elgenvector--why would lsd need a bigger steering radius.seems like it shouldnt be any different than normal 4 wheel drive.--i understand that about turning and physics though but it would only bea problem if it were engaged...and if i were on ice i would want every bit of traction possible...also tire wear would be very minimum it would seem.------------personally i think i will get a truck wth lsd in the rear...non 4/4.i dont know that much about the 4/4 aspects of rangers so i dont know whats available/possible.

 

280z has it!
It would only affect anything when in 4x4. We dont get much snow around here so i wouldnt have it in 4x4 on the road anyways. But i dont want to do anything that will mess up anything down the road.

 

First of all NO, you absolutely wouldn't want a limited slip diff in the rear, then you wouldn't be able to turn your truck at all. It is an absolute requirement that the inside tire rotate slower than the outside tire in a turn - that's what the differential is for in the first place. The reason for the limited slip diff is to remove the differential's tendency to stop or slow down the tire that has good traction when the other tire has poor traction.

Maybe I'm not understanding the question being posed here, but I think the differential might need explaining - just to get us all on the same page.

**please correct me where I'm wrong*** and we can work through this together.

Let's stick to 2wd vehicles first.

Driver turns car to the right, differential slows down the rear passenger side tire and increases the speed of the rear driver's side tire.

Driver hits a patch of black ice. Rear driver side tire slips on the ice. The differential (because its just a mechanism) automatically slows down the rear passenger tire - the car fishtails as a result.

4wd with limited slip differential in the front.

Driver turns the truck to the right, the rear differential slows down the rear passenger tire, speeds up the rear driver side tire. The front differential keeps both tires moving at the same speed. Truck turns, but not sharply and the front tires skid on the pavement during the turn.

Driver hits a patch of black ice, the rear driver tire speeds up as it loses traction, the rear passenger tire slows down because the rear differential kicks in, truck wants to fishtail - BUT... The front tires keep rotating at the same speed and the truck moves in a straight line and the fishtail was avoided.

The limited slip differential truck in essence becomes a front wheel drive vehicle when 4wd is engaged. This is for extreme limited slip differentials only, modern 4wd systems are much smarter than this.

 

uuhhhh?...what do you mean by "speeds up"? slows down?------to avoid confusion...at no time ever does a differential slows or speeds anything up.it only turns as fast as the driveshaft is turning(1:1)
i dont understand why you say you cannot turn with lsd...trust me its not impossible to turn with lsd.
your scenarious are not quite logical in my opinion....you will not go fishtailing out of control if you hit ice with a lsd and one wheel starts to spin for a second....it just wont happen.

 

Then please explain to us all what a differential is. Perhaps you could clarify this for everyone?

 

Simple enough. This will save me a lot of typing: http://auto.howstuffworks.com/differential.htm They also talk about limited slip differentials, which I personally find to be very useful at times such as this season of the year. After driving rigs that have it for about 600,000 miles, I would not want to be without it.

 

I guess I don't see intrinsically what was wrong with my explanation, but whatever.

http://web.mit.edu/2.972/www/reports...ferential.html

Here is a second link that explains differentials as well.

I guess where I went wrong was in assuming that limited slip differentials do not allow the wheels to turn at radically different rates period - such as the transmission in my '83 Ranger where with the 4wd system engaged turning a corner was almost impossible without axle windup. But now that I think about it Positraction has been a feature for quite a while now - I just never associated it with limited slip differential action.

 

If you weld the spider gears or spool the front axle and have manual hubs YOU WILL LOVE IT if you do any offroading. If you have auto hubs DON'T even think about it. It's not a question of if, but when it will kill you. When you unlock the hubs you won't know it's there, but when you lock them in nothing will stand in your way. A locker/spool up front will take you more places than one in the back.
The other option for your front axle is some sort of automatic locker that engages under throttle (such as a detroit locker) then you would be able to drive in 2wd with your hubs locked in and the locker would only engage under throttle in 4wd. You could grab a "pocket locker" or "Lunchbox locker" which replace your spider gears. they can often be found for $200 or less.
I'm going to be running an auto locker up front and a spool out back in my truck with a twin stick 205 when i go 4x. This will allow me to drive 4xhi OR 4xlo , slip the front axle out to take a turn while the rear axle stays in the original range, and then slip the axle right back in while maintaining throttle all the way around the corner. Big fun

Also LSD SUCKS offroad. If you pick a wheel off the ground with LSD it can still spin when it overcomes the clamping force of the clutch pack. LSD out front is better than an open diff, but out back LSD will help you on a boat ramp and on a drag strip, but not much else.

99xlt: if you have any more questions like this slip over to the offroad or axle forum, this has actually been gone over a couple times.

Justin