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Why Reading Your Tyres Matters

Your tyres are the only contact patch between you and the road. They wear in patterns that tell you about alignment, suspension, and pressure. Learning to read those patterns is one of the most rewarding skills for a classic car owner. It saves money, improves safety, and keeps these older machines driving as intended.

Before you start, ensure your tyres are inflated to the recommended pressures when cold. Then look at each tyre across the tread. Run your hand over the surface. Note any high or low spots, smooth patches, or exposed cords. What you find will point you towards the likely cause.

Centre and Edge Wear: Pressure and Load

Over-inflation causes the centre of the tread to bulge, so only the middle band contacts the road. The result is rapid wear down the centre, while the shoulders remain relatively untouched. Under-inflation does the opposite: the tyre squashes, the sidewalls flex, and both edges wear faster than the centre. In extreme cases, the sidewalls overheat and may fail.

Check pressures monthly, and always before a long drive. Classic cars often sit for weeks, and tyres lose pressure naturally. If you have fitted modern tyres to older rims, the recommended pressure may differ from the original handbook. A good starting point is to follow the tyre manufacturer's advice for the load, then adjust by a few psi to suit your car's weight and driving style.

• Over-inflation: Centre wear, harsh ride, reduced grip.
• Under-inflation: Edge wear, overheating, poor fuel economy.
• Heavy loads: Rear tyres may show edge wear even at correct pressures.

One-Sided Wear and Feathering: Alignment Angles

If one edge of a tyre is worn significantly more than the other, suspect camber – the vertical tilt of the wheel. Too much negative camber (top leaning in) wears the inner edge; too much positive camber wears the outer edge. Classic cars with independent rear suspension or modified ride heights are especially prone.

Feathering, where the tread blocks have a saw-tooth edge you can feel when running your hand one way but not the other, points to incorrect toe. Toe-in or toe-out drags the tyre sideways as it rolls, scrubbing the tread. This is common after replacing steering or suspension components. A proper four-wheel alignment on modern equipment will correct it, but make sure the technician understands older cars – some need shims or eccentric bushes rather than simple adjusters.

Also check for worn wheel bearings, which can let the wheel tilt and cause one-sided wear. Jack up the car and rock the wheel top and bottom; any play means investigation.

Cupping, Scalloping and Flat Spots: Suspension and Braking

Cupping (also called scalloping) shows as a series of dips or scoops around the tread. It usually stems from worn shock absorbers or struts, which fail to keep the tyre pressed firmly to the road. As the wheel bounces, parts of the tread lift and wear unevenly. Worn bushes, ball joints, or tie rod ends can have the same effect. If your classic car feels floaty over bumps or continues bouncing after you push down on a corner, the dampers are suspect.

Flat spots – a single smooth patch on the tread – are the classic result of locking a brake under hard braking. They can also appear if a car has been stored for years with the tyres deflated and the weight pressing on one spot. Once a flat spot is deep enough, you will feel a thump through the steering or seat. A professional tyre shop may be able to shave the tyre true, but often replacement is the only safe option.

• Cupping: Worn dampers, unbalanced wheels, or worn suspension bushes.
• Flat spots: Brake lock-up, storage damage, or a seized brake caliper.
• Diagonal wear: Often a combination of toe and camber faults.

Diagnostic Checks in Your Garage

You do not need a fully equipped workshop to start diagnosing. Begin with a tyre pressure gauge and a tread depth gauge. Check pressures cold and record them. Measure tread depth at three points across each tyre – inner, centre, outer. If you find a pattern, investigate further.

For alignment, a simple string line or a dedicated gauge can give you a rough idea, but a professional alignment is worth the cost. Before you book it, inspect the suspension and steering for play. Worn components will ruin a fresh alignment. Check ball joints, track rod ends, and bushes with a pry bar. Look for cracked rubber, excessive movement, or shiny metal where parts have been rubbing.

Wheel balance is another factor. If you feel a vibration at a particular speed, get the wheels balanced. Unbalanced wheels can cause cupping and uneven wear over time. Also check that the wheels are true – a buckled rim will create a rhythmic wear pattern.

Preventative Habits and When to Replace

Rotate your tyres if your classic car allows it – many older cars have different sizes front and rear, so rotation may not be possible. If you can rotate, do so every 5,000 miles or once a year, whichever comes first. Keep pressures correct, and check them before every long journey. Avoid harsh braking and aggressive cornering, which accelerate wear.

Replace tyres when tread depth reaches 1.6mm across the central three-quarters of the width – that is the UK legal minimum. But for classic cars, consider replacing earlier. Age matters as much as tread. Rubber hardens and cracks over time, even if the car has done few miles. Most manufacturers suggest replacing tyres after six to ten years, regardless of tread. Look for the DOT code on the sidewall to find the manufacturing date.

Finally, address the root cause before fitting new tyres. If you simply replace worn tyres without fixing alignment or suspension faults, the new set will wear in the same pattern. Take the time to diagnose, repair, and then enjoy the improved handling and safety that fresh rubber brings to your classic.