2025.09.21 – Load Index, Speed Index, Tyre Markings

Summary

The subject addresses tyre specifications through the concepts of load index, speed index, and practical tyre marking interpretation. The information is relevant for understanding tyre safety, vehicle compatibility, and professional tyre assessment.

Context and Scope

The scope covers three factual areas: numerical data for tyre load index, numerical data for tyre speed index, and a sample tyre marking with its components explained. These elements collectively describe the technical aspects of tyre specifications.

Exhaustive Narrative of Facts

Load Index Data

Load index numbers range from 70 to 120, with each index corresponding to a tyre load capacity in kilograms. For example, index 70 equals 335 kg, index 75 equals 387 kg, index 80 equals 450 kg, index 85 equals 515 kg, index 90 equals 600 kg, index 95 equals 690 kg, index 100 equals 800 kg, index 105 equals 925 kg, index 110 equals 1060 kg, index 115 equals 1215 kg, and index 120 equals 1400 kg. The terminology is presented as “BELASTINGSINDEX” with “DRAAGVERMOGEN PER BAND IN KG.”

Speed Index Data

The speed index is introduced as “SPEED INDEX” and “SNELHEIDSINDEX.” It lists maximum speeds in km/h for different codes. N corresponds to 140 km/h, Q to 160 km/h, R to 170 km/h, S to 180 km/h, T to 190 km/h, H to 210 km/h, V to 240 km/h, W to 270 km/h, Y to 300 km/h, ZR(Y) to 300+, and ZR to more than 240 km/h.

Tyre Marking Example

The tyre marking 235/35 R19 91Y is used as an example. The number 235 indicates tyre width in millimeters. The number 35 indicates the aspect ratio, representing height as a percentage of width. The letter R denotes radial construction. The number 19 indicates the rim diameter in inches. The number 91 is the load index, corresponding to 615 kg per tyre according to the load index data. The letter Y is the speed index, corresponding to a maximum speed of 300 km/h.

Practical Takeaways

• Tyre load index numbers correspond directly to maximum supported kilograms, with higher numbers meaning greater capacity.
• Tyre speed index letters denote maximum safe driving speeds.
• Example marking 235/35 R19 91Y shows how width, aspect ratio, construction, rim diameter, load index, and speed index are encoded.