you started to accelerate and return weight to the LR. But as I started out with this, weight follows grip and there is also a LF/RR cross. What is being described above in other posts when ackerman or LF tire turning speed is adjusted is you are changing the grip level or balance across the front, when weight is being moved back to the rear. Try looking at it in this way. Read the posts about how changes to LF tire steering rate fixed a problem. When I read them they were all consistent with the following thought. Weight was on the RF to the apex, then apex out in all cases when weight was returning to the LR, it got there too fast. The general way it's usually looked at on here is you then get tight because the rears start driving the kart in a direction you don't want to go and you have to fight it with the fronts. In other words your locked down apex off. Now look at what the fix in the posts above did in all situations. The fix increased the ability of the LF to grip the track apex off. Back to weight follows grip. By increasing the grip at the LF, it held or detoured weight traveling to the LR at the LF.

I'll stop. I either made a case for using the grip ability at the LF, to help control LR engagement or I didn't. And the case I tried to make was altering grip at the LF, alters the path and in turn the speed at which weight is returned to the LR.
 
Quick thought using my general BS. I always say when accelerating apex off, you only need to transfer enough weight to the bigger RR tire, so it's faster surface speed can out accelerate the LR. Controlling weight to the RR so it can out accelerate the LR and gradually moving it back to the LR, can control total direction of travel.

Now, taking weight off the RR too soon is no different then increasing weight to the LR, from the front too soon. The net result is you reduce the ability of the RR to out accelerate the LR. It makes no difference if the RR looses ability to grip or if the LR gains ability to grip over the RR. The net result is you will have to fight the direction the rears want to go, with the front wheels and you will be tight or locked down coming off. ... that is assuming you have the grip up front to fight the rears... if you didn't then this would be about push, not rpm loss coming off. ...

edit: ... anytime you loose anything in the ability of the rear staggered solid axle to operate in what I describe as the ideal way to go in the direction you want to go, it has to be made up with control of direction with the fronts. And any direction control from the fronts, eats hp, causes conflict between tires and slows you down. ... now if over all your closer then everyone else to the ideal and your out front... then it really doesn't matter
 
Adjust rear track and rf camber-caster need the high cross for corner speed. My buddy finished top 5 a lot more cross then 58% Lower cross will help and be fast but not competitive at a certain level. Just my opinion.
 
4palsracing said:
thanks everyone haven't checked on the thread here in a few days so I'll try and answer everyones questions on tires they were punching 42-44 on the duro with the lr at 48+or- 1 and grip was excellent so I don't see tires being the issue. balance however is a great concern and all of us seem to strongly agree that cross was way too high, and at one point we added two washers of cross and that is what made the kart nearly fly off the track coming out of 2 & 4 that bein said the extra washers put us right at 59% cross, and that was the last run for the kart that day. so before we put the kart back in the trailer I took seven washers of cross out. haven't been back on the scales yet but this should definitely put its cross in the low 50% range. now we have to be much closer on cross but then I say what about nose weight and why are they recommending such low nose weight (right at 44%) when every other major kart manufacturer out there are saying there karts should be in the 46-47%+ on nose weight. it sucks we made the wrong move at one point but it was a for sure sign we should have decreased cross. kart was lined up with accutoe advanced so it wasn't anything crazy wrong with alignment. Thanks again to everyone for all the advice just a little rusty after not working on setup for a few years
Click to expand...

Theres your issue right there. Grip was excellent because they were too soft, by a lot.
Your tires should have been around 54.

Not all manufacturers recommend 46-47 nose on their champ buggies, theyre different from flat karts.
 
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