Traction Four Wheel Drive vs. Front Wheel Assist

[DavidAubke]

What is the difference between "four wheel drive" and "front wheel assist"? I understand that my BX2350 features the latter but I don't know what that means to me in practical terms.

From doing a little web and TBN searching, the best I can come up with is that "FWA" just refers to the fact that the front wheels are smaller than the rears. I've seen some forum posters caution that confusing the two systems can lead to front drivetrain damage - that FWA is a light-duty variation of FWD and that we should be careful how we use it. The only way I've been able to put that advice to use is to fret over using tire chains on my front tires on dry ground.

 

[bikerdib]

I'm not sure but it could be because tractors usually don't have true 4X4. Only one front wheel will pull. You'd need a limited slip (or positive track) type differential on the front to have four wheel drive.

 

[MarkV]

The terms tend to used interchangeably here on the forum. A true 4 wheel drive tractor will have the same size tires on the front and back. Normally only see them in big Ag applications.

MarkV

 

[PHILIP8N]

I'm not sure but it could be because tractors usually don't have true 4X4. Only one front wheel will pull. You'd need a limited slip (or positive track) type differential on the front to have four wheel drive.

Which front wheel pulls your tractor? Left or right? My F250 has true 4x4 and has an open diff in the front. Both front wheels pull on my Kubota and F250. Sometimes one wheel has less traction than the other wheel, the one wheel with less traction spins faster than the one wheel with the most traction, hence, the operation of the differential, makes it easier to steer too. I have not seen very many factory limited-slip front diffs, been years. Some off-roaders add front limited slips, or air lockers, or electric lockers. You only notice the lack of both wheels being powered on an axle (front or rear) when one of the wheels is limited by traction. The wheel with the less traction spins faster. A limited slip (positraction) slows this process down and sends a percentage of the power to the wheel with the most traction, but it is limited, as the name implies. A locker, well, locks the axles together mechanically, just like the rear axle on your Kubota. This can be done mechanically, like your Kubota with a heel pedal, with air, or by electrics. It can also be done mechanically like the old Detroit lockers (click, click, click around corners). Philip.

 

[samofsweden]

What is the difference between "four wheel drive" and "front wheel assist"? I understand that my BX2350 features the latter but I don't know what that means to me in practical terms.

From doing a little web and TBN searching, the best I can come up with is that "FWA" just refers to the fact that the front wheels are smaller than the rears. I've seen some forum posters caution that confusing the two systems can lead to front drivetrain damage - that FWA is a light-duty variation of FWD and that we should be careful how we use it. The only way I've been able to put that advice to use is to fret over using tire chains on my front tires on dry ground.

Hi. I would say "a front wheel assist" is an hydralic support, front wheels have hydralic motors, which help u when you got stuck. "Four wheel drive" is more of a permanent solution.

 

[RobertN]

True 4WD would be lockers front and rear, ie a spool.

It is impossible for your F250 to have both an open diff, AND full 4WD; that is a diametrically opposed statement. It is certianly possible that in some slippery situations, both front or both rear tires will turn. But that is not "true" 4WD. My Ram 2500 does that too; it has a limited slip in the rear diff, open front.

Which front wheel pulls your tractor? Left or right? My F250 has true 4x4 and has an open diff in the front. Both front wheels pull on my Kubota and F250. Sometimes one wheel has less traction than the other wheel, the one wheel with less traction spins faster than the one wheel with the most traction, hence, the operation of the differential, makes it easier to steer too.

 

[PHILIP8N]

True 4WD would be lockers front and rear, ie a spool. It is impossible for your F250 to have both an open diff, AND full 4WD; that is a diametrically opposed statement.

I respectfully disagree. When I lock in 4WD, and I am on pavement, and no tires are slipping, all 4 tires are providing power to the ground. That is 4WD. If one front tire is on an ice patch, and the other front tire is not spinning, there is still a small amount of gear torque being applied to the non spinning tire (a clutch or cone in a l/s diff would transfer more torque to the non spinning tire). At that point and time, I still have 4WD, it just happens that I cannot put power to all 4 tires due to the traction bias differential. Are you saying that all manufacturers of 4WD trucks with open front diffs are mis-advertising? Philip.

 

[arrabil]

My F250 has true 4x4 and has an open diff in the front.

I think he is trying to say that your F250 isn't true 4x4 either. And by his definition it is not. I've always been on the fence about it. "True" 4x4 requires lockers front and rear. But your F250 is a 4x4 too. So....

 

[funwithahoe]

Honestly, I wish an engineering group would define these terms and post them to a board where no one could disagree with them and the companies had to use the exact terms without misleading.

A 4X4 means all 4 wheels have the potential to pull but generally only one front and one back at a time - Otherwise why need a diff lock on your tractor? No more than one front pulls unless some after market engineering has been applied.

Nonetheless, I understand all the confusion - Why would anyone think 4X4 was anything less than all 4 wheels pulling?

These are terms men feel pasionately about! I have seen guys in a bar just about get into a fist fight over whether or not their front wheel pulls when they have there switcha-magig pulled in or whatever.:thumbsup: I decided it is best to just agree with them!

 

[DavidAubke]

Sooo... I shouldn't worry about overworking my "front wheel assist" drivetrain? It's called "front wheel assist" and not "four wheel drive" solely because the wheels are smaller in diameter than the rears?

I'm clear on the functionality of open, limited-slip and locking differentials. My experience is that they're all called 4x4 and that if you want to be more specific you've just got to add "... with a limited-slip differential" or "... with lockers".