Tyre Load Calculator

Selecting the right tyre pressure for a vehicle is not as easy as people might think - especially if the owner at a later stage change the tyre specification to something different than what the vehicle was sold with.

The intention of this app is to raise awareness that different specs of tyres requires different pressures to carry the same load. IT IS AN EDUCATIONAL TOOL ONLY AND IS NOT INTENDED TO REPLACE MANUFACTURERS TABLES.

On a passenger vehicle, the owner may change to a lower profile tyre. It may have a different load rating than the original tyre but would almost certainly fall under a passenger spec tyre again.

On a 4x4 or Commercial vehicle it becomes much more complex. Sizes, load ratings and specifications can vary considerably since the same size tyre can be supplied in both Passenger spec and Light Truck or Commercial spec. There is also a much bigger difference in laden and unladen weight on these vehicles, compared to passenger vehicles.

Although inflation tables exist for many tyre systems, it is not common that this data is passed on to owners if they buy new tyres. It is also questionable if Tyre Shops ever consult these tables as it is common that they inflate small cars at pressure X, large cars a pressure Y and pick-ups as pressure Z regardless of the tyre specification.

As a result, most tyres are inflated based on gut feel.

While this is good enough for most owners, there are those who are rightly concerned about this approach, and would prefer a better tool that gives more precise indication based on actual manufacturers data.


This application covers the following Metric tyre systems:

ETRTO - European Tyre and Rim Technical Organisation
TRA - US Tyre and Rim Association

It use the Load Index (LI) as well as the Tyre Pressure as input and returns the load that a single tyre can carry.

4x4 owners in particular often use tyre pressures much lower than tabulated values. This has a drastic effect on the load a tyre can carry and is highly influenced by the tyre specification.

Tyre inflation tables covers several pages. This is impractical on a mobile device, both in terms of screen size and programming wise. I therefore mapped the tables and devised formulas for each tyre system to CALCULATE the load a tyre can carry based on the Load Index and Tyre Pressure.

The above results in an acceptably small margin of error within tabulated values. I CAN HOWEVER NOT GUARANTEE THAT THE TABLES THE FORMULAS ARE BASED ON, ARE CORRECT.

ALSO, the assumption is made that the same trends within tabulated values, are also valid outside tabulated values. THERE IS NO GUARANTEE THAT THIS IS THE CASE!



DISCLAIMER

THIS SOFTWARE IS PROVIDED "AS IS" AND ANY FITNESS FOR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE DEVELOPER, OR ANY OF HIS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; INJURY, OR LOSS OF LIFE.) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.