Load index
The load index , also load index (LI) Load index or load number called, is a coding and indicated for vehicle tires , the maximum permissible load. The index is noted on the side of the tire. A table can be used to determine the maximum permissible load per tire in kilograms.
Tabular listing
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These values refer to a tire pressure of 2.5 bar. Instead of a tire with a certain index, a tire of the same type with a higher index can and may be used.
At speeds over 210 km / h (for tires with V- speed index ), 240 km / h (for tires with W-speed index or also with the ZR label) or 270 km / h (for tires with Y-speed index) the permissible The load depends on the speed. For example, a tire with a V speed index at its maximum speed of 240 km / h may only be loaded with 91% of the maximum load corresponding to its load index.
Two load indices indicate truck and van tires. The first number indicates the load capacity for single tires, the second for twin tires.
PR number
The designation PR stands for ply rating and is a code for the load capacity of different versions of a tire size with regard to their substructure. It used to correspond to the number of carcass layers, more precisely the number of layers of cotton cord in the substructure. The indication "8 PR" means: "The tire can be loaded like a tire with 8 layers of cotton cord in the substructure, regardless of how many layers of another type of cord are present in the substructure." A direct indication of the load capacity can be found in the PR -Number cannot be derived. This can be seen from the fact that different tire sizes with the same PR number do not have the same load capacity.
Today the PR number can only be found sporadically on C-tires (light truck tires, many of which are available in different load-carrying capacities) and on tires with a diagonal construction . "The tire load capacity is always to be seen in combination with the speeds driven [...]. The tire or vehicle dealer can be asked for details. ”Some sales organizations of tire manufacturers publish technical guides for certain types of tires, in which a tire model-specific table is printed for certain tires with a PR number, from which the respective load capacity of this particular tire model is printed with different Air pressures and speeds can be read, possibly supplemented by certain load-related restrictions. In the standards book of the ETRTO (European Tire and Rim Technical Organization) all tables for the load index and PR numbers are available.
The load index (LI) has prevailed for specifying the load-bearing capacity.
See also
Individual evidence
- ↑ The identification of the car tire. Guide to the designations in the vehicle registration document and on the tire wall. In: www. adac.de . ADAC eV, accessed on October 28, 2018 (point 2e).
- ^ A b c Max Bohner, Wolfgang Keil, Siegfried Leyer, Wolfram Pichler, Wolfgang Saier, Harro Schmidt, Paul Siegmayer, Heinz Zwickel: Book of tables for motor vehicle technology. Tables, formulas, overviews, standards. Mathematics, basic knowledge, specialist knowledge of automotive technology, materials science, drawing, standard parts (= European reference book series for automotive technology .). 10th edition. Verlag Europa-Lehrmittel, Nourney, Vollmer GmbH & Co., Haan-Gruiten 1994, ISBN 3-8085-2070-1 , p. 228 (Head of the working group and editing: Rolf Gscheidle).
- ↑ a b The identification of the car tire. Guide to the designations in the vehicle registration document and on the tire wall. In: www. adac.de . ADAC eV, accessed on October 21, 2018 (point 2, sub-item “C tires for light trucks and off-road vehicles”).
- ↑ For example, the technical guide contains agricultural tires. 2008/2009. of CGS Reifen Deutschland GmbH (Hanover 2007. Online in: www.adk.bg. АДК - Адимекс и Кондев ООД (ADK - Adimex & Kondev LTD), accessed on October 28, 2018 (PDF; 3.11 MB)) - next the explanation of the tire designation PR on page 6 - for the individual tire sizes of a certain tire model, which is a bias-ply tire, such tables on pages 58-61. Supplemented by a footnote with the restrictive condition that the values for 30 km / h apply for field use with continuous, high torques.
Web links
- GTUE-Informative - Type-approved tires are also permitted with a lower speed and load index under certain conditions (PDF; 624 KB)