The tyre asphalt interface influences a wide range of pavement properties. Pdf effect of tire inflation pressure on rolling resistance. This allows parameters such as gross contact area, groove or void area, contact length and contact width to be assessed. Vertical load is the load actually seen at the tire contact patch. Consequently, the predicted friction forces are inaccurate and an exact design of the steering components is currently not possible. Unit loading over the tires contact patch areas can easily vary over a 2. Theoretical results open the way for the experimental identification of the tire footprint and of the tire road grip conditions. Oct 01, 2016 several researchers have worked in the field of friction estimation, and many tire models have been developed to predict the tire road friction. The contact patch is a combination of tread, tread grooves, and any other tire design features such as siped rubber, which maintain contact with the road as the tire rolls. Then an appropriate equation relating the patch length to the vertical load is used to calculate the load. The tire contact patch, or tire footprint, is the area of the tire that directly connects the vehicle with the driving surface. Most motorcycle tire manufacturers place a colored paint dotmark on their tires corresponding to the lightest part of the tire to aid. Using the contact patch size we can find that frequencies over roughly 8 hz should be filtered out for a quickly moving car. They can be used on passenger, truck and agricultural tires.
Retreading 86 introduction 87 planning a retread plant visit 87 plant inspection 87 definitions 90 retread plant inspection checklist 92 12. The discussion is limited to the comparison of the static and free rolling states of both tire types, examination of the effect of the bead. Tires are essential components of vehicles and are able to transmit traction and braking forces to the contact patch, contribute to. The tire is the only component of a vehicle in direct contact with the road surface and transmit the enginemotor power of driving, turning and stopping to the road. Lift the bike again and you will see the contact patch of the tire. A strainbased intelligent tire to detect contact patch. Using your tire retread and repair tool, run over the radial patch from the inside of the tire. Analysis of tireroad contact area in a control oriented test bed for. The starting point for an analysis of wheelrail contact is the identification of the size and shape of the contact patch. The contact patch analysis of solid tire on drum testing. As always, you can contact tire rack for helpyep, were all about contact. For the extension of the linear theory to cover the nonlinear range of the slip characteristics, it may be tempting to employ eqn 7.
Harzole up303g60 60pc tire repair patch small medium and square patch 30pc 218 5454mm square patch, 15pc 158. Make certain your cargo reaches its destination safely and on time by ensuring your fleets tires are properly maintained and managed. Rolling resistance an overview sciencedirect topics. Second, the tyre spreads the load over an area roughly the size of a mans foot, and although the surface it rests on is far from smooth, the rubber tread deforms. For high performance driving, the tires contact patch. Relationships among the contact patch length and width, the tire. Tire contact patch footprint is a part of the tire which is in actual contact with the road surface.
When going to a wider tire and assuming that the contact patch is now wider but shorter in the longitudinal direction assume same inflation pressure and load in each case hence we end up with same contact patch area, it would seem that the benefit could also be coming from the distribution of the cornering load across the contact patch as. Think of the trampoline outer frame as the tire bead. Pdf estimation of vertical load on a tire from contact. In the case of a solid cylinder, the contact between the cylindrical surface and the flat ground would be through a contact line.
Oct 18, 2019 the contact patch will vary in shape and size depending on the geometry of the tire, and this affects various performance characteristics of the tire. The system is based on the use of a laterally illuminated. Inflation and pressure plays a huge role on the contact patch of tires. Longer and narrower tire contact patches are most often found on passenger vehicles. The first part of this paper presents the results of experimental estimation of the contact patch area depending on the normal wheel load and. Griptester fitted with both tires at a range of tire inflation pressures and for a. A plug is simply inserted into the punctured area, making it unreliable. This approach uses the tire test bench with the set of contact patch monitoring based on image processing procedures. If the car creates any aerodynamic lift, then the vertical load on the tire will be less than the weight on the tire. This includes the weight resting on the tire contact patch plus any aerodynamic downforce.
Estimation of the tire contact patch length and normal. Contact patch width is a polynomial order 2 function of wheel load while there is a linear relationship between tire contact length and wheel load as well as between tire deflection and wheel load. At this full tire load point, if you do not have enough camber, the contact. Analysis of tire contact parameters using visual processing. Although simple in principle it is affected by factors such as surface texture at differing scales, tyre properties and vehicle dynamics. Once the steps have been completed, your tire is ready to hit me back on the rims and filled to the pressure needed to be back on the road. Since the tire is supporting the same load regardless, the contact patch will be bigger at lower pressures. If you notice a problem, youll want to consider purchasing replacement tires. Getting a grip examining the elements of tire traction. Accurately measuring the tire footprint plays an important role in analyzing the interaction of the tire with the road surface.
Imagine a trampoline to create a mental illustration of how the tire contact patch is stretched. To determine what type of tire is on a vehicle, just read the information on the sidewall of the tire. Tire contact patch characterization through finite. Contact patch is the portion of a vehicles tire that is in actual contact with the road surface. Bridgestone develops tires that result in the maximum performance of vehicles by using ultimat eye, its unique technology to visualize the contact patch. Tire rolling resistance has been reduced for the purpose of. This research study the effect of tire inflation pressure on rolling resistance, contact. Martin dher es, france p ana giotis tsiotras 2 scho ol of a er osp ac e engine ering ge or gia institute of t e chnolo gy, a tlanta, ga 303320150, usa abstract in this pap er w. Tires with a higher profile or aspect ratio that is, the height of the sidewall is fairly large compared to the width of the tire, tend to have a long and narrow contact patch. Pdf analysis of tire contact parameters using visual processing. A rubber stem, or plug, must be applied to fill the puncture injury and a patch must be applied to seal the inner liner.
Understanding the tire contact patch will help you set the camber through the exception. The contact patch of most tires is about the size of your hand and has to handle a lot more weight and force than those big reeboks do. The experi mental procedure used was modified from a previous study that had considered the. Results and discussion from test 1 area of print on paper was calculated manually and also theoretical area was calculated with the equation, a wp 1 a area of contact patch of tire wweight of vehicle p contact pressure. Laboratory investigation of the landing aircraft tire contact. In this article, an intelligent tire, which has an embedded accelerometer placed on the inner liner of the tire, is used to estimate the tire contact patch length parameter and normal load.
Tire construction plays an important part in determining what type of tire repair product to use. The design of the contact patch is an engineering feat that is specific not only to each manufacturer, but for each individual tire. This process involves energy losses, mainly due to hysteresis of the rubber material. Plug repairs do not involve taking the tire off the wheel for a proper inspection. Studies have found that the contact patch has a circular shape at higher tyre. Finally, it was found that modal shapes change due to contact patch restriction. The contact patch will vary based on tire design, construction materials, type of tire. To do this for new profiles, drawings may be available but, after running for a little while, profiles will deviate significantly from the design case and it is essential to have accurate geometrical information of the worn profiles. This paper discusses the application of noncontact methods to analyze the tire surface contact interaction. Laboratory investigation of the landing aircraft tire. Experimental measurement of onvehicle rolling tire contact patch shear energy intensity at various slip angles under the direction of dr.
Measuring grip and the contact patch ulster university. Pacejka, in tire and vehicle dynamics third edition, 2012 7. The size and shape of the contact patch, as well as the pressure distribution within the contact patch, are important to the ride qualities and handling characteristics of a vehicle. An increase of tires air pressure leads to a raising of stresses in the contact patch, combined with increasing vertical load.
Tires must be removed from the rimwheel assembly and inspected for all possible damageincluding damage to the inner liner. How to repair a punctured tire with pictures wikihow. With your trampoline comparison at the front of mind visualize the rf tire surface as it rolls through the turn. Tire, finite element modeling, footprint phenomena, contact patch. The contact patch is the only connection between the road and the vehicle. Do this for the front tire as well, as the front and rear tires can and will likely have different specs on width and diameter. A short and wide tire contact patch, which is usually found on low profile or performance tires, can provide you with more control, corner stability and tire traction. While the actual contact patch cant be seen by simply glancing at a vehicle, it is easy to see its location by viewing the profile or the outside of the wheel. For this tire contact patch exercise think of a trampoline we are going to compare a trampoline to how a race tire works. Tire contact patch lowering pressure gain traction. Miscellaneous 94 use of chains on radial truck tires 95 tire siping 95 dynamometer tests 96 mixing radial and bias ply tires 96 noise 97 ti re storage. The test program was similar for each of the tires under investigation and consisted of visual processing of contact patches under the following conditions. The vertical load on a moving tire was estimated by using accelerometers attached to the inner liner of a tire.
Pdf relationships among the contact patch length and. Estimation of the tire contact patch length and normal load. This part covers the dynamics of a tires contact patch. Magic formula tire model an overview sciencedirect topics. Regardless of whether knowing what the actual contact patch area might be useful, thats at best only a crude approximation. Tires are flexible so the contact patch is different when the vehicle is static than when it is not. Tire contact patch pressure distribution model for the static. The contact patch will vary based on tire design, construction materials, type of tire, tread and shoulder design, and sidewall construction.
That is a lot of force from those four tire contact patches. The tire contact patch where the rubber meets the road. The effect of contact patch restriction for tire vibration characteristics. Camber and the tire contact patch joes racing products.
The contact patch is your cars connection to the road. Simulating the tire contact patch region the answer is 27. In fact, a typical tire contact patch is about the size of your hand. The static contact patch of some friction measuring devices. Dimensional contact patch stress field of solid and. Jan 25, 2014 place a sheet of paper under the tire and slowly lower the tire until all of the bikes weight of off of the jack. Your cargo is valuable whether you haul freight or a bus load of first graders. Place a sheet of paper under the tire and slowly lower the tire until all of the bikes weight of off of the jack.
Compared to other areas of highway research there has been relatively little work. Design, analysis and testing of a formula sae car chassis. The contact patch will vary in shape and size depending on the geometry of the tire, and this affects various performance characteristics of the tire. So for the same tire drop of 6% the 29 wheel has a 2. The simplest method to measure the tire contact patch is to apply paint and load it onto cardboard placed on a. Low profile tires most performance tires have a short and wide contact.
The original undeformed conditions are restored when the deformed area leaves the contact patch again. Wheel energy measured a 75millimeterlong footprint for a 700 x 23 tire inflated to 112. Contact patch data was related to insitu measurement of wet grip measured using. Full set of equations 176 user scaling factors 178 longitudinal force pure longitudinal slip. This design allows pneumatic tires to possess the most versatile traction options at both low and high speeds.
Tire contact patch characterization through finite element modeling and experimental testing thomas mathews vayalat the objective of this research is to provide an indepth analysis of the contact patch behavior of a specific passenger car tire. Statistically, the larger the load on the tire, the larger its contact patch. The shape of a tires contact patch or footprint greatly influences its performance and is dependent on its profile or aspect ratio. Estimation of vertical load on a tire from contact patch. The contact stresses imposed on the road or, in this case, on the vrspta surface, are then calculated during postprocessing of the data. Tire pressures, tire widths, wheel widths, and contact patch. The contact patch analysis of solid tire on drum testing by finite element method j phromjan1,2, and c suvanjumrat1,2, 1department of mechanical engineering, faculty of engineering, mahidol university, nakhon pathom, 73170, thailand 2laboratory of computer mechanics for design lcmd, department of mechanical engineering, faculty of engineering, mahidol university, nakhon pathom, 73170. Chemicalcure reinforced truck tire patches vulcanize chemically on tube and tubeless biasply tires.
A single contact patch between the wheel and the rail is typically the size of a small coin. The acceleration signal was processed to obtain the contact patch length created by the tire on the road surface. The contact patch will vary in shape and size depending on the geometry of the tire and the suspension settings. The first part of this paper presents the results of experimental estimation of the contact patch area depending on the normal wheel load and inflation pressure for. You might be surprised to hear just how important those few inches are in determining how your car handles when driving. However, in the case of a wheel this contact is a surface contact patch, the size of which depends on the stiffness characteristics and the load of the tire.
Since the wear characteristics of tires is a highly competitive area between tire. They still use the semiempirical static forceslip mo dels, ho w ev er, to compute the corresp onding friction force. The wider the contact patch, the better your car can grip the road. This is part 6 of my 10 part series on how race car tires tyres work. In addition, the shape of the contact patch will influence the performance of the tire and the vehicle its mounted on. Pdf relationships among the contact patch length and width. For a rolling tire, deformation of the tire material occurs while entering the contact patch. Aug 26, 2020 those few inches are called the contact patch.
May 12, 2018 the current tire models, which are used for simulations in the early development stage, calculate inaccurate pressure distributions in the contact patch that do not correspond with measurements. Below, we tackle some important factors related to contact patch of tires. This doesnt account for engine or driver excited resonance at higher frequencies, simply the forcing done by the road on the car. The vertical, transverse or lateral and longitudinal forces loads are therefore measured in one line across the tire contact patch in real time by the array of instrumented. Tire contact patch characterization through finite element. It is commonly used in the discussion of pneumatic i. Think about the part of the turn where cars choose to cut or push. Understanding the way the tire interacts with the road at various loads, inflation pressures and. The highest values of contact length and width and tire deflection occurred at the highest wheel load and lowest tire inflation pressure. In that resp ect, suc h mo dels can be b est describ ed as quasidynamic mo dels. You can roll it in any direction, as long as you make sure to get every spot of the patch. Tire inflation pressure of vehicle affects various factors such as fuel economy, tread wear, rolling resistance, contact patch area and braking distance etc. Tire pressures, tire widths, wheel widths, and contact. For high performance driving, the tires contact patch would.
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