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total toe:
+0.25 °
+2.00 °
+0.08 °
total toe:
+0.25 °
+2.75 °
+0.08 °

DJ’s Alignment Specifications

The wheel rotates around an axle and the axle is part of a spindle. To steer a front wheel, the spindle rotates about an axis, called the steering axis, that is nearly vertical. In the Tundra and Sequoia, the steering axis is an imaginary line through the centers of the upper and lower ball joints. The upper ball joint is at the outer end of the upper control arm and the lower ball joint is at the outer end of the lower control arm.

Look down at your feet and turn them inward so your toes are closer together than your heels -- this is called "toe-in.” Now make your toes further apart than your heels -- this is called "toe-out.”

In wheel alignment, "toe" is much the same. Positive toe (or toe-in) describes that the forward edges of the front wheels are closer together than the rearward edges when the wheels are viewed from above the vehicle. Similarly, negative toe (or toe-out) has the forward edges further apart than the rearward edges.

You will see two different measurements of toe -- "total" toe and "individual" toe. Suppose you draw a line (imaginary, of course) that is in the plane of the left wheel (or perpendicular to its axle) and parallel to the ground. This line sticks out in front of the vehicle and "points" where the left wheel "points.” Now draw a similar line for the right wheel. These two lines meet somewhere -- with positive toe (or toe-in), they meet way out in front of the vehicle. The angle between these lines is called "total toe.”

The vehicle manufacturers specify total toe with a very tight tolerance. It is extremely important to get total toe correct because your tires will "scrub" sideways a bit as you roll down the road if it is not. In fact, incorrect total toe is a BIG, BIG cause of premature tire wear.

Total toe is usually set positive a small amount for a rear-wheel-drive vehicle. In the case of the Tundra and Sequoia, the spec is +0.08 degrees.

Now let's add a third line down the middle of the vehicle, called the "geometric center line.” Again, the left wheel line meets this center line way out in front of the vehicle, and the angle between them is called "individual left toe.” Similarly, the right wheel line meets the center line and provides an angle called "individual right toe.” Not surprisingly, total toe is simply the sum of the two individual toes.

If you think about it, it will be obvious that the measurements of individual front toe depend on how the wheels are steered. The significance of individual front toe is that they have to be EQUAL WHEN THE STEERING WHEEL IS LEVEL or your steering wheel won't be level when you go straight down the road.

Camber can be described in two ways, which are equivalent to each other. It is the lean of the plane of the tire relative to vertical, the plane being perpendicular to the axle about which the wheel rotates. It is also the angle between the axle and the horizontal. Positive camber is a lean outward and negative caster is a lean inward.

Camber is usually set slightly positive. In the case of the Tundra and Sequoia, the spec is about +0.25 degrees.

With most wheel aligners, camber is measured relative to gravity, which is why the alignment is measured on an "alignment rack,” which is a lift rack with runways that are set flat and level.

Now it gets fun. Remember the steering axis, about which the spindle rotates to steer the wheel left or right? Caster is the lean of this axis toward the rear, or it is the lean of the axis from the vertical when viewed from the side.

So, what is caster for? Picture the left wheel and its spindle. If caster is positive, meaning the steering axis is leaned toward the rear, then the left wheel tends to steer itself to the right when it rolls along. The more it is steered to the left, the harder it tries to steer to the right. A similar thing happens with the right wheel, which tries to steer itself to the left.

These two wheels try to steer themselves toward each other. If caster is the same on both wheels, then the forces will be equal when the vehicle is rolling straight ahead. If you steer to the left, the force steering the left wheel to the right is greater than the force steering the right wheel to the left, and so the steering wheel centers itself if you let go of it. The higher the caster is, the stronger the forces are and the harder the vehicle tries to steer itself straight ahead. This produces STEERING STABILITY.

If caster is reduced, the steering forces are reduced correspondingly. If caster is reduced enough, then the forces are too small and the steering system becomes unstable, meaning the wheels oscillate by steering left and right like a paint shaker.

So, how much is enough? It depends on LOTS of things and varies from vehicle to vehicle. On many Mercedes’, the caster spec is as high as ten 10°. On many pickups and such, it is commonly 3° to 4°. My Tundra can be "in spec,” according to Toyota, with caster at 0.5°, which is blisteringly stupid of them -- it is UNSTABLE.

The specs I have recommended put camber and toe at quite reasonable values and put caster right at the upper end of the range recommended by Toyota. In my opinion, caster should be even higher than that. I WON'T recommend setting it higher than that because of the liability involved, and because Toyota has NO grounds for complaint at my recommendation, but it's your truck and you can set it how you like.

Wheel alignment equipment manufactured by Hunter Engineering is "the standard" for alignment equipment all over the world. It is the best-selling alignment equipment in Japan. It is used for audit in nearly every vehicle assembly plant in North America and is used for this purpose in Toyota's plants, even in Japan.

So, yes, it is common for an alignment shop to have this equipment. You are likely to find it in at least 80% of the shops in the country, and it is commonly found in Toyota dealerships because it is recommended by Toyota to Toyota dealers.

Hunter has manufactured four different alignment consoles that have the "CAMM" screen, which makes it extremely easy and fast to set camber and caster on a vehicle with the suspension type found on the Tundra and Sequoia. These consoles are the models 211, 311, 411 and 611.

Excerpts from posts by DJ @

Hope this helps. I was able to open this file with a Microsoft Word Program.[/I]
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