Normal load или Extra load переводится как "Стандартная нагрузка" или "Дополнительная нагрузка" на русский не требуется, а на английский: Standard load или Reinforced load

Which tires to choose - "NORMAL LOAD" or "EXTRA LOAD"?

The "XL" marking can be found quite often, while NL is simply not indicated on the sidewall. Nevertheless, this term exists in tire slang. Is it worth overpaying for tires with the "XL" marking?

Despite the loud name "EXTRA LOAD", a tire with this marking has only a higher load index, and that's all by 3 points or 75 kg. If you are faced with a choice - which tires to take, then there is no need to endow them with special strength, because a larger carrying capacity can be achieved in different ways and not always coincide with the same methods by which the tire is endowed with greater strength.

Let's start, of course, with what load index is recommended for your tires by the car manufacturer. If tires with a standard index are suitable, then there is no point in overpaying...