Is it any difference between Highlander 2WD and 4WD if driving on the flat road or snowy road?

Question

My friend told me it is only making difference if driving on the mountain road that 4WD wins over 2WD, otherwise, it is exaclty that same. plus 4WD eats more gas than 2WD even drving on flat road. Is it correct?

Answer 1

A 4WD will help you in all adverse conditions whether it is a hill or a flat road.  4WD is so much better if there is chance you will be driving in bad weather.  It causes all four of your tires to move at the same time in the same direction and reduces your chances of spinning our or fish taling.

Answer 2

Hi,

actually, no, there is much more to this than just the 2WD/4WD mountain road idea. Stay with me and I'll give you the full answer.

With all Toyota SUVs, there is a system called STAR that incorporates Vehicle Stability Control, all-speed Traction Control, four-channel ABS, Electronic Brake Force Distribution, and Brake Assist in one system.

The STAR system is on 2WD and 4WD Highlanders.

What the STAR system does is:

1. Stability Control- cancel out/lessen the steering input, accelerator input and even braking input because the vehicle is sliding

2. Traction Control- brake each wheel independently of the others, for example, the ABS system will brake only the front passenger wheel or that wheel and the driver's rear wheel if they lose traction (four-channel ABS)

3. Electronic Brake Force Distribution- the braking force can be shifted front to back, side to side, or diagonally across the axles to brake wherever the pressure is needed

4. Brake Assist- in a panic stop, full braking force will continue to be applied if the driver pulls their foot off the brake pedal in anticipation of an accident (driver presses 100% then nervously pulls back to 60%, Brake Assist continues to press at 100% until the accelerator or brake is pressed again)

These four systems are above the 4WD system. STAR comes into play whenever the vehicle's sensors (steering, braking, accelerator, yaw, pitch) detect that the vehicle is no longer moving in a straight line or in a controlled curve.

In other words, if you were going too fast on an off-ramp to an expressway and you hit a bit of sand or snow going around that curve. Instead of sliding off the ramp into the ditch, STAR would cancel out the accelerator input, moderate the brake if you stomped it too hard, cancel or lessen the steering input if you tried to steer into the slide too much and do whatever it could to try and bring you back into a correct curve. And it reacts and works before you can even take your foot off the accelerator.

Now, STAR bends the laws of physics, it doesn't break them. So if you wanted to dump your Highlander into the ditch, you can still do it.

As I said, these are all independent of 4WD, but the two systems do work together.

What about the mileage question? If it is a standard, non-hybrid Highlander then yes, you do lose 1-2 mpg on the 4WD because of the extra weight of the rear 4WD gearbox.

On the Highlander Hybrid, there is no difference in mileage between the 2WD and 4WD because the rear electric motor for the 4WD system turns on and off instantly only when the front wheels slip on snow, ice, sand water, etc. So a 4WD Highlander Hybrid rolls as a 2WD for most of the time.

So, the main thing is the STAR system, which they all have. 4WD is really a personal preference or a desired if you live where the weather is not always 70 degrees and sunny with no rain, dirt or snow.

This is not like 4WD on a truck or 4WD systems of the past.

Answer 3

Being a mechanical device, the differential abides by the laws of physics which state that energy always takes the easiest route. So, if one wheel is on a slippery surface (like ice) then all the energy will be sent to that wheel and away from the wheel with traction. The end result is that you lose all forward motion!

When four-wheel drive mode is engaged, the front and rear axles are locked together, so at least one wheel on each axle can be driven by the engine effectively.

You can force a 4x2 vehicle to act similar to a 4x4 on occasion by gently pressing the brake pedal to slow down the wheel that's spinning and transfer energy to the wheel with traction.