I'm looking at the new models and they have the concentric drive system...what is it? What is the difference between it and the old drive system?

Thanks...
Spanky
'96 Xplorer 300 4x4

 

Someone else may be able to explain it better than me but I'll give it a shot.
The drive sprocket for the rear chain has been moved to align with the pivot point of the rear swingarm. This keeps the chain tension adjustment constant as the swingarm moves up and down thus causing less stress on the chain and smoother power transfer to the rear wheels.

 

SP5004x4 is correct. By aligning the pivot point of the swingarm with the center of the front drive sprocket, the chain is no longer a factor affecting the suspension system. For example, on a "normal" chain driven ATV as you press down on the back of the quad and compress the rear shocks--the chain will tighten and loosen depending on where the swingarm is in relation to it's full range of travel. The chain tension affects how the rear suspension operates. So the Engineers need to factor this effect in when they design a suspension system. The Concentric Drive system would theoretically allow the swingarm to rotate 360 degrees without affecting the chain tension or rear suspension. Thus the Engineers can design a suspension system optimized for the best ride effect without regard to the limitations imposed by the chain and drive system or the effect of engine torque. The Concentric Drive system is also thought to improve power transfer to the ground.

 

Ahh, but here is the kicker. The Polaris concentric drive is not 100% true concentric. Another person in these forums told me about this. I did not believe him at first, so he told me to do this: I hooked a ratcheting tie down strap to the swing arm and the frame. As I tightened the suspension down, the chain did indeed tighten up a bit. Definitly not as much as a regular setup, but it did tighten up. This is why you must have a very small bit of deflection in the chain. Some people tighten the chain as tight as they can. This will cause sproket and chain problems. My manual says to have 3/16 inch deflection, and I have never had a problem.

 

There are a couple more differences between the concentric drive system & the old style. The other guys did a good job describing what the concentric drive does, but there are more advantages. Concentric drive will help your chain last longer, as it won't slap as much over bumps & such, and is easier to adjust. The swingarm on the concentric drive models seem to be a little heavier than the old style, especially in the front swingarm pivot points. Lastly, the machines with the concentric drive have a shaft to the front on the 4wd models. Eliminates 2 chains and 4 sprockets compared to the old models. I don't think the chains were that trouble prone, but were a pain in the rear to try to lube. Shaft drive is much neater, easier to maintain.

 

Farmr123,
Ditto in the "easier to adjust" comment. The concentric models are extemely easy to adjust.

 

Thanks guys...I thought it was mainly about the chain tension. But that's bonus if it also improves power transfer. I'll just have to take a closer look at the dealer.

Thanks again...
Spanky

'96 Xplorer 300 4x4