or a different sprocket on the rear axle to adjust for the tires being the same size.
this is where we need to know the tire size so he can adjust the sprocket size.

also, with over sized tires i would bet he lost some bottom end on the scrambler.
he can also get some bottom end back by using a different rear axle sprocket and transmission gears from a 2002 eplorer 250 to spin the front drive shaft slower....

 

I talked to OPT about different size sprockets and he said it shouldnt make that much of a difference. I would say tire size and sprocket size would be a similar situation. I'm sure he'll chime in shortly.

 

Changing the tire ratio will ony make the AWD kick in at a different time than stock and I have seen itr mess up the handling drastically.
Most the time when a vent stopps up it is due to either a belt shredding and not getting the strings out or a vicious little mouse building a home in one of the vents

 

right, right...
thare is some give on the tire/sprocket ratios and as long as the front axels are spinning faster than the front tires he should be ok.
i was just saying if he wants some low end grunt back he can adjust for that.
the ideal tranny would be from a 2002 xplorer, this has hi/low and a slower turning front drive shaft, for larger tires.
or he can just get the gears and install them in the tranny himself. (this is what i did) only i dont have hi/low. part #3233729 & 3233730 about 60 bux each
installing these gears turn my front drive shaft about 14% slower for better low end power....

a quick check. he can set the scrambler on jack stands, mark the top of the tires and with the tranny in gear and 4x4 hubs engaged spin the rear tires by hand and make sure the front tires turn at the same speed or slower. rember the rear tires will turn 1/5 turn before the fronts engage....

 

Back to the power lose and sluggish running either set the secondary setting to a lighter setting or get a complete clutch kit to compensate for the added weight and torque at the rear wheels.The bigger tires change the torque felt by the secondary to get it to work.

 

Yeah i put a 12 tooth in place of a stock 13t rear output drive sprocket and every thing is fine in awd until you go to turn,feels like you have a GO-rilla preventing you from turning,craziest thing,straight absolutely fine,you dont get 5feet in a turn then bamn! damn!.put 13t back just fine now....now with same size tires maybe........

 

<div class="FTQUOTE"><begin quote>Originally posted by: MECHANIKE

Yeah i put a 12 tooth in place of a stock 13t rear output drive sprocket and every thing is fine in awd until you go to turn,feels like you have a GO-rilla preventing you from turning,craziest thing,straight absolutely fine,you dont get 5feet in a turn then bamn! damn!.put 13t back just fine now....now with same size tires maybe........</end quote></div>

yep, you slowed down the rear axle speed by doing this, making the front wheels do more work. you also need to slow down the front drive shaft speed. you can do this by changing the gears in the transmission with the part numbers i supplied.....

good thing about polaris is they have true 4x4 (like having a solid axle up front)
bad thing is this makes it harder to turn

going down 1 tooth like you did on the output drive sprocket is like going up 3 teeth on the rear axle sprocket....

 

best thing is to stay with stock tire sizes and not worry with it.

 

Front 25-8-12, Rear 25-10-12. If I run the explorer gears, to slow the front, will I need to change the sprocket ratio in the back, to even it out? And to answer a few of the previous questions, I called the electric hubs clutches, and when it overheated the clutches, I noticed after riding at about 30 mph. I had been riding in mud, water, sand, cutline, and other scenarios including hills, at a lower speed. Was traveling with another Scrammy and a 'Gade 800 (Which by the way towed my sorry a$$ home [img]i/expressions/face-icon-small-smile.gif[/img] ) My wife and I don't need to go fast. We would much rather make 4 miles a day, and use the winches for 2 of them. That is more fun to me than bouncing over moguls at 60 mph. I am getting older, (mostly more payments) and feel less like I will injure myself in 4' of watery mud. So if there is a way to make this Scrammy run 30 Mph top speed, but turn these tires like they're nothing, she'd be all over that. I did not check the vent tube. I will, though. What about the heat on the clutches themselves, should I be concerned with their integrity? Anything I should check? They will get different weights, springs, and buttons, possibly a helix, but I am certainly not going to add all that to a set of clutches that might fail in 2 miles.

Any other suggestions? I am probably not going to remove the tires as I can neither afford to replace them, nor do I really want to. I would like to make the machine work with those tires, as in the mud it is a beast. I broke trail for both of the aforementioned atv's, and the 'Gade had a set of Mud Lites, with alum rims as well. Couldn't touch me. Could, however, tow me home.

Thanks for all your input, it is much appreciated!

 

You changed the gear ratio about 13% in the rear and 9% in the front when you put 25" tires on. You can get a clutch kit that will wind up to a higher rpm before engaging so it doesn't slip as much, but to get the 4-wheel drive to work right the front tires should be an inch taller than the rears like the stock setup. JMHO.