Finished prototype Mustang disc brake spindles

Discussion in 'Classic Mustang Specific Tech' started by degins, Jun 6, 2005.


  1. 69gmachine

    69gmachine Member

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    Glad to hear things are going well for your enterprise.

    The ackerman angle is fixed, so the centerline of the outer tie rod relative to the lower ball joint will only move as required to stay on an imaginary line drawn between the lower ball joint pivot point and the outer tie rod pivot point. Since most R&P kits are designed to work with the stock geometry, the drop of the steering arm needs to stay the same as well. Moving the tie rod pickup towards the ball joint 1" is fairly conservative, but I certainly wouldn't move it in more than 1.5". Since you are reluctant to absorb all the risk on this, tell us how many sets you would have to produce to make it worth your while. Maybe you could take a deposit from the members? Alternatively, if I was to put up half the funding (assuming I can actually afford it), would you be willing to let me in on half the profits from this particular spindle design? I can provide drawings if you are willing to move ahead on this project.
  2. dodgestang

    dodgestang Active Member

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    I'm always up for new things.

    Send me a pair. I'll put them on DT. If I don't die from a spindle failure the next time the car makes an attempt...you can consider them fully tested. ;)
  3. degins

    degins Member

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    So, bnickel suggests that the tie rod mounting point for an R&P spindle be moved 1.5" toward the pin and 1" outboard as opposed to the Granada/67-73 geometry. 69gmachine suggest 1-1.5" toward the pin. More opinions?

    Also should this spindle have a drop to it and how much. I think the spindle should be designed for a flange mounted caliper bracket. I assume that the bracket should fit a late model caliper designed for a large rotor (PBR on 13"?).

    69gmachine,
    If there enthusiasm for this product, it will manifest itself here in the form of suggestions and answers to these questions. Then I can determine if a project is feasible.
  4. 69gmachine

    69gmachine Member

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    I don't know where Bnickel came up with the 1" outboard, but that will give you virtually no Ackerman. That may be OK for a track only car, but you will hear a lot of complaints from the guys who drive their cars on the roads and have to turn at relatively slow speeds. If you draw a v with the apex at the center of the rear axle, and each of the lines intersecting the lower ball joint, the steering arm pivot point has to fall on this line to have 100% (sometimes called "true") Ackerman. The factory design has the intersection several feet behind the rear axle. If you draw lines from the lower ball joint through the steering arm pivots, you can see where they intersect. Since there is a slip angle associated with a moving tire that increases with speed, and Ackerman is intended to make the arc of the outboard tire wider than the inboard tire such that they both follow the radius of the turning arc, this benefit is intended only for relatively low speeds, such as manuevering in a parking lot. Make it match the factory angle and you'll have a lot more happy customers. It's been a while since I took my measurments, but I recall the factory design is somewhere around 11 degrees inboard of longitudinal. The PBR caliper is light weight, readily available and relatively inexpensive, so yes, a mounting pad for this caliper would be great. Last thing, Bnickel correctly pointed out that raising the pin and brake mounting points relative to the body of the knuckle will effectively lower the car, so there is no need or benefit in lowering it further by "dropping" it by making the overall height shorter than stock.

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