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After reading about all the electrical modifications that have been made on different machines, i.e. reverse override switch delete, 3 headlight and work light mods etc, I was wondering if it would be possible to wire in a switch that would activate the Hilliard clutches so that you could effectively "lock" the machine in AWD without having to wait for wheel slip to trigger it. Not only would it give bragging rights over the ol Grizzlys, but it would have functional applications too such as when plowing snow, where you want positive traction before the push even starts.
It sounds good in my head, but is it feasible?
 

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I guess it's possible but I mean it only takes a split second after the rear tires slip for the front to engage so I don't see a real need..other wise the steering would be a bear having it locked in all the time
 

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At first I wasnt too sure about the 4x4 on these machines, but after testing them and then buying a newer model, I really dont mind it. I ride some pretty tough trails and like having the easier steering compared to my older 4x4's.
 

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It's not possible, because the engagement is mechanical, not electrical. You can change the gearing with tire size, but that's a perminate fix the other way.

The grizzly's 4x4 is stone age technology, so you already have the bragging rights. You won't notice the 1/5th of 1 wheel revolution of slip, it's a fraction of a second.

My truck that is 25 years old has the same 4x4 system as a 2012 grizzly.
 

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Discussion Starter #5
It's not possible, because the engagement is mechanical, not electrical. You can change the gearing with tire size, but that's a perminate fix the other way.

The grizzly's 4x4 is stone age technology, so you already have the bragging rights. You won't notice the 1/5th of 1 wheel revolution of slip, it's a fraction of a second.

My truck that is 25 years old has the same 4x4 system as a 2012 grizzly.
Huh, I guess I don't understand the Sportsman AWD workings as well as I thought I did. I thought it was some sort of electrical sensors and controls that detected the rear wheels turning faster than the other driveline components and then engaged the clutches which operate on some electromagnetic system? I thought thats what those wires were for running down inside the strut?
Interesting stuff, glad I'm learning haha
 

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It's not possible, because the engagement is mechanical, not electrical. You can change the gearing with tire size, but that's a perminate fix the other way.

The grizzly's 4x4 is stone age technology, so you already have the bragging rights. You won't notice the 1/5th of 1 wheel revolution of slip, it's a fraction of a second.

My truck that is 25 years old has the same 4x4 system as a 2012 grizzly.
Huh, I guess I don't understand the Sportsman AWD workings as well as I thought I did. I thought it was some sort of electrical sensors and controls that detected the rear wheels turning faster than the other driveline components and then engaged the clutches which operate on some electromagnetic system? I thought thats what those wires were for running down inside the strut?
Interesting stuff, glad I'm learning haha
It's okay, its common, I even thought that's how it worked at one point. The wires running down to your hub, basically activate or deactivate a magnet, which basically causes the armature to engage or disengage the hubs. When all wheels have traction, the rear wheels are pushing on the fronts or "overrunning" the fronts. This force keeps the front wheels from engaging. When the rear wheels slip, that forward momentum force is gone, causing the hubs to lock in, and keep pulling along. As soon as the rear wheels gain traction again, they put that "overrunning" forward force on the front wheels, causing the front end to disengage again, until it happens again.

1/5 of a wheel slip is not a threshold for a sensor, its about the time it takes for the system to react. Now, I shorthanded a lot of what else is going on, in part because I'm not a mechanical or powertrain engineer.

Like I said, it's no biggie. I too thought exactly like you did. Until I sat down one day and actually read through a service manual about how it works.
 

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It is possible to make the Polaris Sportsman have all time four wheel drive with a simple wire mod i have done it on my 98 Sportsman due to the fact that the slip thing with the tires i didn't like. It took some searching in the circut board out front but I found which wires are activated from the switch then which wires activated the hubs and ran a jumper wire from one to the other. Basically bypassing the sensor that activated when the tires slipped. So as soon as I press the Four wheel drive button I am in Four wheel drive, like it much better this way.
 

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It doesn't make sense because there is no wheel sensor detecting slip. Whether you have the old system, or the newer system ('05+) it works under the same principle. The 4x4 only engages when torque is transferred from the rear wheels to the front. When the rear wheels lose the torque on the system (ie. they lose their traction) the power moves to the front wheels as well.

There's nothing electrical that can be done. It's not an electrical engagement, its mechanical.

You may have tricked the system, but changing a few wires won't do it.
 

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If there isn't any eletrical to it then why are there wires ran down to the Magnets in the hubs that lock the hubs to the splines that cause the front wheels to spin. I guess I should say that I have it so the Magnets are turned on as soon as I hit the button, Before I ran the jumper wire the front wheels wouldn't engage with out the rear wheels losing traction and at that point is when there was power sent to the magnets. So I'm not saying it is the best way or right but it worked for me. Try at your own Risk.
 

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Wires run down to the magnets because magnetic force is used to get the clutch assembly with the rollers and cage to mesh with the armature plate. The power wire is so that this magnetic force that causes the armature plate to mesh with the hub's clutch assembly can be turned on or off. When the clutch hub is in contact with the armature, the front wheels do spin, but they spin slower then the rears. At this point, it has made contact with the splines on the axles. But the rollers in the clutch housing are still in the neutral position. When the rear wheels slip, all of a sudden the torque pressing on the front wheels is gone. This causes the rollers to ride up in the cage, causing the front wheels to grab and go. When the rear wheels regain their traction, they start "overrunning" the front wheels again, causing the rollers to fall back into the natural position in the cage. The front wheels still turn on the own power, but much slower then the machine is actually traveling. They are not entirely freewheeling even though the rears have traction. Thats why in the service manual it says tire size is so importation. It a ratio of how the machine is geared internally for wheel speed.

I'm not sure what you may have wired in. The rollers can be wedged in their cage, causing the 4x4 to always stay engage. You might have a combination of wedged rollers and the hot magnet. I'm not possibly sure.

Each front wheel has its how "clutch assembly" and armature plate. But if you look, there are no electronic sensors on the wheels or hubs.
 

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Thanks for the insight. Nothing seems to be hot or wedged and switches between 4 and 2 wheel drive just fine. So guess I'm not sure what I did, but it works for me. I will have to do some more research on what I jumped its been I while since I did it. Glad you can set things straight with facts and info like you did. Respectful thanks
 

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I don't understand how people can really feel the awd engage, just to put it straight, polaris has the best AWD out there. It goes from 2wd to AWD seamlessly, no lever to pull or button to push for diff lock, no hydraulic pressure difference between the front wheels, when u want true AWD, flip the switch and when it slips minutely, you have AWD, and you don't have to worry about the switch being in awd all day because when you don't need it, it doesn't engage
 

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Thanks for the insight. Nothing seems to be hot or wedged and switches between 4 and 2 wheel drive just fine. So guess I'm not sure what I did, but it works for me. I will have to do some more research on what I jumped its been I while since I did it. Glad you can set things straight with facts and info like you did. Respectful thanks
I'm was thinking out loud there incase I missed something. All that matters is that you are happy with what you've got. Maybe I missing something here that would explain what you did. It's all good either way.

and to clarify by "hot" i just meant live, or on, or activated, not actually temp hot. I see that was a poor choice of words on my part.
 

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Thanks for the lesson Blueline. I'm always happy to learn more about how these things work.

So if someone were to "hotwire" the AWD switch they would essentially be just "leaving the switch on." Not forcing it into 4X4 at all times.
 

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As far as I've come to understand both systems, whether it is 2004 and older or 2005 and newer system, they both use rollers inside of a cage that move based on how much "force" the driveline is under because the rear wheels have the weight of moving the machine and rider. The best way to describe this is the difference between pushing an empty wagon, and the same wagon with 600 pounds on the wheels. You need more force to move the wagon.

The electrical component to both systems is basically using electricity to turn off and on through the switch, a magnet that attracts these pieces together (armature, roller cage, etc) so that the connection is made to transfer power through the drive shafts, into the hubs to turn the wheels.

Here, you can see in this video all the pieces that work together from a pre-2005 unit. You can see the armature, roller cage and rollers, etc.


This article talks about wedging the rollers. Which is the action that gets the fronts to engage. Rollers moving inside their cage, not electricity.

I wrote to Matt Cowen, the Engineering Product Manager at Hilliard Corporation and asked a few questions about the Hilliard Overrunning Clutch used in the Sportsman ATV's.

First my questions, followed by the response from Hilliard with their permission to share the information:

1) I regularly engage the AWD clutch for 4-wheel engine braking by causing the rear wheels to slip in reverse, stopping, then putting the machine in forward before descending the hill. Will this harm the clutch at all?

2) When I perform the above maneuver the clutch remains engaged, even while powering forward, until I switch off the AWD engaging coil. Is this normal operation for the clutch?

3) Is there a way to engage the clutch prior to wheel-spin, allowing me on-demand AWD?

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Mr. Anderson,

The condition that you are asking about above is called "wedging". What you are doing is locking the rolls in the reverse profile of the clutch (it is a bi-directional clutch set-up) and proceeding in the forward direction thus not allowing the clutch to overrun (which is the normal condition). This in turn locks up the drive train and makes the system steer like a fully locked differential. This condition is

Advantageous if going down a steep hill because it will only allow the front wheels to move as fast as the drive train. This will fully utilize the engine brake because when going downhill the weight distribution of the bike goes to the front end and that is where you want the majority of your traction.


This "wedging" will not hurt the front gear case, but it could accelerate the wear of the the drive train components (such as the front prop shaft) because it does completely bind up the system and the bike

will be very difficult to steer. Because of the binding and additional steering effort, neither Hilliard nor Polaris will recommend doing this.


You can get the system out of the "wedging" condition without turning the power off to the AWD system, but it is very difficult and

not always repeatable. The only true, 100% way to release the clutch is to turn the power off and put the bike in reverse. This will release the pressure on the clutch and the springs inside the clutch will return

the rollers back to the neutral position.


To answer #3, there is no way to drive the front wheels at the same time as the rear wheels without the rear wheels slipping. The bike is geared to have a 20% speed difference from the back to the front.

This means that it takes the rear wheel to slip or spin 20% (1/5th of a rear tire revolution) before the front wheel to drive the system. This is necessary to give the bike a tight turning radius and to prevent the bike from automatically "wedging". If the front to rear ratio was 1:1, every time you turn the handle bars even slightly, the front wheels would act like they have a fully locked differential and it would take

you 30 feet to turn a 90 degree turn (like driving a new Kawasaki Prarie with the front gearcase locked). Becuase when you turn, all of the wheels on the bike are now moving at different speeds dictated by the ground speed, and the front clutch would not be able to overrun. With the 20% speed difference, the AWD can be on all the time and it will only be there when you need it. You won't get any of the side effects

of all the other systems that don't allow you to turn the 4wd on and off. Basically, having the front wheels driving the same speed as the rear wheels would be like driving a tank and would be hard on the arms

and not very fun.


I hope I have answered all of your questions and not confused you to much. Browse through the overrunning clutch section on the Hilliard web site (Hilliard Industrial Clutches, Brakes, and Oil Filtration) for more info on how overrunning clutches work if you have any more questions. Have a good day.


Thanks,

Matt Cowen

Engineering Product Manager

Drive Train Products

Hilliard Corporation


phone: (607) 733-7121 ext. 376

fax: (607) 733-1045
 

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The four-wheel-drive engagement on my Honda 2001 foreman is very simple you push a button and engages and will stay that way engaged until you turn it off nothing else to it. It seems with the Polaris system and I guess Yamaha and others, you must momentarily lose control before you can return in control. I ride my Honda over basketball size rocks sometimes And it’s definitely nice having the front tires pulling While the rear tires are pushing. It sounds like in the all-wheel-drive system you would have to continually bump the throttle to make the tires spin to actually engage the front axle And when you stop to analyze your next path you’ve lost your four-wheel-drive again. I guess that’s kind of dumb but I’m not an engineer.
 

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The four-wheel-drive engagement on my Honda 2001 foreman is very simple you push a button and engages and will stay that way engaged until you turn it off nothing else to it. It seems with the Polaris system and I guess Yamaha and others, you must momentarily lose control before you can return in control. I ride my Honda over basketball size rocks sometimes And it’s definitely nice having the front tires pulling While the rear tires are pushing. It sounds like in the all-wheel-drive system you would have to continually bump the throttle to make the tires spin to actually engage the front axle And when you stop to analyze your next path you’ve lost your four-wheel-drive again. I guess that’s kind of dumb but I’m not an engineer.
The engagement due to wheel slip is not noticeable and you do not need to bump the throttle to engage. When you need the 4WD it’s there, that simple. When you don’t need it, like when steering, it’s not there, that simple. It really is a user friendly system. BTW, this thread is 8 years old, but thanks for your opinion.
 

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Its actually the best 4x4 system in the game. Its instantaneous and practically bullet proof. You know whats DUMB having to ride around in locked 4x4 or un-locked 4-wheel drive which is really 3-wheel drive and then when you're stuck having to stop and pull a lever, push in a button, or flip a switch.
 
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Each system has it's advantages and disadvantages, but the Polaris system certainly does enhance control more so than Honda and Yamaha, but the Polaris system can be more easily 'upset' by changing tire sizes more so than Honda or Yamaha. In the Polaris system, the front wheels have to rotate faster than the rear wheels either by gear ratio or outside diameter of the tires. If you change the OD ratio of the front to rear tires, it will alter the AWD engagement which might be an advantage for some operators or terrain and disadvantage in other situations. With the full time 4 wheel drive changing tire sizes may only result in the front pulling more than the rear driving or the rear driving more than the front pulling, but either situation will result in stress on the drive system leading to eventual drive line damage. It sucks when the output shaft of a TRX500 breaks and the machine becomes a front wheel drive or rear wheel drive 4x2 and it requires engine removal and partial disassembly to install a new output shaft. About a $2500 repair and it is not uncommon.
 

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So if I’m understanding this correctly, it’s ok if the front tires are slightly smaller diameter or same diameter as rear. The big no no is if the front is slightly larger....correct?
 
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