Thread: ladder bar ajustment

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About a quarter of the way thru this season I was having a real tough time when my car launched, it took a violent left turn and damn near drove me into the wall. After measuring both tires, one was found to be 1/4 inch larger than the other. We were making chassis adjustments, shock adjustments, and wheelie bar adjustments to try and figure it out. AFter putting on a new set of tires, all of the problems went away. We also found that our pressure gauge was off by 2 to 2 1/2 lbs.

yeah, what 60 said!!!! Borrow a stagger stick or a tire tape from one of your local dirt trackers and compare the tire circumfrence.... No guarantees that tires the same size will tape out to the same measurement... I've seen as much as 3/4 of an inch difference in two tires of the same make and the same size...

You need to get an adjuster kit for the ladder bars and install it. Then you can pre load the right side to compensate for torque. If you scale the chassis the right rear should weigh between 60 to 100 lbs. heavier that the left.The reason for the large weight differences is that it depends on how stiff thw chassis is. The stiffer the chassis the less the pre load and so on. Frank @ ECD Performance Products

It sounds like it is square enough so maybe it is getting shift from the panhard. I recently replaced a diagonal link to a wishbone locater. WOW the car does everything way-WAY better. Are the shocks adjusted as far as spring rate for car weight. I am also really surprised that car can't break 100mph in the 1/8. It sounds like a fast car and 23,-2400lbs, that car should fly, possible 9.90 car. Tire pressure is critical on some-most cars. 1psi in tire pressure has a large increase in equivelent spring pressure. Hope that helps.

I had the same problem when i first took the car to the track this spring. The first thing i checked was my tire stagger on the rear tires ( that was the way i used to set up my dirt track cars also) I noticed that there was 3/4 of an inch differance in the circumfrance of the tires. After talking to Hossier, they instructed me that after buying and mounting the new set of tires, put 10 psi of air in both tires, check the circumfrance ( stagger) and what ever tire is smaller, add another 30 psi ( to make 40 psi ) of air in the the smaller tire...let it stand for about 15 minutes,( not in direct sunshine) let the air back out to 10 psi and check it again. You just simply keep doing this untill the tires are excactly the same size. Hoosier informed me that this is there way of stretching there tires for proper stagger. They then informed me that once you have completed one burnout with a new set of tires, that you can no longer stretch the tires anymore. So if you buy a new set of tires, make sure the stagger is correct before mounting them on the car.

Excellent advice maxed out,I was just fixing to ask "how did you fix the problem"?Did the tire company send you new tires.

NOPE...had to pay for them. And sorrry, but it wasnt Hoosier it was Micky Thompson tires ( old age memory still has a problem switching from my dirt track car to the drag car.... )

CHeck tire pressure, but also the date code and mold number on each tire(should be same on mold number and close on date). Air up both equally, then check diameter around center. Should be within 1/8" or so. Much more and it will tend to drive to one side as one tire is larger then other.

How old are shocks? Pull them and compress/pull them and see if they are stiff or any odd movements. Shocks don't last forever. Try swapping their sides and see if it changed direction of push.

Yes check the tires with a string to find the true Circumfrence of each tire while jacked up. Check distance from center front to center rear both sides. Check diagnal measurement as well. And your diagnal bar can adjust the rear end.

Don't no if any body mentioned it yet didn't read all replys.Had same problem but car made hard right off the line.Checked every thing twice inside and out every thing was cool.Untill I found out that the weld on my Axle Tube right at the Axle Housing had faild.When and if you do any preloading,I put some one in my cars that weigh the same as i do if not it can mess you up with your final result

A broken weld, that will do it. The other day someone had a simaler problem but with the front end. After looking at it I found that his nut holding the A arm was lose, simple fix.