Here's some quick tips on when you start looking for replacement tires. Knowing you have a busted tire is one thing. Preventing flats before they happen in another. If you can identify these warning signs then you can replace a worn out tire before it ruins your next ride.

Here are some signs that will tell you a tire is ready to be replaced:

• Worn-down tread, especially in the center
• Missing or broken knobs
• Aged and cracked rubber
• Sidewall damage - abrasions, cuts, or 'sweating' sealant
• Warped casing
• Frequent flats
• Poor handling

Finally, time is a killer of tires.  Keep track of how old your tires are.  Rubber will only keep for two to four years before becoming hard and brittle.  A tire may not have any visible signs of wear and still be bad if the rubber is too hard.  If your tires are more than five years old, get new ones!

Here are the main factors you need to consider when shopping for new bike tires. First it’s about knowing what will fit, then you can refine your search to pick out the models that will give you the performance you’re after.

This is another example of the French sizing method.  27.5 inch and 650B tires technically refer to the same size as both fit on the same diameter wheel (584mm).  

The term 27.5 inch is mostly used in the mountain biking world filling the gap between 29 inch and 26 inch. Tires designated as 27.5 inch are usually (but not always) mountain bike-focused with more tread for off-road riding.

The term 650B is more commonly used with gravel and touring bikes. They typically have less tread than mountain bike tires.  They're fast rolling on a variety of surfaces, but they offer more traction and comfort than standard 700C tires.  The outside tire diameter of 700C and 650B is very close.  This allows many gravel bikes to swap between the two wheel sizes.  700C is fast and efficient with a bigger rim and skinnier tire while 650B is smoother and more comfortable with a smaller rim and fatter tire.  

Once you know the size tire you need for your wheels, the next step is to choose the right tire width. Obviously a road rider will be looking for a skinnier tire than a mountain biker, but even small differences in width can make a big difference when it comes to how your bike performs.

Here are the most common bike tire widths:

While the size and width of your tire are important, so too is the actual tread pattern on the surface of the tire. A tire’s tread pattern largely determines the level of grip and rolling resistance and is specifically designed for certain terrains. For example, mountain bike tires feature large knob patterns for better traction on loose terrain. Road bike tires, however, have a slicker tread pattern that rolls faster on smooth surfaces.

There is a wide range of tread patterns out there which means riders can select the best tire that works with their riding style and expected terrain. There are general differences between bike types, though, that can help you narrow down your choices when looking for the right tire for your bike.

Mountain bike tire tread:

Mountain bikes tires have aggressive tread patterns to gain traction on loose terrain such as dirt, mud, and rocky trails. Certain mountain bike disciplines demand specific tread patterns that best suit the conditions.

• Cross-country tires: This tread features smaller, more tightly spaced knobs that allow for the right balance of low rolling resistance and sufficient traction for the fast-paced, firmly packed trails of XC circuits.
• Trail, all-mountain, and enduro tires: Medium-sized knobs provide traction over a range of off-road terrains. There is often a more aggressive tread pattern and larger knobs along the sides of the tire for increased traction when cornering. In enduro riding, front tires typically have a heavier tread pattern than the rear tire.
• Downhill tires: The most aggressive tire tread available, downhill tires have large, tall knobs that can grip even the muddiest conditions. This design helps to rid the tires of mud and debris as they roll, too.

Road bike tire tread:

Slick tires have a tread pattern that is so smooth that it’s barely noticeable. The center of the tire has slick rubber designed for rolling fast on paved roads, with slight tread on the sides to channel away water and boost traction when cornering.

Gravel tire tread:

Splitting the difference between road and mountain tires, gravel tires feature a fast-rolling yet grippy tread pattern. Many gravel tires have a tight grid of small knobs around the entire tire while others have a smooth tread along the center with grippier bits on the side to help with cornering in loose gravel.

Commuter/hybrid bike tire tread:

These tires come with a semi-slick tread pattern that does well in a range of conditions. The relatively slick center tread rolls fast over smooth surfaces like city roads or paved bike paths. The sides are a bit grippier with small knobs or deep channels to direct water away, allowing commuters to safely ride in wet conditions or navigate occasional off-road sections.

Selecting the correct inner tube means matching up to the diameter and width of your tire. Conveniently, bike tubes can fit a range of tire widths so you don’t have to go searching for the exact size down to the millimeter. This is because tubes can stretch as they inflate to adapt to a range of widths. For example, a mountain bike tube may list its size as 29 x 1.9-2.3”. When getting a tube, find one with the same diameter as the tire and make sure the tire width falls within the range labeled on the tube’s packaging.

Bike tube valves are either “Presta” or “Schrader”. The hole in your wheel’s rim determines which valve type you need. Presta valves are much narrower with a small nut that unscrews to let air in and out. Remember that some Presta rims have a deep profile that requires long valve lengths that will stick out of the rim enough for inflation. In a pinch, riders can use a Presta tube in a wheel made for Schrader valves, but it’s best to use an adapter to prevent damage to the tube’s valve stem. Schrader valves are wider so they can’t fit into Presta rims and they have an inner pin to control the flow of air.

Tubes vs tubeless bike tires, which is better?

Tubeless bike tires can be used with tubeless compatible rims without inner tubes. Without tubes, you can run lower tire pressures without getting pinch flats (caused by the tube being squished). Lower pressure also offers more comfort and traction off road, so many mountain bikers and gravel riders choose to go tubeless. Tubeless conversion requires tubeless compatible tires and rims, tubeless rim tape, and almost always an air compressor. Because tubeless can be a pain to set up, most commuters and casual riders won’t bother.

How much air should I put in my bike tires?

Every tire has a recommended PSI range on the sidewall, and it’s best to stay within those limits so you don’t get flats or blowouts. You can adjust the air pressure within that range to suit your preference.

What bike tube valves do I need?

If your tube’s valve looks like what’s on your car, you need a Schrader valve. If it's a long and skinny valve with a twistable top, you need a Presta valve.

What is a good TPI for bike tires? What does TPI stand for?

Threads Per Inch. A higher TPI (120) is lighter and more performance oriented for riders who want speed benefits. A 60tpi tire is more durable but slightly heavier.

How much tread do I need for bike tires?

Thinner tires with less tread are faster on smooth surfaces, and wider tires with more tread are better from loose, challenging roads and trails.

Are there bike tires with puncture protection?

Yes, some tires come with reinforced material in the rubber casing that can help prevent punctures. Check the tire’s description to know for sure.