Hint: They are made by GBC...

 

Update: I am running completly stock now - no performance mods. I went up one tooth on the front sprocket and dropped 2 teeth on the rear sprocket. I went with 21x12x9 GBC Mud Sharks. The actual height is around 20.5" and the actual width is around 10.5". I still have wheel spin problems and it is affecting my acceleration. When I ride the DS on concrete or pavement, it is like riding a different ATV! I feel more pull and throtle response, the motor is under more of a load, there is no wheel spin, the RPMs don't hit 7000 instantly, I accelerate faster, shift earlier, and generally run at lower RPM. Off pavement/concrete I have major problems with wheel spin. The large front end weight bias must be contributing to this. I might sell the DS and this is one of the reasons.

 

Scooby, as I mentioned in my Chain Roller post, I recently adjusted the preload on my rear shock (about 1 1/4") for it to be stiffer. It made a world of difference!!

The bike hook's up incredibly now! I would say, on my bike, it made at least a 200% difference! From a roll now, without jerking on the bars, gunning it, and the front will come right off the ground, on various surfaces (dirt, grass, etc.) I thought it pulled hard before, now it’s just flat out crazy!

Prior I drag raced my friend on his Polaris 500 Scrambler. I was even with him for the first 3 gears, then I’d start to pull away (traction in my opinion). I adjusted the shock, raced him again, total blow out now!

Food for thought.

 

Scooby... I thought of one good way to test what the difference is between your situation and say, KawasakiKid. Is there anyone, competent, in your circle of aquantences, that weighs more, and is capable of riding an ATV? The main difference I can surmise between you and KawasakiKid is rider 'size.' Your 170 lbs. is pretty lightweight on an ATV. I think one good, FREE test that could prove extremely effective is for you to have a larger rider give your ATV a go and see if you can see as much wheel spin when that person guns it on soft dirt. Also you could time the ATV from point A to point B and see how that comes in. Or heck, if you want to be on the ATV, have a second person sit on it, (or strap on a seriously heavy backpack - at least 90 lbs.) that'll add lots of weight and you'll still be the one riding.

 

I mentioned the weight difference and traction before and In think there may well be something to it. My brother and I just got back from a weekend riding and raced many times with both riders. I have the 22" edge paddles stock everything else, when I drag race the first 2 gears are almost straight up and down, When my brother races the front hardly comes up(I come out of the hole at full throttle ) I am the better racer and shifter between us. I weigh about 275 and he weighs about 175. ( he is still learning to race but 100 lb's is as good as 10 HP and he should be much faster but not so far)

 

I'm 275 as well. Before I adjusted the rear shock though I didn't really notice the wheel spin. But after drag racing a few of my friends and being surprised they were keeping up while I was in the first 3 gears...After I adjusted the shock, raced again, no chance for them now, I'm otta there 2-3 quad lengths in mid 2nd gear.

 

When I was playing around with the rear shock pre-load I thought I noticed easier wheelies but I wasn't sure of the reason. What do you think is the reason for better traction with more rear shock pre-load? Could it be that it reduces the wheelbase slightly, balancing out the weight better? Or is the shock not absorbing/dissipating as much energy when you nail the throttle, thereby transferring more power to the ground? Or put another way, with a soft rear shock, as you gas the motor, the spring compresses and the rearend drops, which causes the wheelbase to increase, freeing up the tires to spin at will?

 

I've heard several different opinions on rear shock settings regarding traction. Some people will tell you a softer suspension will result in better traction due to the weight disipation and transfer to rear tires. On the other hand, I've had people tell me that a stiffer rear suspension will result in better traction because upon acceleration the rear end is pressed harder to the ground than with loose.

I agree and disagree on both these theories. I've seen one way work and then not. I think it strongly depends on suspension geometry and weight balance / distribution.

For example on my '69 Mustang I have a Shelby Rally Sport type suspension package on it, front & rear sway bars, shocks, and stiffer springs. The car will kill a corvette in the corners but has very poor hook up on acceleration. I took one leaf out of the rear springs and I got a tad bit more sway in the corners but hook up was much better.

In regards to my DS, I think stiffer was better, all the way.

 

Update: I stiffened up the rear shock preload and the front shock preload. Now with a 17 tooth front sprocket, 38 tooth rear sprocket, 20.5" Mud Sharks, I am getting much better traction and once again feel a pull under acceleration rather than having major wheel spin with gradual acceleration. Only problem is the mud sharks are too soft. The tread is between 3/4" to 1" deep though, and will last a little longer than the razrs and dominators. Next time I'll have to look for a harder tire.

By the way, stiffening up both the rear shock preload and the front shock preload has improved the handling quite a bit. Now when I go off of a small jump (2 to 3 feet ramp), at around 20 mph, I barely even feel the landing!!!! FYI: I weigh 170 lbs.