Little by little we keep moving forward with the acronyms and nomenclatures that appear on the walls of our Continental tires.
This time we are going to pay attention to the “load capacity index” and the symbol for the speed category, which are the same as the numbers and the letter that come after the tire size and are always together with or without parenthesis.
In this picture, after the size (130/70-12) and the abbreviationof the kind of tire (M/C= MotorCycle), we can see 62L. “62” is the load capacity index and “L” is the symbol of the speed category.
What is the reason for that number? In this case “62”, refers to a table that designates the load or weight that a working tire can stand up to.
The table is based on to columns. The ICG one, shows the index “62” that we see on the tire. In the next column the “Mass or maximum weight in pounds is indicated.
In this case, the tire can stand up to 584 lbs. as long as it doesn’t exceed the specified maximum speed which is indicated by the letter “L” and corresponds to symbol of the speed category.
Therefore, the “L” says that in this case the tire can’t exceed 120km/h. If we went faster, for each kilometer per hour over 75 mph, the tire capacity would diminish below 584 lbs. The size of the tires is directly related to the load capacity index. In the case that the index is higher than the one for that size it is mandatory by law to be marked on the side of the tire as “Reinf”, Reinforced or RFD. In this case “62” is above the normal index which is 56. As you can see, this tire can withstand more load than what it normally would have been able to handle.
As we have already said, a tire looses load capacity if it goes over the maximum speed allowance of the speed symbol.
In the big sizes, we find a paradox. Previously they were marked with 120/70ZR17 or190/50ZR17. In that case the speed symbol was “Z” and indicated that the tires could go faster than 150 mph with no limit!! That was impossible, because even though some crazy human being invented a machine that could go up to 300 mph, do you think that the tires would have stood up to such speeds?
That’s why the regulatory agencies for tires and rims (they are different in each country), decided to limit the maximum speed. They decided to keep the “Z” and set the speed limit with the symbol “W” which is up to 168 mph. For example: 190/50ZR17 (73W).
But now, there is another paradox. There are some motorcycles that can reach up to 185 mph or more, as is the case of the Suzuki Hayabusa GSXR1300 (This is just an example but not an advertisement for any particular brand or model.) If we say that the speed limit for the tires is 168 mphand the motorcycle can go more than 185 mph, will the tires explode? Will they disintegrate? Let’s see.
This motorcycle uses the tire sizes 120/70ZR17 (58W) and190/70ZR17 (73W). The front tire can support 58=520 lbs. and the rear tire 73=804 lbs. Both tires can support up to 1324 lbs. The weight of the motorcycle in motion is about 551 lbs. Let’s suppose that the driver weighs 176 lbs. 551 lbs. +176 lbs. = 727 lbs. total weight while riding.
If the motorcycle traveled at a speed of 168 mph (don’t even consider this on the highway) the tire would support up to 1324 lbs. according to the load capacity index. But imagine that it reached 185 mph. According to the regulations, for each 6 mph over the load capacity limit, it would decrease 10%. Therefore if the motorcycle reached 185 mph, it would lose about 30% of its load capacity as can be seen in the following table.
In summary, the tires of a motorcycle riding at 185 mphwould withstand about 926 lbs. The motorcycle weighs 727 lbs., which means that there would be a remaining margin and no problem would occur because of the tires.
Anyway we would have to keep in mind the time that we could maintain that constant speed, which would not be much.
We hope you have liked this topic, and that you have learned a little bit more about our motorcycle tires.
