Ok so i read the thread from the cal tracs about how to adjust them!

I have long bars on my truck that nonnie and I made and installed. I have been to the track but don't have a track close enough that will give me acurate times. Now that being said you guys that are running long bars how are yours adjusted.
I started off with my pinion angle in the negatives and then i put the pressure towards the rear end causing the front of the pumpkin to go down...I did notice here that the truck didnt squat very much( similar to stalling up and the rear is lifiting) so basically preloading while just under normal driving.......then last tuesday night i pulled the bars up tight causing the pumpkin to go towards the bed of the truck.....the truck has more squat when leaving but i dont have 60' times to prove what is better!

Some one school me on geometry of the rear and how the angle and pressure affects the way the truck leaves!

 

You don't want it to squat

 

I agree

It has been my observation that squatting is only a sign of weight transfer which is a plus and generally helps with hooking.

If you're dead hooking though you don't want it to squat more. Optimally, you would dead hook, no squat, your pinion angle stays spot on and you go, but that's not how it always works.

 

^yep. Not saying that if your truck squats its bad because its prolly gonna happen...but just because it squats more doesn't mean its better

 

ahhh so i need it to stay as straight as possible without squatting.....man now i got work to do! I thought that the squat and trasfer was what you wanted! With my radials and the set up i have now i hooked last night and the truck left on the bumpstops with a 2/4 drop!
I might need to preload the bars and ask it to lift the front end then!

 

Well with a truck one of the hardest parts about hooking is that the weight is so unevenly distributed throughout the vehicle. By getting your truck to squat you transfer that weight over the back tires effectively distributing the weight more favorably.

With that said though, you don't want your truck to intentionally squat, all other things perfect.

 

well given the circumstances what would you want as far as pre "leaving"

1) push the bars out so that it pushes the rear?
2) pull them in to pull on the bottom lifting the pinion angle?

i cant see in my head what causes what and with a 5,000 lb truck its hard to tell what its doing!

 

Your bars shouldn't allow the pinion angle to change more than maybe 1/2 of a degree. Set it up (with the race setup, and proper weight distribution) and see how it launches and adjust from there in 1/2 degree increments

Adjusting the bars in or out should only rotate the rearend housing, it shouldn't pull the entire rearend back and forth IMO

Sometimes the best way to do this is go spend a day at the track on a slow T&T session and try lots of different settings and record what gives you the best results, it takes time to dial this stuff in, and like I told you over the phone. Basic principles apply but no two trucks are the same when it comes to setting up rear suspension for the most efficient launch. There's tons of variables

 

I just built me a set and am curious how to set them up.

 

yea i understand the pinoin angle but i get more movement out of the rearend with the angle pushed up towards the bed....i guess it serving its main purpose of reduced wheel hop so ill try a day at the track and see what it does!