Tires are one of the biggest contributors to bike handling performance. They could be considered the most critical component on your bike. They are also the most consumable item on your bike, but what makes tires wear out? When should you replace bike tires? In some cases it’s obvious — missing or smooth tread for example. In other instances, it might be that your bike handles or rides poorly.
The major cause of premature tire wear is prolonged use of the tire with low pressure — it’s just that simple. It’s because sidewalls of tires usually fail before the tread is worn out. Low pressure causes the sidewall to bend and flex over and over again much more so than it would if it were properly aired.
Signs You Need To Replace Bike Tires
Cracks
Cracks along the sidewall of road tires or mountain bike tires is a dead give-away you have sidewall damage and your tire needs replaced. Another indicator is uneven tread wear such as a smooth or bald band on the right and left side of the tire, with good tread in the middle. Checking and adjusting the inflation pressure before each ride with a pressure gauge is the most important thing you can do to prolong the life of your tires.
Frequent Flats
Frequent flatting is a red flag. Several flats in a week or multiple flats on longer rides likely means that your tire needs replaced. This is a no-brainer really. It happens because the tread is so thin it can no longer protect the tube from sharp objects. It happens to road tires and mountain bike tires alike.
Tread Wear
Worn out tires are obvious to a professional, but if your tires wear out gradually you might not notice it. The solution is simple — when your tires are new, make a mental note of how thick the rubber is on the contact point of the tire to the pavement, or how much tread they have, and visually monitor it over the miles. Keep checking it and you’ll see it disappear. When it does, consider replacing the tire.
Squaring Off
Even if the tread on your road bike tire seems fine, another indicator, squaring off, could also mean that your tire is history. Mountain bike tires often get a smooth center while the knobs on either side look fine. Squaring off happens mostly to rear tires because of the extra weight. Squared off tires handle poorly and aren’t as fast. It’s a sure sign that you need to replace the squared off tire as soon as you can.
Exposed Casing
Exposed casing is also very obvious if you look for it. This occurs on front and rear tires if you ride them long enough. If you keep riding on the tire, you’re asking for trouble because the only thing keeping the tube inside is a thin section of casing, which was not designed to contact the road and will wear much faster than the rubber tread. Exposed casing looks like a series of diagonal threads, typically on the side of the tire, but can occur almost anywhere on the tire.
Bulges and Bubbles
This one happens all the time. You’re riding along, and feel a regular bump. Or you might just notice a bulge in your tire before you get on your bike particularly on the sidewall of the tire. This is dangerous because the tire can burst at any time causing you to crash. If you have a bulge or bubble in your tire, fix it immediately with a tire boot if it’s small, or replace the tire altogether.
By Mileage
If you’re still not sure if your tires are worn out, there are a few guidelines applicable per mileage for road bike tires. Most road bike rear tires require replacement in the range of 1,500 to 3,000 miles. Front tires usually run upwards of 2,000 to 4,000 miles. Back tires wear more quickly than the front because about 60 percent or more of your weight is on that tire. Mileage data is not applicable for mountain bike tires because riding style (abuse) is too much of a factor. Another part of the equation for both mountain and road tires; the lighter you are, the longer your tires will wear. The more you weigh, the faster they wear out.
Attrition by Age
Tires wear out even if you don’t ride the bike. If you store a bike for more than a few months be sure to check the tires. Wear is not always obvious because you haven’t been riding the bike. But rubber hardens over time and cracks. Even more serious is that the casing — sometimes referred to as the sidewall — can rot, crack, and separate. Also known as dry rot, if you see frayed threads or cracks, or rotting of any type, don’t ride. The tire may appear to hold air just fine, but it won’t for long when you hit the road. Blowouts are common on aged tires. Blowouts scare the hell out of you and cyclists riding close to you — and can lead to a crash.
Ride Quality
It might be that your tires pass the test for wear but you still hate them because your bike is slow, feels heavy, or cornering is twitchy or unstable. Poor handling is common on puncture-resistant, heavy tires made for flat protection, or even some of the all-weather tires. But they have their advantages. If you live in an area of inclement weather, bad roads or puncture weeds, they are worth their weight in gold. The choice is yours. Lighter tires handle and accelerate better but you’ll be fixing more flats and replacing them more often because they wear out faster.
Experiment With Tire Pressure
It’s been previously stated that proper pressure is important to your tire, but what good are rules unless you can break them. In the last decade it has become trendy to pump up tires as high as they will go. Or that the more pressure, the faster the bike will ride. At least one brand of tire actually requires 140 psi. That much pressure can make a bike ride harsh. Super high pressure can make the bike bounce depending on how heavy you are. It transmits road shock, fatigues the rider, causes the premature failure of bike frames and wheels and makes tires more prone to flats.
Stay at the lower end of the pressure zone for comfort and rough roads. Running lower pressure can yield a bike that corners better and gives a far nicer ride. Properly inflated tires roll over bumpy roads smoother and faster and get you home without shaking your teeth loose. On ultra-smooth roads however, when rolling resistance is crucial, such as in a time-trial or triathlon, go as high as 140 psi if your tires are rated to take it. The suggested inflation range is a good starting point but don’t be afraid to experiment with it. The point is, when should you replace your bike tires? Keep an eye on them and they will take care of you.