So what exactly am I really going to gain by going up to a 28" tire from a 26" I bit of ground clearance I guess....but anything else?

As a side note, I like the IPT Terracross, but it's only offered in 26". Not sure if ITPs generally run small or true to size. Anybody running the Terracross that can comment.....

 

If you went from 26 to 28 you get 1" more clearance and probably a little more surface contact. When I went from the 25 to a 26 the tire was an inch wider. More square inches on the ground makes more traction. These are your 2 main reasons for going to a larger tire.

 

Like Moose said, more height, width, traction and look better to boot!

 

Yeah, I could see a small increase in contact patch. But the tire is smaller diameter, so maybe a bit more ummmph for wheelies, and jump off the line without a clutch mod......No?

 

More ground clearance with larger tires with less acceleration and top end.

 

TLC, how do you end up with less actual top end speed? Is it the clutching? I would have thought with a larger tire you go further with each revolution. Are quads limited to a certain amount of RPMs or is it the clutching where the larger tires rob top end?

Funride, I agree with TLC on the acceleration part. The engine/transmission/clutching has to overcome forces against a tire patch that is a greater distance out from the center of the hub. So, it needs more force to spin the larger tires. If I were to go to (or could go to) a 27 or 28 I would definetly get my clutching redone.

 

The larger tires are heaver, A 500 Scrambler with its stock 22' rears and 23" front tires will go faster then a Scrambler with 25" tires because it will not get the high top end rpm it once had.

We but 26" tires on a 660 grizzly,same thing, top speed and acceleration both went down.

I rode across a smooth hard frozen lake, and had more top end then a 500 efi Sportsman, I know it was because he had 26" tires vs my 25" Mud lites.

 

My opinion is bigger tires= less speed.

 

Maybe the 26" ITPs is the way to go for me. Would like a bit more ground clearance though. Don't want to mess with the clutch right now....but not sure. Endless freakin' tire research. I been reading around that the 850 could turn 28s no problem without any clutch mods.

 

I am with you there. I finally decided on 26'' Bighorn. Although they are basically a 27'' or so I have read. I don't know yet as I pick up my new 850 XP today. For what little you gain in ability, I don't want to give up acceleration and drivablity and good handleing on fast trails. But for the guys that do mainly mud I would agree the larger tires and clutch work would be worth it.