Hey guys,

Have any of you experimented with your alignment? My cars been lowered ever so slightly and the outside edge of my tire (at correct 35psi) wears out quicker than the rest, I'd like to go with a "custom" maybe even "performance" camber, any suggestsions?
Whats stock?
also I believe stock is 0 toe in right? Any changes I can make maybe move the tires together 1/16th inch ?

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1985 Iroc-z, 14 second 305, new engine in the works.

 

Depending on how much you lowerd your car you may need camber plates. I personally like to run about one degree of negative camber. When adjusting your suspension you must take into account all three planes. Caster, Camber, and Toe. Caster will increase your contact patch and scrub radius, it is adjusted by rotating your upright in relation to the lower ball joint. This adjustment would have to be done with an adjustable plate. Caster will effect the feel of the steering and the cars ability to center itself. Usually the more caster the heavier the steering. Camber will effect the contact patch during cornering and where it will end up. Positive camber will increase your ability to turn. Negative camber will lessen your turning radius but increase your contact patch in a corner. Third gens usually start out with some positive camber, I guess they wanted execs to be able to pull out of their parking spots easily. So lowering your car probably increased the camber and that is generally considered a bad thing when it comes to performance. You can adjust it somewhat by rotating the bolts that connect the strut to the upright. Toe is the most common adjustment. It is the angle of the tires in relation to each other and the steering wheel. My general rule of thumb is the bigger the tires the less toe you want to run. 17" 245s You may want to start out with a couple 32nds or a 16th positive. This will help the car track down the road and keep the rearend from wanting to slide out easily. Sorry for the lecture. Hope this helps

 

Wow now thats a real pro!
Couldn't have asked for a better response!

So I want more caster
1 degree negative camber
and...

So as far as toe on a 16" tire I want about 1-2/32's of inward toe?

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1985 Iroc-z, 14 second 305, new engine in the works.

 

My 92 is lowered almost three inches.I had to get caster/camber adjustment plates to get my
geometry correct.My current settings are as follows:
Caster:+5.5 degrees
Camber:-1.5 degrees
toe in:1/32"
This is with 245/45-ZR16's on stock 92 16x8"Wheels.The inside wears out a little faster than the outside,and at high speeds,the positive caster makes it very stable with a little more effort required to bring it off center.
Bought my caster/camber plates (and strut tower brace)from Ground Control Racing:
http://www.ground-control.com/
I also have Global West's Del-A-Lum A-Arm Bushings,Lakewood Rear Lower Control Arms and Adjustable Panhard Bar,Etc...
Car handles great!
-Rich-

 

Do you happen to know what the stock caster Is just so that I can compair?

I'm interested in adjusting it

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1985 Iroc-z, 14 second 305, new engine in the works.

 

i run an alignment shop. www.asbdcnow.com/tredalign when you lower a car the camber decreases or goes more negative (leans inward). the OE specs are

camber 1.00 +/- 0.50 degrees
caster 3.00 +/- 1.00 degrees
toe 0.15 +/- 0.10 degrees per side

but on the camber i would recommend no more than -1.00 anything over 1 degree either way wears that side of the tire like the other post said with the -1.5 degree camber. handles great just wears the inside of the tire.

as far as caster, the higher, the harder the steering is to turn. the lower, the easier it is to turn. raising caster doen't increase the contact patch. it changes the relationship of the spindle to the the road in turns and projects the load point either ahead of the tire (+) or behind the tire(-) you want positive that way when you brake, the car doesn't feel like it's diving. if caster was 0, then when you turn the wheel, the spindle moves parallel to the road and the weight of the vehicle would be directly on top of the tire. when you make caster positive, (upper strut mount behind the lower ball joint when drawing a line straight down from the top), then on the left spindle turning left, the spindle pushes down towards the road. the right spindle turning left would go up. vice versa turning right. also this puts the load(weight) in front of the tire.

this increases stability in corners. caster itself is not a tire wearing angle. but when turning it changes camber. this is called camber roll. so, the higher the caster, the higher the camber roll. it can wear the outside edges of the tire if too high.
i would scan pictures of caster so you would understand it better, but i don't have an URL to post it too yet. on our cars, caster and camber is adjustable. the top plate slides forward/backward for caster and left/right for camber. but is limited. so you may need aftermarket plates to get more adjustment.

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mrrjjdh03@aol.com moderator at www.fl-thirdgen.org



[This message has been edited by mrr23 (edited December 12, 2001).]

 

-.5 camber
+4.5 caster left
+5 caster right
+1/16 toe
Will be an excellent wearing performance street alignment(I've did alot of third-gens this way). Should not need camber plates with a modest lowering job.


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350 with stealth intake, holley carb, 470 lift cam. 700r4 with .5 boost valve, vette servo, tci lock-up kit, B&M megashifter. Richmond 3.73 gears, powertrax locker, timkin bearings, synthetic lube. Custom 3 inch single into 2 2.5 pipes. 1 1/2 drop springs, 1 5/16 solid front sway bar, 1 inch rear bar, custom subframe connectors, custom LCA relocation brackets. Kobel ground FX, currant red metallic paint. Lots of other stuff...
82camaro

 

mrr23:

Thanks man, great response as well!!!

I saw illustrations of caster, basically waht im understanding is 5+ is the way to go?

I think i've got my numbers

Thanks!

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1985 Iroc-z, 14 second 305, new engine in the works.

 

Well I suppose increasing the contact patch would be technically wrong, but it will increase the dynamic loading on the wheel during a turn. If you could look at your wheel from the side, continously while your car enters a corner, you would notice the wheel will travel in an arching motion in relation to the automobile. the slope of this angle is directly influenced by the caster angle. Another way to wittness the effect of caster is to measure the hieght of your car with the wheels straight and then with the wheels turned. The prior post about setting the caster for braking is a good observation, but you want to be carefull about this line of thought. True a setting of the upper strut mount ahead of the plate will produce favorable characteristics during braking, but during acceleration out of a corner, when the weight is transferred to the back of the car the steering wheel will lose its ability to self center making the car feel hard to aim down the straight and possibly make it tail happy (oversteer).

My settings are the following on a GTA with stock rims and no lowering.

toe 1/16
camber .7 degrees
caster drivers side 5 degrees towards drivers door
caster passenger side 4.5 degrees towards the door

And as long as we are laying out our credentials in order to gain clout.

I am a chassis engineer for the company that makes big yellow earth moving machines
former places of employment include:
Roush Industries
GM powertrain

 

Why are people staggering their caster?

.5 less for the passenger?

Is that for the weight of the driver?



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1985 Iroc-z, 14 second 305, new engine in the works.

 

Camber and caster are adjustable in stock form.

No modifications should be nesscsary in order to get -1 deg of camber and +5 deg caster at stock ride height.

For street use I would not recommend anything higher than -1.5 deg camber.

A little bit of toe in is good for the street - 1/16" to 1/32".

Caster split is used to make the car track straight on crowned roads (all city streets are crowned for water drainage).

On a lowered car it is usually not a problem to get -1.75 deg camber without modifications. If more negative camber is what you need (for racing purposes) there is no need to buy expensive camber plates. Obtaining extra negative camber with camber plates that allow the upper mount of the strut to be tipped farther inward has disadvantages - increased S.A.I. for one. The best way is to slot the strut mounting holes - but this should only be performed by professionals.

The front suspension on ThirdGens is highly adjustable from the factory - one of the good points of ThirdGen suspension.

For your car and what you are doing:
Camber -1.25 to -1.5
Caster +4.5 on both sides.
Toe 1/16" toe in.

If you drive aggressively in the corners the extra camber will give you more front end grip while cornering and will help to keep the outside of the tire from wearing out faster than the inside. But if most of your driving is casual "sunday drive" driving, then stay closer to only -1 deg camber.


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Karl Hunter
Hunter Motorsports
Vancouver, B.C. CANADA

 

Wow

Looks like i hit a good topic

Keep it come'n guys!

I'm interested in caster right now i think the most, at least I've learned the most from it today, other than low speed driving what are the disadvantages of say 5 degrees caster am I going to be fighting the wheel to turn?

-1 camber
+5 caster
1/16th toe in

That seems to be safe yet an approvement

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1985 Iroc-z, 14 second 305, new engine in the works.

 

Don't get carried away with +caster (I'd stop at +4 for normal driving; FWIW I do my own alignments). Setting caster much outside the factory range (either higher or lower) changes the relative heights of the tierod ends, which affects the steering of the tires. Your "slight" lowering has already lowered the inner tierod height, so the last thing you need is to raise the outer tierod end too much by going heavy on the +caster. You might well end up with a car that's "twitchy" going over one wheel bumps and then you'd have to get the bumpsteer corrected. Note that bumpsteer correction is not a normal alignment shop procedure (it's too time-consuming to be profitable) and usually requires a mod to the tierod stud holes in the spindles to accept a straight shank bolt rather than the normal tapered rod end stud.

Norm

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1979 Malibu w/some cornering tweaks and a few other interesting things

[This message has been edited by Norm Peterson (edited December 13, 2001).]

 

I would stagger the caster a bit or it will have a small pull constantly toward the ditch. Don't be suprised if you can't get past -.5 camber--some thirdgens won't go past -.5, but that's plenty anyway. The main thing you need to realize from all these posts is that the stock setting are terrible, some negative camber is good, addtional positive caster is good, and you want a little bit of positive toe. The actual optimal settings are going to vary depending on how you drive, spring rates, sway bar size, ride height, tire size and construction, and a bunch of other stuff.

------------------
350 with stealth intake, holley carb, 470 lift cam. 700r4 with .5 boost valve, vette servo, tci lock-up kit, B&M megashifter. Richmond 3.73 gears, powertrax locker, timkin bearings, synthetic lube. Custom 3 inch single into 2 2.5 pipes. 1 1/2 drop springs, 1 5/16 solid front sway bar, 1 inch rear bar, custom subframe connectors, custom LCA relocation brackets. Kobel ground FX, currant red metallic paint. Lots of other stuff...
82camaro

 

I agree third-gens are highly adjustable, but the purpose of the plate wouldn't so much be to extend adjustability as it would be used to free up the strut motion. The aftermarket plates come with a much better bearing construction that frees up the strut. This is important, because after lowering the car the strut will be more sharply angled towards the car. This will cause a loading situation on the strut mount. The stock strut mounts over time under these loading condition will start to cause binding in the strut rod as well as the strut mount. It wouldn't hurt to also add a strut brace, since the strut force loads are now more directed off center of the strut tower.

[This message has been edited by DAVECS1 (edited December 13, 2001).]

 

My car already does feel "twitchy" over one wheel bumps, but it just feels loose at any speeds relitivly high, and I only mean like 70, so I think the toe in and caster can help that out, and the change with the camber will help me corner a tad better, and hopefully balance out the wear since its heavy on the outside edge. As far as my setup:
Homemade SFC's 1 3/4 mild steel tubing(stiff)
Spohn adj. poly/sphyrical LCA
Relocation bracket
Lowered by previous owner (about 1")
Spohn Adj Panhard (soon)
And Firehawk SZ50 EP's

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1985 Iroc-z, 14 second 305, new engine in the works.

 

Do you have some idea what your alignment settings currently are? They aren't that hard to measure if you have a level driveway and only a little math is required.

Norm

 

They SHOULD be stock, when i got the car I took it in for an alignment and all was set up to OEM specs, but I'd like to change them to the numbers I posted above.

If i can find them out i'd love to my car pulls very very lightly to the driverside, and wears out the outside edge of the tires.

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1985 Iroc-z, 14 second 305, new engine in the works.

 

it should be lower on the driver's side. it is to offset the crown of the road. a car will pull to the lower caster side. most roads, like the ones here in florida, are sloped downward to the right to drain off the rain. so, if caster was equal on both sides, the car would drift to the right. that is why you want the caster to be higher, by no more than .5 degrees. you can also do this with camber, but the oppsite way. a car will pull to the higher camber. again, make the camber higher on the left side by no more than .5 degree.

 

that is a better description af caster. i like that one. i was only laying out credentials to verify what i do. not for chest beating. i could tell by your post that your extremely knowledgable in the chassis field. i noticed your caster is lower on the right. are the roads in your areas sloped to the left? usually you would want it lower on the left side. here in florida the roads are crowned to the right. so we set caster lower on the left side to compensate. also my knowledge of alignment theory comes from my training at Hunter Engineering in bridgeton, missouri. the makers of alignment machines.

 

without knowing your current specs on the car, the slight pull to the left could be caster too high on the right side causing a push to the left. outside edge wear indicates that toe is too far inward (+). other reason could be camber too far outward (+).

other pulling could be dragging brake caliper.

 

Sorry for getting huffy and all. It was one of those days. You know,, the ones that never end. Anyway I am not sure I understand what you are saying about the roads in your area. The roads around here are crowned in the middle. I actually set the caster as such to compensate for my big butt sitting in the car. The reason I went to 4.5 is because most shops do not have the capability to dial in tenths of a degree. Idealy it would be nice to have the drivers side caster at approximately 4.7 to 4.8 degrees. Once again I apologize. I almost ruined a good thing. It has been a while since I have been able to talk to some people that have a good knowledge of performance setups. It would be nice to get some people knocking around ideas for good setups in this forum. I will restrain from being such a donkey from now on.

 

Hahaha


Nice

Thanks donkey or not you helped

 

i didn't take it personally. in florida, the roads lean from left to right (left side higher). this is to drain off water. so, if caster was equal, the car would drift to the right because of this. so, we make caster lower on the left to compensate.
and don't restrain yourself. it backs up the system.