[Ron Sutton]

Calculated the rear is easier, unless you have a double A-arm rear independent suspension … then it is exactly the same as the front. For all other common rear suspension types, here are the quick methods.

Panhard Bar/Track Bar: The RC is located horizontally & vertically at the center of the two pivots. If the bar is level and both sides are 8” off the ground … the roll center is 8” above the ground. If the bar is at an angle with one side at 11” & the other at 12” … the RC is at 11-1/2”. (But this angle will make the car handle differently on LH & RH corners.)

The RC is located horizontally exactly in the center of the two panhard bar pivots … which is why it makes sense to have the bar centered in the chassis on street, road race & AutoX cars … so the RC is centered in the chassis. Some oval track cars use a J-bar, which is not centered horizontally, and therefore neither is the RC.

Watt’s Link: The RC is located horizontally & vertically at the center of the bell crank pivot that is attached to the rear end housing.

Leaf Springs: The RC is located horizontally in the center … halfway between the two sets of leaf springs. The RC is located vertically at the height equal to the mating line where the leaf spring connects to the housing spring pads. If lowering blocks are utilized, the RC height is in the center of the lowering blocks.

Triangulated 4-links: Draw a line connecting the IC of the lower set of trailing arms … to the upper set of trailing arms … and where that line crosses the axle CL … is the rear RC.

Diagonal Link: The RC is located horizontally & vertically at the center of the two pivots. If the diagonal link is centered, so will the RC be. If the diagonal link is at 6” on one side and 7” on the other … the RC height is at 6-1/2”.

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