I have a '97 Scrambler 400 w/RCR mods and am looking to replace the badly balded tires that came on it. Do the tire sizes really make a difference in how the 4 wheel drive works. I've heard you have to keep the 1 inch difference between front and rear for it to work properly. If this is the case would a smaller back tire than stock cause the front hubs to lock in sooner or make no difference at all?

I am looking to run some Pure Sports Bandit XC's (21x7x10 and 20x10x10). I don't mind the loss of ground clearance (I think it would probably feel better in the turns with it a little lower) but don't want to screw up the 4 wheel drive engagement.

 

The smaller tires spin faster, that's all. Which means the gears could lock right up and not move, or blow all to hell. 1inch (1/2inch, actually) is nothing to worry about, since there could be that much variance in a set of tires any way, and since I presume you'll be on dirt and not tar in 4 wheel drive, the tires can slip easy,anyway. In fact, some mud runners(pick-ups) run a size or two smaller in front to keep them spinning faster and keep the front up on top of the mud.

 

Oh, smaller tires are like having lower gears, so if you get to concerned, change your rear sprocket. (I have no idea to what size)

 

Thanx for the reply. I have a better picture of what I'm dealing with now, I think. I thought there might be some adverse effect on the 4 wheel drive engagement if not using the same stock tire size ratio. The only thing that might change, if I understand you correctly, is the speed in which the four wheel drive actually engages the front hubs. Smaller rear tires - faster engagement . The smaller tires on the rear and the increased rpm's of the rear tire would replicate the wheel spin of a larger tire, right?

Thanx for the help and let me know how close I am to understanding this.

 

Your over all tire size should be the same front to rear, regardless of the rim size. Unless you have the R&P gears set up to operate at different rates of rotation from front to rear!

Rick