Index LI – What the Load Index on the Tire Sidewall Says About Load Capacity
There are several designations for the load capacity of a vehicle tire. In addition to the abbreviation LI for Load Index, the English variant Loadindex as well as the terms Load Capacity Index or Load Rating Index are also common. Regardless of the designation, it always refers to the same key figure: It indicates the maximum weight for which a single tire is approved.
As an established tire supplier, Interpneu AG deals with these technical specifications daily and ensures that the appropriate and permissible tires are available for every vehicle.
Where can the load capacity of a tire be read?
The actual load capacity of a tire is indicated directly on the tire sidewall. There you will find it along with other important information such as tire size, speed index, and DOT number for determining the tire's age.
Load index on tires and in the vehicle registration certificate
The load index is essentially relevant in two places: directly on the tire itself and in the vehicle registration certificate. Both specifications must match.
The load index explained simply – using a tire designation example
In the exemplary tire designation 245/50 R19 105W, the number 105 stands for the tire's load capacity. This load index corresponds to a maximum load capacity of 925 kg per tire.
This is the actual load capacity of the mounted tire. The subsequent letter W indicates the speed index.
Based on the information in the vehicle registration certificate – for example, for compact or mid-range vehicles – it is possible to determine which load capacity is prescribed for the respective vehicle axle.
The load index entered in the vehicle registration certificate may be exceeded by the mounted tires, but must never be undershot. Vehicles that, for example, require an LI 92 may not be operated with tires of LI 87.
Table instead of calculator: The load index at a glance
The load index is deliberately regulated in a complex way because it is directly safety-relevant. The correct tires play a decisive role in driving stability and load-bearing capacity.
Although the load index is not intuitively structured, a load index table allows all relevant load capacity values to be assigned quickly and clearly.
Structure and meaning of load capacity classes
The load index is a numerical standard designation with two- or three-digit numerical values. The index starts at 20 and ends at 204. These numbers do not directly indicate the weight but serve as placeholders for a precisely defined kilogram value.
The lowest load index 20 corresponds to a load capacity of 80 kg, while the highest index 204 allows a load of 16,000 kg. However, these extreme values play no role in everyday passenger car use. LI 20 is used, for example, for very light mopeds, while LI 204 is intended for the heaviest commercial vehicles.
Relationship between LI number and kilogram value
The load index increases in single steps from 20 to 204, resulting in a total of 184 different load capacity levels. However, the weight increase per index step is not constant.
From LI 20 (80 kg) to LI 28 (100 kg), the difference is 2.5 kg per step. Between LI 28 and LI 35, the load capacity increases in 3 kg steps, up to LI 40 in 4 kg steps. As the load index increases, the differences become larger and larger.
In the upper range of the load index table, a single index step can even make a difference of up to 550 kg.
Relevant load index range for passenger cars, vans, and motorcycles
Typical passenger car, SUV, and van tires fall within a load index range of 50 to 130. This corresponds to a load capacity of approximately 190 to 1,900 kg per tire.
Motorcycle tires typically range from LI 30 to LI 90 and can therefore carry approximately 100 to 600 kg.
Special features and influencing factors for load capacity
The load index is standardized worldwide, but there are aspects that need to be considered. Tires react differently to factors such as tire size, air pressure, temperature, and speed.
Deviations from the prescribed load index
In principle, it is permissible to use tires with a higher load index than prescribed in the vehicle registration certificate. The same applies to the speed index.
As long as all other tire properties meet the requirements, it is irrelevant whether the load index exactly matches the required value or exceeds it.
However, falling below the prescribed load index is not permitted – for both the load and speed indexes.
Load index and speed index: Observe load reduction
Immediately after the load index, the speed index always follows, e.g., 102V. This tire is designed for 850 kg load capacity and a maximum speed of 240 km/h.
At high speeds, the permissible load capacity is reduced. At 240 km/h, a tire with LI 102 may only carry approximately 91% of its original load capacity.
This reduction rule applies to all tires from speed index V (240 km/h) and higher. The maximum reduction is 15%.
Reinforced tires: XL, C, Reinforced, and other markings
XL / Extra Load / Reinforced
XL or Reinforced tires have a reinforced construction and can carry more load at higher air pressure. For each additional load index, the air pressure should be increased by approximately 0.1 bar.
C-Tires for Vans
C-tires (Cargo or Commercial) are designed for use on light commercial vehicles and are engineered for high continuous loads.
CP Tires for Motorhomes
CP tires are specially developed for motorhomes and are designed for high loads, long standing times, and difficult surfaces.
Relationship between load index, air pressure, and temperature
The load capacity of a tire largely depends on the correct air pressure. Deviations can negatively affect safety, wear, and efficiency.
Temperature fluctuations also affect tire pressure. Cold temperatures lower it, strong heating increases it.
Dual marking for single and twin tires
For certain vans, tires with dual marking are used, e.g., 98/96H. The higher value applies to single tires, the lower value to twin tires.
Concluding example calculation
- Axle load: 1,100 kg
- Load capacity per tire: 550 kg
- Required load index: at least LI 88 (560 kg)
A lower load index is impermissible – however, there is flexibility upwards.