OK, maybe you don't have to be an expert, but can someone tell me what the difference is between the "tracking" and the "balancing" on your car tyres? I think one or the other is something to do with all your tyres "pointing" the same way so they wear evenly and presumably so the weight of the car is distributed evenly or something, but I don't really know! Keep any replies simple! :D

tracking is where they all point straight to avoid the outer edges wearing before the main thread
balancing is where weights are added to the sides of the tyres to balance them on each side

Thanks! So I wasn't far off then! Now you've got me wondering: I've just had the balancing done on my car (was shaking when I went over 60mph. It's much better now!), so how does a car become "unbalanced" in the first place?

when you drive on to kerbs or hit them against kerbs when parking or drive over bumps and things like that

Ah, I see. I live in a narrow, steep street and parking can be tricky. I'm often bumping the kerbs so that makes sense then. (Makes me sound like I'm a right dizzy driver!).