OK, lets compare IRS from the different manufacturers. This has been my experience.

Load = Driving down a trail, hitting bumps, watching the suspension squat.

Suzuki 300 King Quad.....harsh ride, ok articulation and it squats a fair bit when you sit on it and it really squats when its under load.

Polaris 335/500 Sportsman.....awesome ride, good articulation and it squats a fair bit when you sit on it and I swear it touches the ground under load....hehehe...well at least the 335 almost did with a 350 lbs guy on it.

Grizzly 660.....No idea....how does it perform? squat? articulation?

Cat 500i.....very good ride, awesome articulation, and so far it doesn't squat nearly as bad as any other IRS machine. I put 400+ lbs on the back rack(2 guys) and it was not even that bad yet. Under load it does squat but not that much and when it does squat really hard sometimes it goes right back to normal.

Any other quads that I missed? Give me your opinions on each IRS system and what you think of each system.

 

What about the 300 Arctic Cats??

 

The 300 cats are the same as the king quad or so so close to being the same. No difference.

 

There is a lot of difference in the King and 250, 300 ACs. Ac uses upper and lower control arms which keeps the tires straight up and down kind of like this [ ]. The King uses a single control arm, which makes the tires lean in or out as the suspension goes through its travel kind of like this ( ). I know hard to understand. The AC also has more travel I don't know the #s off the top of my head but I'm thinking 4+ inches more than the King. It is a much smoother ride, and it articulates better.

I ride with a 660 and stock the articulation is very poor. But when you take the sway bar off it makes a huge difference. I would say that it is second behind the Cat because of the cats longer travel and longer control arms. It does squat somewhat under a load. about like the Polaris.

 

The AC 250 and 300 have 6.5 inches of travel. The King Quad and Quad Runner 250 only has 3.9 inches front and 4.9 inches rear of travel according to ATV Magazine. I prefer the handling of the Cats due to the fact King Quad bottoms out more while crossing large obstacles like logs and rocks.

 

The main difference is the dual a-arm setup of the Arctic Cat compared to the single wishbone design on the KQ. Ever look behind a king quad and notice that the tires aren't actually perpendicular to the ground? The have a toe in looking effect that I guess is supposed to level out after you sit on it. I would prefer the AC setup.