4WD really?

didn't say it did, and i was asking the OP

Why does it matter?

I used to drag race can got into 10 sec class many years ago. We used spools then not Posi's becaust they did not cut it. Also axle ratio play a big factor in traction on launch because the taller the axle ratio, the more the weight/traction shift between the rear tires on acceleration. It is acttuall easier to do a burn out with a 3.08 than a 4.56 and harder to get a got launch with a taller axle because of the traction shift. The reason that car ALWAYS fish tail to left on a hard launch is because of torque weight shift on rear wheels (more weight on left rear and less on right rear) which cause side with more traction to pull rear end to the left. Intheory if you had a deep enough rear axle and suspension setup you would not even need a posi on a hard launch if on a good tractive surface. I new a low buck racer in 70's that understood this problem as well and he did not have the money for a posi but he did understand why it did what it did. His solution was to use air shock with different air pressure in rear and he found (which you would) that if he got press set correctly (loaded RR heavier than LR) that it would alwasy launch with both tires spining with a open diff. No surprize to me but I am sure the whole concept escapes you with your lack of understanding of the physics involved.

First of all you do not get yourslef in the situation. Second, lockers or some LSD's do not play well at all in front drive axles because of two reasons. First Ujoints are not constant velocity when they are flex (this likely escapes you too) and the further they are flexed or bent the more they vary speed accross the joint (speeding up and slowing donw in two complete cycles per second) When a locker is used it can cause a big torque bind and whipping of wheel unless you are on a very slick surface. Next, when you turn the front wheel have diffenet rolling radiuses and a locker would cause front end to bind up a lot in a turn on a tractive surface and guiding problems on a slick one. (this is also the reason that whole truck feels tight in a tiurn on a hard surface in 4x4 because there is speed difference netween all axle and wheel invovled and it binds up in drive line unless s slick surface can relieve it. Years ago even detriot recognized this and had some full time 4x4 system with a differentail between front and rear but this was more complex and costly to do (Jeep even had a selectable 2wd, full time 4wd and conventail 4wd in on Tcase design for a while) But all the pphysics of how and why rhing work escapes you because you like to flap your gums and feel like a big person which we know you are not.

----------------- TheSnoMan.com

...can I get an "amen"!?

Down off my soapbox now.

Later,

Spdloader

Matt,

Sorry but I'm coming into this late.

His Cherokee is probably full time 4WD. If a wheel slips on my Jeep Commander, the vehicle computer applies the brake to the slipping wheel. Wheel slip is detected by the ABS sensor. If in a 'rock crawling' scenario, 4WD Low range will lock both F/R differentials, plus the center differential. The Cherokee full time 4WD is far more sophisticated than the simple part time 4WD.

: >Jeff Strickland wrote: : >> Your truck has what are referred to as "open differentials." Open diffs are : >> the easiest to make, and they operate more smoothly from the perspective of : >> the vehicle operator. You have found the downside. : >>

: >> An open diff applies power equally to both rear tires (and front tires in : >> 4WD) UNTIL one of the tires begins to slip due to lost traction, then the : >> diff will apply full power to the tire that has lost traction. The result in : >> 4WD is that it is common to see diagonal tires spinning when traction is : >> compromised. : >>

: >> If the vehicle has limited slip differentials, then power ought to be : >> applied to the tire that still has traction. And, a vehicle that is equipped : >> with a locker will get equal power to both tires on the same axle without : >> regard to the status of the traction under each tire. : >>

: >>

: >>

: >>

: >> > Is this really 4WD or 3WD... or is something not working right? I know : >> > in my 98 Cherokee all the wheels churn in snow or mud. : >> >

: >> > Thanks. : >> >

Russ,

The next time you get in that situation, try applying the brakes simultaneously with the gas. This will slow down the slipping wheel and transfer some torque to the spinning wheel.

Hey Sno Blower, I think you missed your meds...

Next time you want to spew out some long winded rant to refute something I have said, why don't you actually try refuting what I said, rather than spewing a bunch of loosely related personal experiences disguised as facts...

Ya, ya, You got in the 10's with your old Chebbie with a single cylinder

Spools? Are you friggin kidding me? Why don't you start comparing to bicycles or bulldozers now?

Your first and second points (in your final paragraph) have nothing to do with peg-leg 4X4's and how they work or compare to a limited slip REAR end... Care to try it again?

Speaking of flapping your gums Sno Blower, consider engaging your brain FIRST... Have you got a direct rebuttal to anything I have said? Try catching up on your meds, it couldn't get any worse. Sheesh!

You wouldn't be in Little Rock, Ar. would you?

Mark

Are you stupid, or justj putting on a show?

A vehicle with a locking diff will turn both tires at the same speed (or all four tires if a 4WD, and both axles have a locker installed and working) no matter what the state of the traction is.

Technically, no. Technically, the tire that is spinning is spinning uselessly. Yes, there is some residual friction that is moving the car forward, but if the car was in a compromised condition, the tire could spin all day long and the car would not be going anywhere. This means that the tire that HAS traction, and is still getting a small amount of the engine power is the tire that is physically moving the car forward.

Not so. What I said was that the power applied to the tire that has traction is not enough to move the vehicle, making my earlier statement that the spinning tire gets all of the engine's power virtually correct. (The statement is not entirely correct because a small amount of power is directed to the tire with traction.)

That's not what you said.

What you did say was that power is never applied equally. The fact is, power is applied equally UNTIL one tire breaks traction, then thatj tire gets all of the available tire -- with the caveat I described earlier, several times.

That much is true. And, it's what I've been saying all along, and what others have said, and what you seem to NOT have been saying until now.

If by "you really need it" you mean that one tire spins uselessly and you can't get going as a result, then yes, that is true.

Are you stupid, or just putting on a show?

If that were actually true, then a car with a locking rear end would simply spin both tires and spew smoke and rubber, never moving forward. But we all know that the spinning tire(s) can and do move the car in both situations... If the "under-powered" tire could move the car in this situation, (and the spinning tire could not) then in the ditch scenario the "under-powered" tire could move the vehicle as well, we all know that the "under-powered" tire will never move the car in the ditch straddle scenario......

Are you stupid, or just putting on a show? GO back and read again! In my post (Thursday, January 11, 2007 2:52 PM) I said: "Because the open differential is never going to power both axels when you start applying torque and spinning..."

Are you stupid, or just putting on a show? GO back and read again! In my post (Thursday, January 11, 2007 2:52 PM) I said: "Because the open differential is never going to power both axels when you start applying torque and spinning..."

And exactly what I have been saying from the start...

On Thu, 11 Jan 2007 18:33:52 -0500, the world came to an end when Matt rearranged some electrons to form:

On Fri, 12 Jan 2007 12:29:53 +0000, Snowblower rearranged some electrons to form:

Maybe too many cans of Pabst Blue Ribbon.

"SnoMan" wrote in message news: snipped-for-privacy@4ax.com...

Ok I have to step in here. Both axles WILL recieve the same amount of torque so long as BOTH wheels have traction. The moment one looses traction, the one without traction will then recieve most, if not all, of the torque. It's just like a planetary gear set. The axle with traction is the held member (lets say sun gear), and the spider gears are the carrier-n-pinions (input in this scenario), and the spinning axle is the output (call it the ring gear). Only difference in this scenario is there is no reduction in speed or torque through the differential. The differential does NOT increase or decrease torque, that is all up to the ring and pinion gear. The ONLY thing the differential does do is allow two wheels on the same axle to turn at different speeds around a corner. The differential WILL NOT distribute torque evenly unless both wheels have EQUAL traction. I tell ya what. Walk up to a truck (with an open diff) on a lift while the wheels are spinning (slowly), and grab one wheel. If you notice the other wheel will continue to spin, and you will feel little (if any) resistance to your hands holding that one wheel. (I know I tried it). Now if you have someone grab the other wheel, BOOM instant traction and they both turn, cause there is NO WHERE for the torque to go, but the weakest of the two people will let go first and then that wheel will start spinning. Same instance here. The only advantage of a LIMITED slip differential is that it requires more torque to break away that one wheel.

"Ford Tech" wrote in news:bAZph.85237$ snipped-for-privacy@newsfe14.phx:

What do you think of Torsen differential offered on the Ranger FX4/Level 2 ? I have a 2wd Ranger now with a limited slip and may buy a 4wd Ranger as my next truck.

From what I have heard, those a pretty good differential. They use the smart locking differetial design. Basically what happens is they stay locked unless both wheels have traction and one of going faster than the other, then it will unlock.

Ford Tech

My son had an aquaintance at Little Rock AFB who buried an older F150 up to the frame. Wanted to use my son's new Explorer to pull it out. Ha! I understand he had quite a time getting it out.

Mark

snipped-for-privacy@gmail.com wrote:

And a late reply right back at ya..... :)

I did consider fancy electronics, but I guessed a '98 Cherokee probably wasn't that advanced. I'm no Jeep expert though, I'll concede that!

Matt