A motorcycle balances on two contact patches about the size of your palm. Tires therefore have a huge influence on grip, stability, braking and comfort. Understanding the sidewall markings and choosing the right type is worth the effort.
Reading the sidewall
A typical rear tire marking looks like 180/55 ZR17 73W:
- 180 is the width in millimeters;
- 55 is the aspect ratio (sidewall height as a percentage of width);
- Z indicates a high-speed rating (older notation), and R means radial construction (bias-ply tires show a dash or “B”);
- 17 is the rim diameter in inches;
- 73 is the load index and W the speed rating (up to 270 km/h, about 168 mph).
Also look for the DOT code, whose last four digits give the week and year of manufacture, and for “TL” (tubeless) or “TT” (tube type). Always use sizes and ratings approved for your bike, as listed in the owner’s manual.
Types of tires
- Sport: soft compounds for maximum grip on dry roads; they wear quickly and need heat to work well.
- Sport-touring: a balance of grip, wet performance and longevity, often with dual compounds (harder center, softer shoulders).
- Touring: hard-wearing, stable under heavy loads, good in the wet.
- Adventure/dual-sport: from road-biased (90 percent pavement) to knobby off-road tires.
- Cruiser: designed for heavy bikes and long life.
Choose by how you actually ride, not by the most aggressive tire available.
Pressure
Motorcycle tires are very sensitive to pressure. Check it at least weekly, with the tires cold, using the values in your manual (often higher with a passenger or luggage). Under-inflation makes the bike heavy to steer, overheats the tire and increases wear on the edges.
When to replace
Replace tires when they reach the tread wear indicators or the legal minimum tread depth, when they show cuts, cracks or bulges, or after about five years even with tread left, since rubber hardens and loses grip. Flattened centers, common on touring bikes, change handling noticeably. Most riders replace front and rear with the same model, which ensures predictable behavior.
New tires need care
New tires have a slippery surface from manufacturing. Ride gently for the first 100 miles or so, gradually increasing lean angle, and be especially careful in the wet. For more on safe riding in poor conditions, see riding in different weather, and for overall care, a regular maintenance routine.
