Street Motorcycle Tire Buyer’s Guide

When many bikers think of performance, they often end up comparing engine size and horsepower. But seasoned riders know that having the right tires can make all the difference.

Whether a rider is looking to do some off-roading or preparing for the wetter fall and winter seasons, having a good set of tires could be key to a great ride. Many bikers take them for granted, but tires play a key role in grip, steering, shock absorbing and supporting the frame of the bike.

That’s why it’s extremely important for riders to know when it’s time to replace their tire. Air pressure is important here, but it’s not the only factor that bikers must consider. Because of the varied conditions that riders use their bikes in, there’s no simple answer for how often riders should replace their tire. That ultimately depends on a variety of factors including the type of rubber compound the tire is made out of, the terrain that the biker typically rides on and the tread pattern on the tire.

The tread pattern is the system of grooves that is featured on the tire and plays a large role in determining the amount of grip a rider will have, especially in wet conditions. Over time, these grooves will begin to wear down and give the wheel a smoother look. This is a good visual cue for when a tire needs to be repaired. Those who buy a new tire may want to take a picture of what the groove pattern looks like so they can see the degradation over time. Many tires also have tread depth indicator bars which are visible in the grooves of the tire.

A tire’s lifespan is greatly affected by the rubber compound that the tire is made of. Harder compounds will last longer and exhibit less wear over time, but softer compounds offer superior grip. A rider looking for maximum performance will likely opt for a softer compound, but they’ll have to be sure to monitor their tires closely and be prepared to replace them. Some brands, like Dunlop and Bridgestone, offer silica-enhanced compounds that get better grip in the rain or wet conditions. Any rider changing their tire right before a rainy season might want to spring for a silica compound.

Tires generally perform better the hotter they get. With this in mind, riders should realize that when they buy a brand new tire, it’ll be cold and need to be “broken in.” Many riders might assume that this means hitting the freeway and getting up to top speed, but most tire companies recommend that bikers go easy on their tires for the first 100 miles or so. Tires have less traction when they’re first bought, so riders won’t want to be pulling any stunts or severe lean angles on a pair of new tires.

That said, a tire that gets too hot can blow out, and this is where tire inflation comes into play. The manufacturer should recommend a general tire pressure, measured in psi, to optimize performance. This is important, as an underinflated tire will build up too much heat and fail, while an overinflated tire will be especially susceptible to puncture. Bikers can counteract this by carrying around a tire pressure gauge so that they can check their tires easily. It’s a good idea to check tire pressure about once a week and always before a long ride.

It’s also important for riders to remember that tires will respond differently to inflation when hot or cold. In general, it’s best to refill tires when they are cold. If a rider must inflate on-the-go while the wheels are hot, they’ll need to inflate about 4 psi over the recommended value. Some manufacturers will provide separate numbers for cold and hot tires.

Tire inflation also contributes to a bike’s load carrying capacity. In fact, even if a rider abides by the weight limits imposed by the manufacturer, it’s possible to overload a bike if the tire is not inflated properly. Tires have load limits that riders should check before buying.

Much of the other information about a tire can be included right in the size information. When shopping for the Bridgestone Battlax BT45, for example, bikers may see something like “110/90V-18.” Each of these numbers and letters corresponds to a different part of the tire.

The first number is the section width of the tire, in millimeters, so this version of the BT45 is 110 mm across. The second number, after the slash, is the ratio of section width to height expressed as a percentage and is usually either 90, 80, 70 or 60.

The letter typically corresponds to a speed rating for the bike, meaning the top speed that the tire can withstand. This is an important value for riders to keep in mind, as pushing the bike higher can have negative consequences on the tire. A “J” means up to 62 miles per hour; an “N,” 87 mph; “P,” 93 mph; “S,” 112 mph; “H”, 130 mph; “V,” 149 mph; and anything over that is either a “W” or “Z.” So in the example above, the tire is rated up to 149 mph.

The final number is the rim size, in inches – in the BT45 example, the tire is made for 18-inch rims. Trying to mount a tire on an improperly-sized rim can be both dangerous and highly ineffective.

First-time riders should keep in mind that there is a big difference between rear and front tires, mainly that the rear tires are larger. A rider should select matching rear and front tires to keep their bike properly balanced. Many tire manufacturers suggest replacing tires at the same time, though rear tires tend to wear down differently. A brand-new front tire combined with a worn rear tire can also lead to improper balancing.

This also gets into the different types of tires. Riders should realize that there is a large difference between bias and radial tires, and street bikes are manufactured to work with either one or the other. When buying a replacement tire, riders need to be sure that they get the correct type of tire and be sure to never place a bias tire on the front and a radial on the back, or vice-versa.

Aligning the wheels correctly can also greatly affect the bike’s balance and how quickly a tire wears down during use. Riders should re-align their tires every time the rear wheel is removed or the chain is adjusted.

In general, if a rider is simply looking to replace their current tire due to wear and tear, they can play it safe by buying the tire that the bike is shipped with. This is known as the OEM part and can usually be found online by going to either the tire manufacturer’s website (their name is usually on the tire) or consulting the owner’s manual.

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Filed in: Buyer's Guide • Motorcycle News