Get to Know... Your Bike's Tires

So you walk into your local bike shop thinking, maybe I want a bike. You scroll through the racks of bikes. Your eye catches the flash of shiny new colorful bikes. Your heart beats a bit more intensely and a tingle rushes through you from the increase in blood flow. Then, your eyes catch the eyes of the sales associate walking towards you. The conversation begins…

You test ride lots of bikes and choose a shiny new one just for you.

You get it home and start riding. Slowly, you get to know your bike. How it sounds as the chain travels through the gears, the feel of the tires on different roads, and the nooks and crannys that get dirty and are difficult to access when you’re cleaning your bike. It’s no longer that shiny new bike that caught your eye in the rack. It’s your partner out on the road now. The rush of that first meeting is gone, but you can keep the magic alive by finding new ways to enjoy every ride out on the road. Selecting the perfect tire for your bike can make a significant difference.

At first glance, they may not seem like an exciting part of the bike, but your tires have a great effect on the quality of your ride. Just a round piece of rubber, right? Not quite. Like most of the components on a bike, there are lots of different types of tires and levels of quality which will be reflected in the price. Tires are different for road bikes and mountain bikes. There are also several types of specialty tires. Remember, the purpose of the road bike is speed and efficiency. Off road you need traction to get through the trails. The wider the tire, the more supple the ride. The skinnier the tire, the faster the ride.

Road bike tires are offered in multiple widths, commonly 23c, 25c, and 28c. The narrower frame/fork and brakes on road bikes limit the maximum width possible. The diameter of the wheel is generally 700c (older road bikes often run a 27 inch wheel diameter). Your tire size will be molded into the sidewall of your tire (e.g. 700c x 28c). The type of road tire you run on your bike will depend on the type of riding you do. If you’re a commuter, you’ll look for something durable and resistant to flats. Tires like these may contain Kevlar or carbon and have reinforced side-walls. Race tires will have less durability, run higher pressures, and be lighter in weight. Often they come in lots of different colors to match your bike. Many manufacturers offer dual compound tires. They have different types of rubber on the top and sides. The idea behind this is to increase rolling efficiency and to provide more grip in the corners. In general, road tires are slick with very little to no tread. Cyclocross bikes have modifications to allow for fatter (32c to 42c), knobby road tires. These tires also work on some types of hybrid bikes; like those with 700c wheels but meatier frames like mountain bikes (sometimes listed as an “urban” bike).

Mountain bike tires need to have a large surface area and knobby tread to be effective off road. Like road bike tires there are many manufacturers, qualities of rubber and casing, and levels of pricing. In general, mountain bike tires have a 26 inch diameter. Widths of tires can vary in inches depending on intended use.

All tires have three basic aspects, compound, casing, and tread. The quality and content of the rubber will effect how the tire feels on the road, specifically the hardness and rebound. Often manufacturers will make dual compound tires. The center of the tire will be a harder rubber than the rubber on the sides. This improves cornering and maximizes traction.

The inner structure, the casing, greatly influences ride quality, weight, and durability. The casing consists of nylon fabric that can be wrapped in various orientations for improved durability and compliance. The casing can be qualified by its TPI (threads per inch). The higher the thread counts the more supple and lighter weight the tire. For example, an average mountain tire may have a TPI of 60 and a racing road tire will likely have twice that. High end tires will typically have high thread counts, weigh less, and cost more.

Tread design (pattern and shape) can help you determine how the tire will perform. More knobs will give you more rolling resistance on the street, but can make all the difference in which line you take bombing out on the trail. Hybrid or comfort tires offer multi-use options. A smooth center surface will be more efficient on the road and knobs on the side will give light off road capabilities (e.g. hard pack trails). Profile, shape, and spacing will dictate rolling resistance, cornering, and traction.

Another aspect of your tires to consider is air pressure. Molded on the side wall of your tire is recommended pressure per square inch (PSI) range. On the streets your best defense against flats is to run your tires at maximum pressure. For a more supple ride, run your tires at the lower end of the range. When mountain biking, riders frequently run lower pressure to increase traction on the trails. One item to remember when running a lower pressure is that you increase the possibility of pinching your tube, which will cause a flat. The lower the tire pressure, the more precise you must be in picking your line on the trail.

There are several more advanced tire topics (e.g. clincher v. open tubular tires) that we don’t have space to cover here, but look for them in future blogs.

Happy riding and may the anti-flat Goddess have your back on your next ride!

-Kelli & Sara