Conflicting information on ladderbar adjustment need clarification *debate*

[SUPERSTOCKRACER]

Over the last 4 years I have been getting conflicting answers concerning front ladderbar placement to either increase wheelstands or limiting a wheelstand.
I have heard from a few chassis shops if you lower the front ladderbar,it will increase the wheelie, whereas others have stated that if you raise the ladderbar on the crossmember it will increase the wheelstand.
From my experience on my Hemi, when I had the ladderbar in the top hole, it wheeelied way high, then i lowered it 2 holes and it helped control the wheelie.
But my chassis guy who does all highend super promods, top sportsman cars says when I lowered the bar it should have made the car hit the tires harder and wheelie more which is contradicting whats actually happening to my car.
Any thoughts?

 

[Endangered Species]

If I'm thinking right, when you put your ladder bar up, the car should wheelie more. If you drop them it shouldn't lift as high.
The way I'm thinking is take 50 pounds and put it on the end of a 10 foot stick and try to lift it, the weight is heavier than it would be if it was on a 5 foot stick.

But looking at the Dave Morgan book and if I'm reading this right the lower the bar the more the front should lift because it moves the instant center in front of the center of gravity. Like a lever... the longer the lever the more weight you can lift.

If I get a chance I will ask Ed tomorrow when I'm talking to him.

 

[SUPERSTOCKRACER]

If I'm thinking right, when you put your ladder bar up, the car should wheelie more. If you drop them it shouldn't lift as high.
The way I'm thinking is take 50 pounds and put it on the end of a 10 foot stick and try to lift it, the weight is heavier than it would be if it was on a 5 foot stick.

But looking at the Dave Morgan book and if I'm reading this right the lower the bar the more the front should lift because it moves the instant center in front of the center of gravity. Like a lever... the longer the lever the more weight you can lift.

If I get a chance I will ask Ed tomorrow when I'm talking to him.

Thats exactly what I'm talking about. Jakesaid the same thing, lower the bar and it hits harder and bigger wheelies but in my case the opposite. When I was in the top hole, my car wanted to wheelie like crazy. Now my wheelies are controllable in the 2nd bottom hole. go figure.

 

[Endangered Species]

Thats exactly what I'm talking about. Jakesaid the same thing, lower the bar and it hits harder and bigger wheelies but in my case the opposite. When I was in the top hole, my car wanted to wheelie like crazy. Now my wheelies are controllable in the 2nd bottom hole. go figure.

Ok now I do know this and Morgan says the same thing. The higher the bar it will hit the tires harder. Same goes with the Cal Tracs, if you put the bar in the top hole it will hit the tires harder.

 

[robinsonwr]

Ok now I do know this and Morgan says the same thing. The higher the bar it will hit the tires harder. Same goes with the Cal Tracs, if you put the bar in the top hole it will hit the tires harder.

Moving the bar up causes the instant center to move toward the rear which transfers weight toward the rear causing wheel stands or harder hit to suspension. Moving the bar down causes instant center to move weight transfer forward which controls the hit on the tires. Many ladder bar cars utilize lower settings to offset the shock to the suspension and prolong the hit of a transbrake application. I guess it all depends on how you have the car set up and the dynamics of the total package.

 

[SUPERSTOCKRACER]

Moving the bar up causes the instant center to move toward the rear which transfers weight toward the rear causing wheel stands or harder hit to suspension. Moving the bar down causes instant center to move weight transfer forward which controls the hit on the tires. Many ladder bar cars utilize lower settings to offset the shock to the suspension and prolong the hit of a transbrake application. I guess it all depends on how you have the car set up and the dynamics of the total package.

thanks to both Kev and robin for replying. It makes sense because my light blue dodge is setup on 2nd botton hole also.Wheelies are pretty much the same now on both cars.60 foots are better not going as high believe it or not.

 

[moparpoor]

Yes by moving the ladder bar up or down you move your IC or lift point.Moving the bar up raises and shortens IC.This should hit the tire harder.Tire height and bar length will very the changes and effects.

 

[SUPERSTOCKRACER]

I'm wondering why Jake told me the complete opposite thing?

 

[tallhair]

I'm wondering why Jake told me the complete opposite thing?

do you race against him?

 

[moparpoor]

In a perfect world with a dead hook a lower and longer IC will cause more front end lift.Simply you are pushing the lift point out farther.Theories!Now for reality!With a higher and shorter IC or lift point will cause harder or more violent hit to compensate for lack of traction.This tends to cause big wheelies and broken parts!!

 

[SUPERSTOCKRACER]

In a perfect world with a dead hook a lower and longer IC will cause more front end lift.Simply you are pushing the lift point out farther.Theories!Now for reality!With a higher and shorter IC or lift point will cause harder or more violent hit to compensate for lack of traction.This tends to cause big wheelies and broken parts!!

your right on the dead hook deal. this is what happened with 2nd hole on the bottom, and a 3000 rpm launch footbraking. 1.31 60 foot on the back wheels.

 

[dvw]

Raising the bar raises the instant center. This will increase the load placed on tire. If the tire can deal with the additional load applied to it there will be more traction. If the load is to great it will deform the tire and spin. Lowering the bar,tightening the rebound on the shocks, stiffer springs, weight on the nose, limiting front suspension travel will all help. If the car isn't spinning, upward motion is wasted ET.
Doug

 

[SUPERSTOCKRACER]

Raising the bar raises the instant center. This will increase the load placed on tire. If the tire can deal with the additional load applied to it there will be more traction. If the load is to great it will deform the tire and spin. Lowering the bar,tightening the rebound on the shocks, stiffer springs, weight on the nose, limiting front suspension travel will all help. If the car isn't spinning, upward motion is wasted ET.
Doug

thats exactly true, with my hemi, liked the big wheelie but was only getting 1.29 -1.31 60 foots with big wheelies, calming it down, and not being as much fun nets me a 1.27-1.29 60 foot. going high looks cool but in reality slows me down.

 

[Budnicks]

Raising the bar raises the instant center. This will increase the load placed on tire. If the tire can deal with the additional load applied to it there will be more traction. If the load is to great it will deform the tire and spin. Lowering the bar,tightening the rebound on the shocks, stiffer springs, weight on the nose, limiting front suspension travel will all help. If the car isn't spinning, upward motion is {"JUST"} wasted ET.
Doug

Bingo we have a winner...

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thats exactly true, with my hemi, liked the big wheelie but was only getting 1.29 -1.31 60 foots with big wheelies, calming it down, and not being as much fun nets me a 1.27-1.29 60 foot. going high looks {"REALLY"} cool but in reality slows me down.

Exactly, moving forward & out of the beams, is what any drag car should do... Wheelies are for the fans &/or to get up & out of the beams quicker... SSR do you have wheelie bars on either car ??, they can help with launch set-up also, especially if your having violent launches... Have you scaled either car to see where the weight actually is ?? I'm just curious... carry on

 

[SUPERSTOCKRACER]

Bingo we have a winner...

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Exactly, moving forward & out of the beams, is what any drag car should do... Wheelies are for the fans &/or to get up & out of the beams quicker... SSR do you have wheelie bars on either car ??, they can help with launch set-up also, especially if your having violent launches... Have you scaled either car to see where the weight actually is ?? I'm just curious... carry on

NO WHEELIE BARS BUD. i have scales and have all the weights written down. i can play with front shock settings to either increase or decrease wheelie height. right now i'm in a good place with both cars.
i just needed to set the record straight in my head. i knew i have the cars setup weak now.

 

[flyinmike]

i agree with budnicks i've been drag racing a long time and i lowered the front of my ladder bars to keep the front end down. when i launch i want to move forward out of the beams

 

[dvw]

Yes by moving the ladder bar up or down you move your IC or lift point.Moving the bar up raises and shortens IC.This should hit the tire harder.Tire height and bar length will very the changes and effects.

Close but not quite. The instant center with Ladder Bars can only be moved up or down, not forward or back. Draw a line upward vertically through the front spindle to the center of gravity height (roughly cam C/L). Intersect that line from the rear tire contact patch. This is the the neutral line. If the the ladder bar pivot is above this point the rear housing will separate from the body (rise). Below this point ,the housing will draw up into the body (squat). The bar adjustment controls how far the housing will move in inches. The shocks control how quickly it will move. The more power, gear, loose converter, higher or rearward C/G location will require a lower setting or possibly a new longer bar. Watch my video, bar is right on the neutral line, no housing movement at all. Looking at Chris's pic it appears slightly above. Note wheel well to wheel lip dimension. My car needs the bar raised to separate the housing and add more load. Similar car to Chris but I have less power. Hope this helps explain it.

http://www.youtube.com/watch?v=YCj63p9V8oI
Doug

 

[moparpoor]

You are correct DVW ! I should have written it differently. My actual point was to explain the effects of a shorter,higher,or both shorter and higher IC.
How about this. A higher IC , shorter IC, or both will hit the tire harder. The only way to change IC length with a ladder bar is to change the bar design or length.

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By the way DVW you are a brave man running that car in those conditions. Track conditions were crap.Track surface was damp, cold, and it was windy!!!!

 

[SUPERSTOCKRACER]

great info here from both dvw and moparpoor.thanks to both of you.