Toe, camber and caster in plain words
Every alignment sheet comes down to three angles. Once you can picture them, the numbers start to make sense.
Toe
Look down at the car from above. Toe is how much the wheels point inward or outward compared with straight ahead. Too much of it scrubs the tyres along the road as you drive.
Camber
Stand in front of the car. Camber is how much the top of the wheel leans in or out. It affects how the tyre sits on the road in a corner and where the tread wears.
Caster
Look from the side. Caster is the backward lean of the axis the front wheel steers around. It helps the steering feel steady and return to centre by itself.
Caster is the hardest of the three to measure, because the wheel has to be swept left and right to find that axis. The lean of the strut tube on its own isn't caster, although the two are related.
How the app handles it
- Toe and camber are measured with your iPhone on the rim, and your first check is free.
- For caster, you steer about 20° each way on turn plates, or on plastic bags with a little grease between them under the front tyres.
- Turn-plate caster runs can differ by 10 to 30′, so average three.
Before you adjust anything
Measuring is for anyone. Adjusting is for people who know suspension work. If that isn't you, take your numbers to a shop. For the correct values, use the specification for your own car.