Does A 4WD Truck Need Limited Slip

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ppine

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Yes. Otherwise you have 2wd on different axles.
 

Wild one

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This is where you are going off the rails.

Torque is only a force. HP is force x distance/time.

Put 100# on the end of a 1 foot long bar that is perpendicular to the ground and anchored so that the fixed end cannot move. Like on a lug nut that you've already set to 100 #/ft. The torque is there for eternity, even though the tire is not moving.

Now, if that lug nut is attached to a wheel/tire that is in contact with the ground, and there is little enough resistance that the wheel will start to turn, you then have HP. If you maintain force perpendicular to the bar, HP is the result and will vary based on how fast the wheel turns and how much force is applied.

An open diff (apart from extremely small, generally unmeasurable differences due to manufacturing tolerances) will ALWAYS apply equal torque to both wheels. It's physics 101. Ok, maybe 102.
In laymans terms when it comes to ICE engines, HP is torque X rpm divided by 5252,lets employ the "Kiss principle" here,hopefully you know what that means.Some guys might be baffled with BS,but i'm well past that,lol.
In real life with an open diff,the wheel with the least amount of traction,will always receive the majority of usable torque,other wise the wheel on dry pavement would push the vehicle out of the ditch even if the other wheel is off the ground,little tidbit for you,it won't.If you're stuck with an open diff according to your theory of applied torque to the tires,you should have the same amount of usable torque at both tires,and drive right out of the ditch/snowbank/mudpit etc., i'd love to see that happen.And that sir is physics 101.Did you even read the links you were trying to shove down my throat,they don't really agree with your idea you don't need a limited slip diff,in a snowbank :Big Laugh: When you're stuck "applied" torque means squat,what you need is"usable" torque,as all the applied torque in the world,still isn't going to make the wheel with the most amount of traction spin,if the other wheel is on ice or in the air.You can compensate some by applying a restriction to the wheel with the least amount of traction (BLD) but realistically in real life,a limited slip diff will do more towards keeping you moving then a BLD system will
I know you'll try to put another spin on this,as that seems to be the way you work:waytogo:
BTW the OP was asking about whether a limited slip diff was needed with a 4X4,how you managed to spin this off to a theory that only works on paper is beyond me.When your stuck with an open diff,nobody really gives 2 sh!!ts about your applied torque theory,they're more concerned about the usable torque that's available,just saying:Big Laugh:
Keep a shovel handy for the next time your applied theory works in a snowbank,you might need it :waytogo:
 

TestPilot57

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...according to your theory of applied torque to the tires,you should have the same amount of usable torque at both tires,and drive right out of the ditch/snowbank/mudpit etc.
You do have the same amount of torque applied. Unfortunately, the tire with the least traction limits the amount of torque that can be applied.
...your idea you don't need a limited slip diff,in a snowbank :Big Laugh:
No one "needs" an LSD. For decades 99+% of vehicles driven were 2WD cars with open diffs. FWIW I have an LSD in my truck and would never buy one without it unless it were not possible.

My response was to the claim that without LSD you only have a 2WD truck when you paid for a 4WD one.
 

DILLIGAF

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My response was to the claim that without LSD you only have a 2WD truck when you paid for a 4WD one.

Well go in the snow / mud in 4wd without a locker and send me the video of all your 4 wheel spinning. Ill wait.

I have a 3WD truck in the snow / mud. since they dont make a locker for the Gen 3 front diff.

So yes everyone that buys 4WD truck without lockers dont have actually 4WD... lol..

I just came back from Limestone Mountain, I had to use the Bypasses on 2 different trails because my JK dosent have lockers. I slid sideways on a 5000 ft cliff. That made my ass pucker. because under load it became 2wd even on loose rocks.


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Dean2

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You can lead a horse to water but you can't make it drink.

Peace, out.
You can be as dismissive as you like but the problem is, you are talking to guys who actually use our 4x4s in really rugged locations. Deep mud, snow, loose rock, steep grades etc. However you cut it and whatever the theory, lsd in the rear and a locker in the front will take you WAY WAY more places than open diffs in really tough country. Brake limiting and traction control are actually handi caps in most really bad terrain. I know this doesn't apply to 70% of 4x4 users but for some of us, LSD and/or lockers are not nice to have, they are need to have.
 

Wild one

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You do have the same amount of torque applied. Unfortunately, the tire with the least traction limits the amount of torque that can be applied.

No one "needs" an LSD. For decades 99+% of vehicles driven were 2WD cars with open diffs. FWIW I have an LSD in my truck and would never buy one without it unless it were not possible.

My response was to the claim that without LSD you only have a 2WD truck when you paid for a 4WD one.
Here's a test for you to do with a pegleg truck,lol. Find a dyno shop with an in ground dyno,ask them if you can back the drivers side tire onto the roller,and keep the pass side of the truck off the dyno,then jack the pass side rear tire off the ground,and chain the hell out of the truck to the ground so it won't fall off the jack,then fire the truck up and put it in gear and give us the dyno reading off the drivers side tire.Remember dyno's only read torque,so using your theory we should get a dyno number off the drivers side wheel showing applied torque. I'll wait for your hypothesis :Big Laugh: :waytogo:
 
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