A Ladder Bar Hole Tuning/Adjustment

[CraigG]

Hey Guys,

Bar Hole location Question = Relationship to Effects on initial Hit of Tire:

? Raising bar will Increase Hit which may bounce or crush the tire
? Lowering bar will Decrease Hit and soften initial hit of the tire

SO, if raising launch RPM from 3500 to 5000 will increase initial application of power -
THEN, raising the bar will help compensate for initial hit increase provided the tire stays applied to ground and avoids bouncing or crushing?

Thanks Guys for the clarification.
Craig

[MAURICE BLENDHEIM]

Craig… Do you have a Specific Problem you are trying to overcome? MB

[CraigG]

yes break loose on initial hit - recovers guessing 10 feet.

Want to understand relationship of bars to torque input.

Thanks, Craig

[MAURICE BLENDHEIM]

What is your Baseline Setting? What Tires? What type of Car? Springs, Shocks ? There potentially could be other variables that are compounding your problem. MB

[Mike Pearson]

I race a ladder bar car. my car is set up with 2 degree down angle on the ladder bar with 2 degrees of down pinion angle. It will not work at all if the bars are past level or running up hill in the front. All measurements are taken in relation to the frame or rocker panel. if the car is set up correctly no preload is best. my car is 3140# and i have a 110 lb spring rate on the shocks. Typically the bolt holes are too coarse of an adjustment. I use ride height if i need to make any adjustments. Start with the shocks loose on the front and rear and the tighten as you test.

[SGSST109E]

HAve you ever set your car up on scales? Do you have equal weight on the rear tires?

[Jeff Stout]

I think knowing height of front holes in relationship to rear end brackets holes would need to be first. Then plotting out if the bar is going down, straight or uphill.

[CraigG]

Hey thanks guys I really appreciate all your good input.

I think the next step is to follow through with many suggestions and is to be able to individually scale all four wheels, invest in a good pair of double adjustable rear shocks and look at springs and height adjustments – of course getting a good video to review and share.

Any other ideas are also greatly appreciated.

Thanks, Craig

[MAURICE BLENDHEIM]

Craig… An afternoon with a friend, a level work area, a couple of measuring tapes, plumb-bob an 8’ straight edge, a square, welders chalk and a chalk line could make a big difference. Plotting the wheelbase and squaring are a priority. A good baseline would be trying to get the bottom bar as close to parallel to the ground as you can. Adjusting ride height may be required to establish this. Make sure nothing is binding. Once you have these simple essentials done, you can start with some minor tuning adjustments. It would be nice if you shared some details about your car. We are all here to offer assistance and the more information you give, the better the response and results will be. Assumptions of what your car is, may not be the best way to achieve positively. MB

[Dragsinger]

All the above comments are valid.

In my experience with engines in the 700-horse range and cars in the 3000-pound range, a 2 or 3-degree down angle works well. And as stated above, the down angle is in relation to the body, not the ground.

If you want the ultimate set of tools. Build yourself a set of stands or tables about 30" high. Set up the car, at ride height, driver weight in the seat, and rear wheels removed.
This offers an excellent view of your setup plus allows easy adjustments.

Beyond this, a drive-on rack is perfect but few of us have those.