In vehicle dynamics, slip angle (also known as sideslip angle) is the angle between the actual direction of travel of a rolling wheel and the direction towards which it is pointing. Slip (usually described as percent slip), is the relative motion between a tyre and the road surface on which the tyre is moving on. This slip can be generated either by the tyre’s rotational speed being greater or less than the free-rolling speed, or by the tyre’s plane of rotation being at an angle to its direction of motion. Fig.1 shows a top view of how slip angle occurs when the vehicle is turning right.

It is called slip angle, because the part of the contact patch that is to the outside of your turn is moving faster than the wheel itself is in the direction it (the contact patch) is pointing , while the part on the inside is moving more slowly. Since the outside part is moving faster than the tyre it must be slipping and hence is the name of ‘Tyre Slip’. The inside part is gripping better than it would if moving in a straight line. For this reason, the contact patch ‘walks’ itself into the turn.

Mathamatical model of slip angle

The slip is generally given as a percentage of the difference between the surface speed of the wheel compared to the speed between axis and road surface. Fig.2 shows that slip angle is the vector sum of wheel forward velocity and lateral velocity. Mathematically, slip could be represented, as:

where , w is rotational speed of the wheel, r is wheel radius and v is vehicle speed. This indicates that a positive slip means the wheels are spinning and negative that they are skidding. Locked brakes, wr = 0, means that slip is -100% and spinning on the spot, v = 0 and wr ≠ 0, means that ∞.

Slip angle , therefore, is the angular difference between the direction the tyre contact patch with the road is pointing and the direction of the wheel (Fig.3). In actual case, the tyre tread does not point in the same direction as the wheel. This is because a tyre is being made of rubber, the sidewalls deform, and the tread pattern itself can ‘squirm’ when the wheel is turned from the straight-ahead.

In fact, modest slip angles are ‘good’ as tyres generate progressively more grip with increasing slip angles (Fig.3).For every type of vehicle and tyre the modest slip angle or the good slip angle is different and for all the tyres in your car, the slip angle might be different at any point of vehicle dynamics.When the limit exceeds, where after no further grip is generated. Thereafter, increasing slip angles are ‘bad’, and the tyre will tend to lose grip. Because of the slip angle, the contact patch of the tyre (Fig.3) need not be in the same orientation as the whole wheel, often lagging a few degrees behind. Greater the slip angle will obviously mean that the larger portion of the contact patch is slipping (Fig.3). At some point there is so little part of the contact patch that there is no slipping, which means that traction is lost and the tyre begins to slide. As the tread element moves through the contact patch it will be deflected further from the wheel mid-plane(Fig.3). This deflection gives rise to the slip angle, and to the cornering force.

Tyres seem to operate at their peak performance when they are under a few degrees of slip angle, they generate the most grip at that particular slip angle. For race and high performance tyres this optimum slip angle is around 6 to 10 degrees while this number is a little lower for street tyres (Fig.4).

Measurement of slip angle

There are two main ways to measure slip angle of a tyre: on a vehicle as it moves, or on a dedicated testing device. There are a number of devices which can be used to measure slip angle on a vehicle as it moves; some use optical methods, some use inertial methods, some GPS and some both GPS and inertial.

Various test machines have been developed to measure slip angle in a controlled environment. Sensors measure the force and moment generated on a dynamic vehicle, and a correction is made to account for the curvature of the track. Other devices use the inner or outer surface of rotating drums, sliding planks, conveyor belts, or a trailer that presses the test tyre to an actual road surface. These days computer simulation models are available for measuring tyre slip angle. Technicians can use a simple tyre finite element model to generate lateral, tangential and radial tyre accelerations for a fixed load and slip angle. The profiles are validated by using experimental data. The simulated acceleration profiles are used for the estimation of slip angle and tyre/road friction coefficient.

Effects of slip angle

Each tyre will have its own slip angle. A tyre that is not slipping has a slip angle of zero degrees. The ratios between the slip angles of the front and rear axles will determine the vehicle’s behavior in a given turn. If the ratio of front to rear slip angles is greater than 1:1, the vehicle will tend to understeer, while a ratio of less than 1:1 will produce oversteer (Fig.5).

Actual instantaneous slip angles depend on many factors, including the condition of the road surface, but a vehicle’s suspension (Fig.6) can be designed to promote specific dynamic characteristics. Incidentally, a vehicle suspension system may include; Coil spring, Leaf spring, Hydraulic and Air Spring or their combinations. This is very important for racing car as they need to take sharp turns on high speeds.

A principal means of adjusting developed slip angles is to alter the relative roll couple (the rate at which weight transfers from the inside to the outside wheel in a turn) front to rear by varying the relative amount of front and rear lateral load transfer. This can be achieved by modifying the height of the roll centers, or by adjusting roll stiffness, either through suspension changes or the addition of an anti-roll bar. Because of asymmetries in the side-slip along the length of the contact patch, the resultant force of this side-slip occurs away from the geometric center of the contact patch, a distance described as the pneumatic trail, and so creates a torque on the tyre.

Comments (0)

ADD COMMENT

Link Copied!

The Yokohama Rubber Co., Ltd., has entered into a new agreement to serve as the official tyre supplier for BMW M Motorsport, the division responsible for the brand's global racing endeavours. This collaboration will debut at the prestigious Nürburgring 24-Hour Race and throughout the Nürburgring Langstrecken-Serie in 2026.

This renewed partnership revives a historical connection between the two companies, who previously worked together on the same iconic circuit from 1980 to 1990. During that initial decade-long stint, their combined efforts secured two overall victories. After an interval of nearly four decades, they are reuniting for the current season to compete in the premier SP9 class, fielding the BMW M4 GT3 EVO. For this campaign, Yokohama will equip the vehicle with its high-performance ADVAN racing tyres, with the shared objective of capturing another overall win.

Beyond its tie-up with the BMW team, Yokohama Rubber continues its longstanding commitment to the Nürburgring. It will provide its tyres to numerous leading teams contesting both the endurance series and the 24-hour event this season. The company is focused on achieving an overall championship victory for a vehicle equipped with its YOKOHAMA brand tyres.

Franciscus Van Meel, CEO, BMW M GmbH, said, “We are excited to welcome YOKOHAMA as Official Partner of BMW M Motorsport for our Nürburgring programme. YOKOHAMA’s technical expertise and motorsport passion strengthen our drive for maximum performance and precision. Their support allows our team to focus fully on what defines BMW M Motorsport: pushing the limits on every lap. We look forward to a strong endurance season.”

Team: Schubert Motorsport
Class: SP9
Car: BMW M4 GT3 EVO
Tyres:
ADVAN A005 (for dry conditions); Sizes: front 300/680R18, rear 330/710R18
ADVAN A006 (for wet conditions); Sizes: front 300/680R18, rear 320/710R18

Race Schedule (as of date of this release)
March 14 (Sat): NLS Round 1
March 21 (Sat): NLS Round 2
April 11 (Sat): NLS Round 3
April 18 (Sat) –19 (Sun): Nürburgring 24-Hour Race (Qualifiers) , NLS Rounds 4 & 5
May 14 (Thu) –17 (Sun): Nürburgring 24-Hour Race
June 20 (Sat): NLS Round 6
August 1 (Sat): NLS Round 7
September 12 (Sat) –13 (Sun): NLS Rounds 8 & 9
October 10 (Sat): NLS Round 10

Comments (0)

ADD COMMENT

Link Copied!

Hankook Tire has introduced the Laufenn X FIT AT2, a new addition to its all-terrain tyre lineup aimed at drivers who require durability and adaptability without compromising on everyday driving comfort. Positioned as an affordable option, this tyre is engineered to handle a mix of on-road and off-road conditions while delivering long-lasting value.

Building upon the foundation of its predecessor, the X FIT AT2 brings several performance upgrades. It features enhanced traction across varied landscapes, a 15 percent improvement in tread longevity and reliable handling in different weather conditions. The tyre is designed to fit a broad spectrum of light trucks and SUVs, with availability ranging from 15 to 22 inches to accommodate popular vehicle models in the market.

This launch reflects Laufenn’s ongoing strategy to diversify its offerings as it strengthens its presence in over 100 countries. Since its introduction in Europe, the brand has consistently expanded its range for both passenger vehicles and commercial applications, responding to shifting consumer needs. The X FIT AT2 reinforces this direction by providing a balance of rugged capability and composed road manners for those who frequently transition between highways and rougher terrain.

Engineered for resilience, the tyre incorporates a reinforced structure, including select sizes with three-ply sidewalls to resist cuts and impacts. Its tread design features directional and lateral grooves that enhance water dispersion and grip on slippery or loose surfaces. Additional protective elements such as offset shoulder blocks and rim guards help shield against debris and curb damage. A two-step deep sipe pattern promotes uniform wear, contributing to extended usability.

Certified with the Three-Peak Mountain Snowflake symbol, the X FIT AT2 offers dependable performance in dry, wet and snowy winter conditions. It comes with warranty coverage tailored to its sizing, offering 60,000 miles for P-metric versions and 50,000 miles for LT-metric options. With this release, Laufenn continues to round out its portfolio alongside existing lines such as the S FIT, G FIT and I FIT series.

KC Jensen, Vice President – U.S. Passenger Car and Light Truck Sales, Hankook Tire America Corp, said, “The X FIT AT2 represents the next step forward for the Laufenn brand as we continue to deliver practical, dependable solutions for everyday drivers who also want the freedom to explore off-road. Building on the success of the original X FIT AT, this second-generation tyre offers a stronger blend of durability, versatility and everyday comfort at an accessible value.”

Comments (0)

ADD COMMENT

Link Copied!

Comerio Ercole is set to make a significant impact on the global stage in 2026 with its participation in two major industry exhibitions. The company will showcase its latest advancements at both Chinaplas 2026 and Tire Technology Expo 2026, highlighting a comprehensive portfolio designed to enhance precision, productivity and sustainability in polymer processing.

At Tire Technology Expo, Comerio Ercole will present integrated systems tailored for the tyre industry, focusing on high-performance rubber calendering and digital intelligence. A flagship solution is the TRIPLE 4-roll calendering unit. Its innovative "S" configuration provides remarkable flexibility by enabling the processing of both textile and steel cord, as well as the production of rubber sheeting, all within a single line. The system’s capability for simultaneous lamination ensures high precision and product stability while minimising defects. Downtime is a critical factor in tyre production, and the patented FASTEEL system directly addresses this. By automating the steel cord change process, it dramatically reduces changeover time from hours to minutes, allowing the line to continue running during preparation and thereby maximising plant availability and operator safety. Following the calendering process, the SUPERCUT system guarantees clean, precise transversal cuts for both steel and textile-reinforced rubber, integrating guillotine and high-speed rotary blades to minimise waste and streamline downstream winding.

Simultaneously, at Chinaplas 2026, taking place in Hall 2.1 at Stand C85, the company will place a strong emphasis on its patented HYDROPLUS concept for PVC and plastic calendering. This technology suite is engineered to deliver micrometric precision and robust process stability through advanced hydraulic controls. Central to this is HYDROGAP, a system that achieves exceptional thickness uniformity with high-resolution gap positioning. Complementing this are HYDROSAFE, which ensures rapid roll separation for ultimate protection, and HYDROTHERM, a feature that intelligently compensates for thermal expansion to maintain precise gap settings during fluctuating operational temperatures.

Beyond mechanical innovation, the company is driving digital transformation with its CELEMETRY and MINERV-AI platforms. CELEMETRY focuses on sustainability by converting production data into actionable insights for environmental reporting and energy optimisation. MINERV-AI captures and standardises operational expertise through artificial intelligence, supporting more effective maintenance protocols, training procedures and overall operational consistency. Through these combined efforts at both exhibitions, Comerio Ercole is demonstrating a holistic approach to advancing the plastics, rubber and tyre industries.

Comments (0)

ADD COMMENT

Link Copied!

The seventh edition of Trelleborg Tires’ Tractor Driver of the Year competition took place at the Cremona Circuit in Italy on 28 February 2026, drawing 50 skilled participants from across the nation. Held at a venue renowned for its professional standards, the event has become a fixture in the agricultural calendar, offering a platform for drivers to demonstrate their expertise while experiencing advanced tyre technology in practical scenarios. After a demanding day of challenges, Francesco Coppe emerged victorious, distinguished by his exceptional precision and versatility across the various disciplines.

The competition featured a series of exercises designed to assess core abilities, including manoeuvring, loader operation, reverse driving and trailer handling, culminating in a field regularity test. Throughout these tasks, participants directly observed the benefits of Trelleborg’s ProgressiveTraction technology, which aims to boost traction, reduce soil impact and enhance overall efficiency. This year, Fendt joined as the technical partner, supplying the machinery for the event. The tractors used, such as the Fendl 300 Vario Gen5, 500 Vario Gen4 and 800 Vario Gen5 models introduced in 2025, exemplified how modern agricultural engineering supports operators in achieving high performance with comfort and ease, both on road and in the field.

Daniela Gambatesa, Marketing Manager Italy, Trelleborg Tires, said, “The ‘Tractor Driver of the Year’ once again confirms its position as a landmark event for the agricultural sector: a unique opportunity to celebrate expertise, innovation and professionalism. This 7th edition recorded a remarkable participation of tractor drivers, highlighting the growing importance of the initiative. A key highlight of the event was the new ‘5,000 Hours of Guaranteed Performance’ campaign dedicated to ProgressiveTraction® treads, originally launched in July 2025 and now featuring a customised look for Fendt tractors equipped with VarioDrive technology. This initiative allows us to prove in real working conditions the long-term durability and efficiency of our tyres, offering tangible support to agricultural professionals in their daily operations. The collaboration with Fendt as technical partner further reinforces our shared commitment to excellence, combining advanced technology with high-performing solutions for the industry.”

Silvia Uderzo, Advertising & Sales Promotion Specialist, Fendt Italia, said, “Fendt has believed in the ‘Tractor Driver of the Year’ project since its early editions, reflecting the trust and importance we attribute to this initiative. Taking part again this year represents a valuable opportunity to enhance the skills of tractor drivers and to demonstrate how the technology, performance and comfort of our machines play a decisive role in improving operational efficiency. The partnership with Trelleborg Tires confirms our shared commitment to delivering increasingly high-performing and sustainable solutions to agricultural professionals, combining innovation with close attention to their real operational needs.”

Comments (0)

ADD COMMENT

Link Copied!