What is Full-Time Four-Wheel Drive?
3 Answers
Full-time four-wheel drive means that at all times, the vehicle is independently driven by all four wheels. In English, it is abbreviated as "AWD" (All-Wheel Drive) to distinguish it from 2WD (which includes FWD and RWD). Full-time four-wheel drive distributes driving force to all four tires through a flexibly connected central differential, and then via independent differentials on the front and rear axles. Unlike purely mechanical differential locks, the differential in full-time four-wheel drive can be either a viscous coupling or a multi-clutch type, but both allow for a speed difference between the front and rear wheels, as well as between the left and right wheels. Whether a vehicle has full-time four-wheel drive depends entirely on the construction of the transfer case. Below is relevant information: Disadvantages: It only starts transferring power to non-slipping tires after detecting slippage in a particular tire, which means the response can be slower. More importantly, these viscous or electronic differentials cannot completely lock the power distribution at 50:50 like a mechanical differential lock. Because of this, full-time four-wheel drive is often dismissed by hardcore off-road enthusiasts as "fake off-roading," unable to match the capabilities of part-time four-wheel drive in extreme conditions like climbing mountains or fording rivers. Advantages: Theoretically, it is the ideal driving method for vehicles, providing better tire grip, more effortless high-speed cornering, and easier handling, thereby enhancing both safety and performance. Since power is always distributed to all four wheels, when one wheel begins to slip, the system automatically intervenes to redistribute power to ensure optimal traction at all times. This system offers significant handling advantages on slippery surfaces. As a result, more and more SUVs and sedans adopt full-time four-wheel drive not just for off-roading but for the stability and active safety it provides, especially in high-performance cars. Section: Excellence and Safety
All-wheel drive (AWD) means that no matter if it's sunny, rainy, or snowy, all four wheels are constantly working to propel the car forward. The most noticeable feeling when driving this type of vehicle is its exceptional stability on slippery roads—the steering wheel responds instantly with just a light touch, and tires rarely slip even during high-speed cornering. With my old two-wheel-drive car, I’d often get stuck in muddy terrain, but now I can plow through without hesitation. However, I should warn you: this system does consume more fuel—urban commuting can see about 15% higher fuel consumption compared to regular cars. Maintenance costs are also steeper, requiring more frequent checks on components like the transmission and differentials. But if you frequently drive on mountain roads or live in snowy regions, AWD can literally be a lifesaver!
Simply put, full-time four-wheel drive means the engine's power is always distributed to all four wheels simultaneously. Unlike automatic four-wheel drive that only engages the rear wheels when slippage occurs, or part-time four-wheel drive that requires manual mode switching. I particularly love its performance in daily driving—exceptional tire grip when taking rainy ramp turns, no wheel spin when starting on snowy slopes, and rock-solid stability on muddy roads like walking on nails. However, be aware that prolonged use increases drivetrain wear and shortens tire lifespan. Budget-wise, allocate about 30,000 yuan extra, with fuel consumption increasing by at least 2 liters per 100 km. But the safety it provides is absolutely worth the price.
