whynotfab
+1y
Your best bet would be to remove your bed, and measure very carefully.
Set the truck at ride height, and figure out what type of front/lower brackets you'd be using (a crossmember, new hangers on the inside) and measure from a point there to the center of the underside of the axle. I usually drop the tape down 2" to consider in the tabs.
For your upper bars, they need to be as triangulated as possible.. Figure out where you'll be mounting the tabs for those, and measure from a point where the holes on the tabs would be, to the center of the axle. Make sure everything clears your bags, etc.
For help with knowing how far out the tabs will stick, so you can measure better:
Measures 2.25" from end to center of the hole.
Measures 4.25" from end to center of the hole.
2.75" from inner part of the arch, to the center of the hole.
2-5/8" from inner part of the arch, to the center of the hole.
So just take those lengths into consideration, and be sure to order all 4 of your bars adjustable so you have a little room for small measurement error, and can adjust your pinion once its all welded up.
As for the actual install *REMEMBER* Measure twice (or 5 times) and cut once , set the truck at ride height, and set the pinion. Bolt your tabs to the bars, might have to trim/grind a little on some.. and sit the bars in place how you planned. Get both sides symmetrical and all your measurements perfect so both sides match, and tack it. Jack the truck up and down as far as a bag would extend, from laid out, while checking the pinion throughout the motion with an angle finder. If it doesnt change, and if anything..maybe 1 degree both ways.. your good to go, weld it all up damn good..
Sorry for the long ass reply, and I have one other idea you might think sounds crazy.. use some cardboard wrapping paper type tubes, and cardboard tabs lol.. duct tape stuff together and mock it up for measurements LOL.
What type of bag brackets are you going with? Well I hope I helped somewhat in all that rambling.. Im usually on aim, so hit me up if you got more questions: WhyNotFab
Good luck!