I was looking to get two bighorn 2.0 for the rear but they are 26" and have 25" on the front. will it work or no?
jim83
I wouldn't recommend it as you'll have the tires spinning at different rpm's and I'm willing to bet the transmission/transfer case wouldn't like it for very long. It doesn't work on 4 wheel drive trucks for the same reason....but it can if they change the ring and pinion in the differential. We don't have that option on these.
you guys do realize the rear diff is 3.70 and the front is something like 3.85 ...correct?
doh: it should be ok as far as gearing is concerned, my math was bass ackwards. the only issue i can think of is it may put more force on the sprague carrier when the tires do slip. instead of the armature dragging and already putting things in a bind, it could shock the system when it slips and the AWD is engaged if that makes sense ...I wouldn't try it if I were you.
doh: it should be ok as far as gearing is concerned, my math was bass ackwards. the only issue i can think of is it may put more force on the sprague carrier when the tires do slip. instead of the armature dragging and already putting things in a bind, it could shock the system when it slips and the AWD is engaged if that makes sense ...I wouldn't try it if I were you.
opcorn:The front "differential" is not truly a differential like in automotive. The effect of different size tires is not the same.
The way the on-demand system works is that there is a gear ratio difference between front and rear axles. The front ring gear is turning slower than the rear ring gear by about 20%. Once you activate AWD, you are still in 2wd until the rear wheels slip. When you have traction, the rear wheels are driving (100 rpm for example). This makes the vehicle roll and the front wheel will roll at the same speed (100 rpm). If you lose traction at the rear, those tires may still be turning (100 rpm), but because they are slipping, the front tires start to roll slower and slower (100, 95, 90 rpm, etc). Once they have slowed enough that the front ring gear is going faster than the front tires (80rpm vs 79.999), relative motion between the cage and ring gear cause the roller clutch (the ones people blow up) rollers to cam out and lock the ring gear to the front axles. Now you are actually in 4x4 and the front and rear are turning at different speeds. Once you regain traction at the rear tires, they propel the vehicle again and the front tires roll at the same speed and the roller clutch unlocks. This AWD On-demand operating principle dictates there be a speed ratio. The ratio difference is somewhat defined by wheelbase and trackwidth so that the front doesn't try to lock in during tight turns.
By running a larger tire on the rear, you are essential gearing the rear axle to be slightly faster relative to the front. That one inch tire diameter difference would increase that "gear ratio" by about 3%...This means it would take about 3% more slip at the rear before the front would engage. More slippage at the rear is a less optimum traction condition...may have slight effect on handling since rear is slipping a bit more. It may increase the harshness when the front engages during full throttle launch in low traction conditions. It will not create driveline windup like some people may think...like that when turning an old 4x4 truck on asphalt. On other vehicles like a Rhino or other ATV manufacturers, different sizes on front and rear would create problems. Polaris's system is unique.
You could try it and see if the effects are acceptable.
More confused now???
The way the on-demand system works is that there is a gear ratio difference between front and rear axles. The front ring gear is turning slower than the rear ring gear by about 20%. Once you activate AWD, you are still in 2wd until the rear wheels slip. When you have traction, the rear wheels are driving (100 rpm for example). This makes the vehicle roll and the front wheel will roll at the same speed (100 rpm). If you lose traction at the rear, those tires may still be turning (100 rpm), but because they are slipping, the front tires start to roll slower and slower (100, 95, 90 rpm, etc). Once they have slowed enough that the front ring gear is going faster than the front tires (80rpm vs 79.999), relative motion between the cage and ring gear cause the roller clutch (the ones people blow up) rollers to cam out and lock the ring gear to the front axles. Now you are actually in 4x4 and the front and rear are turning at different speeds. Once you regain traction at the rear tires, they propel the vehicle again and the front tires roll at the same speed and the roller clutch unlocks. This AWD On-demand operating principle dictates there be a speed ratio. The ratio difference is somewhat defined by wheelbase and trackwidth so that the front doesn't try to lock in during tight turns.
By running a larger tire on the rear, you are essential gearing the rear axle to be slightly faster relative to the front. That one inch tire diameter difference would increase that "gear ratio" by about 3%...This means it would take about 3% more slip at the rear before the front would engage. More slippage at the rear is a less optimum traction condition...may have slight effect on handling since rear is slipping a bit more. It may increase the harshness when the front engages during full throttle launch in low traction conditions. It will not create driveline windup like some people may think...like that when turning an old 4x4 truck on asphalt. On other vehicles like a Rhino or other ATV manufacturers, different sizes on front and rear would create problems. Polaris's system is unique.
You could try it and see if the effects are acceptable.
More confused now???
you wouldnt want to go the other direction, the bouncing around would cause the rollers to engage and probably break lots of stuff, but smaller up front will only make the diff spin faster. the front diff is like an overrunning clutch so it is designed to slip in the direction of rotation.. it would do what it was supposed to do.. now if you wanted 4wd, it would take a little more to get the front to engage, and you might get more of a slamming into awd effect when it did engage. it's always better to run the same size tires, you could get away with this for a while if you wanted to.
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