Fellows I don't know what is the big mystery and what is so hard to understand about this...ok here we go, if you are on a Sportsman in a sideways position the side nearest the hill compresses inwards leaving the opposite side to expand outward not shifting the entire bike just the axle part till it either touches or don't. On a sideways camber with a solid axle expanding till it hits the riding area under it. So this brings us to when a solid axle bike starts leaning toward the lower side the weight shifts toward the off camber side do to a solid axle has no choice but to shift the weight do to the design. But with the IRS not having the opposite wheel linked to it the center of gravity stays with the wheel that is compressed on the upper side. I have seen many situations where bikes were riding off camber or sideways that the solid axle let one of the wheels on the rear raise up as where the IRS rear wheel stayed planted due to the IRS. I guess what I am trying to say is with IRS one wheel doesn't have to move cause it is not directly linked to the other rear wheel. Also with a solid axle the weight is shifted down hill due to the bike itself is linked to the whole bike where as an IRS is not. If this makes sense to you. Think of it in terms the solid axle is connected to the bike in a manner that when the rear wheel shifts in a sideways position where the rear wheel is on the down hill side all the weight is shifted down hill. This is not particulary true and anyone with an IRS system will tell you that when the wheel expands on the down hill side the bikes center of gravity stays more upward due to the IRS just letting one wheel move. The only reason that a sportsman feels more tipsy to some people is the fact of the higher sitting height due to the larger ground clearance the Sportsman has. Nobody is going to make me believe that a solid axle bike is less tipsy in an off camber situeation. I have rode Sportsman, Artic Cat and Honda in off camber sideways trails and in every spot where the Honda and Artic Cat wheel lifted off the ground the Sportsman stayed planted touching touching the trail. So how can anybody say the solid axle is more safe in sideways off camber situations.

 

that's true Andy, it is even worse for the 500

 

I side rolled my Scrambler 400 yesturday on my woods track. A lot of it had to do w/ "stock" tire roll. I have 5 more lbs. of air in each tire that spec. requirements and when I dove off the downhill side, I noticed that the wheel was on the ground and the tires were folded under on the bottom side. The only damage that was done, was a quarter size tear in the "NEW" seat cover. It didnt roll but so far until the tree caught it.
Personally, I feel that with a smaller profile tire and wheels, this would not have happened.

EC

 

Just becuase the high side wheel is still making contact with the ground doesn't mean the rig is any more stable. The fact that the high side wheel is expanding is off set by the fact that the the lower side wheel is compressing. So the center of gravity is shifting downward. Its a optical illusion. With a straight axle you may be lifting one wheel off the ground, but your not compressing the opposing wheel down. So your center of gravity isn't shifting as much. You should see the films of the testing they did with the 4 wheel IS on the Jeep. Plus if your going around a corner at high speed, and lift the inside wheels off the ground, they will not land at a right angle to the ground. They will pivot downward, giving the vehicle a tendancy to roll the opposite way once they make contact with the ground again. Ever jack up an IFS truck and look at the angle of the wheels when you set it down again. They both toe in, big time. Which is not to say the 4 wheel IS is bad. On level ground that is very uneven. Or going up hills with lots of dips and bumps, it will keep the wheels in contact with the ground. Traction equals action. Happy trails.

 

GRIZZ two question! How you going to go around a corner and raise the inside wheels all the weight is on them.Ok so you on off camber and you say downside wheel is compressed what happens to the other three that are all independant of the down hill compressed wheel.I don't really understand,all there is to know about the IRS.But when you compare it to jeep don't the jeep have a stabilizer bar missing,isn't this why Polaris IRS is better than ZUKI's.Only asking.CM

 

Another good thing about body english is being able to bail off quickly if it rolls.

Hugh

 

If you drive your quad in a complete circle it will leave to lines. The one your outside tires made, and the smaller one on the inside, that your inside tires made. Thats why your outside tire has to turn faster, because its covering more ground. If you are going very fast you will lift the inside tires off the ground. Posssibly rolling your quad. To answer your second question, I don't know.

 

ok here we go again you are riding sideways on a hill if it is a solid axle the wheel on the upper side will raise up due to the wheels being of one piece due to it being a solid axle. Ok so you are riding the same hill the upper wheel does not raise up as easy due to the IRS being 2 seperate units also gravity is not shifted down hill due to one wheel being independant of the other. So this why IRS handles sideways off camber riding so well...any questions

 

fair enough 3tv lets see how many agree with me on here and how many agree with you. If I am wrong I am not to big to swallow my pride. Since you want to get into physics ever heard of for every action there is an opposite or equal reaction...well with a solid axle being compressed because of an off camber situation the other wheel goes into the opposite direction cause it is of one solid piece thus causing the whole bike to shift toward the wheel that is expanding thus causing the gravity to shift towards the down hill because of gravity. Now with an IRS when you have the same action the other wheel is not affected because they are not of a solid piece thus not affecting the other wheel thus not affecting the shift off the bike toward the down hill side...now lets hear argue about newton's law, I guess he is wrong to.

 

Here is a question to think about. How many of you guys have ridden a Sportsman actually. After that, how many of you have ridden one in hairy situations. This isn't a Jeep either. A little weight difference here. If you haven't done it, then what grounds do you have to base your arguement on other than just stuff you figured out in your own head?

ATVING used to have an Arctic Cat. He has ridden it in that stuff. Now he has an SP500 and he says it doesn't have that problem. Thats good experience to go on. What can you say to that that carries any weight? Nothing other than just to argue. Why can't people just face the fact that what they have isn't always the best in every situation? I can.