How to Read Tire Sidewall: What Does 77h Mean on a Motorcycle Tire?
Motorcycles have captured the hearts of Americans for decades. Given the vastness of our nation, which allows for thousands of miles worth of scenic roads and high-speed stretches, it’s easy to understand why. Feeling the wind in your hair as you coast along the coast, through a National Park, or across an endless desert is an experience second to none.
However, all that freedom comes with a bit of responsibility and a lot of homework. Motorcycle tires, understandably, play a major role in the overall health and function of your bike, although few people give them much attention; it isn’t until you’re searching for motorcycle tires for sale that you realize just how varied your options are. Knowing how to read tire sidewall is key to finding the right tires for your unique motorcycle.
Knowing the numbers
Motorcycle tires use one of three coding systems: metric, standard, and alpha (short for alphabetical). All of these systems are used to communicate vital information such as width, diameter, aspect ratio, load capacity, and speed rating. Let’s break down examples from each.
Metric: 130/90 — 16 M/C 67 H
In metric codes, 130 translates to the tire width in millimeters. The 90 is its aspect ratio, which is calculated by dividing the height by the width; this number is a percentage. The dash indicates the tire construction, in this case, bias-ply (meaning it consists of multiple rubber plies overlapping each other). The 16 indicates rim diameter in inches, the M/C designates the tire as motorcycle tire specifically, the 67 translates to its load index (or the maximum weight that each tire can carry when inflated to its maximum psi), and the H is its speed rating.
A motorcycle tire that ends with 77 H can withstand 412 kgs, or 908 lbs of weight, and can endure speeds of up to 201 km/h, or 130 mph.
Standard: 3.00 H 16 4PR
As you can already tell, standard codes are much simpler. The 3.00 refers to the tire’s section width in inches, the H remains the same (speed rating), the 16 indicates its rim diameter, and the 4PR shows its ply rating (an expression of the tire’s strength and capacity). Because standard inch tires don’t specify an aspect ratio, it’s assumed to be 100%.
Alpha: M T 90 — 16 Load Range B
In alphabetical tire codes, the M refers to the vehicle designation — motorcycle, of course. The T is the tire width code, the 90 shows the tire’s aspect ratio (again as a percentage), and the dash also refers to tire construction. Once again, the 16 indicates rim diameter in inches, and Load Range B is the ply rating — which relates to load capacity.
Why it matters
These numbers can seem a bit overwhelming at first, but they’re crucial to your safety. If you don’t know what your bike can (or can’t) handle, you increase your odds of getting into an accident. Carrying more weight than recommended or flying beyond the speed rating limit can result in your tires exploding under the strain. In this case, knowledge is safety.
According to the data provided by the U.S. Census Bureau in 2018, more than 10 million American households possess motorcycles. If you’re interested in joining this rapidly growing group, you need to understand the basics, including knowing what type of battery to use, how to care for your bike in the off-season, and what information the tire sidewall communicates (and, of course, why all of that matters) is essential to both keeping your motorcycle and in tip-top shape ensuring your own safety. Rather than run the risk of a blowout at high speeds, do your research.
