Motorcycle Tyres - What You Need to Know
- Published May 11, 2022
Motorcycle tyres come in a variety of sizes and profiles. While the visual differences may appear minor, they can drastically impact your riding experience.
Choosing the right set will depend on your type of riding and affect the tyre’s performance and lifespan. If you are unsure about what type of tyre to choose, read on for a detailed breakdown of the options available.
Motorcycle Tyre Types
There are six main types of motorcycle tyres:
1. Sport Tyres
Sports tyres are for high-performance street bikes. They’re lightweight and designed to provide exceptional grip and nimble handling. Because they’re made from softer compounds and have a sharper profile, they generally have a shorter lifespan but allow you to lean deep into corners.
2. Sport-Touring Tyres
Sport-touring tyres are arguably the perfect all-rounders – providing a healthy balance of traction and mileage. These tyres are usually constructed from harder compounds in the centre for crunching miles and softer compounds on the outer edges for cornering grip.
3. Touring/Cruiser Tyres
Touring tyres are for heavy motorbikes, such as Harley Davidsons. They’re designed with deeper tread patterns to handle long-distance travel and wet conditions. Touring tyres also have stiffer sidewalls to account for the extra weight of riding with pillions or panniers.
4. Off-Road/Knobbly Tyres
Off-road tyres, commonly referred to as knobbly tyres, are designed for rough terrains, such as sand, gravel or dirt. These tyres have thick tread blocks and reinforced sidewalls to provide maximum grip on loose surfaces and reduce punctures.
5. All-Terrain Tyres
All-terrain tyres act as a middle ground between road-going tyres and off-road tyres. While they somewhat resemble their off-road counterparts, the tread pattern is road-biased, making them more suitable for use on tarmac and some light off-roading.
6. Race/Competition Tyres
Race tyres, commonly known as slicks, are used on track and provide maximum grip once they’ve reached temperature. These tyres achieve ultimate traction by using incredibly soft compounds, but their lifespan is only a fraction of a road-going tyre as a result.
Motorcycle Tyre Construction
In terms of construction, motorcycle tyres come in two primary forms: bias-ply (or cross-belt) and radials.
1. Bias-ply
Bias-ply, also known as cross-ply tyres, were the go-to option until the 1980s when radials were first introduced. These tyres are constructed from horizontally laid carcass plies (often made from nylon or polyester) that stretch from bead to bead. The result is a thicker, more robust tyre suitable for touring and cruisers.
2. Radial
Radial tyres revolutionised the market in the ‘80s by laying the plies perpendicular to the bead and applying a layer of belting above to strengthen the centre of the tyre. Although a seemingly minor change, the result was a tyre with independent tread and sidewall characteristics suitable for higher speed applications.
Motorcycle Tyre Markings
Decoding the string of numbers and letters on the sidewall of your motorcycle tyre might seem overwhelming at first, but this section will break down everything you need to know.
Size
There are three numbers you need to look for when it comes to size:
- Width of the tyre (mm)
- Aspect ratio (or sidewall height) of the tyre (mm)
- Size of the wheel (inches)
For example, let’s take a 190/55/17 rear tyre. This equates to a tyre that is 190mm wide, 50% of 190mm tall (approximately 95mm), and fits onto a 17-inch rim.
Simple, right?
Speed Rating
The speed rating is a capital letter that corresponds to the speed at which the tyre is capable of being taken over. For instance, a 190/55 ZR17 has a speed rating of “Z”, meaning it’s suitable for speeds over 149mph.
| Rating | Speed (mph) |
|---|---|
| J | 62 |
| K | 69 |
| L | 75 |
| M | 81 |
| P | 95 |
| Q | 100 |
| R | 105 |
| S | 113 |
| T | 118 |
| U | 125 |
| H | 130 |
| V | 149 |
| W | 168 |
| Z | 149+ |
Type
Using our example of a 190/55 ZR17 again, the “R” represents the construction type of the tyre, meaning radial.
The letter “B” would indicate that the tyre is of belted-bias construction, and the lack of a letter following the speed rating would represent a bias-ply construction.
Load & Speed Index
The tyre’s load and speed index is a two-digit number and letter combination (usually found in brackets) that should be read together.
If it were to read “73W”, the “73” would represent the maximum load capacity the tyre can withstand, which would be 365kg at full pressure. The “W” would indicate the maximum speed the tyre can withstand under load capacity, which would be 168mph.
Tubeless/Tube-type
The letters “TL” would indicate that the tyre is tubeless, and “TT” would represent a tube-type tyre, meaning it has an inner tube.
Rotation Arrow
Most tyres are designed to rotate in a single direction. Specifically, the tread pattern is designed to channel water away from the motorcycle when moving forward. Running a tyre backwards could reduce traction and possibly even lead to aquaplaning if you’re riding in the rain.
Ensure the arrow is pointing in the correct direction, as a backwards-fitted tyre is dangerous and will lead to a failed MOT.
Date Code
Tyres don’t last indefinitely, so it’s crucial to know the age of a tyre, especially if you’re buying a used machine.
The production date code is a four-digit number representing a two-digit week and two-digit year. For instance, the date code “2820” would mean the tyre was manufactured in the 28th week of 2020.
Motorcycle Tyre Legal Requirements
For motorcycles over 50cc, the tread depth of your tyres must be at least one millimetre (mm) throughout the central three-quarters of the tyre. For motorcycles up to 50cc, all the grooves of the original tread pattern must be visible.
Most tyre manufacturers build a treadwear indicator into the tyre, set to the minimum legal limit of one millimetre. As the tread depth of your tyres changes with time, so does their ability to grip the road and channel away water effectively.
FAQs
How Do I Know What Tyres To Get for My Motorcycle?
We recommend starting with your owner’s manual, as this will contain the manufacturer’s tyre recommendations for your motorcycle. Googling the make and model of your machine is also a reliable option, or reading the sidewall of your current tyres and matching up the size, type, and load/speed indexes.
What Size Tyres Do I Need for My Motorbike?
Your owner’s manual should contain the tyre sizes required for your motorcycle. It’s essential that the tyre’s height, width and diameter measurements are compatible with your wheel.
If in doubt, your current set of tyres will have a size code printed on the sidewall, containing all of the information you need.
Do Motorcycle Tyres Need To Match?
Motorcycle tyres are tested and developed in pairs, so you should always match the front and rear. You will also fail your MOT if you mix radial and bias-ply tyres.
Final Thoughts
The world of motorcycle tyres is full of jargon that can be difficult for even the most experienced riders to understand completely. Coupled with ever-evolving technology and conflicting tyre reviews from other riders, we can hardly blame you if you’ve felt overwhelmed.
Hopefully, this guide has shed some light on the intricacies of tyres and answered any questions you might have had.
If you’re still left scratching your head, reach out to us, and we’d be more than happy to help!