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  • #16
    Be sure to check your lower A-arm mounting bolts. They can loosen up, and with the pounding the suspension takes, will "oval" out the mounting holes in the chassis, causing the bottom of the tire to slide out. Ran into this problem on my Lark many years ago. Wider wheels with different offset will make it worse.
    Eric DeRosa


    \'63 R2 Lark
    \'60 Lark Convertible

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    • #17
      Thanks again Guys! I will recheck the control arm bolts. (Remembering previous posts on their propensity to loosen over time)
      On my rebuild I tried to use new fasteners everywhere, having read once in 'Auto Restorer' it was basically cheap insurance. On the suspension, it was always grade 8.
      I know my tires are too wide and my next set of 4 will be closer to stock. Makes better sense, I guess, for a 50 year old machine that wasn't designed for today's tire.
      Oh Jeff, on that reach rod... I noticed the tires while scooting under the car to replace mine. The r-rod had nothing to do with my alignment, as you mentioned, but had I not been replacing the old, floppy one, I never would have seen the belt shining thru until I was changing a tire on the side of a road, in the rain. :-)

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      • #18
        Originally posted by tomnoller View Post
        I know my tires are too wide and my next set of 4 will be closer to stock.
        Tom
        My 83 Avanti, ( I know-not a 63, but I don't know any way they differ in front suspension ) wears 15 X 8" rims that were on it when I purchased it three years ago (P215 60R15 tires with about 7" of tread on the front). It had several thousand miles on it then and I've put a couple thousand more on it. There is no noticeable differential wear on the front tires. It does have a complete rebuild on it with a professional alignment by the local specialist.

        So based on one data point (Me) the tire width is not the controlling parameter.

        Bob

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        • #19
          i am confused; someone needs to set me straight. What is the relation ship between scrub radius and the center of the rear axle bearing. I always thought that scrub radius was the measurement between where a line drawn through the center of the king pin meets the ground and the center of the tire contact patch with the ground. If the line through the king pin meets the ground towards the inside of the line through the king pin the car would have positive scrub and towards the outside would be negative.

          Ron

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          • #20
            Originally posted by Alan View Post
            A Stude tire does not ride in the center of the tread. The weight on the tire is inline with the rear wheel bearing. There is also back spacing of the rim and the king pin inclination angle. All of the wear will be in an area called the scrub radius. If you measure the front of your car you will find the scrub radius right there where it is worn. I have been crying about this for years but Stude Rich thinks I am crazier than Mad Man Muntz.
            Alan,
            I agree that area is the most common wear spot on Studes, but disagree that it is by design for the contact area to line up with the rear wheel bearing. I submit it is due to so many folks nowdays not knowing how to set up the front end.

            The upper & lower arm geometry is such that, if the car sits higher, it has more negative camber; if it sits lower, it has less. The early 1960s Studes tended to sit higher, so the problem became more pronounced; one way it was dealt with was to introduce the offset, upper/inner pivot shaft. Suffice to say, when adjusting the front end, one need not worry about too much positive camber. No matter if the car is 1950s or 1960s vintage, it is nearly impossible adjust in too much positive camber on a Stude, unless it is sits like a "low-rider". As I mentioned earlier, it is safe, and saves a lot of time later, to just set it up for max positive camber (and caster) and forget about it.

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            • #21
              Originally posted by rstrasser View Post
              I always thought that scrub radius was the measurement between where a line drawn through the center of the king pin meets the ground and the center of the tire contact patch with the ground. If the line through the king pin meets the ground towards the inside of the line through the king pin the car would have positive scrub and towards the outside would be negative. Ron
              Yes, Ron is also correct.

              The scrub radius is the distance in front view between the king pin axis and the center of the contact patch of the wheel, where both would theoretically touch the road.

              The kingpin axis is the line drawn through the upper and lower pivots. The inclination of the steering axis is measured as the angle between the steering axis and the centerline of the wheel. Changing camber angle changes the scrub radius, as does changing the width and offset of the tires and wheels on a vehicle.

              If the kingpin axis intersection point is outboard of the center of the contact patch it is negative, if inside the contact patch it is positive. The term scrub radius derives from the fact that either in the positive or negative mode, the tire does not turn on its centerline (it scrubs the road in a turn) and due to the increased friction, more effort is needed to turn the wheel, so wider tires and wheels move the contact patch outward and increases the scrub radius.

              Positive scrub radius works well with long/short A-arm suspensions with less caster and steering axis inclination, which is why Stude engineers designed it in.

              jack vines
              Last edited by PackardV8; 12-05-2012, 02:43 PM.
              PackardV8

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              • #22
                Joe; What I meant is the weight of the car at a particular wheel is centered at the rear wheel bearing, the outside bearing is just for stability and to keep the wheel from flopping over in turns. When I lazered the front end of my 53K there was almost 3" between the King Pin inclination point and the center line of the rear wheel bearing. On my tires and rims, which were the 5" stock type with 2 3/4" back space and 215 X 70 X 15" tires that ware patch was right there. Ask Pat Dilling what he thinks of looking at the beautiful skies of Nevada.

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                • #23
                  What I meant is the weight of the car at a particular wheel is centered at the rear wheel bearing, the outside bearing is just for stability
                  Alan, clarification is in order. It's not clear to some here if you're referring to the rear axle wheel bearing or the inside front wheel bearing?

                  jack vines
                  PackardV8

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                  • #24
                    Sorry Jack; Sometimes I think that since we are talking about the front end that everyone would think that it would be the inside or larger bearing that I was talking about.

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                    • #25
                      Again, I believe we are over-thinking. While the above principles, tech terms, etc. may be helpful in course #101 of an auto tech school, a thorough grasp is not need to align a Stude front end. All that is needed is the OEM caster, camber, and toe in/out adjustments. Camber is about insuring the front axle/spindles are parallel/near parallel to the ground, when sitting on an even surface. Since most Studes will not dial in to camber spec, it works best to just max out positive camber with the upper shaft and eccentric adjustment shaft, then forget it. If camber is at zero, tire/wheel width and wheel backspace are irrelevant.

                      If one feels safer measuring camber and trying to adjust it per factory specs, measuring requires a level with bubble vial, placed squarely against the outer hub, adjacent to the outer wheel bearing. Adjusting it (assuming the upper shaft is installed properly) requires only a 7/16" wrench, a 9/16" wrench, and a 1/4" allen wrench.

                      Caster does make much difference, one way or the other, since the minuscule adjustment range provided is not enough to matter when it comes to handling, tire wear, etc. There simply is no discernible difference between say, 0 and 4 degrees of caster, even if there's that much difference between sides.

                      Toe in/out can be measured by line of sight, and is kinda hard to screw up with 20/20 vision. For adjustment, it requires only a 1/2" wrench and pair of pliers.

                      The above tire wear is due to negative camber and/or tow out. Baring worn out, or distorted parts or frame, it is fixable as described above.

                      Why make it complicated, when it really is this simple?

                      I believe if we over analyze things, it only discourages folks from fixing and driving their Studes.

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                      • #26
                        Agree with Joe on 99.9% of his analysis. Caster is where we disagree.
                        There simply is no discernible difference between say, 0 and 4 degrees of caster, even if there's that much difference between sides.
                        Joe and I have both been driving Studes for many miles over many years, but I think most of his cars have PS. Without PS I can tell a great deal of difference between 0 and 4 degrees. With negative caster, cars without PS will steer and park easier, but will wander on the highway. With zero or positive caster, it will be more harder to park but more stable and stay straight on the highway.

                        As Joe says, the Stude front end doesn't have enough adjustment, but I want all the positive caster the adjuster will deliver. As Joe said earlier, crank the top all the way to the rear to get all the caster available and then confirm it's also delivering all the positive camber the eccentric will provide. If necessary, give up a bit of caster for the correct camber.

                        Most pre-'61 kingpins won't even get to 0 caster, much less positive. '62 and later kingpins were redesigned and will sometimes give +1 or 1.5 caster.


                        If camber is at zero, tire/wheel width and wheel backspace are irrelevant.
                        True, if you can get to zero. In my experience, the wider the tire/wheel and the more offset, it changes the geometry enough so there is more difficulty in obtaining and maintaining zero or positive camber. Sometimes there's just not enough camber adjustment for wider tires and wheels.
                        PackardV8

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                        • #27
                          If your front end is tight check for cracks around crossmember and may sure upper mounting has not been incorrectly repair, if you can't adjust it out. The frame may be sprung or something bent. On these cars the higher the ride height the more it will pull the top of the tire in(more negative camber which is what you have) If you have changed springs possibly they are too strong. The lower control arm should not be level but point downward a few degrees. A quick check for excessive toe-in/toe-out is simply run your fingers across the face of the tire. You will feel an sharp lip on the edge of each tread in one direction and not in the other. If you feel lip(s) running your hand from inside out would indicate excessive toe-out. The opposite direction toe-in. I wouldn't concern myself with scrub radius if the rest is set correctly it will take care of itself. If you can get to one degree negative camber you should be ok As to caster try for 0 to 1 positive but you will likely be stuck on the negative side. Too much positive makes these cars heavy to steer.

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                          • #28
                            Toe-in via string or big calipers referencing tire tread, sidewalls, or even wheels can be plus or minus 1/8 inch or more due to runout of those components unless efforts are made to establish a plane of rotation first or the car is rolled forward or back about 45 inches (1/2 tire revolution) to use the same features for the fore and aft measurements.

                            it is widely acknowledged that if there is no toe-in, a bit of wander may result.

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                            • #29
                              Due to deviation from factory setting, tires, wheels, etc., after making sure wheels are centered to box, I finalize the toe adjustment by toeing it out till it starts to wander and pull it back till the wander stops. Tires show minimal wear after 11000 or so miles.

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                              • #30
                                To: tomnoller,----Your Stude is 'dragging it's foot'!..............recheck the toe-in.

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