HEY. WHAT IS THE BIGGEST TIRE I CAN SAFELY PUT ON MY 07 OUTLANDER 400. I RIDE ON A LOT OF ROCK AND THE STOCK TIRES ARE JUST NOT GOING TO CUT IT. I NEED MORE SIDWALL AS I ALREADY BENT UP A RIM. ALSO I WOULD LIKE TO GET SOME STIFFER SPRINGS CAUSE ON SOME MODERATE SPEED WHOOPS IN THE TRAILS I BOTTOM OUT, ARE THEIR ANY AFTERMARKET SPINGS I CAN GET THAT ARE STRONGER TO HELP PREVENT HITTING FRAME ON LANDINGS? I AM A PRETTY BIG GUY AND STOCK SPINGS ARE A LITTLE WEAK TO HOLD MY BUTT UP. ANY HELP WOULD BE GREAT, PLEASE GIVE ME WEBSITES IF POSSIBLE. THANKS.

 

You can put as big a tire as you want - question is, do you have the power to turn them with a particular tread design. Going to a taller tire will change your gear ratio and your low will not be low, more like your low will be like 2nd gear.
High Lifter makes some springs that will lift your machine 1" to 2" and add about 100lb more spring rate on each end of your machine.
Here is the link:
http://www.atvoutfitters.net/lift_springs.htm

 

high lifter will definatly have the spring, the whole kit is like 125$$, i think. as far as tires just get a good 6 ply tire and that will stregnthen the side walls a lot!