Tire contact patch calculation

Then an appropriate equation relating the patch length to the vertical load is used to calculate the load. Rieger 2004 measurement of the slip of tread blocks in the contact patch. It is within this interaction area called the tire footprint or contact patch that tire forces and moments arise and that wear occurs. Jan 25, 2014 the paper should be outline paper divided into oneinch blocks, it makes measuring the contact patch easier. Analysis of tire contact parameters using visual processing. Inch measurement tires are fairly easy to understand however metric tires use a more difficult system to read. The leading edge of the contact patch is pointing in the steering direction while the rearward portion of the contact patch lags behind on the old heading. If this calculator doesnt work in this site or if you need a mobile friendly site, try the new bnd. From 390 lb to 773lb almost double the tire load the contact patch size only increases by 25%, even assuming laterally constrained sidewalls.

Each of these four small patches of rubber is known as the tire contact. Jun 29, 20 when you install wider tires without changing anything else, the size of the tire s contact patch i. Hudson, presents experimental data on the effect of tire. A bigger contact patch does not give a tire more resistance to sliding. 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. When you install wider tires without changing anything else, the size of the tires contact patch i. Is there a way to estimate contact patch size given tire size plus tire volume and rider weight. Sep 06, 20 how do wheel size and contact patch size affect top speed. Estimation of vertical load on a tire from contact patch. This is the reason why it comes with a contact patch wider than an allseason tire.

It differs for different types of tyres and sometimes under different road conditions. 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 different car tires. Specifically, ive tried to build a unicycle that maximizes contact patch for riding on soft snow. Contact patch calculation the best free software for your. Town fair tire tire contact patch also known as tire footprint. The calculation of the composite slip shown in equation 7 should be modified because the tire contact patch length varies depending on the normal load. We can then calculate the size of the contact patch as the wheel load divided by. During the rainy season, tires should quickly heat up in order to ensure the contact with the roads surface. Tire tech information calculating approximate tire dimensions. Contact patch is the portion of a vehicles tire that is in actual contact with the road surface. Jan 22, 2009 id say thats got to depend entirely on the amount of reenforcement in the tire, which is going to vary, potentially pretty significantly. Is there a way to estimate contact patch size given tire size. Correspondingly this causes a rise in selfaligning torque. Tire contact pressure table 1 truck tire performance properties many factors, both tire related and operations related will affect this tireroadway interaction.

The width of the contact patch has a considerable effect on the torque and indirectly on the side force because of the consumption of some of the friction by the longitudinal forces involved. The tireroad interaction magic formula block models the longitudinal forces at the tireroad contact patch using the magic formula of pacejka. Inch up is the process of mounting a lower aspect ratio tire and larger diameter wheel on your car. Higher tyre loads increase deflection and accordingly enlarge the contact patch so that the pneumatic trail is extended. Contact patch area calculator and much more wheels. Instead, you can do it by measuring the surface area of each tires footprintthe part that presses into the groundand the pressure inside each tire. Contact patch the risks due to under and over inflation. If the line touches the road inboard of the contact patch, scrub radius is positive. The bridging effect of the slab is significantly larger than the tire contact area. The design of the contact patch is an engineering feat that is specific not only to each manufacturer, but for each individual tire.

The tire contact patch length are calculated using following two equations. Its depressing that most of what im considering produces a contact patch area less that primacys on stock rims now, the compound is gonna be better. Ii902f, truck tire pavement contact pressure distribution characteristics for the bias goodyear 1822. This approach uses the tire test bench with the set of contact patch monitoring based on image processing procedures. Use our tire size calculator to calculate the diameter, width, sidewall, circumference, and revolutions per mile of any tire. This is part 6 of my 10 part series on how race car tirestyres work. The tireroad interaction magic formula block models the longitudinal forces at the tireroad contact patch using the magic formula. Because pneumatic tires are flexible, the contact patch can. The tyres of your car may seem imposing to you, as if solidly anchored into the ground, but in reality the contact with the road is very often no more than a few squared inches of rubber.

Believe it or not, most tires have a fairly small contact patch a little larger than the size of your hand. Contact patch area calculator and much more scion frs. Apr 16, 2019 the distance between the center of the tire s contact patch and the point where that line touches the road is the scrub radius. On the other hand increasing the inflation pressure for a given tyre load will shorten the pneumatic trail and reduce the selfaligning torque. S 0 is the width of tire section and k 0 is the function of s 0 in that k 0 1. This part covers the dynamics of a tires contact patch. You dont need to be a sideshow strongman to calculate the weight of a car. Oct 26, 2016 the reason that the contact patch is even bigger than this calculation suggests is that, at the back and front edge of the contact patch, the pressure exerted on the ground is not very high. How do wheel size and contact patch size affect top speed. If the line touches the road outboard of the contact patch, scrub radius is negative see figure 2. Tire contact patch lowering pressure gain traction engine basics. Tire model in driving simulator university at buffalo.

Jul 02, 2016 this is part 6 of my 10 part series on how race car tirestyres work. Contact patch area calculator and much more wheels tires spacers hub sponsored by the tire rack contact patch area calculator and much more scion frs forum subaru brz forum toyota 86 gt 86 forum as1 forum ft86club. The contact patch of a tyre is the section of the tyres tread that is in physical contact with the road surface. The acceleration signal was processed to obtain the contact patch length created by the tire on the road surface. Furthermore, for the actual tire with carcass compliance, the spin torque will generate an additional distortion of the carcass which results in a further. Perhaps the most important part of tire design is how the tire interacts with the road surface. If you take that number and multiply it by four that is how much rubber is on the road. The tire contact patch, or tire footprint, is the area of the tire that directly connects the vehicle with the driving surface. The force of friction is proportional to the normal force fmu x n, where f is along the surface and n is perpendicular to.

Measurement of the slip of tread blocks in the contact patch. Additionally, the calculated contact patch pressure rises from 6. It is commonly used in the discussion of pneumatic i. To help them compete, racing tyre manufacturers make the contact patches as.

The vertical load on a moving tire was estimated by using accelerometers attached to the inner liner of a tire. The shape of a tires contact patch or footprint greatly influences its performance and is dependent on its profile or aspect ratio. Speedo reading tire 1 is assumed accurate tire susp. These are the only points of contact between the vehicle and the road. Difficult is an understatement when describing driving in snowy conditions. As a result, not much of the tires surface area is touching the ground. At the point where the tire is just barely touching the ground, almost no weight is supported. 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. The tire contact area is essentially irrelevant if you want to check bearing capacity under a 7 inch slab. A laboratory study was conducted to measure vertical tire contact pressures to obtain a. 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. This part covers the dynamics of a tire s contact patch. Feb 09, 2012 the contact patch of a tyre is the section of the tyres tread that is in physical contact with the road surface. For high performance driving, the tires contact patch would.

A tires contact patch is the area of the tire that comes in contact with the ground, much like a footprint. 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 forces on a tire during acceleration and braking deform the sidewall enough that the contact patch moves a noticeable amount. Static steering torque increases linearly in traditional calculation,24 but. While this unusual combination of millimeters, percentages and inches is a byproduct of the evolution of global tire. In addition, the shape of the contact patch will influence the performance of the tire and the vehicle its mounted on.

Whats the best way to calculate tire contact areas. The size of the contact patch is roughly equal to the weight of the car divided by the compressed air pressure inside the tires. By calculating the contact patch area with the above assumptions, we should then be able to calculate average pressure in the contact patch since we know the. Im currently playing with tire sizes to get for the rims that i already have. Low inflation pressures tended to cause the wheel load to be distributed more heavily to the contact patchs central area for the radial tire and more heavily to the sidewall contact area for the bias tire. Tire contact patch shape length vs width post wed aug 01, 2012 4. Analysis of vehicle static steering torque based on tireroad. Most modern passenger car and light truck tires feature size designations that indicate the tire s dimensions in a combination of metric, mathematical and english systems.

Tire contact patch lowering pressure gain traction. You are not likely to get a bearing capacity failure in confined soil. Hard to believe, but shaq puts more rubber down than most cars do. If you had an infinitely rigid carcass and tread youd have a line of contact patch with nearinfinite unit pressure.

Smithers has the tools and expertise to help engineers understand and optimize the tire contact patch. Why do you want to check the bearing capacity under the slab. That size is based on a tires overall diameter, inflation pressure, and the weight acting on it. In fact, having the wrong tires can definitely cause an.

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