
Tire speed ratings are represented by letters E, F, G, J, K, L, M, N, P, Q, S, T, U, H, V, W, Y, and Z, indicating maximum speeds of 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 240, 270, and 300 kilometers per hour respectively. Higher speed-rated tires generally have poorer wear resistance and shorter service life. This is because tires with higher speed ratings use softer materials, resulting in significantly reduced friction resistance during driving.

After driving for so many years, I always keep an eye on the tachometer located on the dashboard in front of the driver's seat, usually positioned on the far left or in the middle. The combination of numbers and a needle clearly displays the current RPM. When starting the engine or accelerating, I habitually glance at it to maintain the optimal fuel-saving range between 2000 and 3000 RPM. For manual transmission cars, if the RPM drops below 1000 during gear shifts, it signals me to upshift. During routine car washes or maintenance, I also check to ensure the tachometer is functioning properly. If the needle stops moving, I first check the fuse or the dashboard power supply to prevent the issue from escalating into engine damage. Nowadays, some cars even project the tachometer onto the windshield via HUD for convenience during high-speed driving, or use a mobile app to monitor RPM in real-time through the OBD interface, which is quite practical for remote viewing—just remember to update the software regularly. In short, remembering its location isn't hard, and developing this habit can extend your car's lifespan.

As an enthusiast of automotive technology, I particularly enjoy the digital instrument clusters in new car models, where the RPM is displayed directly on the central control screen, and sometimes even allows for customization of colors and layouts. When driving, I monitor RPM changes through the smart interface. Maintaining around 2500 RPM on the highway ensures efficient fuel usage. Older models might only have analog needles, while new cars like Tesla feature touchscreen systems that also integrate data logging. I installed a small OBD scanner in my car, and by connecting it to a phone app, I can get real-time readings, especially useful when remotely starting the car to check if the RPM is normal. When sharing tips with friends, I remind them to check for significant RPM fluctuations after modifications like car audio upgrades to avoid engine overload. During maintenance chats, we often discuss how digital displays are more precise than analog needles, though mechanical gauges are still reliable.

Thinking back to the days of driving old-fashioned cars, the tachometer was just a simple needle dial displayed prominently in the center of the dashboard. After starting the engine, the needle would wobble noticeably, and the loud noise at high RPMs reminded me to slow down. Nowadays, new cars feature full-color screens with a high-tech feel, but the position remains unchanged, always in front of the steering wheel. During daily driving, I pay extra attention to keeping the RPM around 2500 to avoid prolonged idling and wasting fuel. For manual transmission cars, I shift gears by listening to the engine sound while keeping an eye on the gauge. Occasionally, when it rains or there's a lot of dust, the tachometer becomes blurry, prompting me to stop and check the wiring connections to ensure accuracy. Sharing a fun maintenance story, the sensor in my old car once failed, causing the needle to jump erratically, leaving me to guess the RPM by feel. A reminder for beginners: don’t overlook the small warning lights on the simple gauges of older cars.


