All quality modern tires have a directional rotation. Yes, I know you're now thinking 'I know that', but if you check some motorcycles parked at the parking of your local supermarket you start to see the problem. Many tire designs are also specifically for front or rear fitment, not both. This is crucial in braking, since the front tire has pushing forces applied while the rear has pulling forces. Acceleration applies a forward torque to the rear wheel while the front is along for the ride. Hence, one reason rear tires cost most of the time more is because there are additional performance requirements and wear factors.
Misaligned motorcycle components, such as wheels improperly installed, are a common cause of vibration and other maladies. It's difficult for me to understand why I sometimes see motorcycles with a front tire on the rear or vice versa since the front and rear tread patterns are usually so different. Much more common are tires installed backward. This is due to plain ignorance or a mechanic asleep at the wheel, so to speak. The raised directional arrow would allow a blind man to change a tire. The arrow direction must be the same as the wheel's rotating on the motorcycle.
I remember a now-defunct tire manufacturer that was the flavor of the day a few decades ago. The molded, directional arrows on the tire sidewalls were backward. Small chunks began to fly off the rear tires followed by larger pieces roughly measuring up to 12cm square. The manufacturer quickly corrected the mistake as the complaints flooded in, but these tires disappeared as quickly as their introduction because of consumer fears. I cut tires in half when we find one installed rotationally backward. I want to ensure that re-installation of a potentially dangerous tire by a frugal, but ignorant, rider is not possible.
Proper tire inflation is another big problem in Thailand since many, if not most, tires are inflated incorrectly. Over-inflation or under-inflation will cause rapid wear and adverse handling characteristics, including vibration. Check your owner's manual supplied with a new motorcycle or the tire manufacturers information for the correct inflation for a particular motorcycle and tire fitment. Never exceed the maximum tire pressure. The maximum tire pressure figure is molded into the tire sidewall In fact, find all the pertinent tire information by reading the specifications molded into the tire sidewall. Inflate tires when cold. Cold mean the tires are at ambient temperature and not up to operating temperatures from riding any distance. The reason for this that air expands with heat, increasing the tire pressure.
Fill performance tires with nitrogen which has qualities that make it an excellent substitute for air. The first is that it neither expands nor contracts with temperature changes. Therefore, tires stay at correct tire pressure, no matter the temperature. The secon advantage is that, unlike air, nitrogen does not have water as a component. Condensation will not form inside nitrogen-filled tires, rusting out steel rims and spokes, and oxidized alloy rims. Air is prone to leakage, especially with magnesium-alloy wheels. Nitrogen, while it can leak, is less likely to do so. The one downside is that air is free while nitrogen is not.
Not much motorcycle shops carry nitrogen, but car performance shops and medical supply houses are a likely source. Many race cars and race motorcycles of type use nitrogen for safety and tire-pressure consistency.