Most beginning cyclists don't think too much about tires; they are basically just a rubber hoop that helps you grip the road, right? That might have been correct 30 years ago, but in the modern world, road bike tires come in a wide variety of sizes and styles, designed to provide very high performance in certain situations. This guide will help you make an informed decision about purchasing the right tires for your bike and your style of riding.
The first decision you will have to make about a tire is the size. This has to be matched with two things: the diameter and width of your wheel rims. You will also have to make sure that whatever wheel/tire combo you select can fit in the frame of your bike. A too-big wheel on a frame designed for narrower designs can cause problems.
The most common roadbikewheel size is 700c. The "700c" designation is a historical measurement that corresponded to the inflated diameter and width of the most common road tire size. These days, it just means the tire is sized to match a rim with a 622mm bead seat diameter (inner diameter of the tire / outer diameter of the rim). On all tires and rims, you should be able to find that measurement listed somewhere (often designated as the ETRTO: European Tire and Rim Technical Organization). It will also include the width in mm. For example, a 700c tire with a width of 25mm will have an ETRTO of 622-25.
In some instances, you may also see a 700c tire listed as 28 inches. It's the same size, but to eliminate any confusion, just look for the ETRTO.
The easiest way to determine the size of the tire you need to use is to match your old tires or find the rim measurements on your wheel. The wrong size tires simply won't work, so make sure you get it right!
Most road bikes feature a relatively smooth tread, since they don't have to deal with mud and gravel most of the time. Road bike tread is generally more than sufficient to provide traction on concrete; tests show little difference between tires with fancy-looking tread designs and smooth rubber, except in the rain, when a bit of tread can help.
Some tires feature two types of rubber: a more durable type on the main, middle section of the tread and a less durable and more grippy type of rubber towards the edges of the tread for enhanced grip when cornering. These models are great for people who like to ride fast but aren't strictly necessary for casual riders.
Folks who want a bit more safety often choose slightly wider tires for their road bike that feature a bit more tread. These designs provide a bit more grip on slippery roads, but the benefit is mostly psychological (though that effect should not be underestimated).
Flats are an unfortunate reality for road cyclists, but a few tricks can drastically reduce your incidence. The first thing to do is always properly inflate your tires. Low air pressure can cause a pinch flat or all sorts of other problems, and you don't need a hole in your tire to get there. Your tires simply lose pressure over time, so check them before every ride and top them off if they aren't at or near the recommended pressure.
Some tires offer additional features to reduce the incidence of flats. Tires with Kevlar or other puncture-resistant layers in the rubber can dramatically reduce the frequency. While these tires often cost more, they can pay for themselves by making tubes last twice, thrice, sometimes even ten times longer than normal. They really are a huge step forward in technology.
Other unique anti-flat tires have built in sealant -- a liquid glue that hardens on contact with fresh air. While these won't prevent a flat, they will seal small holes and allow you to re-inflate tires without having to pry them off and patch or replace the tube.
Of course, there is no substitute for smart riding. Keep an eye out for thorns, nails, broken glass, sharp rocks, abrupt bumps and other obstacles that could cause a flat. Prevention is the best protection.
For serious road riders, tubeless tires are a great option. They offer additional flat resistance and can provide a slightly faster, more comfortable ride with better traction because you can run them at lower pressure. Although they do require more maintenance and cost more than normal tires, they are a good option for the very serious rider -- especially riders who ride on rough roads and gravel on a regular basis.
For riders looking to go touring or ride very long distances, foldable tires allow you to carry an extra tire. These designs, as you might have guessed, fold up very small and allow for easy transportation.
Most road bike tires are relatively inexpensive; however, the cost increases with added features and designs for higher performance. The most basic bike tires on the market start around $20, while more advanced models that feature higher performance rubber compounds, puncture resistant layers in the tread and sidewall, and extra lightweight materials will be more expensive. For most riders, a mid-range tire in the realm of $50 will provide the best balance between price and performance.