I noticed yesterday that my driver side front tire is getting really worn on the outside! The rest of the tire is good. Also, the passenger front is the same, but not as bad. I just had it aligned at a shop a few months ago...looks improper camber to me.. What do you guys think?

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71 Malibu (http://stateseven.no-ip.com/chevelle/)
19 yr old college student
Bowtie Loyal

It may also be excessive toe in. I would take it back and have them check the alignment again. Take it to a shop that really knows old cars. A lot of shops today don't even have the specs for the old cars.

Andrew

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Project GatTagO (http://groups.msn.com/projectgattago)

Take it to a shop that has a staff that understands suspension geometry, not any of the chain stores, these guys have no clue! A good alignment shop will put there own alignment specs. in the car, because the original specs are out of step with todays tire tech.

Q-ship, what would the differences be between specs for bias ply and radial tires?
The other day I did an alignment on my '65 Skylark and I just told the computer that it was an 85 Chevy S10 being the two are very similar in design and aligned it to that. It really seemed to be pretty close to what it was with only about 1 degree of caster and camber just like the original car had. I set it at .30 total toe just like the S10, it seems to drive great.

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1965 Buick Gran Sport Convertible
1965 Buick Skylark H/T
"Fan of most anything that moves human beings"

Here are specs. that seem to work well for our old rigs:

Toe-in: 1/16" per side (equal to .3 on the newer align. racks)

Camber: it's probably best to "stand the tire up" if it's not going to be used as a handling machine, so I'd go with 0 to 1 degree negative; more on the negative side if you're the second coming of Mark Donahue.

Caster: If you're interested in straight-line acceleration, try to get all the caster you can, probably 4-5 degrees positive with stock upper control arms. It'll give you more turning resistance but us old drag racers like the stability when going down the track; if it's just a cruiser, 1-2 degrees caster will work just fine.

I suspect that the shop that did your alignment may need to have their rack calibrated. If one of their technicians ever drops one of the head units that mounts to the wheel, the alignment is going to really suffer. I've been down this road with my shop and have had to replace tires for customers due to a dropped head unit without my knowledge.

I hope this information sheds some light on your situation.

Torqueman is on the correct path. The only thing that I would add is that more neg camber will wear tires quickly unless you really drive agressively, and that postive caster will cause hard steering at low speeds and it will impossible to turn a manual steering car at slow speeds, so use good judgement and listen to a good alignment mech., find the alignment shop that does the local circle track racers and you will be farther ahead.

Q-ship, standard camber/caster geometry crosses from one car to another, sure. But what would be changed from bias ply to radial tires? And more importantly, why?

I figure that being the radial tires side walls are softer allowing the tire to maintain contact with the road, the toe and camber at least should be a little more aggressive. Does this sound about right?
Honestly, I never even thought of it, but being you brought it up, that makes sense. The toe on the S10 specs that I used in aligning my '65 Buick gave a toe of almost an eighth inch on each side for a total of almost a quarter inch. As you pointed out, an eighth inch was pretty much standard in the old bias ply days.

The camber would be the same, a little more negative camber will allow the tires to flex while still maintaining good surface contact.

But then for that matter, I don't think the tires have as much to do with it as the simple fact domestic auto manufactures WANTED the car to understeer. A car that understeers is a safer car for the non enthusiast. So the camber, caster, roll center and such promoted understeer for the sake of the idiots that the manufacture thought would be driving the cars. This has proven true of course with one look at all the SUV roll overs these days. The public just cannot handle a car that requires thinking when you drive. http://www.chevelles.com/forum/smile.gif

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1965 Buick Gran Sport Convertible
1965 Buick Skylark H/T
"Fan of most anything that moves human beings"

Bias ply tires of the 60's were of inferior rubber compound compared to todays tires. With neg camber they would wear excessively, and the bias ply have a nasty habit of following ruts in the highway and positive caster would possible cause a dangerous situation of the car being hard to correct when the tires grab the ruts. Also steering box tech then wasn't what it is today as well, and the buying public wasn't willing to drive a car with stiff steering at slow speeds. Hope this answers your questions, I think you will by OK using S10 alignment specs.