A laboratory study was conducted to measure vertical tire contact pressures to obtain a. Using the tire temperatures effectively can pay considerable dividends on the race track, and its worth the effort to learn what they mean and how to adjust setups accordingly. The design of the contact patch is an engineering feat that is specific not only to each manufacturer, but for each individual tire. Tire temperatures are the easiest and most costeffective link you have to the action at the tire contact patch. Believe it or not, most tires have a fairly small contact patch a little larger than the size of your hand. Wedge other pieces of cardboard tightly under the other sides of the tire to define the four edges front, back, left, right of the tires footprint see image below. A narrower tire will have lower weight and slightly less aerodynamic drag, while a wider tire will have a larger contact patch providing better traction, less rolling resistance, slightly improved resistance to flats, and a more comfortable ride. By varying the width of the wheel, it will either enlarge or shrink your tires contact patch, leading to changes in your vehicles handling characteristics. The letter or letters at the beginning or end of this sequence indicates the type of tire. How do wheel size and contact patch size affect top speed. That expanded the contact patch and stiffened the sidewalls to make the tires more responsive, but it also could be unsafe. Dynamic measurement of the fluid pressure in the tire contact. Static steering torque increases linearly in traditional calculation,24 but.
Speedo reading tire 1 is assumed accurate tire susp. Thus, a better measurement of the deformation of the contact patch will provide more information which can be used to improve tyre modelling, model parameterisation and validation. Once done you have a picture of the tire contact patch, and can easily measure the size of the patch in square inches width of the patch times. This approach uses the tire test bench with the set of contact patch monitoring based on image processing procedures. Contact patch is the portion of a vehicles tire that is in actual contact with the road surface. In order to gain an insight into the processes in the tire contact area, a test setup was developed to directly measure the fluid pressure in the water film between tire and road.
Smithers has the tools and expertise to help engineers understand and optimize the tire contact patch. The shape of a tire s contact patch or footprint greatly influences its performance and is dependent on its profile or aspect ratio. True hybrid of mudterrain performance and allterrain road manners. The contact patch is the only connection between the road and the vehicle. An optical tire contact pressure test bench developed by the imma group is described. Ultimat eye technology to visualize the contact patch of tire technology of simulation and measurement supporting bridgestones tire developments 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. As a result, not much of the tires surface area is touching the ground. On a rim, 30 represents the inner width between the flanges in millimeters, as demonstrated in the accompanying diagram for this section. That size is based on a tires overall diameter, inflation pressure, and the weight acting on it. Jan 25, 2014 the tire contact patch all vehicles are supported by a cushion of air contained in four flexible rubber tires.
This is part 6 of my 10 part series on how race car tirestyres work. The simplest method to measure the tire contact patch is to apply paint and load it onto cardboard placed on a steel plate to obtain a print astm f87094, 2010. Tire width intuitively, increasing the size of the tires would also, in theory, increase the size of the contact patch and thus improve traction. With the loaded truck sitting still on flat level ground, go measure the tire contact patch, ie the width and length of each tire contact patch. The contact patch of the tire changes shape by becoming shorter and wider. High aspect ratio tall and narrow contact patch short aspect ratio chort and wide contact patchwhat does this. Since the wear characteristics of tires is a highly competitive area between tire. Measurement of the slip of tread blocks in the contact patch. Tire pressures and contact areas heavy equip tires. Flat plate describes the contact patch or footprint in square inches of ag tire, as shown below. Most tire footprints are roughly rectangular in shape.
While the shape changes, the size area of the contact patch remains relatively unchanged. An lt appearing at either the beginning or the end of the. Measuring tire tread footprint and contact patch pressure. The contact patch simply doubles in size by becoming twice as long. The second number, 584, is universal between tires and. If a tire manufacturer notes that a 23545r17 tire has an acceptable rim width range of 7. Additionally, the calculated contact patch pressure rises from 6. These stand for the first 3 digits, which means in a tire marked p21565 r15 91s, it has a width of 215 millimeters.
It is commonly used in the discussion of pneumatic i. The size and shape of the contact patch, as well as the. This area transmits forces between the tire and the road via friction. Seyedmeysam khaleghian, omid ghasemalizadeh, and saied taheri 2016 estimation of the tire contact patch length and normal load using intelligent tires and its application in small ground robot to estimate the tire road friction. A lower tire pressure gives you a larger contact patch, higher pressure gives you a smaller contact patch. Tire contact patch characterization through finite element. Measurement of the tire dynamic transfer stiffness at. As discussed in better yield post, larger flat plate is important as increased flotation and larger contact patch enables more full weight disbursement, thus reducing compaction. For the measurement of the tire vertical dynamic transfer stiffness, the sha ker table should apply a purely uniaxial excitation in the zdirection at the contact patch. Battlax sport touring t31 sport tire bridgestone motorcycle. Tire contact patch shape length vs width post wed aug 01, 2012 4. This is a very useful tool in understanding tire wear, and can help in the design and overall tread patterns. Tyre deformation captures the force input to the vehicle.
Citeseerx an optical tire contact pressure test bench. The shape of a tires contact patch or footprint greatly influences its performance and is dependent on its profile or aspect ratio. The tyre asphalt surface contact patch influences properties such as friction, noise generation, fuel efficiency to structural performance. 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. In a tire, the tread provides traction, and how the tire interacts with the road surface is the most important aspect of testing. Dcfr is the new standard in tire testing technology that combines a fully dynamic tire test rig with tire patch measurement sensors. This refers to the measurement of the tires width in millimeters, from one sidewall to another. Congratulations to josh blyler for placing 1st, erik miller 2nd, and marcos gomez 3rd at the 2020 king of the hammers race. These are typically installed on passenger cars, light trucks, suvs, and vans. Tire contact patch lowering pressure gain traction. The tire contact patch, or tire footprint, is the area of the tire that directly connects the vehicle with the driving surface. This part covers the dynamics of a tire s contact patch. Seyedmeysam khaleghian, omid ghasemalizadeh, and saied taheri 2016 estimation of the tire contact patch length and normal load using intelligent tires and its application in small ground robot to estimate the tireroad friction. What is a flat plate measurement and how does it affect flotation, traction, and yield.
From 390 lb to 773lb almost double the tire load the contact patch size only increases by 25%, even assuming laterally constrained sidewalls. This is a simplification for measurements conducted on a curved surface, since the contact patch length is shorter than on a flat surface and the contact. The test bench allows performing normal pressure distribution and patch contact shape measurements on passenger car tires. Most tires will have the letter p, which is short for pmetric or a passenger car type tire. Large deformed contact area is made available as a 3d point cloud. Rieger 2004 measurement of the slip of tread blocks in the contact patch. These include ink measurements of footprint shape and groovevoid ratio, optical contact pressure measurement, and multiaxis measurements of footprint stress, motion, and frictional energy. Osa highspeed 3d digital image correlation for rolling. If you mount that tire onto a 7inchwide rim, the beads will be squeezed together beyond the tire design spec, making it difficult to mount the tire and posing an increased chance for bead damage during mounting. 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 static contact patch of some friction measuring devices. 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. However, due to the influence of test equipment and tire operating conditions, the perception of rolling tire characteristics is still in the stage of gradual improvement, especially the analysis of sidewall rolling deformation and dynamic contact peculiarities of tiresroad interactions, which has. Statistics for measuring tyre contact patch springerlink. Mountain bike wheel sizes explained wheel sizing system guide. The nt420v is the nextgeneration allseason truck and suv tire born from nittos passion and innovation. Since the excitation f orce exerted by the shaker table onto the tire has an offset with respect to the rotation centre of the shak er table, an openloop control. Has the potential to provide insight into never before measured tyre dynamics. Since the excitation f orce exerted by the shaker table onto the tire has an offset with respect to the rotation centre of. Ultimateye visualization of the tire contact patch behavior with measurement and simulation technology. The first number, 30, represents a different measurement on tires than it does on rims. We offer several options for realtime tire testing, including the new standard in tire testing, the dynamic contact force rig.
The paper should be outline paper divided into oneinch blocks, it makes measuring the contact patch easier. 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. Estimation of the tire contact patch length and normal. Bridgestone provides digital tools to support fleet businesses management and analytics of tire data to improve efficiency and decrease downtime ultimat eye technology to visualize the contact patch of tire technology of simulation and measurement supporting bridgestones tire developments. For tireroad contacts, a singlepoint contact model for the vertical force f z and longitudinal force f x is used instead of a distributed contact model, as shown in other studies. For most popular tire sizes, there are a wide variety of tire widths available. Analysis of tire contact parameters using visual processing. With a smaller contact patch, the downward force weight of the car acts. The lengthtowidth ratio of the contact patch affects steering and cornering behavior. Visualization of the tire contact patch behavior with measurement and simulation technology. Contact patchthe contact patch, or footprint, of the tire, is the area of the tread that is in contact with the road surface. This paper discusses the application of noncontact methods to analyze the tiresurface contact interaction.
The main goal of this study was the experimental investigation of the fluid pressure in the boundary region between wet grip and hydroplaning. The measurement system is based on the frustration of total internal reflection ftir of light. This paper discusses the application of noncontact methods to analyze the tire surface contact interaction. Wedge other pieces of cardboard tightly under the other sides of the tire to define the four edges front, back, left, right of the tire s footprint see image below. This part covers the dynamics of a tires contact patch. On a tire, 30 represents the inflated tire width in millimeters.
The presentation is scheduled for wednesday, march 6th at 10. The tyre contact patch is an important region in both tyre and terramechanics research. 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 contact patch all vehicles are supported by a cushion of air contained in four flexible rubber tires. A tires contact patch is the area of the tire that comes in contact with the ground, much like a footprint. In racing the sidewall heat generation is small compared to the tire contact patch due to the fact you are running at the limit of adhesion and scuffing the surface. Understanding basic wheel and tire dimensions, terminology. Once done you have a picture of the tire contact patch, and can easily measure the size of the patch in square inches width of the patch times the height of the patch. The wheel width can have a direct effect on a tires contact patch the part of the tire in direct contact with the road if you decide to change to a widernarrower wheel option. An msb tire is lighter than conventional multicross belt construction, it also has more stability since it minimizes heat generation inside the tire and gives high shock absorption. Jul 02, 2016 this is part 6 of my 10 part series on how race car tirestyres work.
By varying the width of the wheel, it will either enlarge or shrink your tires contact patch, leading to changes in. 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. Measuring contact patch shapes and their effect on tire performance at the 2019 tire technology conference in hannover, germany. Bridgestone tire technology bridgestone motorcycle tires. Starting with any tire, shove a piece of cardboard under the base of the tire as far as it will go. Tire contact patch lowering pressure gain traction engine basics. Tires play a vital role in a vehicles operational stability, comfort, and security. Truck tire types and road contact pressures by pedro yap the. If you could place a car on a glass floor and look at it from below, you would see four patches of rubber, most folks are surprised at the size of these four patches, depending on the vehicle each patch is a little smaller than a hand. Supplies less slip area for good traction while riding and improves wear life. This project was carried out for a leading tyres manufacturing company in india and deals with the development of an alternative method to measure the land.
Jun 28, 2016 what is a flat plate measurement and how does it affect flotation, traction, and yield. With over a decade of experience in the automotive testing industry, henning is wellversed in measuring, interpreting, and modeling tire. When you install wider tires without changing anything else, the size of the tires contact patch i. Tire contact pressure table 1 truck tire performance properties many factors, both tire related and operations related will affect this tireroadway interaction.
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