Aligning your toe! No, it’s not exclusively the realm of chiropodists, it’s also car-related. Yeah, sometimes I talk about cars on this blog. Get over it.
Here’s an example of toe going suddenly rather un-aligned. It’s also a good example of how Hummer H2s aren’t really meant to go on trails.
A front-end alignment generally consists of changing the camber and the toe. You might remember that I recently changed the camber alignment of my Subaru, which had the secondary effect of changing the toe. With the camber set and checked, I needed to address the change in toe.
For the uninitiated, a wheel’s toe is its steering angle compared to the wheel on the opposite side of the axle. Generally this is set from the car factory to be slightly toe-in,meaning the wheels are slightly cross-eyed when looking at the front of the car. This makes for a more stable car, but it doesn’t help handling and it doesn’t help tire wear.
Handling is actually (usually) improved by a small amount of toe-out. This helps the car turn into corners better. However, for a street-driven car it can be a little twitchy on the highway, and it also wears out tires.
Tire wear is maximized by setting a neutral toe (ie. wheels totally parallel, neither toe-in nor toe-out). It will also improve handling over a factory setting. Toe is changed by adjusting the tie-rods of the steering system (note that I also recently changed my tie rod) to make them longer or shorter.
This can be done without removing wheels or jacking the car up, and is actually pretty easy once you have a method sorted out. Start by turning the steering wheel all the way to one side, which will expose the tie rod. There is a section of the tie rod with flat spots to put on the adjustment wrench (usually 13mm), and a jamb nut that needs to be loosened.
In the above picture I have only removed the wheel for clarity, but the jamb nut can sometimes be difficult to loosen thus necessitating wheel removal for better access. The jamb nut will be a bit easier to remove if you scrub the threads with a wire brush and then spray them with a penetrating lube like PB Blaster (or WD40 in a pinch).
Once both tie rod jamb nuts are loose (and wheel nuts fully tightened, if you had to remove wheels), we’re nearly ready to get a baseline reading of toe. The only thing left to do is to take the tension out of the tires.
When you turn the steering wheel and the car is stationary, the rubber deforms, reaches a point where it can’t deform any further, then slides across the ground, leaving a little bit of deformed tension in the rubber. This will slightly affect toe readings so we need to roll the car back and forth slightly to take that tension away. Every time you make an adjustment during your toe alignment, you will need to roll the car back and forth to remove this tension before taking another reading.
Those who know me well know that I have a perverse attraction to unorthodox ways of doing things. As such, I present my alignment system (I will explain the easier traditional method afterwards).
What you see above is my toe alignment rig. It is a steel bar with a line-laser on either end and a battery pack in the middle. This gets attached to the wheel with bungee cord, like so:
Also note the angle indicator to ensure the bar is level. But… I get ahead of myself. Before the laser bar can be used, it has to be calibrated. Calibrating it involves clamping it squarely to its twin (at the proper height) and checking the lasers to ensure the beams are exactly parallel.
If they are not exactly parallel, the metal tabs holding the lasers can be tweaked with some pliers.
With one laser bar on each front wheel, the distance can be measured between the beams in front of and behind the wheels. If toe were neutral, these measurements would be equal.
(the laser line is faintly visible in the picture, but much more obvious in person)
Hmm… 73 and 3/8 in front, but 73 and ¾ in back. The back is wider than the front, which means I need to add more toe-out. Turning the tie rods to lengthen them will add toe-out.
A quick note about adjusting tie rods. While adjusting either rod will have the same overall effect (adjusting the left rod adds toe-in or toe-out just the same as adjusting the right rod), you are effectively altering your maximum steering angle when you make these adjustments. If you had your right rod adjusted all the way in and your left rod adjusted all the way out, you might still have parallel wheels, but you will be able to turn the wheels farther to the left than you will be to the right as the steering rack will run out of motion when turning to the right. For this reason, it’s best to adjust the rods equally. It may also have the secondary benefit of not having to adjust your steering wheel when you’re done.
After an adjustment or two, I’ll start upping the accuracy by using my carpenter’s square to ensure square measurements.
When I’m satisfied with the toe setting, I make one last calibration check of the laser bars to make sure I haven’t bumped them out of whack. If that checks out, I tighten the jamb nuts on the tie rods, take a test drive, and if necessary, adjust the steering wheel.
If the test drive involves driving down a straight road with the steering wheel slightly off to one side, it means the rods weren’t adjusted equally. If the wheel is more than a few degrees off I will readjust the tie rods to ensure the steering rack is centred and I can turn the same amount of degrees left and right.
To correct for a couple of degrees of steering wheel deflection, I (slowly) drive down a straight road with the tie rods loose. I make equal adjustments to both sides to centre the wheel, then tighten the jamb juts on the tie rods once I'm satisfied.
Oh yes - I mentioned that I would also introduce the traditional method of setting toe at home. My laser bars, in addition to being slightly more cool due to the addition of lasers (I’m not much of a bar patron, but I might actually go to a LASER BAR), is potentially a little more accurate than the traditional method due to taking measurements at longer distance from the wheel.
The traditional method involves using four jackstands and two lengths of string. A string is tied between two jackstands and repeated on the other side of the car.
The strings must be measured and placed precisely to ensure they are parallel. Measurements can then be taken between the front edge of the wheel and the back edge of the wheel, and compared to the other side.
When the front side distance and the back side distance is the same on all four measuring points, the toe is zeroed. This method is pretty quick to set up and use, but not quite as accurate as my method.
Traditional method:
free!
Cost for building LASER BARS!:
$15 - 4.5-volt line lasers (Dealextreme)
$5 - two 3xAA battery holders (Dealextreme)
$2 - six AA batteries
Incidental supplies for LASER BARS!:
steel bars from my pile o’ scraps
wire from my bucket o’ wires
Here’s an example of toe going suddenly rather un-aligned. It’s also a good example of how Hummer H2s aren’t really meant to go on trails.
A front-end alignment generally consists of changing the camber and the toe. You might remember that I recently changed the camber alignment of my Subaru, which had the secondary effect of changing the toe. With the camber set and checked, I needed to address the change in toe.
For the uninitiated, a wheel’s toe is its steering angle compared to the wheel on the opposite side of the axle. Generally this is set from the car factory to be slightly toe-in,meaning the wheels are slightly cross-eyed when looking at the front of the car. This makes for a more stable car, but it doesn’t help handling and it doesn’t help tire wear.
Handling is actually (usually) improved by a small amount of toe-out. This helps the car turn into corners better. However, for a street-driven car it can be a little twitchy on the highway, and it also wears out tires.
Tire wear is maximized by setting a neutral toe (ie. wheels totally parallel, neither toe-in nor toe-out). It will also improve handling over a factory setting. Toe is changed by adjusting the tie-rods of the steering system (note that I also recently changed my tie rod) to make them longer or shorter.
This can be done without removing wheels or jacking the car up, and is actually pretty easy once you have a method sorted out. Start by turning the steering wheel all the way to one side, which will expose the tie rod. There is a section of the tie rod with flat spots to put on the adjustment wrench (usually 13mm), and a jamb nut that needs to be loosened.
In the above picture I have only removed the wheel for clarity, but the jamb nut can sometimes be difficult to loosen thus necessitating wheel removal for better access. The jamb nut will be a bit easier to remove if you scrub the threads with a wire brush and then spray them with a penetrating lube like PB Blaster (or WD40 in a pinch).
Once both tie rod jamb nuts are loose (and wheel nuts fully tightened, if you had to remove wheels), we’re nearly ready to get a baseline reading of toe. The only thing left to do is to take the tension out of the tires.
When you turn the steering wheel and the car is stationary, the rubber deforms, reaches a point where it can’t deform any further, then slides across the ground, leaving a little bit of deformed tension in the rubber. This will slightly affect toe readings so we need to roll the car back and forth slightly to take that tension away. Every time you make an adjustment during your toe alignment, you will need to roll the car back and forth to remove this tension before taking another reading.
Those who know me well know that I have a perverse attraction to unorthodox ways of doing things. As such, I present my alignment system (I will explain the easier traditional method afterwards).
What you see above is my toe alignment rig. It is a steel bar with a line-laser on either end and a battery pack in the middle. This gets attached to the wheel with bungee cord, like so:
Also note the angle indicator to ensure the bar is level. But… I get ahead of myself. Before the laser bar can be used, it has to be calibrated. Calibrating it involves clamping it squarely to its twin (at the proper height) and checking the lasers to ensure the beams are exactly parallel.
If they are not exactly parallel, the metal tabs holding the lasers can be tweaked with some pliers.
With one laser bar on each front wheel, the distance can be measured between the beams in front of and behind the wheels. If toe were neutral, these measurements would be equal.
(the laser line is faintly visible in the picture, but much more obvious in person)
Hmm… 73 and 3/8 in front, but 73 and ¾ in back. The back is wider than the front, which means I need to add more toe-out. Turning the tie rods to lengthen them will add toe-out.
A quick note about adjusting tie rods. While adjusting either rod will have the same overall effect (adjusting the left rod adds toe-in or toe-out just the same as adjusting the right rod), you are effectively altering your maximum steering angle when you make these adjustments. If you had your right rod adjusted all the way in and your left rod adjusted all the way out, you might still have parallel wheels, but you will be able to turn the wheels farther to the left than you will be to the right as the steering rack will run out of motion when turning to the right. For this reason, it’s best to adjust the rods equally. It may also have the secondary benefit of not having to adjust your steering wheel when you’re done.
After an adjustment or two, I’ll start upping the accuracy by using my carpenter’s square to ensure square measurements.
When I’m satisfied with the toe setting, I make one last calibration check of the laser bars to make sure I haven’t bumped them out of whack. If that checks out, I tighten the jamb nuts on the tie rods, take a test drive, and if necessary, adjust the steering wheel.
If the test drive involves driving down a straight road with the steering wheel slightly off to one side, it means the rods weren’t adjusted equally. If the wheel is more than a few degrees off I will readjust the tie rods to ensure the steering rack is centred and I can turn the same amount of degrees left and right.
To correct for a couple of degrees of steering wheel deflection, I (slowly) drive down a straight road with the tie rods loose. I make equal adjustments to both sides to centre the wheel, then tighten the jamb juts on the tie rods once I'm satisfied.
Oh yes - I mentioned that I would also introduce the traditional method of setting toe at home. My laser bars, in addition to being slightly more cool due to the addition of lasers (I’m not much of a bar patron, but I might actually go to a LASER BAR), is potentially a little more accurate than the traditional method due to taking measurements at longer distance from the wheel.
The traditional method involves using four jackstands and two lengths of string. A string is tied between two jackstands and repeated on the other side of the car.
The strings must be measured and placed precisely to ensure they are parallel. Measurements can then be taken between the front edge of the wheel and the back edge of the wheel, and compared to the other side.
When the front side distance and the back side distance is the same on all four measuring points, the toe is zeroed. This method is pretty quick to set up and use, but not quite as accurate as my method.
Traditional method:
free!
Cost for building LASER BARS!:
$15 - 4.5-volt line lasers (Dealextreme)
$5 - two 3xAA battery holders (Dealextreme)
$2 - six AA batteries
Incidental supplies for LASER BARS!:
steel bars from my pile o’ scraps
wire from my bucket o’ wires
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