Locker rear-ends
08-07-2013 | 12:38 PM
#11
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Using close to 1000lbs of ballast in the rear of the bed.
If was a real ramp, I wouldn't have a problem. My lake is 55ft below normal. I drive down the ramp, then drive another 1/8 mile before I reach water.
The "ramp" (using that term loosely) that I've been using is made up of clay (which is usually wet) and smooth loose rocks ranging from golf ball to soft ball size and all on a 30 deg incline. No, it's not bouldering, but it's no cakewalk either..
If was a real ramp, I wouldn't have a problem. My lake is 55ft below normal. I drive down the ramp, then drive another 1/8 mile before I reach water.
The "ramp" (using that term loosely) that I've been using is made up of clay (which is usually wet) and smooth loose rocks ranging from golf ball to soft ball size and all on a 30 deg incline. No, it's not bouldering, but it's no cakewalk either..
08-07-2013 | 02:09 PM
#12
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From: TRL
While complaining abt my difficulties pulling my boat out of the lake on a dirt/rock "ramp", a workmate suggested installing a locker set-up. I already have a functional limit-slip rear-end and I always spin both back tires when traction is an issue. Hard to believe a locker would make much difference in a situation like this.
Anyone have experience using a locker rear-end vs a limited-slip while retrieving from the beach?
Anyone have experience using a locker rear-end vs a limited-slip while retrieving from the beach?
a locker acts like an open rear until one side spins by a certain amount over the other side which is what causes it to lock up. generally they will stay locked untill you stop and back up while turning which unlocks them. the posi is always locked up but will break loose and slip with traction and turning, etc.
Sounds like your limited slip is already doing what it's supposed to, a locker would be a waste of money.
If you do decide to go with a locker, make sure to verify with the manufacturer that it's ok to tow with it. It's possible it's changed but when I was looking to put one in my old truck years ago, it was advised not to have a locker when towing due to it locking up going around corners under load and would basically blow out the gears.
If you do decide to go with a locker, make sure to verify with the manufacturer that it's ok to tow with it. It's possible it's changed but when I was looking to put one in my old truck years ago, it was advised not to have a locker when towing due to it locking up going around corners under load and would basically blow out the gears.
I discussed this with my off-roading buddy a bit more and got a bit more clarification on his stance.
I always thought the limited-slip simply just had a pre-load on the clutches that would assure both wheels would have some torque being applied. But my buddy was telling me when one wheel starts spinning, additional pressure is applied to the clutches causing a sharp increase in torque to the non-spinning wheel, which breaks it loose due to the inertia of the spinning wheel and driveshaft. Then you have both tires spinning and traction is almost completely lost.
The lockers he was referring to were the air lockers that when actuated, prevent the spider gears from rotating so there's no abrupt torque increase from clutches slipping, then locking up. He admitted the benefit in a situation like at the "ramp" would be minimal, but under certain circumstances (like large loose rocks) might be just enough to make the difference.
I always thought the limited-slip simply just had a pre-load on the clutches that would assure both wheels would have some torque being applied. But my buddy was telling me when one wheel starts spinning, additional pressure is applied to the clutches causing a sharp increase in torque to the non-spinning wheel, which breaks it loose due to the inertia of the spinning wheel and driveshaft. Then you have both tires spinning and traction is almost completely lost.
The lockers he was referring to were the air lockers that when actuated, prevent the spider gears from rotating so there's no abrupt torque increase from clutches slipping, then locking up. He admitted the benefit in a situation like at the "ramp" would be minimal, but under certain circumstances (like large loose rocks) might be just enough to make the difference.
Thx for the feedback guys!
I had initally just compared the Detroit locker aginst the ARB air locker.
The Detroit locker is cheaper and all mechanical, but some complain abt it being too noisy for a truck that spends 99% of it's life on the street.
The advantage of the Air Locker is there's no noise and the differential acts perfectly normal when it's not engaged.
Disadvantages are you need an onboard compressor and the air lines are suseptable to damage. Proper air line routing would be critical.
However, having an onboard compressor might come in handy for other things, like adj tire press out in the middle of nowhere or whatever.
I'll have to look into the electronic versions.
My plan is to sell my 2wd and buy a 4wd.
Thinking abt using front and rear lockers with 4wd. That would be the ultimate set-up for beach launching!
I had initally just compared the Detroit locker aginst the ARB air locker.
The Detroit locker is cheaper and all mechanical, but some complain abt it being too noisy for a truck that spends 99% of it's life on the street.
The advantage of the Air Locker is there's no noise and the differential acts perfectly normal when it's not engaged.
Disadvantages are you need an onboard compressor and the air lines are suseptable to damage. Proper air line routing would be critical.
However, having an onboard compressor might come in handy for other things, like adj tire press out in the middle of nowhere or whatever.
I'll have to look into the electronic versions.
My plan is to sell my 2wd and buy a 4wd.
Thinking abt using front and rear lockers with 4wd. That would be the ultimate set-up for beach launching!
Yea, put more weight in the back to bury you even faster, that's what I would do.
Using close to 1000lbs of ballast in the rear of the bed.
If was a real ramp, I wouldn't have a problem. My lake is 55ft below normal. I drive down the ramp, then drive another 1/8 mile before I reach water.
The "ramp" (using that term loosely) that I've been using is made up of clay (which is usually wet) and smooth loose rocks ranging from golf ball to soft ball size and all on a 30 deg incline. No, it's not bouldering, but it's no cakewalk either..
If was a real ramp, I wouldn't have a problem. My lake is 55ft below normal. I drive down the ramp, then drive another 1/8 mile before I reach water.
The "ramp" (using that term loosely) that I've been using is made up of clay (which is usually wet) and smooth loose rocks ranging from golf ball to soft ball size and all on a 30 deg incline. No, it's not bouldering, but it's no cakewalk either..
Last edited by keegan; 08-07-2013 at 02:21 PM.
Multiple straw-man arguments laced with a little bit of fact and a heavy dose of sarcasm.. 
08-07-2013 | 09:05 PM
#16
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From: Murrayville Georgia
gee sorry keegan, I did not realize you were such an angry automotive engineer. here is the definition of a mechanical locker rear differential.
The Torsen differential* is a purely mechanical device; it has no electronics, clutches or viscous fluids.
*The Torsen (from Torque Sensing) works as an open differential when the amount of torque going to each wheel is equal. As soon as one wheel starts to lose traction, the difference in torque causes the gears in the Torsen differential to bind together. The design of the gears in the differential determines the torque bias ratio. For instance, if a particular Torsen differential is designed with a 5:1 bias ratio, it is capable of applying up to five times more torque to the wheel that has good traction.
this is what most production trucks use. to release the locking action you generally have to back up while turning to release them. I know I am not the expert you are but after 280,000 miles with mine I know how it works.
here is how a standard limited slip works.
The spring pack pushes the side gears against the clutches, which are attached to the cage. Both side gears spin with the cage when both wheels are moving at the same speed, and the clutches aren't really needed -- the only time the clutches step in is when something happens to make one wheel spin faster than the other, as in a turn. The clutches fight this behavior, wanting both wheels to go the same speed. If one wheel wants to spin faster than the other, it must first overpower the clutch. The stiffness of the springs combined with the friction of the clutch determine how much torque it takes to overpower it.
as I said when there is traction present at both wheels it slips, i.e. when turning and both tires have traction.
I may not have a masters in differential design like you apparently do but I have worked on enough of them to know how they work.
The Torsen differential* is a purely mechanical device; it has no electronics, clutches or viscous fluids.
*The Torsen (from Torque Sensing) works as an open differential when the amount of torque going to each wheel is equal. As soon as one wheel starts to lose traction, the difference in torque causes the gears in the Torsen differential to bind together. The design of the gears in the differential determines the torque bias ratio. For instance, if a particular Torsen differential is designed with a 5:1 bias ratio, it is capable of applying up to five times more torque to the wheel that has good traction.
this is what most production trucks use. to release the locking action you generally have to back up while turning to release them. I know I am not the expert you are but after 280,000 miles with mine I know how it works.
here is how a standard limited slip works.
The spring pack pushes the side gears against the clutches, which are attached to the cage. Both side gears spin with the cage when both wheels are moving at the same speed, and the clutches aren't really needed -- the only time the clutches step in is when something happens to make one wheel spin faster than the other, as in a turn. The clutches fight this behavior, wanting both wheels to go the same speed. If one wheel wants to spin faster than the other, it must first overpower the clutch. The stiffness of the springs combined with the friction of the clutch determine how much torque it takes to overpower it.
as I said when there is traction present at both wheels it slips, i.e. when turning and both tires have traction.
I may not have a masters in differential design like you apparently do but I have worked on enough of them to know how they work.
08-08-2013 | 10:45 AM
#17
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Joined: Aug 2012
Posts: 516
Likes: 2
From: TRL
gee sorry keegan, I did not realize you were such an angry automotive engineer. here is the definition of a mechanical locker rear differential.
The Torsen differential* is a purely mechanical device; it has no electronics, clutches or viscous fluids.
*The Torsen (from Torque Sensing) works as an open differential when the amount of torque going to each wheel is equal. As soon as one wheel starts to lose traction, the difference in torque causes the gears in the Torsen differential to bind together. The design of the gears in the differential determines the torque bias ratio. For instance, if a particular Torsen differential is designed with a 5:1 bias ratio, it is capable of applying up to five times more torque to the wheel that has good traction.
this is what most production trucks use. to release the locking action you generally have to back up while turning to release them. I know I am not the expert you are but after 280,000 miles with mine I know how it works.
here is how a standard limited slip works.
The spring pack pushes the side gears against the clutches, which are attached to the cage. Both side gears spin with the cage when both wheels are moving at the same speed, and the clutches aren't really needed -- the only time the clutches step in is when something happens to make one wheel spin faster than the other, as in a turn. The clutches fight this behavior, wanting both wheels to go the same speed. If one wheel wants to spin faster than the other, it must first overpower the clutch. The stiffness of the springs combined with the friction of the clutch determine how much torque it takes to overpower it.
as I said when there is traction present at both wheels it slips, i.e. when turning and both tires have traction.
I may not have a masters in differential design like you apparently do but I have worked on enough of them to know how they work.
The Torsen differential* is a purely mechanical device; it has no electronics, clutches or viscous fluids.
*The Torsen (from Torque Sensing) works as an open differential when the amount of torque going to each wheel is equal. As soon as one wheel starts to lose traction, the difference in torque causes the gears in the Torsen differential to bind together. The design of the gears in the differential determines the torque bias ratio. For instance, if a particular Torsen differential is designed with a 5:1 bias ratio, it is capable of applying up to five times more torque to the wheel that has good traction.
this is what most production trucks use. to release the locking action you generally have to back up while turning to release them. I know I am not the expert you are but after 280,000 miles with mine I know how it works.
here is how a standard limited slip works.
The spring pack pushes the side gears against the clutches, which are attached to the cage. Both side gears spin with the cage when both wheels are moving at the same speed, and the clutches aren't really needed -- the only time the clutches step in is when something happens to make one wheel spin faster than the other, as in a turn. The clutches fight this behavior, wanting both wheels to go the same speed. If one wheel wants to spin faster than the other, it must first overpower the clutch. The stiffness of the springs combined with the friction of the clutch determine how much torque it takes to overpower it.
as I said when there is traction present at both wheels it slips, i.e. when turning and both tires have traction.
I may not have a masters in differential design like you apparently do but I have worked on enough of them to know how they work.
