BMW G 310 R Tyre Size: 6 Critical Specs

Your BMW G 310 R tyre size is crucial for performance and safety. Understanding these 6 critical specs ensures you choose the correct, optimal tyres for your ride.

Key Takeaways

• Identify your BMW G 310 R tyre size for peak performance.
• Learn the 6 critical tyre size specifications.
• Understand aspect ratio and load index.
• Know the speed rating and construction type.
• Find the best replacement tyres for your G 310 R.
• Maintain proper tyre pressure for safety.

Your BMW G 310 R is a fantastic machine, known for its agility and sporty feel. But to truly unlock its potential and ensure a safe, enjoyable ride, you need to pay attention to seemingly small details. One of the most critical aspects is your motorcycle’s tyre size. It’s not just about fitting a tyre that looks right; it’s about understanding the precise specifications that govern how your bike handles, grips, and behaves on the road. Many riders find this information a bit confusing, but it doesn’t have to be. We’re here to break down the BMW G 310 R tyre size and its 6 critical specs, making it simple for you to understand exactly what you need. This guide will empower you to make informed decisions when it’s time for a replacement, ensuring your G 310 R performs as the engineers intended.

Why BMW G 310 R Tyre Size Matters More Than You Think

Choosing the correct tyre size for your BMW G 310 R is paramount for several reasons. Firstly, it directly impacts your motorcycle’s handling characteristics. The dimensions of your tyres affect how the bike leans into corners, how responsive it is to steering inputs, and its overall stability. Using the wrong size can lead to unpredictable behaviour, making spirited riding feel less secure and everyday commuting more challenging.

Secondly, safety is intrinsically linked to correct tyre selection. Tyres are your only contact point with the road. Incorrect sizes can compromise grip, especially in wet or adverse conditions, and affect braking distances. Furthermore, tyre manufacturers design their products with specific load capacities and speed ratings in mind. Exceeding these limits due to an improper fitment can lead to catastrophic tyre failure.

Finally, using the manufacturer-specified tyre size ensures your motorcycle’s suspension and geometry work optimally. Altering these dimensions can throw off the bike’s balance and handling dynamics, potentially leading to premature wear on other components. Understanding your BMW G 310 R tyre size is an essential part of responsible motorcycle ownership. Let’s dive into the specifics you need to know.

The 6 Critical Specs of Your BMW G 310 R Tyre Size

When you look at a tyre, you’ll see a series of numbers and letters molded into its sidewall. This is not random scribbling; it’s a universal language that tells you everything about that specific tyre. For your BMW G 310 R, understanding these 6 critical specs will make your next tyre purchase a breeze.

1. Tyre Width (Section Width)

The first number in the tyre size code, like the ‘110’ in 110/70 R 17, indicates the tyre’s width in millimeters. This measurement is taken from the widest point of the tyre’s sidewall to the other. For the BMW G 310 R, the standard front tyre is typically 110mm wide. This width is engineered to provide a good balance between agility for quick turns and stability on straighter sections of road.

A wider tyre generally offers more grip and a larger contact patch, which can improve braking and acceleration traction. Conversely, a narrower tyre can feel more nimble and easier to flick from side to side. The 110mm width on the front of the G 310 R is a deliberate choice by BMW to optimize its sporty, yet accessible, handling characteristics.

Pro Tip: While it might be tempting to fit a significantly wider tyre for more grip, always stick to the manufacturer’s recommended width unless advised otherwise by a professional motorcycle technician. Deviating too much can negatively impact handling and potentially cause clearance issues with the motorcycle’s components.

2. Aspect Ratio (Tyre Profile)

The second number, separated by a slash (e.g., the ’70’ in 110/70 R 17), is the aspect ratio. This is expressed as a percentage of the tyre’s width. In our example of 110/70 R 17, the aspect ratio is 70%. This means the sidewall height is 70% of the 110mm width, which calculates to 77mm (110mm 0.70 = 77mm).

A lower aspect ratio (like 55 or 60) indicates a shorter sidewall, often referred to as a “low-profile” tyre. These tyres tend to offer sharper handling and better feedback from the road due to less flex in the sidewall. A higher aspect ratio (like 70 or 80) means a taller sidewall, which can provide a more comfortable ride and better absorb road imperfections.

For the BMW G 310 R, the 70 aspect ratio on the front and often a slightly lower one on the rear (e.g., 60) is chosen to strike an excellent balance between comfort for daily riding and the responsive feel needed for more dynamic riding scenarios. It contributes to the bike’s predictable and confidence-inspiring behaviour.

3. Construction Type

Following the aspect ratio, you’ll see a letter indicating the tyre’s construction. For most modern motorcycles, including the BMW G 310 R, this letter is ‘R’, signifying radial construction. This is a critical piece of information.

Radial Tyres: In radial tyres, the body plies (layers of fabric cords) are laid straight across from bead to bead, perpendicular to the direction of travel. Additional belts are then placed underneath the tread. This construction allows the sidewall and tread to function more independently. The sidewall can flex more easily, absorbing road shocks, while the tread remains more stable, providing a larger and more consistent contact patch with the road. This leads to better grip, improved fuel efficiency, and longer tread life.

Bias-ply Tyres: In older bias-ply construction, the plies crisscross diagonally. While offering a stiffer sidewall, they can generate more heat and offer less consistent grip compared to radials. It is highly recommended to stick with Radial tyres for your BMW G 310 R as they offer superior performance and safety.

Always ensure you replace your G 310 R tyres with the same construction type (Radial) unless you are making a deliberate and informed modification with expert advice.

4. Rim Diameter

The number that follows the construction letter (e.g., the ’17’ in 110/70 R 17) indicates the diameter of the wheel rim in inches. So, for this example, the tyre is designed to fit a 17-inch diameter wheel.

The BMW G 310 R typically comes equipped with 17-inch wheels front and rear. This is a very common size for modern sportbikes and naked motorcycles, offering a good compromise between ride comfort and nimble handling. The 17-inch diameter allows for a wide selection of tyre profiles, from taller ones for comfort to lower ones for sportier dynamics. It’s essential to match this number precisely. A tyre designed for a 17-inch rim will not fit on a 16-inch or 18-inch rim, and attempting to force it can cause severe damage to both the tyre and the wheel.

5. Load Index

The load index is a numerical code that signifies the maximum weight a single tyre can support when properly inflated. This number is usually located after the rim diameter and is often a two-digit number. For example, a common rear tyre size for the G 310 R might be 150/55 R 17 M/C 70W. Here, ’70’ is the load index.

Each number corresponds to a specific weight capacity. For instance, a load index of 70 means the tyre can support approximately 335 kg (or 739 lbs). It’s crucial that the load index of your replacement tyres meets or exceeds the original equipment (OE) specification. You can find a chart detailing the weight capacity for each load index online. Using a tyre with a load index lower than required can lead to overheating, structural failure, and a serious accident.

You can consult resources like the National Highway Traffic Safety Administration (NHTSA) for vehicle-specific information, which often includes tyre specifications.

6. Speed Rating

The speed rating, typically a letter following the load index (e.g., ‘W’ in 150/55 R 17 M/C 70W), indicates the maximum speed at which the tyre can be safely operated. This rating is determined by rigorous testing and considers the tyre’s construction, material, and heat dissipation capabilities.

For the BMW G 310 R, you might see speed ratings like ‘H’ (up to 210 km/h or 130 mph) or ‘W’ (up to 270 km/h or 168 mph). The ‘W’ rating is common for sportier tyres and indicates a higher performance capability. It’s vital that your replacement tyres have a speed rating equal to or greater than the OE specification. While you’re unlikely to reach these speeds on public roads, the rating signifies the tyre’s structural integrity at high velocities. A tyre with a lower speed rating than required might not withstand the stresses of higher-speed riding, even if you don’t intend to ride that fast.

Understanding these ratings ensures you’re not compromising the safety of your G 310 R. For an official reference on tyre speed ratings, the U.S. Department of Transportation provides valuable safety information related to vehicle components.

Typical BMW G 310 R Tyre Sizes

While specific tyre sizes can vary slightly based on model year and regional specifications, the BMW G 310 R generally uses the following common tyre sizes. Always double-check your owner’s manual or the sidewall of your current tyres for the definitive sizes on your specific motorcycle.

Common BMW G 310 R Tyre Sizes

Position	Tyre Width (mm)	Aspect Ratio (%)	Construction	Rim Diameter (inches)	Load Index	Speed Rating
Front	110	70	R	17	37	H
Rear	150	55	R	17	69	H

In this table, a load index of ’37’ typically corresponds to 132 kg (291 lbs) for the front, and ’69’ for the rear corresponds to 325 kg (716 lbs). The ‘H’ speed rating indicates it’s suitable for speeds up to 210 km/h (130 mph).

Note that some variations might exist. For instance, some rear tyres might have a load index of 70 and a speed rating of ‘W’. Always confirm with your motorcycle’s documentation.

Where to Find Your Exact BMW G 310 R Tyre Size Information

Locating the correct tyre size for your BMW G 310 R is straightforward if you know where to look. Here are the most reliable sources:

• Owner’s Manual: This is your primary resource. The manual will detail the original equipment tyre sizes, recommended pressures, and often provides advice on tyre maintenance.
• Tyre Sidewall: As mentioned, the full tyre size code, load index, and speed rating are stamped directly onto the sidewall of your current tyres. This is the most direct way to see what’s currently fitted.
• Motorcycle Frame (Sticker): Many motorcycles have a sticker on the frame, often near the swingarm or under the seat, that lists tyre pressure recommendations and sometimes the approved tyre sizes.
• BMW Dealership or Authorized Service Center: If you’re unsure, your local BMW motorcycle dealer or a trusted mechanic specializing in BMWs can provide the exact specifications.
• Reputable Online Motorcycle Forums and Databases: Many enthusiast websites and forums dedicated to the BMW G 310 R will have discussions and specifications readily available.

When in doubt, always err on the side of caution and ensure your replacement tyres match or exceed the OEM specifications for width, aspect ratio, diameter, load index, and speed rating.

Understanding Tyre Markings: A Deeper Dive

Let’s break down a typical tyre marking for the BMW G 310 R rear tyre, for example: 150/55 ZR 17 M/C 69W.

• 150: Tyre width in millimeters.
• 55: Aspect ratio (55% of 150mm = 82.5mm sidewall height).
• Z: This indicates a tyre designed for speeds above* 240 km/h (150 mph). When followed by R, it means it’s a Radial tyre with a speed capability above 240 km/h. For many G 310 R models, you might see just ‘R’ and then the speed rating letter. Some manufacturers use ZR for high-speed rated radials in combination with a specific speed rating letter (like W). For simplicity, focus on the ‘R’ for radial and the final speed rating letter (H, W, etc.).
• R: Radial construction.
• 17: Rim diameter in inches.
• M/C: Motorcycle. This indicates the tyre is specifically designed for motorcycles.
• 69: Load Index (supports up to 325 kg / 716 lbs).
• W: Speed Rating (suitable for speeds up to 270 km/h / 168 mph).

It’s important to note that the “Z” in some markings implies a speed capability exceeding “W” in the old system, but modern tyre manufacturers often use specific letters like “W” or “Y” (for even higher speeds) directly as the speed rating. The key is to match the load index and the speed rating letter.

Choosing the Right Performance Tyres for Your BMW G 310 R

The BMW G 310 R is a versatile motorcycle, suitable for commuting, touring, and spirited weekend rides. Your choice of tyre should match your riding style and priorities.

• Sport Touring Tyres: These are an excellent all-around choice for the G 310 R. They offer a good balance of grip, comfort, and mileage. They perform well in various conditions, including wet weather, and are designed for long-distance comfort and sporty handling. Brands like Michelin (Road series), Dunlop (Roadsmart series), and Bridgestone (Battlax T series) offer great sport-touring options.
• Sport Tyres: If you prioritize maximum grip and performance for cornering and enjoy aggressive riding, sport tyres might be appealing. They typically have softer compounds for ultimate traction but wear out faster and can be less comfortable on rough roads. However, for the G 310 R, a sport touring tyre often provides nearly the same sporty feel with much better longevity.
• All-Weather/Commuter Tyres: For riders who primarily use their G 310 R for daily commuting in varying weather conditions, tyres focused on durability and all-weather grip are ideal. They prioritize a long lifespan and consistent performance.

When selecting replacement tyres, consider brands that are known for quality and consistent performance. Some highly-regarded tyre manufacturers for motorcycles include:

• Michelin
• Dunlop
• Pirelli
• Bridgestone
• Continental
• Metzeler

Always research reviews for specific tyre models you are considering to see how they perform in real-world conditions and how they compare in terms of lifespan and rider satisfaction.

Tyre Pressure: The Unsung Hero of Tyre Performance

Even with the perfect tyre size, maintaining the correct tyre pressure is absolutely critical. It affects handling, braking, fuel efficiency, and tyre wear. Under-inflated tyres can overheat, wear unevenly on the edges, and reduce fuel economy. Over-inflated tyres can lead to a harsher ride, reduced grip (due to a smaller contact patch), and uneven wear in the center of the tread.

The recommended tyre pressures for your BMW G 310 R will be listed in your owner’s manual and usually on a sticker on the motorcycle’s frame or swingarm. These pressures are usually quoted for both front and rear tyres.

Typical Recommended Pressures (Check your manual for exact figures):

• Front: Around 32-33 PSI (pounds per square inch).
• Rear: Around 36-38 PSI.

Make it a habit to check your tyre pressures regularly, ideally before every significant ride, and at least once a week. Use a reliable tyre pressure gauge. Remember that tyre pressure can fluctuate with ambient temperature, so checking them when the tyres are cold is best.

When to Replace Your BMW G 310 R Tyres

Tyres wear out over time and with use. Here are the key indicators that it’s time for a replacement:

• Tread Depth: Most jurisdictions have a legal minimum tread depth. For motorcycles, this is typically around 1mm. However, for optimal grip and safety, it’s recommended to replace tyres when the tread depth reaches 2-3mm. You can check tread depth with a dedicated gauge or by looking for the tread wear indicators (small raised bars within the main tread grooves).
• Cracks and Cuts: Inspect the sidewalls and tread for any visible cracks, cuts, bulges, or embedded objects. These are serious signs of damage and indicate the tyre needs immediate replacement.
• Age of the Tyre: Rubber degrades over time, even if the tyre isn’t used much. Most manufacturers recommend replacing tyres that are six years old or older, regardless of tread depth. Tyres have a manufacturing date code (DOT code) on the sidewall that indicates the week and year of manufacture. For example, “DOT XXXXXX3022” means the tyre was made in the 30th week of 2022.
• Uneven Wear Pattern: If you notice significant wear on one side of the tread or in the center, it could indicate an issue with tyre pressure, suspension, or wheel alignment. Regardless of the cause, this uneven wear can compromise handling and necessitates replacement.

Don’t delay replacing worn or damaged tyres. They are your most crucial safety component.

Frequently Asked Questions (FAQ)

Q1: Can I use car tyres on my BMW G 310 R?

Absolutely not. Car tyres are designed with different construction, load capacities, and handling characteristics than motorcycle tyres. Using car tyres on a motorcycle is extremely dangerous and will lead to catastrophic failure and a severe accident.

Q2: What does the “M/C” marking on a motorcycle tyre mean?

The “M/C” marking signifies that the tyre is specifically designed and constructed for use on motorcycles. It indicates that the tyre meets the specific requirements for motorcycle applications, including speed, load, and handling.

Q3: How do I know if my tyre is radial or bias-ply?

Tyre construction is indicated by a letter on the sidewall, typically after the aspect ratio. ‘R’ stands for Radial, which is standard for modern bikes like the G 310 R. If you see a ‘B’ or no letter, it generally indicates a bias-ply construction, which is less common on performance motorcycles today.

Q4: Can I mix tyre brands on my BMW G 310 R?

While it’s generally not recommended to mix tyre brands, types, or constructions on the front and rear of a motorcycle, it is sometimes permissible with specific combinations. However, for optimal and predictable handling, it’s best to use tyres from the same manufacturer and model line on both the front and rear if possible. If you must mix, ensure both tyres meet the same performance specifications (load index, speed rating) and consult a professional.

Q5: What is the difference between a tyre for the front and rear of my G 310 R?

Front and rear tyres are designed differently to perform specific functions. The front tyre primarily handles steering and braking forces, while the rear tyre transmits power to the ground and bears a greater portion of the bike’s weight. They often differ in tread pattern, profile, and construction to optimize their respective roles. Always use the correct tyre designated for the front and rear of your motorcycle.

Q6: Is it okay to fit a tyre with a higher speed rating than my stock G 310 R tyres?

Yes, it is generally acceptable and often recommended to fit a tyre with a speed rating equal to or higher than the original equipment. A higher speed rating means the tyre is built to withstand higher speeds and stresses, offering an added margin of safety. However, do not fit a tyre with a lower speed rating.

Q7: How often should I check my tyre pressures?

It’s best practice to check your tyre pressures at least once a week and before any long rides. Tyres naturally lose a small amount of air over time, and temperature fluctuations can also affect pressure.

Conclusion

Navigating the world of tyre sizes for your BMW G 310 R doesn’t have to be a daunting task. By understanding the 6 critical specifications – width, aspect ratio, construction, rim diameter, load index, and speed rating – you are well-equipped to choose the correct and optimal tyres for your motorcycle. Remember that the right tyres are not just about performance; they are a cornerstone of safety, directly impacting how your G 310 R handles, grips, and responds to your inputs.

Always refer to your owner’s manual for the precise specifications for your model year. Regularly inspect your tyres for wear and damage, and consistently check your tyre pressure. Making informed choices about your tyres ensures you maintain the exhilarating riding experience that the BMW G 310 R is known for, keeping you confident and secure on every journey.