Why Should You Align Your Car?

This section covers how to align your car track-side or in your garage and takes you through the procedure and the order of what to adjust.

Alignment is a very important part of vehicle set up. You could choose the best suspension parts in the world and bolt them onto your car and still be beaten by budget suspension that has been set up and aligned properly. It is particularly important when competing in a single make championship where all the cars have the same platform, so the winning edge can be achieved through the alignment and set up.

Alignment is all about aligning the suspension and tyres and ensuring that the maximum possible grip from the tyres is being achieved. Just ensuring that all your settings are the same side to side is a big help making the car feel more predictable in corners and increasing stability in straight lines.

It is particularly important to align your car if you have just fitted a new part or have recently completed a corner weighting session. Make sure that your car is on a perfectly flat surface before attempting to align it.

The Required Equipment

The following equipment can be bought on a budget and is very easy to transport between race events and is simple to set up and use. The entire below set up can be bought for £747 which will pay for itself since a good motorsport alignment can cost in the region of £300. The equipment required to complete a full suspension set up is:

  • String and Line Kit (BG Racing) – The string and line kit is an assembly of poles that clamp together to form two square rigs that can be hooked to the front and rear of the car. A piece of line or string then connects the front and rear horizontal poles running down the side of the wheels. This will be used to set the toe. A good make for this is the BG Racing string and line kit shown in the image above.
  • Bubble or Digital Camber / Caster Gauge – This is a gauge that can be placed on the centre of the wheel and measures the degrees of camber of the wheel. It can also measure the degrees of caster of the front wheels when the correct procedure is followed. These gauges can be spirit level or digital. Both have their benefits.

  • Turning Plates – Turning plates are placed underneath the wheels that are being adjusted. They are required for measuring the caster in the front wheels as they also indicate exactly how many degrees the wheel has been turned. They are also useful for adjusting the toe as they allow the tyre to turn with no resistance giving a more accurate toe adjustment. Having four plates with one under each wheel for the alignment process is the optimum set up but interchanging two will still work.
  • Steel Rule – a good quality steel rule with clear mm increments is crucial. It allows the toe to be measured accurately from the wheel to the string.

Advanced Equipment

  • Hub Stands (BG Racing) – For an extremely accurate set up, hub stands can be purchased. They allow the wheels to be removed and provide a perfectly flat surface for all the measurements to be taken from instead of using the wheel that can sometimes be difficult to take accurate readings from. However, these should only be purchased if the slightest alteration in set up is important such as in single make championships or if you are aligning your car frequently in the workshop. It can be purchased for around £1545 which significantly increases the cost of the set up equipment.

The Alignment Procedure

When you adjust one aspect of geometry, it usually affects another area. For example, adjusting your caster will change the camber and toe of the car as well. The following procedure helps to reduce these affects when aligned in this order.

First of all place the car on the turning pates. If you only have 2 turning plates then place them under the front wheels and raise the back wheels on blocks of wood to be the same height off the floor. Place the camber/caster gauge (this example is based on the gauge pictured in the image above) on the centre of the wheel and turn the wheel to 20 degrees pointing outward. At this point set the caster gauge to zero. Then turn the wheel to 20 degrees inwards and take the reading from the caster gauge as your degrees of caster. Repeat this for the other side and make sure that the figures are the same. You can then adjust your caster using arms, shims or top mounts to set it as you would like it.

With caster now set, place the camber gauge on the front wheels, touching the exact top of the wheel and the exact bottom, and read the gauge. The camber can now be adjusted to what you would like on both sides using camber bolts, adjustable arms, top mounts or shims. Repeat this for the rear wheels. You now have caster and camber set on the car.

The final stage of adjustment is the toe of the front and rear wheels. This requires the use of the string and line kit. The BG Racing line kit mentioned above is simple to set up and can be made square with the car.  Ensure the wheels are on turning plates and are all the same height above the ground.  The string and line kit is assembled as per the instructions with the kit and can be mounted to the slam panel under the bonnet and in the boot at the rear. Then slide in the horizontal bars to roughly a central position. Next the string can be run between the two bars, front to rear.

Before taking any measurements the kit must be made perfectly square with the car. Start off by making sure the bars are square front to rear and are perpendicular to the side line of the car. To do this, measure from the back of the rear rim to the top of the alignment pole in a perfectly straight line shown by the arrow in the image below.

Do this on both rear wheels and make sure the measurement is the same. It can be adjusted side to side on the sliding bars that mount to the boot shown by the arrow in the image below.

Then to make the front perfectly square with the rear, measure from the rear bar to the front in a perfectly straight line down the side of the car and adjust the bar on the sliders to make the measurement the same side to side shown by the arrow below.

Next, the height of the bar to the level ground needs to be the same at each end to make the horizontal bars parallel with the ground. To do this, measure from the end of each pole down to the floor shown by the arrow below. Make this measurement the same on all four corners.

Finally, the kit needs to be set square side to side. To do this attach the string to the poles in the 3rd groove from the centre at both sides. Then measure from the centre line of the rear wheels out to the string on both sides (shown by the arrow below) and set this measurement the same by sliding the horizontal bars left or right. Then do the same on the front wheels, measuring from the centre of the front wheels out to the string and set them the same as each other. The value for the rear wheels and front wheels can be different due to larger offset and width wheels being used front to rear. Double check the measurement on the rear wheels again and fine tune.

Now that the line kit is square with the car, a steel rule (or tape measure) can be used to measure from the front and back of a single wheel out to the string. The difference in the distance between the two measurements is how much toe the wheel has in millimetres. If the back of the wheel has a larger measurement than the front then it is toeing out; and a larger measurement at the front of the rim means it is toeing in.

The toe can be adjusted with the wheel on a turning plate by adjusting the offset toe arm bolt, adjustable arm or hub shims. The final toe set up will be in millimetres using the string and line kit. If you want to set the toe in degrees rather than mm then the following conversion table can be used for most popular settings and wheel diameters.

It is possible that the caster and camber will have slightly changed now that all the adjustments are complete so go around, double check and fine tune the caster and camber one more time.

Millimetere to Degrees of Toe Conversion Table

Wheel Diameter (INCHES)

  12 13 14 15 16 17 18 19 20 21 22

Toe

Per

Wheel

(mm)

0 0 0 0 0 0 0 0 0 0 0 0
0.25 0.05 0.04 0.04 0.04 0.04 0.03 0.03 0.03 0.03 0.03 0.03
0.5 0.09 0.09 0.08 0.08 0.07 0.07 0.06 0.06 0.06 0.05 0.05
0.75 0.14 0.13 0.12 0.11 0.11 0.1 0.09 0.09 0.08 0.08 0.08
1 0.19 0.17 0.16 0.15 0.14 0.13 0.13 0.12 0.11 0.11 0.1
1.25 0.23 0.22 0.2 0.19 0.18 0.17 0.16 0.15 0.14 0.13 0.13
1.5 0.28 0.26 0.24 0.23 0.21 0.2 0.19 0.18 0.17 0.16 0.15
1.75 0.33 0.3 0.28 0.26 0.25 0.23 0.22 0.21 0.2 0.19 0.18
2 0.38 0.35 0.32 0.3 0.28 0.27 0.25 0.24 0.23 0.21 0.21
2.25 0.42 0.39 0.36 0.34 0.32 0.3 0.28 0.27 0.25 0.24 0.23
2.5 0.47 0.43 0.4 0.38 0.35 0.33 0.31 0.3 0.28 0.27 0.26
2.75 0.52 0.48 0.44 0.41 0.39 0.36 0.34 0.33 0.31 0.3 0.28
3 0.56 0.52 0.48 0.45 0.42 0.4 0.38 0.36 0.34 0.32 0.31
3.25 0.61 0.56 0.52 0.49 0.46 0.43 0.41 0.39 0.37 0.35 0.33
3.5 0.66 0.61 0.56 0.53 0.49 0.46 0.44 0.42 0.39 0.38 0.36
3.75 0.7 0.65 0.6 0.56 0.53 0.5 0.47 0.45 0.42 0.4 0.38
4 0.75 0.69 0.64 0.6 0.56 0.53 0.5 0.47 0.45 0.43 0.41
4.25 0.8 0.74 0.68 0.64 0.6 0.56 0.53 0.5 0.48 0.46 0.44
4.5 0.85 0.78 0.73 0.68 0.63 0.6 0.56 0.53 0.51 0.48 0.46
4.75 0.89 0.82 0.77 0.71 0.67 0.63 0.6 0.56 0.54 0.51 0.49
5 0.94 0.87 0.81 0.75 0.7 0.66 0.63 0.59 0.56 0.54 0.51
5.25 0.99 0.91 0.85 0.86 0.74 0.7 0.66 0.62 0.59 0.56 0.54
5.5 1.03 0.95 0.89 0.83 0.78 0.73 0.69 0.65 0.62 0.59 0.56
5.75 1.08 1 0.93 0.86 0.81 0.76 0.72 0.68 0.65 0.62 0.59
6 1.13 1.04 0.97 0.9 0.85 0.8 0.75 0.71 0.68 0.64 0.62
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2 Comments

  1. Good day
    Millimetere to Degrees of Toe Conversion Table dont have calculation for 10″ weels
    it is possible to ad it?

    Tkank´s

    1. Hi Carlos,

      Yes we can add this in the near future for you.

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