Off-Road: 101

[KF5ZXT]

[TexasArmadillo]

Alright since Randall clear up the mystery if the piñon brake for me I thought what other questions I might have. Here's is another.

Are rear and front axles different? Could a person use a rear axle as a front axle?

Juggling more fur balls than a constipated cat.

[KF5ZXT]

Short answers, yes; and yes with modification. The main difference being the occurrence or lack thereof, of steering knuckles. People have taken rear axles and lopped the ends off, usually grafting on Dana 60 front steering outers to turn a rear into a front, steering axle.

[TexasArmadillo]

Thanks. I forgot about steering.

Juggling more fur balls than a constipated cat.

[TxPlates]

No question is a stupid one, specially in offroading. As I've learned there are many different ways/views to tackle things. I myself still suck at it, and I've been exposed to it for many years, although many of them not really hands on. So I'm trying to watch/learn as I go to apply it towards my own rig when it shows up.

[TexasArmadillo]

Most of my questions are random thoughts. Here is the next one.



Are turbo chargers or super chargers a good idea for off roading?

Juggling more fur balls than a constipated cat.

[BigTim55]

What is a divorced transfer case? Is it good? Or bad?

Sent from Xavier School for Gifted Youngsters

[KF5ZXT]

Good in that you would not need to worry about changing out the transmission. Bad in that your rear driveshaft is going to be shorter, and thus have worse driveline angles. You'll also need to fab up a mount for the divorced tcase. With a married tcase, you would not need such a mount, but you would need to do something about the trans.

[BigTim55]

[KF5ZXT]

Binding, high speed vibrations.

[BigTim55]

So you would not suggest a divorced tcase?

Sent from Xavier School for Gifted Youngsters

[KF5ZXT]

I wouldn't, but it's feasible, moreso with a longer wheelbase rig. You'll also need an intermediate driveshaft between the trans and tcase.

[BigTim55]

What is the difference between high and low pinion?

Sent from Xavier School for Gifted Youngsters

[KF5ZXT]

Low pinion on the left, high on the right. High is better for front applications, due to the pinion turning the gear on the drive side, and also has the added benefit of having higher clearance from groundward objects. You'll also have a better driveshaft angle with the high pinion.

[BigTim55]

[BigTim55]

What does linking the rear mean? And whats the difference between 3 link and 4 link?

Sent from Xavier School for Gifted Youngsters

[KF5ZXT]

'Links' is a term used to describe a live axle locating setup. There are several different methods for locating a live axle under the truck, including leafs, radius arms, and links. Your rear axle is currently located using leaf springs. A 66-79 Ford Bronco is located using a radius arm setup, which has two arms (both fixed at the axle end) which then run back to the frame (where there will be a joint, typically a bushing or heim joint). A Link system will differ from a radius arm setup in that the mounts at the axle end will not be fixed, but instead have a joint (again, typically a bushing or heim). Since this would allow the axle to rotate with only two links, a third (or even fourth) is added towards the top of the axle to keep it from rotating. The advantage to the link setup vs. a radius arm setup is that as the suspension cycles, your steering knuckle angles maintain their proper geometry. They also, typically, offer much better flex. The difference between a 3 and four link is the number of top links that an axle has. Justin's Explorer has a three-link, mine has a four link. One isn't necessarily better than the other, though a 3 link has less potential for binding (and is also cheaper, since there is one less link/two less joints), but is more difficult to set up correctly, and has less redundancy in case of failure). All three links require a fourth link (I know, sounds off), called a track bar (or sometimes panhard bar), that locates the axle from side to side. Without this link, the body of the truck would just shift side to side when you turn the steering wheel. Most 4 links ALSO require this track bar, but a properly triangulated 4 link does not. A triangulated four link will have opposing links, typically, the bottom links will be angle out towards the ends of the axle, and the top links will be angled in towards the center of the axle. Most newer Jeeps are setup with a four links suspension with bushings. Older ones with leaf springs. I can find the exact years for those, if you like. If Justin ever shows up to something again, I can show you the difference between the three link and four link with a real world example.

For now, here are some diagrams:

This is a triangulated four link:


This is a three link with trac bar (Like Justin's):


This is a four link with trac bar (Like mine):


This is a radius arm with track bar setup (Like Parker's):


This is all very general, of course, there are other types of suspension setups, such as one links, 1/4 and 3/4 elliptical, etc.

[KF5ZXT]

[BigTim55]

Locker question. What locker types are there? I know air lockers and e lockers? But what's the difference? And which locker is "best" not out just those two but out of all of them, I just don't know any others

Sent from Xavier School for Gifted Youngsters

[KF5ZXT]

The term 'best' is subjective of course. In my opinion, there are five main types of differentials:

Open
Limited Slip
Automatic
Spool
Selectable

The way a differential works, is that they transfer power from the engine (through the transmission, through the transfer case, through the driveshaft, and then to the ring & pinion) from the ring & pinion to your axle shafts. The way that each type does this is slightly different.


An open differential has it's own internal gears. The side gears (which are in turn engaged to each axle shaft) are allowed to turn independently from each other. An open differential will apply the power from your motor through the path of least resistance. This is desireable in street driven cars, because this type of differential allows the axle shafts to turn at different speeds, which is necessary when turning. However, because this type of differential always follows the path of least resistance, you may find yourself with one of the two tires either in water, or up in the air. The problem here becomes that once a tire has lost significant traction, all of the engine's power is transferred to the tire with least resistance, in this case the tire in water or in the air. You may have noticed this while driving a car on the street and hitting a large puddle; your engine RPM's will rise dramatically, while your vehicle seems to slow down. This is because the tire in the puddle is spinning at a faster rate on the water's surface, but without any traction to move you forward. Meanwhile, the opposite tire might be on dry pavement, but is getting no power from the engine, causing it to lose rotational speed.


A limited slip is nearly identical to an open differential except that it will contain either springs or clutch packs that, when under a certain amount of torque, will attempt to engage both spider gears at once, which has the effect of transferring power to both axles shafts. This type still allows slippage between the two shafts. I believe there is no debate whatsoever that this type is preferred to an open differential off-road, and on-road under wet conditions. Examples include Eaton Posi-Trac, Gov-Lock, and most stock traction aiding devices.


An automatic locker, like an open differential and a limited slip, consists of internal gears. The difference here is that an automatic locker will engage, when under torque, both side gears into a locked position, forcing the transferred power from the engine to both axle shafts equally. This means that when you have that one tire in the air, or in water, the opposite tire is still getting equal power and will move at the same speed as the tire with no traction. You will not see an increase in engine RPM's while you slow down, unless of course both tires lose traction at once. When not under torque, these differentials will still allow you to turn while on pavement without binding up. Some are more sensitive than others with regards to how much torque is needed to force engagement. Examples include: Detroit SofLocker, Yukon Grizzly.


Unlike the aforementioned differentials, a spool has NO side gears. It is basically one solid peiece of metal. These are generally the cheapest differentials you can find. They force both axle shafts to move at the same speed as the ring gear AT ALL TIMES. Not very street friendly, as they will force the inside tire on a turn to 'chirp' since it is moving at the same speed as the outside tire in a turn, but in a smaller amoutn of space. Since these are very simple, there is nothing in them to break, other than the case itself. So they are very reliable.


A selectable differential is one that is controlled by the user, either through an electonic interface (e.g. E-locker) a cable (e.g. Ox Locker), or pnuematics (e.g. ARB Air Locker). These types vary a little in what type of differential they can be selected into, though most go from an open differential to an automatic locking differential type. These are often the most expensive, often require modification or replacement of the differential cover, and have the most moving parts/things that can go wrong. People love them, because they offer the streetability of an open differential and the off-road performance of an automatic (or spooled) differential. You specifically asked about the difference between an e-locker and an air locker. An e-locker is typically an open differential that can be 'locked' by way of an electronic switch. An air locker is is very similar, except that it is engaged by an electronic switch, that then engages an air compressor which then forces air into a part of the differential that 'locks' it by maintaining a certain pressure.



Soemthing should be said about the difference between a full-case and a 'lunchbox' differential as well.

A full-case differential replaces the entire differential that was stock in the vehicle. They are larger, more robust units that are less prone to breakage. It is required that you remove, and thus re-install/re-set, your ring and pinion to install these units. To my knowledge, all selectable differentials are full-case differentials. Examples include: Detroit SofLocker, Yukon Grizzly, ARB Air Locker, Ox Locker, Full Spool etc.

A lunchbox differential replaces only the spider gears in your old, stock differential with those of the new unit. They basically fit inside your old differential. The upside here is that they are cheaper, can be installed in anyone's driveway, and do not require that your ring and pinion be re-set. They are smaller, and less robust, and thus are not as strong. Examples include Detroit EZ Locker, Powertrax Lock-Rite, Powertrax No-Slip, Mini-spool, etc.

Since you asked for my opinion, I think that full-case, automatic lockers are 'the best.' Of those, I recommend the Detroit SofLocker and Yukon Grizzly. Of course, that all depends on application. If you are driving a full out buggy/dedicated offroad vehicle, then an automatic locker in the front a spool in the rear and you'll be good to go. For a vehicle more oriented to trails, but still having to drive on the street, I'd recommend automatic lockers front and rear; UNLESS, your front axle does not have selectable hubs. If you have full time or automatic hubs, I would recommend an automatic locker in the rear, and a selectable locker in the front.

[TxPlates]

I had the Yukon's in my 2001 Ford F150 that I had lifted awhile back, worked really well. I've also had a power trax no slip, and Aussie in my old Sport Trac. I had an open carrier in the original Trac I had, and when I locked it I replaced the carrier. Was cheaper to do that and get a locker vs a locker that went into the open carrier.

[Gmanpaint]

Ok, This is the hardest part of a SAS to me, and the math is def not my strong suit with the geometry involved. My question is one topic, but two fold at once.
I am sure this is one of the hardest topics to cover, as not all are the same, but their has to be some kind of rules of thumb or a general guideline for it.

Which is the best location for a Trac bar mount on the 1st & 2nd gen Explorers, with full or narrowed width.

Inside frame?
Underside of frame?
Outside of frame?

I was originally going full width, and purchased a Ruff Stuff steering & track bar kit. ($$$!) I got the mount for the outside of the frame, thinking I was going full width, but I changed my mind.
Will I have to purchase a different mount for the narrowed set up?

For those not familiar with this kit, it is a HD DOM tube using 1 ton GM TRE's, Johnny Joints, and has an offset angled Pitman arm TRE. Fully adjustable at all ends.

Also, what is the best way to set up the axle mount for the trac bar? Placement, and dimensions? Pre-fabbed or home made mounts?

Great thread BTW!

[TxPlates]

I'm just curious, why did you change your mind on the full width?

[KF5ZXT]

Thank you sir. 'Ideally,' you want your track bar to be the at or near the same length as your tie rod, so that when it cycles through your suspension, bump steer is reduced, so long as the next step is followed as well. In reality, it is often wherever you can make it fit, especially when modifying a factory vehicle. The longer it is, the more suspension travel you'll be able to utilize. I had a standard width SAS and now a full width SAS, and both track bar mounts were outside of the frame.
The track bar mount on the axle needs to be wherever it needs to be to have the same angle from the ground (at normal suspension rest) as your drag link (the part of your steering that goes from the steering pitman arm to your steering knuckle). You want the drag link and track bar to be as parallel as possible. As far as making the bracket vs buying them, they are so cheap these days due to everyone having a CNC machine that it almost makes no sense to make one yourself, when you can buy one dirt cheap, and modify it as needed. I would say that you do not need a new mount.

Other companies that you can check out for the pre-made mounts and .

[Gmanpaint]