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**robnolimit** · 10-15-2010, 04:05 PM

IAN30, good questions. First rule, "every action creates an equal and oposite reaction", so as the axle is trying to rotate the tire forward (lets say clockwise), the axle housing wants to rotate the oposite direction (counter-clockwise). The 25% rule is so that you have enough leverage to control the axle rotation, its a good rule of thumb. one more note, we want the truck to go "forward" under acceleration, so to get the leverage to help, put 2/3 of your bar span below the axle CL, and 1/3 above. * top bars that are right on the axle CL (elevation) WILL NOT transfer any wieght. ** 4-bars that are parallel (top to bottom bar) WILL NOT transfer any wieght. When it comes to three links (wishbone style) and triangulated four bars, BE CAREFULL, these set-ups build with urathane bushings all around start to bind any time they move away from ride hieght. you can help this by runnung rod-ends in the upper bars to allow them to articulate. Our kits are desinged to have the lower bar level to the ground and the upper bar slopping down at 4-5deg. at RH.

On another note, we now have custom tank-crossmember kits to fir 67-87's with Porterbuilt and others step notch kits. I'l post up some picts on the 67-72 section.

10-15-2010, 04:05 PM	#153
robnolimit Senior Member Join Date: Jul 2010 Location: Dandridge, Tn. USA Posts: 2,226	Re: Make it handle IAN30, good questions. First rule, "every action creates an equal and oposite reaction", so as the axle is trying to rotate the tire forward (lets say clockwise), the axle housing wants to rotate the oposite direction (counter-clockwise). The 25% rule is so that you have enough leverage to control the axle rotation, its a good rule of thumb. one more note, we want the truck to go "forward" under acceleration, so to get the leverage to help, put 2/3 of your bar span below the axle CL, and 1/3 above. * top bars that are right on the axle CL (elevation) WILL NOT transfer any wieght. ** 4-bars that are parallel (top to bottom bar) WILL NOT transfer any wieght. When it comes to three links (wishbone style) and triangulated four bars, BE CAREFULL, these set-ups build with urathane bushings all around start to bind any time they move away from ride hieght. you can help this by runnung rod-ends in the upper bars to allow them to articulate. Our kits are desinged to have the lower bar level to the ground and the upper bar slopping down at 4-5deg. at RH. On another note, we now have custom tank-crossmember kits to fir 67-87's with Porterbuilt and others step notch kits. I'l post up some picts on the 67-72 section.