Strange steering behaviour:
Recently the Chevrolet Spark Lite of a friend of mine suddenly developed a pronounced jerky pull to the left on the steering. Examination of the front suspension failed to reveal any obvious problems, but a knowledgeable acquaintance identified the cause as failed shock absorbers in the McPherson struts.
Both front shocks were replaced (a job that can be done fairly easily at home, by the way), but the problem persisted. After such an operation the wheel alignment has to be adjusted, but this, too, failed to cure the left-tugging steering wheel.
In desperation it was decided to rotate the wheels, and a lump caused by tread separation on the right front tyre was discovered. Each time this spot hit the road the car was nudged to the left. The tyre was scrapped, gleefully, and the problem disappeared.
Lesson learnt from this merry dance: when a sudden change in steering behaviour occurs, first scrutinise the tyres. Make sure you run your hand over the full circumference of each tyre.
Uneven tread wear:
Whether it occurs on the inside or outside shoulder of the tyre (usually due to incorrect toe-in) or in the form of a balding strip in the centre of the tread (over-inflation?) or as “cupping” or worn patches on the tread (shock absorbers?), uneven tread wear almost always means the tyre is destined for the spare wheel or the scrap pile.
It is sure to give you trouble for the rest of its tortured life, because it is the victim of faults beyond its control, faults which should be corrected urgently to avoid ruining another perfectly good, and expensive, tyre.