Tim, I read that post too and your description explains it perfectly. That situation does makes a good case for immediate AWD. (BTW, really enjoyed the vacation pix!)

Harold, for those of us who have never had the front hubs apart and seen what it all looks like, your technical description of how it all works is a little hard to follow. I’ll give you an A+ for effort in getting the concept across though. It’s tough to make something like that understandable in print, and you’ve done the best job I’ve seen. Thanks for taking such a good shot at it.

It seems that buried in your explanation is the answer to my disengagement question. But just to clarify, in your description, when working properly (we’ve all had hubs “lock up” on occasion), the hubs would engage / disengage at will as the rear wheels would slip or regain traction. Is that correct?

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FloodRunner, on the Wisconsin River



[This message has been edited by floodrunner (edited 12-23-1999).]

 

Harold,
If the driveline is the same on the SP 500 and SP 335 how can keeping tire size the same be so important since they each have different tire sizes. On the 500 the front rim is bigger than the rear also. Looking at this if you changed the tires proportionately it really should not matter then, should it? As a matter of fact all of the Polaris quads have the same driveline and differnt tire sizes (I think). And Merry Christmas to all (Remember to Christ in Christmas).
Andy T
Y2K SP 335, Jackson, MS

 

General tire size is not the issue, and wheel size has even less to do with it. The issue is your front tire size COMPARED TO your rear tire size as measured by outside diameter, circumference or tire height. Your front and rear tires should measure relatively close to each other in size no matter which method you choose to use. It doesn’t matter if they’re 22” tires or 27” tires. Wheel size is the INSIDE DIAMETER of the tire and has no bearing on AWD engagement unless the WIDTH of the wheel is wider, effectively reducing the circumference and height of the tire.

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FloodRunner, on the Wisconsin River

 

TxDoc2 -
You won't hear it, and normally you won't feel it either...
I can't find the post now, but I recently read where someone was describing how he had backed off the road an dropped into a mudhole and how surprised he was when the Polaris shot straight up out of the mud. He was puzzeled by the experience, but couldn't explain it. I didn't have time to respond to that post that night, but here goes.
I've done this: pull up to a verticle "step" that is tall enough that the front tires cannot roll over it. Stop. Engage 4wd. Squeeze the throttle. .. Since Polaris front hubs will not engage until the front tires spin, it will not "climb" the step! .. give it more gas.. by the time you break the back tires loose you are applying a lot of power, and when the front wheels do engage, HANG ON! It's flyin' time

This is why I wish there was a way to flip a switch and tell the Polaris "I want 4wd *now*" and have it actually pull itself up *gracefully*.


Tim Bundrick

'98 Polaris Sportsman 500
'00 Yamaha Kodiak
E-mail: http://marina.fortunecity.com//victory/272/index.html

 

some times only one front wheel will unlock causing a pull to one side on the bars,just back up a few feet and it will unlock that wheel.

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clem in PA

 

I didn't think tire size mattered.

 

I agree on the immediate engagement thing to prevent "flying." It's worse on a Scrambler with no low range, because when the power kicks in, it's more air time than you might expect. Some of the guys I ride with are impressed with the way I wheelie accross logs and over obstacles, they don't it's not always intentional. Once you get the hang of it, you can use it to your advantage though.

 

Floodrunner, Inside your front hub is a 6 sidded item that looks like a nut that is meshed to the front axle, either by a key, or splines. There are rollers that fit in the center of the hex sides. There is a spring that holds them there. When the 4wd switch is in the on position, there is power to the electro-magnet that is behind the hex. If the tire and axle are turning at the same speed, then the hub is not engauged. As soon as the axle shaft turns a little faster than the wheel, the hex, which is activated by a small washer that goes between the magnet and the hex, is held from turning(by the magnet). This causes the rollers, that have been doing nothing so far, to roll up the hex. When this happens, the wheel is mechanicaly locked to the axle. When the wheel and axle speed are the same, and no rear wheel slippage is occouring, the rollers will go back to the center of the hex. You are now in 2wd. And you are correct about the hubs engauging and disengauging at will. It is very subtle and you will not notice it most of the time. I hope that this helps you understand how the hubs work. Please excuse the miss-spelled words, I hane not figured out how to use spell-check on these documents.
Later, Dave

 

Lots of ideas here on how the Polaris 4-wd system works. Tire size seems to have little effect. We have used (300 4x4) 22" fronts, 23" front, 25" fronts. 23" rears, 24" rears and 25" rears, little difference. In fact there is no perceptable difference in riding. I've snow plowed with the 22/24 and 22/25 and 25/25 setup and they all work fine. In snow and ice you can tell when the 4wd engages easily and it's the same. I have tried a couple of different setups on my '99 SP500 and have not been able to tell the difference, the engagement is the same, based upon wheel slippage distance. That seems to be the the key. Seems like 1-1-2" max. of rear wheel slippage and the fronts engage irregardless of the tire size, etc. I run with the overide switch eliminated and you can really tell. I run into the ditch on the other side of the road when plowing and it's real easy to tell how much slippage occurs when backing out.

It's more apparent with a machine that has a plow on because of the up-front weight. I was always told that the tire diam. was a factor. That is not so at all. I'm not sure what makes it work right, but the tire diameter seems to have very little to do with it under "true" snow/ice slippage conditions.

It seems that slippage is sensed regardless of the tire size, front or rear.

We first noticed this when we put my original equpment front tires off the SP500 onto my son's '95 300 4x4 which has 25" Realtors on the rear that only measure 24". The 25" fronts are really taller than the rears by a considerable amount visually (maybe 2") and certainly much taller than the stock tires on front. It works exactly the same as before. The rear slippage is sensed and engagement occurs regardless of tire size. It's a great world, isn't it.

<A HREF="http://www.godigital-design.com/96Polaris.html">Schultz Motorsports</A>

 

Thanks for all of the responses. It is amazing at what people know and can explain. Very good descriptions and information.