4 wheel drive all the time? or just when needed

   / 4 wheel drive all the time? or just when needed #81  
If your rear wheels aren’t on the ground, you have other problems besides braking.
 
   / 4 wheel drive all the time? or just when needed #83  
I mean, that totally happened to me the very first time I used my tractor, actually. The dude who sold it delivered it, helped me drop of the backhoe, and left. I decided to break my cherry by moving some heavy stuff with the loader out of my garage to my sloping backyard.

I did everything wrong there, loaded up the bucket, didn't have the hoe on as counterbalance, and was in 2wd. Had the bucket kind of high too.

I got past the gate and away the tractor took off down the hill. Woops, no brakes coz the tractor is front-heavy. I came to a stop by steering it off to the side...what a bonehead! Lucky lucky lucky I was, it coulda been so bad on so many levels. I woulda never lived that down with my wife lol, flipping the tractor at 1st use, that woulda sucked!

So yeh, there's definitely a time to use 4wd when going down hills. BUT...that doesn't mean you always need to use 4wd when going down hills. There's a time when you need 4wd, times when you don't. Using it all the time is just needless wear, but hey, your choice if you wanna spend $$ on preventable repairs.
 
   / 4 wheel drive all the time? or just when needed #84  
"Do set up a video and let us see you do that with forks and a machine out front while you are in a uncontrolled slide. I'd be interested learning how one has the presence of mind to slowly lower the FEL. The slide was over in what 30 seconds?"

One of the many things I have learned in life is that after you make your first stupid mistake you should plan out your actions for when you do it again. In my case the hill I was on was long and grass covered so I was able to lower the pallet full of wood to the point where it touched ground. Did I tear up the grass? Hell yes. Did I tear up the tractor? Hell no. If I had been smart enough to put it in 4wd before I began I wouldn't have needed to tear up the lawn, but as the bumper sticker says "Stuff Happens".

I'm not afraid to admit to my mistakes and I hope someone else will learn from them.
 
   / 4 wheel drive all the time? or just when needed #85  
Exactly my point with Diggin it.
And linked by gears to the rear axles. So the brakes ARE on the rear wheels.
Also linked by gears and a shaft to the front wheels if 4wd is engaged
 
   / 4 wheel drive all the time? or just when needed #86  
I can see y. When in 4wd, are the front and rear axles actually locked together? On some all wheel drive cars they are Not. So maybe being in 4wd just hooks the front axle to the engine and not directly to the rear axle.

It is easy to see a question? If the front and rear axles are locked, that means there is no differential between them. Really? Could be, but easy to see such confusion?

You are right, it's easy to imagine the question given the variety of incarnations of multiple wheel drive!

Cars are a weird reference. There are so many different schemes. I think "all wheel drive" most often refers to having a partial degree of coupling between front and rear, often a viscous connection, so that if you're going uphill in the snow and your primary drive wheels start to spin, the other wheels start to contribute too. Most reasonable to think of this as transferring more and more power to the other wheels, in proportion to how different the front and rear wheel speeds are. It makes life easier for the drive train because when traction is good and all the wheels turn at the same speed, there is no torque being transmitted to the non-primary drive wheels.

Cars are also a less useful reference here because they always have braking on all the wheels. Beyond that, more modern designs monitor wheel rotation with a microprocessor and fire the brakes on individual wheels to remedy various modes of traction loss or control loss. None of which applies to tractors!

And there could be a differential between front and rear, but that's not the only way of transmitting power. In older 4WD designs I think they're rigidly locked together, which does let torque build up (according to variations in wheel speed and the tendency of the wheels to slip a little bit).

AFAIK tractors rigidly lock front and rear together. That can build up torque, and rip up sensitive surfaces especially when turning.

I saw a crowd of young men pushing a small tractor through the woods after the main gear shift lever broke off. Fortunately it was in neutral. But, when they started turning around a clump of trees, suddenly the effort was Herculean and slow. I noticed it was in 4WD and suggested they take it out -- suddenly they were making easy headway again!
 
   / 4 wheel drive all the time? or just when needed #87  
The real misinformation comes from someone who has a reading comprehension issue.
Nope. That is not misinformation. That is misunderstanding.

Misinformation is intentional spread of falsities. People who are just simply slow on the uptake or have trouble grasping things are not spreading misinformation. Not everyone can be a rocket scientist there bub.
 
   / 4 wheel drive all the time? or just when needed #88  
As to where the brakes are, why does that matter? When operating, where the braking effect occurs is what matters. On cars brakes have been built into wheel hubs (the rotors) and on subassemblies secured to the suspension (the calipers and pads). On bicycles brakes are often on wheel rims and the frame, or they're on wheel hubs and wheel mountings.

What experiment could you do while driving these vehicles to tell where the brake mechanism is actually located (without looking at the mechanism itself)? In other words, is there some maneuver in which they will work differently according to where the mechanism is mounted?

No, it doesn't matter to the driver, who only has to care which tires will transmit stopping force to the ground when the brakes are applied.

Unless you are a mechanic who has to fix them, you don't need to know where the brakes are -- just where they take effect.
 
   / 4 wheel drive all the time? or just when needed #89  
If your brake is on the driveline instead of the wheel and the driveline or a universal joint snaps, you now how no way of stopping. (Example: many vehicles and tractors that have their “parking brake” on the driveline or in transmission)
 
   / 4 wheel drive all the time? or just when needed #90  
If your brake is on the driveline instead of the wheel and the driveline or a universal joint snaps, you now how no way of stopping. (Example: many vehicles and tractors that have their “parking brake” on the driveline or in transmission)
If you wanna play the "what if" game....there are lots of mechanical things that could break and leave you without brakes. Still doesn't change the fact that 4wd adds front axle braking
 
 
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