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Discussion Starter #1 (Edited)
O.K. let me start by saying, I may be WAY off with this one, but here it goes...

If anyone on here has ever driven an old tractor (like the common ford 8n or 9n's) with separate brakes for each rear tire, you might already know where I'm going with this. Even though those tractors are only 2wd with open diffs, you can make them perform very well because if one tire loses grip, you can just press on the brake for that tire and the power will be forced to go through the diff to the other tire which has grip. As soon as you start to move again you can release the brake on the one tire and just continue on normally.

So, I was thinking today I wish the samurai had a system like that because then diff lockers wouldn't be needed. It would be a little more complicated because to make the most of it you would want to be able to do that on both axles, instead of like the tractors which only had one driven axle to worry about.

SO... Here is what I came up with, I have no idea if it would work or not but hear me out... Everybody knows what line locks are, right? Well, I'm thinking what if I put one on each wheel, then if I have one tire that is spinning or up in the air, I can just lock it out causing the power to go to the other side.
Another option would be like a hybrid system with a line lock on each front wheel, and get a second parking brake and hook one parking brake to each rear wheel to handle them.

What do you guys think? Has anything like this ever been done?
 

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Back in the day my buddy and I rigged a dune buggy style VW to do what u are talking about.
The rigging for the 2 handbrakes was simple enough and worked good for corners and all that...
If you plan to drive this 4x4 rigged like that...hope that you do NOT need to have any type insurance or road inspection.
It should work as u describe but likely will be VERY quirky.
Don't test in or on any uneven ground...test it carefully at first.
Did u think about the slowing of the braked wheel...taking energy from your total output ?
Remember line locks fade quickly.
Cheaper lockers are achieved with welders. They are not near as quirky as you might think. Many of us have run years with welded diffs.
 

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Discussion Starter #4
Well, with my limited funds my only two options for diffs are basically open or welded. I would be fine with welding them if I thought it would always be better. The thing that worries me is if sometimes, like in shallow mud or maybe snow or ice or something like that, is if it would want to push me straight foreward and not want to steer. Does anyone with welded diffs or solid spools ever have problems with that?
 

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thats actually what modern dynamic traction controlled vehicles do. The simulate a limmited slip differential by progressively applying braking resistance to one wheel when it starts to break loose and spin significanly faster than the other wheel. They use onboard computers to control it though, not manual brake controls.

So even though your theory is not actually a breakthrough, it is something that isn't commonly done with manually controled braking systems. It's essentially what a clutched LSD does automatically. I don't know how you could automate it externally though. would be something interesting to brain storm about.
 

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It's essentially what a clutched LSD does automatically.
Since when does a clutched LSD brake one wheel to force more power to the other?

A clutched LSD partially locks the drive shafts to one another so that some percentage of the power (how much will depend on the clutch packs) will get to both wheels - there is NO braking action going on.
 

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Interesting...
If an LSD is installed in back, slightly applying the emergency brake will lock up the LSD enough to act as a locker.

Interesting how things come around...
;)
 

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Since when does a clutched LSD brake one wheel to force more power to the other?

A clutched LSD partially locks the drive shafts to one another so that some percentage of the power (how much will depend on the clutch packs) will get to both wheels - there is NO braking action going on.
I didn't mean that an LSD applies the wheel brakes for you. I mean that it automatically (through use of the springs and clutch pack in the LSD case) applies enough resistance to the side gears in the differential so that the two axel halves remain turning at the same speed even if there is a difference in resistance from the two wheels. He is in effect manually mimiking this by applying the brakes to the unloaded side by creating an artificial load on that side.
 

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I've attached some sketches of a clutch type LSD - Imageshack is acting up, so I can't post it as a linked image - I might edit the post when I figure out what Imageshack is up to - but I digress...

The lower sketches show how torque is transferred to the wheels - left side shows a straight line, right side shows a turn, where differentiation would normally occur, and where the clutch packs come into play, limiting the differential action - the right side is also applicable to any situation where the wheels are rotating at different speeds, for example, if one is in the air, or a mud hole and has lost traction.

If you need it explained - the pinion gear turns the ring gear, the ring gear turns the differential case, the case is attached to and turns one set of clutch plates, these clutch plates are interleaved with and turn the second set of clutch plates, which are attached to and turn the side gears, the side gears turn the axles, which turn the wheels.

The clutch packs actually couple the side gears to the differential case, forcing them to rotate as a unit rather than "applying resistance to the side gears".
 

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I understand how the clutched LSD works. when both wheels have traction there is enough torque to overcome the force of the spring pressing the clutch on the case against the clutch on the side gears. When this happens the clutches will slip. This allows the differential to act as an open diff when both wheels have sufficient traction. When one wheel is up or loose, there isn't enough resistance from that wheel to overcome the force of the spring pressing the clutch plates together and the loose wheel will be engaged with the LSD case, spinning at the same speed as the wheel with traction.


If you have an Open diff with a wheel off the ground, By applying wheel braking to the unloaded or free wheel in an open diff, you are simulating a load on that wheel. when an equal enough load is created between the free wheel and the traction wheel, the two side gears will spin as one unit allowing the free wheel to turn at the same speed as the wheel with more traction.

I'm not saying it IS an LSD or that it uses the same mechanics. Fiddle brakes are actually kind of opposite the mechanics of an lsd, applying resistance to equalize differential movement as opposed to removing resistance to equalize differential movement. I'm saying that the end result is similar to what an LSD achieves, which is limmited differential movement between an unloaded and loaded wheel.

I'm not sure how bills suggestion would work out... applying braking resistance to an lifted wheel with an LSD. If you forced torque on the lifted wheel with the wheel brakes and overcame the spring tension in the LSD, the clutches would slip creating an open differential situation wouldn't you?
 

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Discussion Starter #15
Yes, I think so, but by doing so you would still put the power down to the wheel that was on the ground, right?
 

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The way I understand it - a clutch type LSD never functions "like an open differential" - unless the clutch packs are worn out.
 

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What you're referring is steering brakes ala sand buggies of the 80s thru today. They're still available and they work off of the hydraulic system. The early units worked with the P-brakes. They performed nicely in their role. However, adapting them to a locker situation might take some serious practicing before attempting a major outing.
game on-citizendan
 

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Discussion Starter #18
I think when he said an "open differential situation" he just meant having the wheels not turning at the same speed, which you should be able to do with an LSD, if I'm thinking right.

Because an LSD will slip if you're in a sticky enough situation, right? So in that case applying braking force on the slipping wheel would transfer the power to the one that had traction, just the same as it would if it was an open diff. Right? Just trying to make sure I got this straight in my head...
 

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yeah, meant the clutches would slip and the wheels would no longer be linked together by the LSD mechanism. Then braking the lifted wheel would transfer all of your drive power to the wheel with traction. Which is what would happen with an open diff if you were to apply braking force to the lifted wheel only.

I think I just repeated your clarification of what I was tryng to convey sohcneondriver.. :rolleyes: so, in otherwords... yes.
 
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