How to buy budget tires using EU labels

How to buy budget tires using EU labels: As an automobile owner, it is imperative to ensure that your vehicle’s tires are maintained in top-notch condition. Dilapidated tires can pose a significant danger to the driver and passengers while also increasing fuel consumption and maintenance costs. The process of selecting new tires can be daunting, but EU labels can be used to ease the decision-making process. These labels provide crucial information about tire performance and are based on three crucial criteria: wet grip, rolling resistance, and external noise. The criteria are symbolized by color-coded icons that are easy to comprehend. While it is not mandatory to have an EU label in Malaysia, many budget tires do carry them. In this article, we will delve into the intricate details of EU tire labels and their effective utilization when purchasing your next set of tires.

EU label: Wet Braking

The performance of a tire in wet braking is a crucial factor that distinguishes an outstanding tire from a mediocre one. Due to the longer braking distance in wet conditions, wet braking has become a safety concern. The difference between the worst and best wet braking test results in the comfort segment can be up to 7 meters, which is equivalent to the length of almost 2 A-segment cars. Therefore, it is of utmost importance to be aware of the wet braking performance of a prospective tire.

To prioritize road safety, the European Union mandated the inclusion of wet braking performance in the label in 2012. The current wet label index is presented in the table below:

Wet grip index, G	EU	Korea	Japan
1,55 ≤ G	A	1	a
1,40 ≤ G ≤ 1,54	B	2	b
1,25 ≤ G ≤ 1,39	C	3	c
1,10 ≤ G ≤ 1,24	D	4	d
G ≤ 1,09	E	5

The wet grip index is a measure of a tire’s performance in wet conditions. It is calculated using the formula below

G, wet grip index = (µ_{candidate tire}/ µ_SRTT )* 1.25 + C, correction factor.

The standard reference test tire (SRTT) produced by Michelin is used as a reference point, and the correction factor C is used to account for temperature and track effects during testing. Picture of SRTT is as below:

The correction factor C, is needed to compensate temperature & track effects in the effort to standardize the test.

Testing procedure

Evaluation speed: 80-5 km/h

Surface: 1.5 mm water depth

The evaluation speed for wet grip testing is 80-5 km/h, and the testing is done on a surface with a 1.5 mm water depth to simulate real-life wet conditions. By evaluating until 5 km/h, external factors can be minimized. The car is fitted with an accelerometer sensor, and the driver simply needs to brake to collect the corresponding data.

What is the difference?

The difference between an A label tire and an E label tire in wet braking can be significant, with an E label tire braking 18 meters later than an A label tire. This difference is illustrated in the picture below, where it can be seen that an A label tire provides a clear benefit in wet grip performance.

EU label: Rolling Resistance

As global warming continues to be a pressing issue in the news cycle, people are becoming increasingly concerned with sustainability, particularly when it comes to the topic of rolling resistance in tires. So what is actually rolling resistance?

The rolling resistance is defined as the energy loss per distance
traveled by the vehicle due to nonelastic deformations of the tires
and losses in the wheel suspension system

Source

The rolling resistance of a tire is primarily caused by hysteresis, a phenomenon that describes the energy loss due to the loading and unloading of rubber as a result of its viscoelastic nature. The main parameter that is measured for tires in terms of rolling resistance is called the rolling resistance coefficient, which is defined as follows:

Rolling resistance coefficient, Cr = Resistance force, Fr / Normal load, N)

With the increasing focus on sustainability and global warming in recent times, people have become more aware of the impact of rolling resistance on tire performance. Rolling resistance is primarily caused by hysteresis, which is a phenomenon of energy loss due to the loading and unloading of rubber, owing to its viscoelastic nature. The rolling resistance coefficient is the primary parameter used to measure the resistance of a tire, and it is commonly expressed in N/kN. The resistance force is usually measured in Newtons, while the normal load is expressed in kilo-Newtons, making the coefficient dimensionless. The values in the EU label tables are also expressed in this unit. The table below illustrates the current rolling resistance coefficient values corresponding to their respective grades.

Rolling Resistance Coefficient (N/kN)	EU	Korea	Japan
RRC ≤ 6,5	A	1	AAA
6,6 ≤ RRC ≤ 7,7	B	2	AA
7,8 ≤ RRC ≤ 9,0	C	3	A
9,1 ≤ RRC ≤ 10,5	D	4	B
RRC ≥ 10,6	E	5	C

How to measure a tire’s rolling resistance?

There are various methods for measuring rolling resistance, but in this article, we will focus on the most common one, which involves a drum test. The image displays a drum setup from one of the biggest suppliers, MTS. The central drum is used to drive the tires, while force sensors are placed at the center of the tire.

The principle behind this method is straightforward. The equipment applies a load to the tire while it is rotated by the drum. By installing a force sensor on the tire, the resistance force that the tire creates to prevent it from rotating can be calculated. The image below illustrates a force diagram that shows the forces acting on the tire. When the tire reaches a steady state, the acceleration forces become zero, resulting in a high degree of accuracy in the measurement of rolling resistance.

So why should we care?

As previously noted, a tire with lower rolling resistance can result in significant savings in terms of fuel consumption and CO² emissions. Let’s take a closer look at the potential impact of switching to a more fuel-efficient tire.

1. Switching from Michelin XM2+ (label E) to Michelin e.Primacy (label A)
2. Numbers based on your whole tire life of 60,000 km with a standard A segment car’s fuel consumption of 6 l/100km.
   • Money saved RM 410
   • Average fuel consumption with the new tires 5.7 l/100km
   • Fuel saved 200 l
   • CO2 emissions reduction 527 kg CO²

*Feel free to download the fuel savings calculator to adjust for your own preference.

EU label: Noise

At first glance, not many people will equate noise coming from the car directly to the tire. Most of the time people are more fixated to the engine noise which dominates the surrounding sound wave. However as we move towards electrification, there will be no noise coming from the engine anymore and thus leaving the tire as the dominant noise source.

Noise rating

Many readers may be familiar with the sound wave labeling system from the EU label. Let us take a closer look at what the corresponding limits signify.

Tire width, T	A	B	C
T≤185	N≤67	67<N≤70	N>70
185<N≤215	N≤68	68<N≤71	N>71
215<N≤245	N≤68	68<N≤71	N>71
245<N≤275	N≤69	69<N≤72	N>72
T>275	N≤71	71<N≤74	N>74

It’s important to note that while the exterior noise level may not directly benefit the driver, it can have an impact on those in the surrounding environment, such as pedestrians and residents near busy roads. Lower exterior noise levels can lead to a more pleasant and peaceful living environment. Additionally, certain countries have noise pollution regulations in place, so a tire with a lower exterior noise level may be required for compliance. From the table above, you notice that the A B C classes are define separately based on the tire width. This reason is fairly simple, as the tire width increases, your contact area to the road surface also increases. This results in a higher frequency of air pumping resulting in a higher noise level. Subsequently a 275mm width tire has a +4 dB allowance more to hit label A compare to a 185mm width due to the same reasoning.

How do you measure exterior noise?

Pass-by noise measurement is a straightforward process that is carried out according to the ISO 362 standard. The procedure involves placing two microphones 7.5 meters away from the center of the vehicle, which must travel a defined distance (at least 20 meters) along the centerline of the microphones at a specified speed (80km/h) with the engine off. The measurement is typically repeated three to four times, and the average is calculated. It is important to note that the test must be conducted under dry conditions, as the wetness of the road surface can affect the noise results. Additionally, the road surface must adhere to the standards defined in ISO 362, as it plays a significant role in the measurement.

Buying guide using EU labels

So, how can you use EU labels to buy budget tires? Let’s take a look at an example using Interstate Tires, which are sold at Lim Tayar in comparison with a JoyRoad Sport RX6 which is a tire brand from China.

Rolling resistance: The Interstate Sport GT is rated with an E rolling resistance, whereas the JoyRoad Sport RX6 boasts a D rating. This indicates that the JoyRoad Sport RX6 is more fuel-efficient and generates fewer carbon emissions in comparison to the Interstate Sport GT. If fuel efficiency is a top priority, then the JoyRoad Sport RX6 may be the superior option.

Wet grip: The Interstate Sport GT exhibits a wet grip rating of C, which is one grade higher than that of the JoyRoad Sport RX6. In the worst-case scenario, this could result in a difference of up to 5 meters in braking distance. In a tropical country like Malaysia, the extra wet braking performances can be quite handy during rainy days.

External noise: The Interstate Sport GT has a significantly lower external noise level of 71 dB in contrast to the 72 dB of the JoyRoad Sport RX6. This implies that the Interstate Sport GT operates more quietly than the JoyRoad Sport RX6, which could be a factor for drivers who prioritize a serene and noiseless driving experience.

One may inquire about the comparison with premium brand tires. Therefore, the EU label of Continental Max Contact 6 is presented below.

Continental MaxContact 6, 225/45 R17

• Rolling Resistance : D
• Wet Braking : A
• Noise : –

The conspicuous disparity lies in the wet braking capacity, where Max Contact 6 emerges as a winner with an A-rated wet braking value.

Summary

By utilizing the EU labeling system to evaluate different tire options, one can make a well-informed and judicious decision regarding the most suitable tires for their needs. When in the market for tires, it is imperative to take into account your individual driving requirements and preferences, such as fuel efficiency, wet performance, or noise reduction. With ample information and a modicum of research, you can procure high-quality and reasonably-priced tires that will ensure your safety on the road and generate substantial long-term savings.