When to replace motorcycle tyres

Replace a motorcycle tyre when the tread reaches the wear bars — 1.6 mm is the usual legal minimum, and wet grip fades well before it — or at any sidewall damage, visible cracking, a squared-off profile, or the age limit, whichever comes first. Tread depth is only one of five triggers, and on plenty of bikes it is not the one that comes up first.

Finding the wear bars

Every road tyre carries tread wear indicators: small raised bars moulded across the bottom of the main grooves. Find them by the TWI mark on the sidewall — a small triangle or the letters TWI — and follow that line into the tread. When the tread surface wears down level with the bars, the tyre is at its limit.

A tread depth gauge removes the guesswork for $5 (€5). Measure the centre and both shoulders, because they wear at different rates depending on how you ride. Legal minimums vary by country — 1.6 mm is the common figure, and some jurisdictions allow 1 mm for motorcycles — but treat the law as a floor, not a target. Wet grip and resistance to aquaplaning fall away steadily below about 2 mm; plan the replacement there, not at the legal line.

The squared rear

Commuting and motorway miles wear the centre of the rear tyre flat while the shoulders stay tall. The result is a squared profile, and it changes how the bike steers: turn-in becomes a two-stage event where the bike resists leaning and then falls in over the edge of the flat band. A squared tyre can carry legal tread across its whole width and still be finished as a motorcycle tyre — the verdict is about handling, not depth.

If a bike that used to steer sweetly has turned reluctant and lumpy in corners, look at the rear tyre's profile before blaming the suspension. Overinflation accelerates the squaring, since it concentrates wear in the crown — one more argument for running the placard numbers.

Punctures: repair or replace

Location decides. A clean, small puncture in the central band of the tread — the classic nail or screw — can be repaired properly: a mushroom plug fitted from the inside by a tyre shop after inspecting the carcass. That is an acceptable repair for road riding, though the tyre formally loses its speed rating.

A roadside string plug is a different thing: a get-you-home measure. Ride gently, keep speeds moderate, and have the tyre professionally repaired or replaced soon after.

Anything at the shoulder or sidewall — puncture, cut, bulge or split — means replacement. That part of the tyre flexes constantly, and no repair holds in it reliably. When in doubt, let a tyre shop see the inside of the carcass; that is where the damage tells the truth.

Tubed tyres on spoked rims play by different rules. A puncture there means the tube is the casualty: it gets patched or, better, replaced, and the tyre itself only needs replacing if the object damaged the carcass. Check the rim tape and find the cause inside the tyre before fitting the new tube, or it lasts a week.

Fronts, rears, and mixing

Rears carry the drive and most of the load, and wear roughly twice as fast — many riders fit two rears for every front. Fronts fail differently: they cup, wearing into a scalloped pattern that shows up as a hum or a vibration through the bars before it looks dramatic. Run a hand across the front tread; if it feels like waves, the tyre is telling you something.

Mixing brands or models front and rear is allowed and mostly fine at road pace, but pairs are designed as matched profiles, and the bike steers best on the pair the maker intended. Fit the matching partner when the budget allows.

The five triggers in one place

Trigger	What you see	Verdict
Wear bars flush	Bars level with the tread surface	Replace now
Under 2 mm in the centre	Depth gauge reading	Book the replacement, wet grip is already down
Squared profile	Flat centre band, stepped shoulders	Replace even with legal tread
Sidewall damage	Cut, bulge, split, puncture, deep cracking	Replace, do not repair
Age	Cracked grooves, date code past 5–10 years	Inspect at 5 years, replace by 10

One condition outranks the whole table: visible cord. If fabric or metal shows anywhere on the tyre, it can fail without further warning — the bike stays parked until the tyre is replaced.

Age deserves its own word, because it catches low-mileage bikes. Rubber hardens with years, not kilometres, and wet grip goes long before the tyre looks bad. The four-digit code on the sidewall tells you the tyre's build week and year — reading it takes a minute.

Make the next decision easier

When new tyres go on, write the date, the odometer reading and the tyre model into a maintenance log. Next time, the question of how long tyres last on this bike has your own answer instead of a forum's. A change in tyre life is a diagnostic in itself: a rear wearing out early points at pressure, a dragging brake, or a different kind of riding year.

And keep the pressures right. Pressure is the single biggest factor in tyre life you control: underinflation eats the shoulders and overheats the carcass, overinflation eats the centre. The same weekly check that protects your grip also postpones every trigger in the table above.