Bridgestone’s Guide for Proper Inflation of Motorcycle Tires

 

For motorsports applications—including racing, track day, and club events—inflation pressure recommendations take into consideration additional important factors beyond the scope of this guide.  

See Bridgestone’s information for racing and track tire applications here:

Track Day Tire Pressure Recommendations Chart

Race Tire Operating Range Chart

 

This guide is broken down into five FAQs:

●      Why is tire inflation pressure important?

●      What are the proper inflation pressures for street applications?

●      How do I check and set tire inflation pressure?

●      What if inflation pressure is too low or too high?

●      What about inflation pressure in other applications, like dirt or adventure riding?

A guide to proper motorcycle tire inflation pressure for safety and performance in street, dirt, and adventure applications.

Q:  Why is tire inflation pressure important?

A: The inflation pressure carries the weight of the bike, helps prevent damage to the tire, and allows the tire to perform safely and as designed.

Pneumatic tires are dependent on inflation pressure to perform their most basic functions, including the following:

●      Carry the load of the vehicle, passengers, and cargo.

●      Transmit cornering forces and help direct the vehicle along a path.

●      Provide acceleration and braking traction.

●      Absorb road irregularities and provide ride comfort.

The right pressure in each tire helps optimize vehicle performance for these functions, and for things like tire wear and fuel economy.  For instance, pressure is key to tire deformation and stiffness characteristics, and it governs the shape of the tire as it engages the road in the contact patch.

Tires are also dependent on inflation pressure for their own durability and for safe vehicle operation. Proper pressure is important to prevent the tire from becoming damaged or subject to failure, and for helping the vehicle perform as the manufacturer intended.

 

Q:  What are the proper inflation pressures for street applications?

A: Vehicle manufacturers’ recommended inflation pressures are found on the vehicle placard or in the owners manual.

Vehicle manufacturers go through extensive testing and evaluations to determine various tire parameters and inflation pressure settings based on the specific motorcycle and its intended use.  Tire manufacturers also have their own testing and performance requirements that depend on pressure to meet their own product expectations.  Ultimately, it is the vehicle manufacturer that establishes and communicates the proper tire pressures for optimum vehicle performance, including for tire safety.  These inflation pressure specifications can be found on a placard applied to the motorcycle frame as well as in the vehicle owners manual.

Vehicle manufacturer recommended inflation pressures are specific to the make and model of the motorcycle.  Heavier motorcycles like cruisers, touring bikes, or adventure bikes tend to run higher pressures due to their own weight and rider and cargo capacity.  On the other hand, dirt bikes tend to run lower pressures because they are much lighter in weight, have reduced load capacity, and have lower top speeds.  Regardless of the type of motorcycle, check the frame placard and/or the owners manual for the proper tire specifications and inflation pressures.

The tire sizes and inflation pressure recommendations for the motorcycle are set to ensure that the load of the bike itself, rider(s), and cargo can be carried—and that the motorcycle will ride and handle safely—up to its maximum capacity.  Overloading a motorcycle beyond vehicle manufacturer specifications is unsafe, regardless of whether the tires can carry the additional load 

In addition, tire inflation pressure should not be increased beyond what the bike manufacturer recommends, including for attempts to accommodate excessive load.  Bottom line:  Don’t overload the motorcycle, and don’t exceed the pressures recommended by the motorcycle manufacturer.

What about the inflation pressure information that’s marked on the sidewall of the tire?  This is the pressure necessary for the tire to carry its rated, maximum load.  The motorcycle manufacturer’s tire pressure specifications may be lower than, or the same as, the pressure indicated on the tire sidewall.  Check the motorcycle frame placard and/or the owners manual for the proper tire inflation pressures.  <This will be a shaded box or sidebar, not necessarily in the body of the text.>

 

Q:  How do I check and set tire inflation pressure?

A: Use a reliable gauge, and check and adjust the pressure only when the tires are cold.

The first step is to have a reliable gauge.  An electronic or higher quality gauge may be worth the investment to some, but gauges don’t have to be fancy or expensive to get the job done.  If you want to check the accuracy of your gauge, just ask your local tire shop to compare readings.

Check pressure when your tires are “cold.”  A tire is considered “cold” if the motorcycle has been stationary for three hours or more.  Tire pressure specifications established by the vehicle manufacturer on the frame placard and in the owners manual are for cold tires.  Although riding causes tire inflation pressure to increase, if the bike was parked for at least three hours before travelling less than a mile at moderate speed, the tires are still considered cold.

To check tire pressure, remove the valve cap, place the end of the gauge over the valve, press straight and firm, and observe the reading.  From there, you can adjust the inflation pressure to reach the motorcycle manufacturer’s specifications.  Remember to reinstall the valve cap when you’re done.  Never release pressure from a “hot” tire to reach the recommended inflation pressure—if you do, you may dangerously underinflate the tire.

If you ride regularly, check your motorcycle tire pressure at least once a week.  Also check pressure before going an extended trip—and before going on any trip if you’re an infrequent rider.  Always use a gauge. A tire can look like it is properly inflated, even if it is not.

While you’re checking pressure, inspect the tread and sidewalls.  Make sure there is adequate tread depth and look for irregular wear, cuts, abrasions, bumps, bulges, or blisters.  Although tires lose a small amount of pressure over time under normal conditions (and due to temperature drops) have your tire inspected by a tire service professional if a tire has unusual loss of inflation pressure or if you see any signs of damage. <This will be a shaded box or sidebar, not necessarily in the body of the text.>

 

Q:  What if inflation pressure is too low or too high?

A: Pressure that is too low can lead to internal structural damage of the tire. Pressure that is too high can allow for more external damage to occur to the tire. Both of which could lead to tire failure, a crash, serious injury or death.

Under-inflation causes excessive heat build-up due to excessive flexing of the tire, and eventually causes internal structural damage to the tire components.  Over-inflation makes it more likely for tires to be cut, punctured, or broken by sudden impact.  These situations can cause a tire failure which could lead to a crash and serious personal injury or death.

In addition to tire damage, improper inflation pressure may also adversely affect the ride and handling characteristics of the motorcycle.  Under-inflation may cause the motorcycle to handle less responsively and to feel “sluggish.”  Over-inflation makes your ride harsher and may cause changes in handling predictability.

Both under-inflation and over-inflation can lead to rapid and/or uneven wear since the tire contact patch is not optimal.  For instance, too little pressure can lead to rapid wear of the tread shoulders, while too much pressure can lead to rapid wear of the center.

Follow the motorcycle manufacturer’s specifications for proper tire inflation pressure.  Check the frame placard and/or the owners manual for that information.

 

Q:  What about inflation pressure in other applications, like dirt or adventure (ADV) riding?

A:  Inflation pressure for focused applications like off-road riding can vary drastically. It is best to follow the vehicle manufacturers recommendations.

Proper tire inflation pressure is one of the most important maintenance items of a motorcycle regardless of the road surface.  Following manufacturer recommendations is critical to the performance characteristics of the motorcycle. 

In specialized applications, such as off-road, it may be necessary to consult directly with the motorcycle and tire manufacturers to evaluate alternate tires and inflation pressures.

Dirt tires, especially motocross tires, are typically designed to operate at lower pressures than street tires.  The size, shape, and tread patterns of these tires are optimized for, among other things, maximum contact with the loose terrain they encounter.  However, low pressures can cause the tire to slip on the rim when subjected to high torque, which is why rim locks may be necessary.

The size and shape of adventure bikes varies almost as much as the type of terrain they cross.  Lowering inflation pressure may give the tire more traction off-road to help conform to the terrain.  Speeds in these conditions must be reduced so the tire does not generate excessive heat.  When lowering pressure to gain additional off-road traction, it is important to have some way of inflating the tire before getting back on the pavement.  If the tires are not set to proper inflation pressure for highway speeds, they will generate excessive heat which may lead to a tire failure.

Therefore, read the motorcycle owners manual carefully for off-roading recommendations.  In addition, don’t hesitate to reach out to the motorcycle and tire manufacturers with any questions and to discuss options—your safety and enjoyment of their products is their top priority.

 

Need more information?

You can download Bridgestone’s Motorcycle Tire Maintenance, Safety and Warranty Guide here

Also, make sure to visit our Technology page and our Motorcycle Tire Data Book.