The load index 91 corresponds to a maximum capacity per tire that is different from the index 94, and this difference of a few dozen kilograms per wheel changes the game for a loaded vehicle. The speed code V remains the same in both cases, which means that the distinction is exclusively about the permissible weight, not about high-speed dynamic performance.
Load index 91 vs 94: how the internal structure of the tire changes
A tire with index 91 supports a maximum load per unit that is lower than that of a tire with index 94. Over four wheels, the cumulative gap represents several hundred kilograms of additional load capacity in favor of the 94.
This difference does not come from a simple marking. It reflects a reinforcement of the casing: additional layers, stiffer sidewalls, sometimes a reinforced bead. The 94 tire can withstand more vertical stresses without excessive deformation of the sidewall under load.
We observe that this structural reinforcement has a direct effect on road behavior. A 94 tire offers less lateral deformation in corners under load, which improves the directional precision of a heavily loaded vehicle. Conversely, the ride comfort when empty may be slightly firmer, as the sidewall is less flexible.
To fully understand the difference between tire 91v and 94v, one must think in terms of the actual weight of the vehicle under usage conditions, not just the manufacturer’s empty weight.
Tire 91V or 94V: impact on hybrid vehicles and recent SUVs
Compact sedans and next-generation SUVs carry a significant overweight compared to models from a few years ago. Hybrid motorization batteries, active safety equipment, large diameter wheels: all of this adds weight to the vehicle.
Manufacturers are increasingly directing recommendations towards index 94 and beyond, where index 91 was previously sufficient. This shift is not arbitrary. It reflects the increase in the maximum authorized weight (PTAC) of these vehicles.
A compact plug-in hybrid SUV with five passengers and a full trunk can easily exceed the load capacity allowed by index 91 with a comfortable safety margin. Fitting a 94V tire in this case is not a luxury; it is a coherent sizing.
- Check the actual PTAC of your vehicle on the registration document (field F2), not just the empty weight
- Consult the manufacturer’s plate on the driver’s door: it indicates the minimum approved load index
- If your vehicle is a hybrid or a recent model with 17-inch wheels or larger, index 94 is likely the original recommendation
Regulatory consequences: Mountain law and 3PMSF marking
The load index can no longer be considered in isolation in areas subject to the Mountain law. Since November 1, 2024, a tire correctly sized for load (91V or 94V) but only bearing the M+S marking is no longer recognized as compliant winter equipment. The 3PMSF pictogram (the snowflake and mountain symbol) is now mandatory.
This means that a driver choosing between a 91V and a 94V to drive in mountainous areas must check two criteria simultaneously: the load index suitable for their vehicle and the presence of the 3PMSF marking. A 94V tire without 3PMSF will not be compliant in regulated areas, regardless of its load index.
We recommend treating these two parameters as an inseparable pair when purchasing, especially for heavy vehicles that require index 94 and regularly operate at altitude.
When to fit a higher load index than the manufacturer’s recommendation
Fitting a tire with a higher load index than that recommended by the manufacturer is allowed. Fitting a lower index is not. This simple rule is often misunderstood.
A vehicle approved for 91V can receive 94V tires without any regulatory or technical issues. The reverse, however, constitutes under-sizing that can lead to premature wear, a risk of blowout under load, and refusal at technical inspection.
Three situations concretely justify the transition from 91 to 94:
- Vehicle regularly loaded to full capacity (large family, transport of professional equipment)
- Towing a trailer or caravan, even occasionally, which puts more stress on the rear tires
- Replacing tires on a model whose current version now recommends 94, indicating that the manufacturer has reassessed the permissible load
Tire pressure and load index: the often-overlooked parameter
The load capacity indicated by the index (91 or 94) corresponds to a nominal inflation pressure. A 94V tire inflated below the recommended pressure will not carry the maximum load advertised. It will behave, in practice, like a lower index tire.
Adjusting the pressure to the actual load of the vehicle is as crucial as the choice of the index itself. Manufacturers generally provide two pressure values: one for normal use and one for a loaded vehicle. This second value is what allows the tire to reach its maximum load capacity.
A correctly inflated 94V tire on a loaded vehicle offers a safety margin that the 91 index cannot provide under the same conditions, even with adjusted pressure. The choice of index and adherence to pressure work together, not one without the other.
Transitioning from index 91 to index 94 represents a marginal investment at purchase for a real gain in safety and tire longevity under stress. On a modern, loaded, or hybrid vehicle, the 94V is not an upgrade; it is the appropriate sizing.
