The search for more forward bite.

W

Wingnutracer

New member
I could use some ideas on getting more bite off the corner that won't impact getting into the corner so much. I completely understand it's a kart frame and all about compromise.
The chassis is an 07 Legend Optimax +. Last setup # was 55% left, 55% rear and 59% cross.
We were running a Jawa. We won't be next race though.
We have a lot of experience with this kart and it likes these numbers. The kart just won't dig coming off and I (set up guy) am out of talent.
 
From what I've seen, your LR is kind of light. If your stager is not right, you're dragging it anyway. A sliding tire has nowhere near the bite of a rolling tire. You can see that when some one locks up the rear axle, the kart spins.

From the desk of Al Nunley
Comments compliments criticisms and questions always welcome.
If the data does not support the theory, get a new theory. (Al Nunley)
 
Just from a quick look at the %'s you posted, I'd say the RR is doing too much work. First step setup wise would be more cross. If you've tried more cross before and picked up a push, add 1/4" or so rear stagger with the increased cross.

Of course there's always the tires. I hate a hard LR, it's the most important "forward bite" tire and I want it "biting". With your current setup, the tires overall might not be worked hard enough because the setup is making bite.
 
Thanks scottiedout, we started with less cross. We ended the night with those numbers. The kart got faster and faster as we progressed. The exit is where we were losing time.
We were thinking more stagger too. The fear is more stagger can loosen it off even more, right?
 
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Wingnutracer said:
Thanks scottiedout, we started with less cross. We ended the night with those numbers. The kart got faster and faster as we progressed. The exit is where we were losing time.
We were thinking more stagger too. The fear is more stagger can loosen it off even more, right?
Click to expand...

Yes Sir the added stagger could loosen it even more, just to clarify Scotties not telling you to do both right off UNLESS added cross creates a slight push, If you got faster but still NO push Add MORE cross first, then if you get a slight push add the rear stagger and it would help even more, Scottie gave your very good info here.

Good Luck !!
 
Wingnutracer said:
Thanks scottiedout, we started with less cross. We ended the night with those numbers. The kart got faster and faster as we progressed. The exit is where we were losing time.
We were thinking more stagger too. The fear is more stagger can loosen it off even more, right?
Click to expand...

The loose off could be a tight entry problem that you may not be noticing, or there's not enough preload (cross or leftside) and the RS's are the only tires trying to do all the work. The added rear stagger could actually help balance the kart if this is the case as well. If the kart doesn't get into the corner properly, it's not going to rotate and exit properly...

If the loose off gets progressively worse through the run, it's usually begging the LR (or both LS's) to do more work.
 
scottiedout said:
The loose off could be a tight entry problem that you may not be noticing, or there's not enough preload (cross or leftside) and the RS's are the only tires trying to do all the work. The added rear stagger could actually help balance the kart if this is the case as well. If the kart doesn't get into the corner properly, it's not going to rotate and exit properly...

If the loose off gets progressively worse through the run, it's usually begging the LR (or both LS's) to do more work.
Click to expand...

:) :)
 
Thanks for the input. We started off skating around. The kart would not take a set anywhere. We increased cross until it had a push. We ran out of practice\heats to make adjustments. I agree on the stagger. That is where we would have ended up next if we had a chance. We were running The West Coast Shootout and the track is 700 mi from us, our first time there. We had a good run, but as you know. There is always room for improvement.
Now, If the kart rolled the center perfectly. What could I do to gain more forward bite? These big 4 strokes make more torque than I am used to playing with. We usually race a TT75 based 119cc open.
 
One thing I have never played with is axle lead. I don't understand what it does at entry, center and exit. I have heard that adding lead can help forward bite, but which tire goes forward?
I am assuming the left rear.
 
Nose-47.0
Left-56.0
Left front spindle all the way up
Right front spindle all the way down
Right front camber-3 1/2
Left front camber- 0.0
Right front castor- 11.0 pos.
Left front castor-7.0 pos.
Front stagger 1 1/2
Rear stagger 1 1/4

Tires maxxis pinks rights
3/4 ounce lambert blue
3/4 ounce mafia original
Mixed together in a glass container which combined =1 1/2 ounces
Take valve stem out squeeze or push down on tire place a small tube on a small funnel
Then with valve stem to the bottom place funnel on valve stem and pour mix into funnel while relaxing tire
Put valve stem in being careful not to move tire not to splash onto side walls put 10 psi air
Carefully carry to roller and let roll 24 hours do not put anything on the outside

Left rear- straight up nothing on inside

Left front - 1/2 ounce lambert blue and 1/2 mafia original
Roll all tires together at the same time.
Before the bashing starts:
I have been out of karting for a few years. Why?
I am in late model stock cars now, but I have a trophy case full of trophies from karting
And I have been on a lot of different chassis and I can say this though experience.
And have outrun big names in karting on old chassis.
I have come to learn they are all a piece of metal and they all will take the same numbers
Now kart manufactors will not like this post as well as tire guru's that want your money
The only reason I am giving out this secret is I am no longer in this sport after a lot hanging around all the right people. Here is my email just in case someone wants to see if I know what I am talking about.
Wayneshell4@gmail.com
 
I listened!
New numbers are 57 left, 61 cross and 56 rear. The lr seems a little high to me but we will give it a try this weekend. We have no ballast on the kart as we are already over the minimum weight. If it shoves the nose we will add 5 lbs to the rf. We will have on an open kart based engine this time.
What do ya think?
 
Wingnutracer said:
I listened!
New numbers are 57 left, 61 cross and 56 rear. The lr seems a little high to me but we will give it a try this weekend. We have no ballast on the kart as we are already over the minimum weight. If it shoves the nose we will add 5 lbs to the rf. We will have on an open kart based engine this time.
What do ya think?
Click to expand...
or move the driver forward a little bit. 44% on the front is a lot less than most people run. I'm just going by what I've seen. You might also try widening the rear track. A lot of people give the same widith number for the rear tread, but I've never found any number that was written in stone.

From my weight percentage spreadsheet, I don't think the LR is too heavy, not when compared to most of the setups I see.
 
alvin l nunley said:
or move the driver forward a little bit. 44% on the front is a lot less than most people run. I'm just going by what I've seen. You might also try widening the rear track. A lot of people give the same widith number for the rear tread, but I've never found any number that was written in stone.

From my weight percentage spreadsheet, I don't think the LR is too heavy, not when compared to most of the setups I see.
Click to expand...

First part about 44 % being little low is most likely correct I'd expect a push, However to tell someone to widen rear track width when you do not know where it is now is bad advise, even worse that you do not emphasis which side to move, If you get a slight push and try to compensate without added nose ADD rear stagger before you widen rear track with.

Good Luck !!
 
racing promotor said:
First part about 44 % being little low is most likely correct I'd expect a push, However to tell someone to widen rear track width when you do not know where it is now is bad advise, even worse that you do not emphasis which side to move, If you get a slight push and try to compensate without added nose ADD rear stagger before you widen rear track with.
Good Luck !!
Click to expand...
I assumed, and I know what that means, the rear track was probably where most people put it. A point could be made that I shouldn't have done that. Never assume. Still, a rear track width of 39.5 inches, + or - a 1/2 inch, is almost universally accepted as the norm. I can't recall ever seeing somebody recommending more or less than that.
From my days in Sprint, "widening the rear track" always meant both wheels. So you're right on that point too. You might be surprised how easy it is to get rid of a push by widening the rear track. And of course more stagger, as you pointed out, might be a help to. If he had mentioned the turn radius, I might have commented on the stagger.

I have this idea that being right 100% of the time, is a lofty goal at best. lol. Thank you for pointing out my errors, along with the thing(s) I got right. I can only hope that I will live and learn.
 
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