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Old 07-06-2009, 08:58 PM   #1
68Coupe
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Default Help with ladder bar adjustments

I have a 68 Mustang bracket car with ladder bar/coils overs. This is my first ladder bar car. Just trying to understand how the bars work.The car has 28x10.5 slicks and runs 6.80's/6.90's in the 1/8th.
Right now the bar are level to the ground.
I was wondering how moving the bars would effect the car.
If the track is so-so would moving the bars up or down help the car to hook better. If i want the car to pick the front tires up more would i move the bars up or down.
I have heard conflicting advise on this and was hoping for some good advise.
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Old 07-06-2009, 09:11 PM   #2
Tod Lane
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Default Re: Help with ladder bar adjustments

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Originally Posted by 68Coupe View Post
I have a 68 Mustang bracket car with ladder bar/coils overs. This is my first ladder bar car. Just trying to understand how the bars work.The car has 28x10.5 slicks and runs 6.80's/6.90's in the 1/8th.
Right now the bar are level to the ground.
I was wondering how moving the bars would effect the car.
If the track is so-so would moving the bars up or down help the car to hook better. If i want the car to pick the front tires up more would i move the bars up or down.
I have heard conflicting advise on this and was hoping for some good advise.
At the risk of oversimplification, lowering the bars in effect "lengthens" them and tries to lift the car further forward if you will. The car will try to transfer more weight but it will "hit" slower. If the bars are already parallel to the ground I would be inclined to look at other suspension components to aid the launch such as shock settings front and rear.

Others may well disagree, your mileage may vary...
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Old 07-07-2009, 10:13 AM   #3
Dick Butler
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Default Re: Help with ladder bar adjustments

68, The above suggestion is "not quite correct" On a ladder bar its length at which it trys to Pick up is set by its length, not its height at the front. If you raise the front it hits harder or more pressure. If you lower it the lift is less. If raising it hurts 60 ft try adding more tire pressure then to support the tire footprint. Have someone watch only the slick or rear tire to see if it smashes flat as indicator it needs more air.
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Old 07-07-2009, 11:30 AM   #4
Harry 6674
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Default Re: Help with ladder bar adjustments

Also if your bars have adjustable links make small adjustments. One flat on the adjuster can make a difference. Always remember where you start and keep a log on the adjustments,the effects it had,track conditions, anything you can think of for future reference. Have fun.
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Old 07-07-2009, 11:49 AM   #5
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Default Re: Help with ladder bar adjustments

Also, remeber as you raise or lower the bars, the driveshaft is moving up or down as well, which could create a problem with tunnel or loop clearence. Could also put the rear joint in a bind. To maintain correct pinion/drive shaft angle both heims at the rear have to be adjusted if you don't have a ladder link setup.
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Old 07-08-2009, 06:45 AM   #6
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Default Re: Help with ladder bar adjustments

Your ladder bar has to have a downward angle in relationship to the frame of the car. The relationship to the ground means nothing. You should have about 2 degrees down angle. the front of the bar lower than the back. An easy way to give a quick check is to park the car on a level surface then step back and compare the angle of the bottom bar of the ladder bar to the bottom of the rocker panel of the car. The ladder bar should be lower in the front in comparison to the rocker panel. Use a protractor or smart level to check and fine tune the angles. you should also have about 2 degrees down pinion angle. When you set up the car take the shocks out and use a solid strut set to the exact installed height that you intend to run your shocks at. Make all of the adjustments so there is no preload. Then reinstall the shocks and put the car back down on the ground and adjust the ride height of the shocks to the same exact dimension of the set up struts. The car should work perfectly with this steup. I am running the same ladder bar set up as you. This is how I set up my car.
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Old 07-09-2009, 07:56 AM   #7
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Default Re: Help with ladder bar adjustments

Mike Pearson, If the cars are the same motor, trans, wheel base tires etc and yours uses a down angle the position might work but.... All the factors must be the same. The Down Angle theory is not a cure all.
It only works when it works. Weighing the car out and finding instant centers for the positions and a starting point for stick versus auto versus T- Brake is THE way to do it but with a ladder bar and at best 3 holes slow choices works. Pinion angle must be adjusted as someone stated for each position tried to prevent bind or breakage. When we had our chassis shop which built and installed 4 links and ladder bars we even found a few cars where NONE of the positions worked. We moved brackets, added holes or moved the crossmember itself if it were too low in the car. It is not just angle it down in the car it could kill traction in some cars.
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Old 07-09-2009, 08:26 AM   #8
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Default Re: Help with ladder bar adjustments

I agree Dick. I tried just moving the bars down on my '65 Chevy II Super Stocker, didn't work. I do have a question tho. I always set up my bars with the left bar in a neutral postion with the driver weight in the seat and the right bar preloaded with approx. 3/4 of a bolt hole. The car leaves straight, decent 60 foot times(1.31-1.34 with the 18 degree 2 bbl combo) but not alot of wheel stand. Does anyone ever preload the drivers side and more preload in the right bar?
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Old 07-09-2009, 10:54 AM   #9
BlueOval Ralph
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Default Re: Help with ladder bar adjustments

On both ladder bar ars I had it was the same left neutral but right 1/2 to 3/4. If you scaled it as I remember it as about 150 lb more on left front and about 75 lb more on right rear this was ona low 9 second Pinto 9.10 to 9.20 et




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Originally Posted by Tilley2007 View Post
I agree Dick. I tried just moving the bars down on my '65 Chevy II Super Stocker, didn't work. I do have a question tho. I always set up my bars with the left bar in a neutral postion with the driver weight in the seat and the right bar preloaded with approx. 3/4 of a bolt hole. The car leaves straight, decent 60 foot times(1.31-1.34 with the 18 degree 2 bbl combo) but not alot of wheel stand. Does anyone ever preload the drivers side and more preload in the right bar?

Last edited by BlueOval Ralph; 07-09-2009 at 12:27 PM.
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Old 07-09-2009, 03:25 PM   #10
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Default Re: Help with ladder bar adjustments

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Originally Posted by Dick Butler View Post
Mike Pearson, If the cars are the same motor, trans, wheel base tires etc and yours uses a down angle the position might work but.... All the factors must be the same. The Down Angle theory is not a cure all.
It only works when it works. Weighing the car out and finding instant centers for the positions and a starting point for stick versus auto versus T- Brake is THE way to do it but with a ladder bar and at best 3 holes slow choices works. Pinion angle must be adjusted as someone stated for each position tried to prevent bind or breakage. When we had our chassis shop which built and installed 4 links and ladder bars we even found a few cars where NONE of the positions worked. We moved brackets, added holes or moved the crossmember itself if it were too low in the car. It is not just angle it down in the car it could kill traction in some cars.
I have raced my car with a ladder bar set up for 30 plus years. I have had both leaf spring and coil over set up under my car. Both combinations required the same set up. I experimented with other set ups with the same result as the person who started this thread. I have also set up several other superstock cars and a few bracket cars. They all responded well to the same set up. They all had good 60 ft times and were easy to drive. I am sure there are different ways to set the cars up. I would be very interested to hear some of the other ways that were sucessful for other racers. I have never had to run a car with preload.
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