Why should expensive scooters use A95 gasoline?

According to experts, the numbers 92 and 95 are the RON cctan value, indicating the anti-knock ability of gasoline. The higher the cctan value, the better the anti-knock ability and vice versa. With E5 gasoline, because the octane value of ethanol is 109, when mixed with A92 gasoline, it will increase the octane value of this mixture by 1 to 2 units, so E5 gasoline has an octane value equivalent to A93 - A94.

Knock is the phenomenon of detonation too early compared to the appropriate explosion time due to the spark plug, occurring at the end of the compression stroke. If it occurs frequently, this phenomenon causes the machine parts to overload, facing the risk of deformation, warping or breaking. Knock causes the engine to heat up, power is reduced, the car runs sluggishly, and a knocking sound is emitted from the engine area...

According to expert research, each type of engine has a different compression ratio (ratio between total volume and combustion chamber volume of the engine cylinder), so the appropriate octane index should be selected. For engines with a compression ratio greater than 9:1, RON 95 gasoline should be used and vice versa.

However, based on actual conditions, manufacturers recommend that vehicles with a compression ratio of over 10:1 should use A95 gasoline. As for A92 gasoline, motorbikes with a compression ratio of 7:1 to 10:1 can operate smoothly.

Currently in the motorcycle market, manufacturers are increasingly improving the quality of designs as well as engine technology. Therefore, engines with compression ratios below 10:1 are becoming increasingly rare and are only found in most manual transmission models. Scooter models almost all have compression ratios greater than 10:1. Therefore, it is recommended that these vehicles use A95 gasoline.