I am assuming that the specs Buick gave for the cars to be aligned were with the driver out? Just struck me that with a driver (only) that could change the alignment a bit. For first drive have 0 camber, +2.25 caster both sides, and toe in will be done tomorrow.
From Larry: "Caster preferred setting is -1/2* (+ or - 1/2*), 0-1* range, 1* side to side variation permitted. Camber preferred setting is +1/2* (+ or - 1/2*), +1*-0* range, 1* variation side to side permitted. Toe in 3/16" (+ or - 1/16") preferred, range 1/8"-1/4". A more performance alignment would have 3-3 1/2* + caster, -1/2* camber, and 1/16" toe in. With the stock A body front suspension, as the suspension travel goes from full extension to full compression, the camber goes positive. The outside tire in a turn (where suspension would be compressed) would have + camber, and the tire tends to roll onto the sidewall, and slip. The opposite happens to the inside tire. This is why our cars understeer moderately when pushed hard into a turn. Big swaybars minimize this effect. Dialing in - camber also helps in this regard. The more positive caster you run, the better the car will track at speed. Positive caster also induces a camber change as the wheels go from straight to full lock. The outide tire in a turn would have increasing - camber as you turn the steering. Mercedes Benz uses like 10* positive caster. If you have ever seen a Benz parked with it's wheels at full lock, you can actually see one tire tilted out at the top, and the other tilted in. Mercedes Benz are some of the best handling cars in the world. Anyway, maybe more info than you needed" I used this setup and was very please with the improved handling. Front end is all OEM parts. - Bill
Yup, saw that....I just don't want to go all nutty with the shims.. The specs I used are also on my white car and I like the way it handles so used it again...now that I have my own camber/caster gauge plan on playing a bit. And also it was neat to see the actual caster change as mentioned, you can plainly see it with the gauge. My question is, if most driving is done with just the driver, is it worth adjusting for that one driver?
Yeah - I got a bunch of shims - crazy! I'm no expert but I think that if you are driving at the cars limit you might notice the impact of the 150-190# in the drivers seat. (unless you are 190-300) I doubt you will notice the setup difference in normal driving. - Bill
Thats kinda what I figured too, thought I would ask anyway. I'll drive it like this for now and we'll see how it works...
I used the MOOG offset upper shaft and it appears that contributed to the shim stack. They are on correctly but need to be flipped. So number and size of shims will depend on your "frame sag"! The handling is also affected by the whole suspension set up, not just the alignment. The important thing is that you are happy with the handling with the way you drive your car! - Bill
My understanding is that the frame sags inward...ie you would have no shims left and have too much negative camber? The offset shafts move the arm outboard, do they not? It would seem to me that GM would try to build the chassis so the arms would be right in the middle at the factory settings, so lots of negative camber would move the arm inboard, lots of positive castor would move the aft end of the arm inboard even more, so lots of shims. You have to wonder why GM didn't use those specs right from the start? I'll drive the car, and we'll see how it goes.
Unless you have set of scales you have no idea how much weight is on each wheel. So tuning for driver would be a total shot in the dark. Besides you really do not not tune front end settings for weight anyway. You tune car balance with spring settings and other adjustments. In order to notice the difference would require lots of work on the scale and testing at limits. It is far more important to get everything mechanically perfect and make sure specs are where they are supposed to be. Of the front end setting toe is the one you can feel the most.
I have access to scales if wanted. I see your point for sure, but if I get my 200 pound friend to sit in the car the camber does change slightly, so would it not make sense if most driving is driver only that you adjust the alignment to that situation? If weight doesn't matter, then why level the car? All that does is shift the weight loads to where it is supposed to be for the alignment settings to match the "standard" or "baseline"? It's a hypothetical question anyway, I was just curious for the most part, won't doing a lot of road racing with it! :laugh:
I am not saying weight does not matter. It just does not make any difference when doing front end alignments. But you cannot do a good alignment if all the basics are not where they need to be. I would set everything else on the circle track cars I worked on before front end alignment. One of these days I am going to scale my car just to see where the weight is. I suspect that a car already comes with more right side than left as stock. Stuff on the right, battery, AC condensor, starter, heater AC core. vs steering column, steering box and power steering pump. I'm not road racing much either but do like to kick suspension ideas around.
the original specs for our cars were based on non radial. with radial tires the camber and caster and maybe even the toe may need to be changed. seems to me someone posted the alignment specs some time ago for radial tires. i think i have them at home. i worked at a trucking company back when radial tires first became available for large trucks. our mechanics worked with ford (truck division) and the radial tire manufacturer to determine new specs for camber, castor, and toe. the trucks just would not steer properly with the old bias tire specs. ** here are the specs i recorded, for radila tires, from this site some time ago. caster +2.5, camber -1/8, toe in 1/16" ***
I do alignments everyday where i work and as far as i know the manufacture sets all the alignments specs with the assuption of a driver/passenger or some weight to be put into the car. Some manufactures such as bmw or mercedes actually asks you to put weight into the car before you start your alignment ex. 150 pounds driver side, 150 passenger side 150 in back seat and about 50 in the trunk. but for the most part a minor amount of weight such as the driver will make a very minor change in the cars front end geometry/alignment specs. hope this helps =)
tim; think that radial tires may have become an option by 1973. i would imagine any of the high end north american vehicles - cadillac or lincoln - came with radials prior to that. tidbit - bf goodrich, canada, 1969 was manufacturing radial tires under licence from pirelli.
