This morning I was doing some research on what I should do as far as lockers go. Below is a post I saw on another forum with a good summary of options. I think I am going to buy the Mini Spool as our Samurai is not used as a daily driver.
Whenever a vehicle turns, the outside wheels travel a longer arc (distance) than the inside tire. An open differential is designed to handle this by allowing the tires to spin at different speeds. Pretty animations, and explanation here: HowStuffWorks "Open Differentials"
. This keeps the tires from scrubbing in turns. But, the tire with the least amount of traction gets all the torque. If one tire's getting traction, and the other isn't – the tire with NO traction spins, and the tire WITH traction just sits there = you're stuck.
A locker makes the axle “solid”. Both wheels will turn at the same speed – so even if one tire is up in the air or free-spinning in loose dirt, the other tire will pull you through. This traction aid is like adding a tire size or two, so you can go more places with less tire, less lift, less gearing correction, less power & MPG loss and may help avoid the need for a new wheel offset. It's far more bang-for-the-buck than larger tires.
Locker selection is one of those areas where there's no such thing as a “best” option. The only way to know which is best for you is to understand how each works, how much each costs, and what comprises they make. All but the selectable & limited slip options are going to be harsher on the drive line. If you beat your rig, design the drivetrain's beefiness as if using a tire size or two larger than what you're running.
Spool ($110): Makes the axle all one piece. The tires always act the same way, are always locked, and will always rotate at the same speed. As with any locker, this will cause you to loose traction if too much power is applied in low traction events (any slick road event). However, this behavior is very predictable and easy to avoid by using less throttle in bad weather (or more throttle if you like to power slide).
Pros: Cheap, more predictable than auto locker in inclement weather
Cons: Harshest locker on tires, axles & other drive train components. Not good to use in front differential. Causes wider turning radius.
Welded aka: Lincoln or Fozzie ($ Cost of weld): The gears inside the diff are welded up basically making it a super-cheap spool. There's a few methods for doing this – anyone want to share pics & links?
Pros: Same as spool, but cheaper.
Cons: Same as spool. IF the weld wasn't done properly, it's easy to over-heat the gears and make them brittle... which means they're break easier.
Lead ($ Cost of lead): Similar to the welded locker. Molten lead is poured into the diff gear set & allowed to dry. Might have to get creative with sourcing lead, and a mini-foundry (search google & youtube: “DIY lead foundry” “lead casting” - that type of thing). WARNING: Lead is extremely toxic, and molten stuff burns – handle accordingly.
Pros: Same as welded, but reversible
Cons: Same as spool
Auto Locker ($200-$300): The locker will “sense” when it needs to be locked or unlocked. When you're turning, it should unlock to save your tires & relieve stress from driveline. Lockrites seem to be more reliable (and popular) than the Detroits.
Pros: Cheap way to save tire wear. The models for Suzuki's have “fuses” (shear pins: $15) in them that are designed to break under too much stress. When front axle is engaged, it's easier to turn than spool.
Cons: The auto locker sometimes “guesses” wrong, and acts like a spool at the wrong time. This can make what's called a “winding & banging” as the axles load up & the locker suddenly releases that energy. Makes a ratcheting sound during turns (this is the locker staying unlocked). They also take a tire rotation or two to engage (so, if the other tire is spinning fast, there will be a shock load on the drivetrain – keep this in mind when “rocking” between forward & reverse). The moving parts & shear pins breaking on trail makes them less reliable than the spool (but theoretically may save your driveline).
NOTE: Toyota & Dana axle users have access to the “Aussie Locker” which has a vastly superior design than those available to Suzuki. No whine / back / ratcheting issues, and they're bulletproof. Must purchas directly: Home page - Aussie Lockers - Welcome to Torq Masters Home of the Aussie Locker
Selectable Locker (ARB: $200+ for compressor & fittings, $800 per differential. KAM: $1,200 & comes with heavy duty axle – KAM is not available for Tracker): Other than price, this is the no-compromise locker. The driver selects when the locker is engaged, and when it's not.
Pros: Easy on tires & drivetrain. Usable in front or rear without penalty. Retains resale value. ARB requires an air compressor to work – which can double as a tire inflater (Need optional $200 kit).
Cons: Price. If ARB air line leaks, or compressor goes out: so does the locker.
Limited Slip Differential ($500): While this technically isn't a locker, it's worth mentioning here. It doesn't “lock”, but if one tire looses traction, it will transfer some (about ½ that of what a locker will) power to the other wheel. It's perfect for vehicles that will see mostly street, and occasional off road use. In any kind of “real” rock crawling, the LSD will just overheat and cause damage to the LSD.
Pros: Street-friendly. Great for snowy roads.
Cons: Price. Limited usability off-road. Calmini only product.
NOTE: If you run a locker, you MUST keep the tire pressure the same or you will have problems. You MUST run a full-sized spare.
What'd I miss Any other advice and thoughts on lockers out there