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post #1 of 20 (permalink) Old 02-17-2008, 11:52 AM Thread Starter
 
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4x4 Question

Can someone please explain to me in a technical manor "WHY" it is bad to drive in 4x4 mode on dry pavement. I have even asked licsened mechanics and they can't give me a straight answer.
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post #2 of 20 (permalink) Old 02-17-2008, 12:13 PM
 
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From what I understand it is torture on the front hubs when turning, PM tear u a new 1 I think he just had a hefty bill on his Supercrew as to what the damage can be. I may be wrong, I can't seem to find the thread about his problem.

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post #3 of 20 (permalink) Old 02-17-2008, 01:38 PM
 
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From what I understand it is torture on the front hubs when turning, PM tear u a new 1 I think he just had a hefty bill on his Supercrew as to what the damage can be. I may be wrong, I can't seem to find the thread about his problem.
it's called torque-bind, happens when front and rear travel at different speeds (which the will) b/c there is no differential between frt and bk. So, when driving on hard pavement where there is no slippage the forces between the front wheels and the back cause a situation where the torque will "bind" or "lock" the drivetrain to the point where no movement is possible w/o breaking something
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post #4 of 20 (permalink) Old 02-17-2008, 03:12 PM Thread Starter
 
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it's called torque-bind, happens when front and rear travel at different speeds (which the will) b/c there is no differential between frt and bk. So, when driving on hard pavement where there is no slippage the forces between the front wheels and the back cause a situation where the torque will "bind" or "lock" the drivetrain to the point where no movement is possible w/o breaking something
Thanx thats the best answer/explaination i've heard yet...
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post #5 of 20 (permalink) Old 02-17-2008, 03:15 PM Thread Starter
 
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You talk about diff speeds between front and rear diffs, but why would they travel at diff speeds if they had the same gear ratio(solid axle front and rear)
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post #6 of 20 (permalink) Old 02-17-2008, 03:27 PM
 
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You talk about diff speeds between front and rear diffs, but why would they travel at diff speeds if they had the same gear ratio(solid axle front and rear)
the same reason why cars/trucks need differentials, when front wheels are turned they are going different speeds, picture in your mind (or draw it on paper) a truck turning right, the left front wheel has to go WAY faster to in relation to the right rear, whcih if your turning from a stand-still is barely moving....so unless your travelling 100% straight-100% of the time, all 4 wheels will be going at varying speeds, this is compensated from side to side by the diffs. but there is no comp. from front to rear (on hard pavement, on slippery surfaces the ground/ice/mud will give)
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post #7 of 20 (permalink) Old 02-17-2008, 05:06 PM Thread Starter
 
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the same reason why cars/trucks need differentials, when front wheels are turned they are going different speeds, picture in your mind (or draw it on paper) a truck turning right, the left front wheel has to go WAY faster to in relation to the right rear, whcih if your turning from a stand-still is barely moving....so unless your travelling 100% straight-100% of the time, all 4 wheels will be going at varying speeds, this is compensated from side to side by the diffs. but there is no comp. from front to rear (on hard pavement, on slippery surfaces the ground/ice/mud will give)
This is true but thats why we have lockers or limited slip diffs. So i ask this, if i had one of these in front/rear were does the problem lie???
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post #8 of 20 (permalink) Old 02-17-2008, 05:23 PM
 
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post #9 of 20 (permalink) Old 02-17-2008, 05:34 PM Thread Starter
 
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Thanx for the great link.

However i understand the purpose of a diff and how it work as i have built many. What it doesn't explain is why i can't drive in 4x4 mode when i have the same gear ratio and limited slip diffs in both front/rear.
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post #10 of 20 (permalink) Old 02-17-2008, 06:06 PM
 
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I realize you are curious as to why it is hard on the equipment, but why would you need to use 4wd on dry pavement?

Limited diffs still would still feel the stress, the purpose of it is to provide traction if needed. But not to take the constant stress from the 4wd system when used in a dry condition.

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