If you ride a bicycle, tires are the items you most likely will regularly replace. The best time to replace a tire is before they become unsafe. Some tires are designed for performance and should corner and brake better because the surface compound provides more traction but will wear down more quickly. Tires designed for durability are a bit heavier, usually have a denser rubber compound and a stronger puncture resistant inner belt. These tires may have lower performance, but resist surface wear better, resulting in more mileage per tire.

Mileage or life length of the tire will vary greatly due to the type of tire. Performance tires, usually referred to as race tires, get less mileage, while a commuter/durable tire will last longer. Aggressive riding by a heavy cyclist, e.g. a big guy, climbing hills will get less mileage. So, determining how long a tire will last is not an exact science. Some literature claims that a rear tire could wear out well under 1000 miles, while other riders claim 2000 miles or much more. It all depends on the type of riding being done.

When to Replace a Tire?

So when do you know when to replace a tire? Normal riding will cause the center part of the tire to wear away. Some tire brands have some divots or dimples molded into the center of the tire’s outer rubber surface, referred to as wear indicators. When the divot is no longer visible you should consider replacing that tire. If there are no wear indicators, a good approximation is when the tire appears to have a noticeable flat area around the center of the tire. This is sometimes called squared or shouldered tires. This is abnormal wear, since most riding is straight line therefore, the middle wears most.

Inspecting the Tire

Aside from normal wear, tire integrity can be compromised by age and unusual impacts, like hitting a curb or sharp or jagged object. You should inspect your tires after every ride and look for any bulges, cuts, or deeply scuffed sidewalls. If the outer surface appears dry and has many small cracks, the tires may be old, and the flexibility and strength could be substandard. If any defects are detected, replacement should be considered. Small nicks in the rubber surface are common and if not very deep do not compromise performance. It is a good practice to check the nicks for debris and remove anything found so that it cannot work its way into the tire and cause a puncture flat.

If riding on compromised tires continues, stopping, cornering, resistance to puncturing etc. may deteriorate, so overall performance and safety will be affected. Puttng too many miles on compromised tires may cause poor cornering and stopping especially if the outer layer is worn off to an inner layer that is not designed for surface traction necessary for stopping and cornering. More on-road flats might also occur. Catastrophic failure, rapid loss of tire pressure, becomes more likely and would likely necessitate on-road tire replacement or even worse, an accident.

Rotate or Replace?

Rotating tires to even out wear requires switching front to rear and rear to front, possibly several times, so that both will need replacing at the same time. If you choose to replace the worn rear tire with the used front tire system, then yes, the rear tire will always be slightly used. Some riders rotate tires front to rear afer some number miles ridden, 250, or 500, or whatever they decide. Both tires are replaced since both should be used up at the same time. This results in even tire wear and predictable handling, but is labor intense. Unless there has been some damage to the front tire, moving it to the rear does not really compromise safety or performance.

It is generally agreed that the newest tire should be on the front because that is the controlling tire for turns and receives more weight when stopping. If a tire fails, it is easier to control and stop the bicycle if the rear tire flats. Moving the front tire to the rear and puttng the new one on the front is quite acceptable since the front tire wears much less than the rear.

Another strategy used by many seasoned touring riders is to typically replace the front tire with every second rear tire change. Most of us know through personal experience that the rear tire wears out first. That tire bears most of the rider’s weight and provides the power to force the bike and rider forward so it will need replacement before the front tire. When the front tire presents enough tread life, you do not need to replace it with the rear. However, if there is physical damage, or the tire is over five years from the manufacture date, you should replace them both.

Deciding when to replace tires is a personal preference as well as a safety issue. Some riders replace both front and rear tires at the same time. This procedure is probably the safest and most performance-oriented solution, but the most expensive.

If tires are replaced at your leisure before performance and safety are affected, there should be more fun and confidence on the road.