PULL BAR TECH
Center line of bracket is front edge of .250 wide slot. You can put a peace of 1/4 aluminum in slot and measure center line of axle. Also note when slot is running straight up and down you are at 8 degrees of pinion angle.
A: 2.5 back
Will make a lot of load, will need moisture to make it work.
Will make load to the rear tire under a mechanical pull, needs some mositure.
C: 2.5 forward
Will run good in slick, makes pull based on the traction available.
Pull Bar Length: Pull bar length is more of a driver preference due to the drive he is look for. Some where between 28" and 32" will deliver the max load numbers for length. This will also pull the front of the car harder due to the length and center of gravity location. So with that being said you need to balance out the load and pull point with the weight in the front of the car.
Angle of the Pull Bar: The angle will add drive to the car faster and dissipate faster going down the straight away. 16-18 degrees on a 30" Pull Bar is a good starting point. Location on rear end depends on how much moisture you have in the track.
Load of Pull Bar: This is what will cost you all the money when it comes to Pull Bars, remember the cooler the Bar looks the more it will cost. The more it cost the better it works? Ask your Pull Bar guy what the delay load is for his bar, if he don't know than move on. Ours is 1.5 seconds @ 1.25 travel and the load is 2250 lbs. Load delay is only important on the slick, if he is trying to sell you a bar that come from UMP country than be most likely don't have a clue.
Loads: This is another gimmick to sell you something that don't work. Why I say that is because we already know we need load from 1800 to 2200 pound and we know the race track and the tire are going to make the biggest impact on the load decision. You need to collet the data over time to what works best on your car per given track conditions.
Load Delay: This is the big secret and is the hardest thing to understand but hear is a general idea of how it works. Load delay is the time difference between full pull and full load to the tire, here are some samples to how it works.
Solid Bar: Zero time delay, also the most drive you can make in a pull bar.
Spring Bar: The more spring rate the shorter is the load delay. Still very small and we will rate it at a .5 or less.
Spring and Biscuit: Now it become more difficult and will take a lot of testing to get right so listen to the Pull Bar guy because this can take years. Delay time when done right 1.5 to 2.0 seconds .
Biscuit (XFactor): This is the highest load delay you can get, it also will cost a little money. The biscuit allows load delay while it is getting into position and the better the biscuit is at doing this the shorter the life of the biscuit will be. Delay time can be1.5 - 3.0 second .
Just a short note to let you know that there is some stacked biscuit pull bar with load stops and concave washer to increase the load or different color biscuit. This is all cool but will take a small army of engineers to make it work.