Wet Skid Resistance of Car and Truck Tires

1974 ◽  
Vol 2 (2) ◽  
pp. 102-116 ◽  
Author(s):  
A. Dijks
Keyword(s):  
Surface Texture ◽  
Road Surface ◽  
Skid Resistance ◽  
Test Results ◽  
Side Force ◽  
Force Coefficients ◽  
Truck Tires ◽  
Braking Force ◽  
Wet Skid Resistance

Abstract Two test trailers for measuring tire characteristics are described. One of the trailers is specially built for testing car tires and can steer, camber, and brake the test tire. This trailer is provided with a five component measuring hub. The second trailer, for testing truck tires, is restricted to braking only. Braking forces are measured with a dynamometer. The determination of peak and locked wheel braking force coefficients is discussed. In addition, for car tires, a method for obtaining side force coefficients is given. Test results are given for both car and truck tires showing the influence of road surface texture, speed, and tread depth on skid resistance, and the results are compared.

Skid Resistance of Passenger Car Tires on Wet Surfaces

1968 ◽  
Vol 41 (4) ◽  
pp. 780-806 ◽  
Author(s):  
G. Maycock
Keyword(s):  
Road Surface ◽  
Skid Resistance ◽  
Passenger Car ◽  
Force Coefficients ◽  
Potential Value ◽  
Lubricating Film ◽  
High Speeds ◽  
Wide Range ◽  
Road Surfaces ◽  
Braking Force

Abstract This paper reports investigations into the effect of tread pattern, pattern modifications, tread material, and tire casing construction, on skid resistance of passenger-car tires at speeds between 25 and 80 mph on a range of wet road surfaces. The technique was to brake the front wheels of a car until they locked, and to record deceleration of the vehicle. From the deceleration record, both peak and locked-wheel values of braking force coefficients were obtained. The method is described and an assessment of the errors is given. The experiments showed the importance of adequate drainage of the region of contact between tire and road, particularly at higher speeds, in order to remove the lubricating film of water. Such drainage can be provided either by a tread pattern or a coarse road surface. The results indicate the importance of each and their inter-relation. Results of various modifications to a standard tread pattern are given; these show that on smooth surfaces worthwhile increases in wet road adhesion at high speeds can be obtained by suitable design of tire tread patterns. Magnitude of increases in friction due to changes in tread material are given for both peak and locked-wheel coefficients. Ratios of peak to locked-wheel coefficients have been calculated over a wide range of surface and tire combinations. They show the potential value of devices enabling a vehicle to make use of these high coefficients.

Second Paper: Studies on the Skidding Resistance of Passenger-Car Tyres on Wet Surfaces

1965 ◽  
Vol 180 (1) ◽  
pp. 122-157 ◽  
Author(s):  
G. Maycock
Keyword(s):  
Road Surface ◽  
Smooth Surfaces ◽  
Passenger Car ◽  
Force Coefficients ◽  
Potential Value ◽  
Lubricating Film ◽  
High Speeds ◽  
Wide Range ◽  
Road Surfaces ◽  
Braking Force

This paper reports investigations into the effect of tread pattern, pattern modifications, tread material and tyre casing construction, on the skidding resistance of passenger-car tyres at speeds between 25 and 80 mile/h on a range of wet road surfaces. The technique used was to brake the front wheels of a car until these wheels locked, and to record the resulting deceleration of the vehicle. From the deceleration record, both the peak and locked-wheel values of the braking force coefficients were obtained. The method is described and an assessment of the errors involved is given. The experiments showed the importance of adequate drainage of the region of contact between tyre and road, particularly at the higher speeds, in order to remove the lubricating film of water. Such drainage can be provided either by a tread pattern or a coarse road surface, and the present results indicate the importance of each and their inter-relation. The results of various modifications to a standard tread pattern are given; these show that on smooth surfaces worth-while increases in wet road adhesion at high speeds can be obtained by suitable design of tyre tread patterns. The magnitude of the increases in friction due to changes in tread material are given for both peak and locked-wheel coefficients. Ratios of peak to locked-wheel coefficients have been calculated over a wide range of surface and tyre combinations, and they show the potential value of devices enabling a vehicle to make use of these high coefficients.

Road surface texture and skid resistance

2015 ◽  
Vol 3 (4) ◽  
pp. 043001 ◽  
Author(s):  
Minh-Tan Do ◽  
Veronique Cerezo
Keyword(s):  
Surface Texture ◽  
Road Surface ◽  
Skid Resistance

Angular Parameter for Characterizing Road Surface Microtexture

2000 ◽  
Vol 1723 (1) ◽  
pp. 66-72 ◽  
Author(s):  
Minh-Tan Do ◽  
Hassan Zahouani ◽  
Roberto Vargiolu
Keyword(s):  
Profile Analysis ◽  
Road Surface ◽  
Skid Resistance ◽  
Analysis Program ◽  
Simple Method ◽  
Coarse Aggregates ◽  
The Difference ◽  
Tire Friction ◽  
Tactile System

Development of a device for measuring road surface microtexture and the determination of a microtexture parameter related to wet road/tire friction are discussed. A laser autofocus system was selected from existing devices. The required characteristics were defined from consideration of the contact between wet roads and tires. The autofocus principle is presented briefly, and comparison is made with a tactile system. The microtexture parameter, called the theta parameter, is defined from the useful parts of the texture profiles, that is, those in contact with the tire. It characterizes relative positions of profile peaks. A simple method was proposed to define the peaks. The profile analysis program is presented briefly. Relevance of the theta parameter was validated on surfaces composed of coarse aggregates with planar exposed faces. The specimens were polished using a projection method to emphasize the microtexture contrast between surfaces. Friction was measured using a skid resistance tester (SRT) pendulum. Profiles were measured using both laser and tactile systems. Characteristics of profiles are given. The statistical distribution of theta values obtained on a profile may be described by an exponential function. Close agreement was found between theta values obtained from laser and tactile profiles, values from laser profiles being somewhat lower. The difference is attributed to profile length. Fair correlation was found ( r2 > 0.80) between theta values and SRT friction, and similar tendencies were observed from laser and tactile data.

The influence of road surface texture on the skid resistance under wet conditions

2018 ◽  
Vol 234 (3) ◽  
pp. 313-319
Author(s):  
Rebekka Kienle ◽  
Wolfram Ressel ◽  
Tobias Götz ◽  
Markus Weise
Keyword(s):  
Friction Coefficient ◽  
Film Thickness ◽  
Water Depth ◽  
Surface Texture ◽  
Water Film ◽  
Road Surface ◽  
Skid Resistance ◽  
Water Film Thickness ◽  
Pavement Surface ◽  
Wet Friction

Due to their influence on traffic safety, skid resistance and drainage are important surface properties of a road and their optimization and durability is still focus of ongoing research. Under wet conditions, these two characteristics are connected as a wetted road cannot provide a sufficient skid resistance without a working drainage system. The wet friction is mainly affected by the road surface geometry and the water depth. Herein, we describe a novel numerical approach to study the influence of the surface texture – mainly the microtexture – on the wet friction coefficient. This method is based on the hysteresis effect, which is the main friction force on rough surfaces under wet conditions. We therefore use an already established friction model for dry surfaces and extend its range of application by an additional consideration of water films. A drainage model has been developed to calculate the water film thickness for a given road surface and geometry (pavement surface runoff model) as systematic measurements of water film thicknesses in situ are difficult. The water depth determines the number of contact points between the pavement and the tyre. Based on three-dimensional measurements of a surface texture, the friction coefficient is calculated. By this newly developed model approach, it is possible to identify the main factors influencing wet skid resistance in regard to the pavement surface microtexture and the water film thickness.

Predicting Tire Tread Performance from Composition. I

1970 ◽  
Vol 43 (5) ◽  
pp. 1070-1081 ◽  
Author(s):  
J. H. Lane ◽  
C. A. McCall ◽  
P. F. Gunberg
Keyword(s):  
Wear Resistance ◽  
Regression Analysis ◽  
Experimental Program ◽  
Skid Resistance ◽  
Test Results ◽  
Independent Variables ◽  
Test Conditions ◽  
Composition I ◽  
Heat Buildup ◽  
Wet Skid Resistance

Abstract Wet skid resistance of tread compounds, as measured by the British Portable Tester, and heat buildup, as measured by the Goodrich Flexometer, can be predicted accurately from a knowledge of composition and modulus, while wear resistance, as measured by the Pico Abrader, can be predicted with only fair accuracy. The predicting relations were developed using multiple regression analysis from data obtained in a designed experimental program. Independent variables included four polymers (emulsion SBR's of 0, 23.5, and 40% bound styrene and cis-polybutadiene), extender level, carbon black N−285 loading, and modulus. Field test results are presented for compounds selected to show improved wet skid resistance while maintaining wear and groove cracking resistance at present-day levels. Test conditions influencing tire wet skid testing results, particularly the phenomenon of partial hydroplaning, are discussed.

The Relationship Between Texture and Pavement Friction

1978 ◽  
Vol 6 (4) ◽  
pp. 215-232 ◽  
Author(s):  
J. J. Henry
Keyword(s):  
Standard Test ◽  
Skid Resistance ◽  
Side Force ◽  
Force Coefficients ◽  
Speed Dependence ◽  
The Relationship ◽  
Pavement Friction ◽  
Slip Method

Abstract The transient slip method is shown to be a useful technique to evaluate the speed dependence of pavement friction. From the results of transient slip tests with a standard test tire, it is possible to predict skid resistance, speed gradients, and side force coefficients. Transient slip data can be predicted from wet pavement macro-texture and microtexture and, therefore, skid resistance-speed gradients and side force coefficients can be predicted from texture measurements.

scholarly journals RESEARCH OF BRAKING PECULIARITIES OF USED CARS

Transport ◽  
2002 ◽  
Vol 17 (3) ◽  
pp. 85-90
Author(s):  
Valentinas Mitunevičius ◽  
Saulius Nagurnas
Keyword(s):  
Experimental Measurements ◽  
Test Results ◽  
Paper Briefly ◽  
Force Coefficients ◽  
Eu Directive ◽  
Braking Force ◽  
Used Cars ◽  
Braking Process ◽  
The Eu

This paper briefly describes some analysis of a car braking process — the peculiarities of car wheel-to-road adhesion, the influence of distiibution of braking forces on car stability between front and rear axles. The requirements of EU Directive 71/320/EEC to braking force coefficients of car front and rear axles are exposed. Structural designs of braking systems are analyzed with respect to their meeting the EU standards. Experimental measurements ofbraking force coefficients for some models of cars which are used in Lithuania, are presented with the analysis how these coefficients meet the EU standards. The analysis of test results, suggestions for the ratio of braking forces of car front and rear axles are presented.

Tire-Road Interactions — Harmony or Conflict?

1989 ◽  
Vol 17 (1) ◽  
pp. 66-84
Author(s):  
A. R. Williams
Keyword(s):  
Rolling Resistance ◽  
Major Effect ◽  
Road Surface ◽  
Interactive Effects ◽  
Central Theme ◽  
Water Drainage ◽  
The Road ◽  
Truck Tires ◽  
Road Surfaces ◽  
Tire Wear

Abstract This is a summary of work by the author and his colleagues, as well as by others reported in the literature, that demonstrate a need for considering a vehicle, its tires, and the road surface as a system. The central theme is interaction at the footprint, especially that of truck tires. Individual and interactive effects of road and tires are considered under the major topics of road aggregate (macroscopic and microscopic properties), development of a novel road surface, safety, noise, rolling resistance, riding comfort, water drainage by both road and tire, development of tire tread compounds and a proving ground, and influence of tire wear on wet traction. A general conclusion is that road surfaces have both the major effect and the greater potential for improvement.

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