Useful Info

[Typrus]

As per the Hunter Engineering Company Wheel Alignment Specifications 1987-2004 book....

1987 Toyota Tercel Wagon 4x4
Front Wheel
Alignment Specifications-
Caster (Degrees) - 2.42 +/- 0.5 (Cross 0.0, Tol. 0.5)
Camber (Degrees)- 0.58 +/- 0.5 (Cross 0.0, Tol. 0.5)
Front TOE (Degrees)- -0.1 +/- 0.1
Front TOE (Inches) - -0.05" +/- 0.05

SAI (Steering Inclination Angle) - 11.8 +/- 0.5
Turning Angle- 36.3/33.3 +/- 1.0

No Rear specs.


Ball Joint-
ZERO Perceptible movement in axial or radial play allowed (If you want how to test this, download the FSM)


Suspension/Chassis Heights

Measure in front from control arm-body bolt center to ground
Measure in rear from lower trailing arm to body forward mount bolt center to ground.

Meaure at curb weight (Nothing/noone in car, full tank of gas and all fluids full)

Front- 9.25"(235mm)
Rear- 10.75"(273mm)



Front camber is adjusted by means of an eccentric cam bolt channel on the lower bolt of the McPherson Strut to knuckle mount.


Front Caster is adjusted by means of shims on the strut rod (Sway Bar) to move control arm forward or rearward.

(Note: I believe that reversing the 3rd bolt on the upper Strut bearing mount would move the top of the Strut forward, decreasing Caster... This is BAD!)

Toe is adjusted by means of manipulating the relation of the inner to outer steering tie rods.




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So.
Caster is the measurement of the angle between a line drawn through the upper and lower steering pivot points (Upper bearing plate and lower ball joint) and a verticle line. Caster is important as it effects directional stability in a straight line. 0 degrees of caster would make the wheel turn completely flat. The spindle moves in a flat plane. Changes in caster make the wheel's camber angle change in a turn.

Negative camber will aid in steering ease, but severely compromises directional stability. Avoid it if you can.
Positive camber will help you stay in a straight line and will make your car want to stay in a straight line. Though, a severe enough angle will make it hard to steer and can cause the wheel to snap. If you go drive your car and go into a corner, then suddenly let go of the steering wheel, it will "snap" back to straight at a certain speed. The more positive camber, the faster it snaps. This can be dangerous in that if it snaps hard enough, it can actually overcorrect in the other direction before returning straight. This is why steering damper are installed. They help control the wheel snap.

For example... Our cars have 2.42 degrees positive caster. We are pretty stable to about 100mph (based on experience) A Mercedes Benz averages 10-11 degrees positive caster. They can handle 180mph on the Autobahn all day long without issues. But they need beefy dampers to prevent your arm being taken off in the event of letting go of the wheel.

Also, the more caster you have, the more the wheels will camber in a turn. This is to to the spindle moving at an angle, rather than in a flat plane. If set up right, this action will create a "Camber Roll" which helps counteract body roll. Where the force of the turn pushes the body down, the Camber Roll pushes it back up. It helps you stay level.



Camber is important for more reasons than, before today, I knew.
Not only does it see if the wheels are contacting the road flat, but it determines such things as bearing load, cornering stability, and the likes.
Excess camber will do far more bad than good. For instance, wearing down to the steel cord on the outer or inner edge before the rest of the tire is hardly worn at all.


The more negative the camber, the more inward the top of the wheel is in relation to to bottom. This aids in corners because as the weight of the vehicle transfers over, it presses the otherwise angled tire flat to the road, giving maximum traction. It hurts things as well. The more negative the camber, the further out on the spindle the load from the vehicles weight is transferred. In a classic Taper-Roller bearing setup, this puts much higher loads on the smaller outer bearing. On bearings like ours, dual-ball bearing setups, it puts a sideways load on the bearing. This is not good, as they were designed only for a direct up-down load. This sideways load can actually cause the ball bearings to fire out of the race, destroying them.

The more positive camber, the more the top of the tire leans out in relation to the lower.
This will do harm in the corners. As the weight transfers outwards, the tire has a tendency to want to fold over on the sidewall. Less traction is offered, and if it does succeed in rolling onto the sidewall, you risk tire blowout by a loss of bead.
The positive camber transfers the load to the inner edge of the spindle. On a Taper-Roller bearing,this put more weight on the larger bearing. While still not as good as having a proportional load on both bearings, it will do less harm than the opposite.
However, again, on bearing like ours, too much load can destroy the bearings outright.


Toe is essentially how much the tires point in one direction or the other. If both tires point towards each other at the front, this is Toe-In, or positive Toe. If they point out, this is Toe-Out, or negative Toe. To a degree, positive toe will aid in directional stability, but minimal amounts are desired. Toe out is typically not recommended except on FWD cars.
As the tires move under rolling resistance (pushed back) braking (pushed back) or acceleration (pushed back in RWD cars, pulled forward in FWD cars) the toe will change. With RWD vehicles, a little bit extra toe in is needed at rest, because the action of the assembly moving back will even the equation out. In FWD vehicles, the toe is out at rest, because the action of the tires pulling forward will even out.

As a quick diagnosis of toe, run your hand along the tops of the tire. Feel if it is smooth or rough.

Smooth In, Toe In. Smooth Out, Toe Out.
What that means is that if you run your hand inward and its smooth, but it is rough on the outward move, you have a Toe-In problem. If it is rough in, but smooth out, you have toe-out problems.



So tires are important in the bearing issue as well. A smaller offset rim (Negative offsets move the rim further out, positives further in) will put higher stress on the outside of the spindle. This creates higher stress on outer smaller taper roller bearings, and puts lateral loads on ball-bearings. Not good, unless Positive Camber is used to counteract this.
A larger offset rim will secure the load further in on the spindle. While alone this is bad, it can be used in harmony with negative camber to balance out.

The further out the centerline of the tire is from the spindle center, the further out the load is put. Not good. An extreme example of this is Bato Wheels. The tiny diameter wheels that are very wide and placed very far out from the side of the vehicle. This will destroy bearings very rapidly. Not good.

So if you desire wider tires, and nothing else, keep the stock rim offset. It adds more tire in equal amountds in either direction, not harming wheel bearings. If you want more negative camber, get rims with a higher offset. This will bring the load back over the center of the bearing pack.


Now this is an issue with us due to clearance problems. We can't really do much in the way of higher offsets because we get inner wheel well interference. For that purpose, I really dunno what to suggest, next to lengthening the control arm and pushing everything out.


Taller and wider wheels exaggerate the effects because they equate to larger leverages.

[Gasoline Fumes]

(Note: I believe that reversing the 3rd bolt on the upper Strut bearing mount would move the top of the Strut forward, decreasing Caster... This is BAD!)

Weren't the manual steering models setup like that?

[Typrus]

Well, thats the thing. The only vehicles recommended with negative caster or anything near it are either very old, or have manual steering. Again, as I said above, negative caster aids steering effort, but hinders directional stability. The 81 Corolla Tercel doesn't like high speeds all that much. Its manual steering.

[keith]

Excellent description. I see some hot rodder wanna be's putting a lot of negative camber on extremely low profile tires. Really not the way to go for maximum cornering. On high profile tires that are driven to the limit a lot, a little extra camber helps the handling and tire wear. The factory settings are for the average driver. The extra camber helps prevent the tires from rolling over in a hard corner, keeping all the tread flat on the ground. With low profile tires (45 or 35 series), the tires will never roll enough to flatten the tread out on the ground so they will not hold a corner as well.

But then again, the guys who do this are young and know everything there is to know, don't they.

[Typrus]

Well, a factory style change, say, within -2 degrees or so is probably going to get you best results, unless you have say a Ferrari. Heh. The lower the profile, the stiffer the sidewall, simply by the fact there is less of it. A well inflated 55, 50, or less is almost never going to lay over.
Your body roll isn't going to make up for enough that when going straight the outside of the tire is off the ground... Enough negative camber to indeed be negative, but not enough to lift the tread at all is probably going to see you best. Straight line you still have full contact, just less pressure on the outside, and in cases of hard body roll, you get near even pressure across the whole tread.
Thats the whole point in Neg camber. Make the tread as flat as possible in extreme cornering. If you ever even do extreme cornering.

Would you say thats accurate?

[keith]

Yeah, sounds about right. It was funny, earlier that day (the day you posted), I saw a Nissan PU (I have one of those too) with rims and what looked like 35 series tires and a negative camber on the order of 10 degrees. It looked like it only had about a fourth of its rubber touching pavement. He didn't have much wheel well clearance either. It looked like both lower ball joints had broken. Thats what brought on my comment. I should have included that in my original reply.

[ColSwede]

I wanted to build all new strut towers up front and couldn't find new, stock coil springs, so I was given a part number for some that would fit but, lift the front end. Due to this lift, the camber is horrifically positive. How can I overcome this positive camber to get a good, healthy front end alignment?

[Petros]

too much lift will wear out your cv axles because of the larger angle, and often the top seal of the strut will get damaged because there is not enough rebound travel (the piston will damage the seal at the top of the travel).

you may have to cut down the springs. As I recall, you can get aftermarket stock spec springs from Moog.

[simon84]

I got Moog springs for the front on my last tercel. The top caps of the strut (that hold the strut cartridge) ended up popping off (for the reason stated by Petros above). And eventually the springs cracked. Overall I was not impressed. Last time I looked, they were not available any more.
I had lifted the terc with a 2" rubber spacer above the strut top mount (the three mounting bolts were replaced with longer bolts tack welded to the mounting plates). So the lift was not part of the actual strut assembly but the new springs sat taller until they broke. I would not get new springs again after that experience unless they were rusted out or broken. I agree that CV axle life is probably shorter but I figure that's the price you pay for the lift.

[Petros]

best to find toyota springs at a wrecking yard. the front springs from either the 2wd or 4 wd Tercel from 83-86 are interchangeable.

I had some struts off a FWD tercel I got in a trade (for stripping and junking a 2wd Tercel), the strut assembly are about an inch (25 mm) shorter, but oddly the springs themselves are slightly stiffer (but dimensionally identical) to the ones in my T4wd. They had a slightly larger wire dia, but were the same otherwise. I installed those spring in the front of my car when I replaced the dampener cartridge in my original struts, and it only raised it a bit, but they are durable and do not sag despite the many 100,000 miles on them.

[ColSwede]

Are the alignment specs in this thread also the same for an '83 Tercel wagon 4wd? I'm taking mine in today to get new sneakers put on and the alignment done and the shop needs the specs, as their machine doesn't go back to 83.

[Petros]

yes, all the 4x4 tercel wagons are mechanically identical.

[ColSwede]

Awesome! Thank you. Sadly, the shop couldn't do it Friday so I gotta figure out a new day...