Maintenance
Replacing a Tyre Before It Forces You To
Tyres give several clear warnings before failing, and reading them turns an unpredictable roadside stop into a planned workshop job costing the same money.
A tyre almost never fails without warning. The signs are visible for weeks beforehand and are easy to check if you know where to look.
Tread depth is the least useful indicator on a bicycle
Bicycle tyres do not need tread to grip asphalt. The contact patch is small enough that water is displaced without channels, unlike on a car.
Tread patterns on road tyres are largely cosmetic, and a completely smooth tyre grips as well or better on a hard surface.
This is why judging a bicycle tyre by tread appearance misleads. The relevant measure is how much rubber remains above the casing.
The wear indicator is a hole, not a pattern
Many tyres have small circular dimples moulded into the centre of the tread. They are cut to a specific depth and disappear as the tyre wears.
When they are no longer visible, the tyre has reached the end of its intended life. It is the clearest signal available and most riders do not know it exists.
Tyres without indicators show the same thing through profile change. A round tyre that has developed a flat strip down the centre is worn.
Casing exposure means the tyre is finished
Beneath the rubber is a woven casing, usually a lighter colour. Any glimpse of it means the protective layer above has been worn or cut through.
At that point the tyre is holding pressure with the casing alone, and a failure can be sudden rather than gradual. This is not a condition to ride out.
Cuts that have not reached the casing can be assessed individually. Anything with visible threads should be replaced rather than monitored.
Sidewalls fail from age rather than distance
The sidewall does not contact the road and does the most flexing. It degrades through ultraviolet exposure and repeated deformation.
Fine cracking along the sidewall indicates the rubber has hardened and lost flexibility. A tyre in this condition can fail while the tread still looks serviceable.
This is why tyres on a rarely ridden bike need checking by appearance rather than by distance. Age is doing the work that riding would have done.
Repeated punctures are a diagnosis
Several punctures in a short period usually indicate a worn tyre rather than bad luck. Thinner rubber allows debris to reach the tube more easily.
They can also indicate something embedded in the casing that punctures each new tube. Running a finger carefully around the inside finds it.
Either way, the pattern is information. A tyre that has started puncturing frequently has told you what it is going to do next.
Questions readers ask
My steering feels notchy in the straight-ahead position. What is that?
An indented headset bearing race, usually caused by riding with a loose headset. The notch cannot be polished out, so the bearing needs replacing, and the adjustment needs correcting afterwards.
How long should bearings last?
It depends far more on water and grit than on distance. A bike with mudguards and dry storage can go years; one ridden through salted winters without guards may need attention annually.
