These units can be adjusted off to where they don't do anything on a street setup. Your suspension will travel normal. If they are not adjusted all the way off they will start working and, when your suspension travels up and down much they become a solid link (bind). This would also happen when you you accelerate hard and the springs wrap up. If you were running weak leafs with the adjustment backed off you would run the risk of changing your pinion angle (driveshaft alignment )under hard acceleration and you could damage u-joints, push yokes into transmission,etc. When the Caltracs do their thing the suspension in effect becomes solid link.
Awhile ago I read an article on a 68 Mustang wheelstander super stock that uses them. He preloads each side differently for traction tuning. I think I saw an article on these units in the Mopar Performance magazine a year or so ago.
I've talked to guys at the drag strip about them. They like them because they can preload each side differently. They said snubber-block type traction bars didn't give the precise adjustment like Caltracs.
I looked into the basic geometry of the Caltrac setup. The axle end "pivot point" of the unit is several inches or so below axle centerline and the front link lower bolt hole is usually less inches from the spring hanger hole. As a result when the axle assembly rotates (wraps up) on hard acceleration, the travel distance of the Caltrac front bracket is "magnified"( An inch of travel at the front bracket equates to far less travel at the axle,) As far as binding up, a little travel in the rear amounts to a quick lockup at the front. This action is further enhanced by "shortening" of the front half of the spring leak when it wraps up on heavy acceleration.
I diagrammed all this out in full size scale drawings for a 1957 Pontiac leaf spring type setup. You would be surprised to see how little travel distances in the rear axle housing( up and down or rotating) affects things like driveshaft alignment, pinion angle, etc. I'm making myself a setup similar to the Caltracs for installation of the 57 rear end under a big block 63 Lemans.
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