After speaking with thousands of clients one-on-one, we have discovered that most of them have no idea what size tires they have on their bikes. How do you determine the size of your bike’s tires? For street tires, there are three typical sizes: Metric Sizing (Most Common), Alpha Numeric Sizing (Most Cruiser), and Inch Sizing are the three most common sizes (Mostly Dirt Bike)
Get down on the ground and have a look around. If you have aftermarket wheels on your motorcycle, the actual tire size may differ from what is specified in your owner’s manual or on the standard sticker.
If you want to be sure your bike is completely stock, consult your owner’s manual or an online data spec sheet.
The Most Common Motorcycle Tire Format – Metric Tire Size
For example, take a tire number 180/70R-16, the following number represents:
- The first value (180) represents the tire’s width in millimeters.
- The aspect ratio (70), which is the height of the sidewall, is the second value. The height is 126mm, or 70 percent of the breadth.
- The rim size is determined by the third number (16). The diameter of the rim, in this case, is 16 inches.
- You can identify if the tire is Bias Ply or Radial by the letter between the second and third digits, either R or B. The tire is Bias Ply if there is no letter.
Alpha Numeric Tire Sizes:
For example, MU85B16 is the tire size,
- The breadth is the first group of letters. 140 millimeters equals MU. For all of the Letter Designation Breakdowns, use a Street Tire Size Conversion Chart.
- The next letter will be B or R, which stands for Bias Ply or Radial, respectively.
- The rim size or rim diameter will be the last number.
For Dirt Bikes, Vintage or Side Car Tire Format
For example, 5.00-16 is the tire size of your bike then,
- The tire width in inches is represented by the first number (5.00). 5.10 millimeters Equals 127 millimeters
- The rim size, also known as the rim diameter, is the second number, which is 16 inches.
- The numerical tire sizes commonly range from 2.75 or 80mm (MH) to 6.0 or 150mm (MV). To see all of the sizes in between, look at a Street Tire Conversion Chart.
Radial Vs. Bias Ply Tire
Bias Ply tires were the first and are ideally suited for large loads, which is why we see them on the majority of heavy cruisers and touring motorcycles. Bias Ply tires are made of alternating layers of cords laid down from bead to bead across the tire, made of materials like Nylon, Rayon, or Polyester. It results in an extremely rigid sidewall that can support a lot of weight, but the tires become hot and are less maneuverable than their modern Radial siblings.
Radial tires, which first appeared on motorcycles in the 1980s with extremely restricted applications, have layers that run radially across the tire and are often constructed of steel. Only the tread portion of the tire has these alternating layers of steel belts. Steel belts dissipate heat faster than bias cords. At the same time, radial tires’ sidewalls are thinner and more flexible than Bias Ply tires, allowing the tire to be more nimble and provide better rider sensation.
Motorcycle Tire Load Rating
The next set of digits and letters (77H) represents the tire’s speed rating and load index. This code is the same whether the tires are Metric or Alpha/Numeric. Just because the “tyre size” is the same as the “acceptable” size for your wheel or rim does not guarantee it is a good match for your motorcycle or riding style.
- The numbers (77) refer to the tire’s load-carrying capacity. 77 pounds equals 908 pounds in this situation. A common load rating chart ranges from 47 or 386 lbs to 87 or 1,202 lbs.
- The letters (H) stand for the tire’s speed rating. H denotes a top speed of 130 miles per hour in this case. A typical speed chart will display J, which is 62 miles per hour, all the way up to W, which is 168 miles per hour.
- Occasionally, we’ll notice a ZR in the tire size, followed by a separate Load Rating / Speed Index designation. This Z denotes a maximum sustained speed of more than 149 mph, while the 91W denotes a top speed of 168 mph.
Motorcycle Tire Speed Rating
You must select a tire for your car that meets or exceeds the load capacity of your vehicle and your riding style. Just because a tire is the proper size and is inexpensive does not guarantee that it will be able to “carry the load” or “sustain the speeds you travel.” When it comes to buying tires, buyers frequently disregard load and speed ratings. Running tires that aren’t designed for your vehicle or riding style might result in premature tire wear or even tire failure. In conclusion, it is Dangerous! It’s not a good idea.
Choosing The Right Tire Size Of Your Bike
Motorcycle tires are one of the most crucial safety features on any motorcycle, second only to motorcycle brakes. Using the correct tires on your motorcycle will ensure that you have the greatest ride possible and achieve your desired results. If you want to stay on the road, you’ll need softer tires. If you want to get higher mileage, get harder tires. If you want to go off-road further, you’ll need knobbies tires.