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Message: <blockquote data-quote="Bob_Sheaves" data-source="post: 3087" data-attributes="member: 14">HI!One thing you do not say is how much travel you currently use-for the following explanation, I am going to assume 12" or less total jounce to rebound travel.A leaf spring does not follow a prescribed arc, much like a fixed link. As the suspension cycles, the spring changes it's effective length from rebound (generally the shortest dimension), through the "flat" (longest dimension) and then shorter again as it moves to the full jounce position. The dimension changes are (in your case) handled by the shackle at the rear of the spring-minimizing the binding that would occur if both ends were rigidly mounted. Simple design, no? The problem with a link that is fixed (with rigid ends - like heim joints) is that the link induces a compression force to the forward section of the spring, precicely at the wrong time (that is to say, when the spring wants to "get longer" the link tries to shorten it)The problem of powertrain induced waveforms in the spring shape (the "wrap" caused by the application of power-either by engine torque or brake torque) should be controlled by a series of "links" that resist this effort and transfer it to the vehicle center of gravity-as you surmised. One problem that arises from installing a rigid link is the altering of the design "anti-squat" and "anti-dive" geometry built into the existing suspension. Altering the travel (by a greater arch in the spring, and/or installing a rigid length link, or even installing taller tires) will affect the amount of traction you have under both accelleration and braking. The ideal position and relationship of the "traction link" will minimize these issues.I would approach this (since you stated later that this is primarilly a street driven vehicle) as follows:1. The length of this added link shall be the same length as the measurement from the front mount center of the spring eye to the center of the spring mounting pad.2. The front pivot vertical location (when looking atthe car from the side) shall be centered on the front spring bolt (same centerline).3. The rearmost mounting bolt centerline shall be the same distance above (or below) the centerline of the axle as the spring to axle pad dimension (depending where the spring is mounted the new link should be mounted on the opposite "side" of the axle centerline)..4. The forward end of the link should be mounted on a frame bracket (inside the frame) that is isolated from NVH by a solid urethane bushing that is greaseable (using a silicone grease). This will control fore-aft and vertical deflection of the link. Personally, I would fab the bracket with a series of bolt holes to allow adjustment vertically over a range of +/- 3 inches to allow fine tuning during testing (a sliding bracket would be a cleaner design, but more costly to fab).5. The axle end of the link would be mounted to the axle housing tube so that (when looking down on the car from the "top") the link is parallel to the vehicle centerline. In this location, I would use a "voided bushing" (see previous comments for a description, or look at a Jeep XJ engine mount bushing) with the rubber blocks placed so that they are vertical and the openings in the bushing as fore and aft. This will allow the axle mounted bushing to deflect fore and aft as the syspension cycles from jounce to rebound.Hope this help you and not confuses you more....Best regards,Bob Sheaves</blockquote>

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