ETC+CDL vs Diff Lockers

[Brian McVickers]

I thought this dialogue started between Euromom and Scott is a good one but did not want to take up too much of Articulates thread with it so here it is...

I have Traction Control with a Center Locking Differential and find the setup to be incredibly capable. However I can think of two benefits to having a rear or front and rear Differential Lockers:

1 - Reliability, with Electronic Traction Control you are relying on your brake system and all of its parts so if the ABS or other component fails you now have lost capability. With an air locker or similar you have a mechanical component that may be less likely to have problems.

2 - The ETC and CDL combination has a bit of a delay while the ETC is thinking and deciding what to do. A locker has an instantaneous action which may be safer in some situations. The ETC could also potentially cause more trail wear as it spins a tire while it's thinking.

These are just some thoughts about something I don't know a whole lot about so if I am way off base here feel free to point it out!

Also - What is the reason for disabling the ETC in deep sand? Is it so that you don't dig yourself in??



Quote:
Originally Posted by eurorom
How do you figure that, have you actually used the Xterra or Frontier in deep sand on the dunes? I am very relunctant to venture in a very remote area with DEEP SAND on a Xterra or Frontier.However I will get a NISMO Frontier with the locking differential and try it out....AGAIN
I tought I would need momentum and speed to climb the dunes???


I have driven many vehicles (05 Jeep GC, Discovery II, Freelander, Range Rover, 4Runner, etc.) with traction control and find it to be a significant improvement over open diffs.. Pull the fuse or wire in a dissable switch for deep sand if necessary.
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#95 Yesterday, 03:01 AM
expeditionswest
Super Moderator Join Date: Jun 2005
Location: CA and AZ
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Here are a few good examples of traction control in use:

http://www.expeditionswest.com/adven...r42_climb1.wmv

http://www.expeditionswest.com/adven...scott_lift.wmv

http://www.expeditionswest.com/adven...over_mound.wmv
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Scott Brady, Tread Lightly Master Trainer
Expeditions West

 

[asteffes]

I think one huge issue with pseudo-limited slip and traction control systems that rely on the brakes is that it's easy to overheat or wear out your brakes! I've seen this happen with track-driven Infiniti G35s that use the rear brakes to simulate a limited slip rear differential - after a session or two, the brand new rear brake pads were completely worn down to the metal backing plates. The brakes are actuated by the computer to minimize wheelspin which, on a track-driven car, happens all the time. If you're spinning the wheels a lot in sand or other low-traction surface, I would imagine a vehicle with a brake-based TC or LSD system would suffer similarly.

 

[david despain]

i have to agree with the brake wear issue. i know of folks with discovery IIs that go off road a lot and brake wear is a concern. to just a weekend warrior i would imagine its just an anoyance and incovienance to only get a year or less out of a set of brakes and/or rotors. as to the deep sand question, momentum is your best friend in the really soft stuff and this system by design will rob you of momentum usually at the worst possible moment. now having said that for 99.99% of the drivers out there this system works great and doesnt place undue strees on the really expensive components ie transfer cases and drivlines and 3rd members etc. take you average soccer mom who just uses the little knob to the left to hang her purse on that accidently drives to get junior from school with the diff lock engaged and blows up the x-fer case even though it kinda drove strange and now u have an unhappy customer that wont buy that brittish crap again cause its in the shop again. but thats a whole other issue altogether. my wife loves the ETC and i must say that in the snow it works fantastic.

 

[Scott Brady]

Traction control has a few issues:

1. Delay, with various degrees of response, some harsh. This can unsettle the vehicle.
2. In order for the traction control to work, it must slow or stop a spinning wheel, which robs power.
3. CDL or part-time transfer case is an absolute necessity IMO, for traction control to be safe and effective.
4. Traction control requires wheelspin to activate, so it is harder on the trails and the vehicles tires.
5. It is electronic, which can fail
6. Some systems can get confused in mud and sand, and lock the brakes down (to stop the spinning wheels) until the truck gets stuck. The Land Rover system does not have this problem.

The best solution is CDL+Traction Control+Selectable Lockers. I have found times when traction control is better than a locker (like ice and snow).

The Range Rover system is incredibly effective, the best I have tested.

 

[Scott Brady]

Here is a video BEFORE I installed the CDL on my Discovery II. It is kind of hard to see the tires spinning, but the vehicle had to work very hard to clear the obstacle.

http://www.expeditionswest.com/vehicles/ewvehicles/Land_Rover_Discovery/ricepeakLR.WMV

 

[goodtimes]

Ya know, I really don't like a bunch of fancy gadgets controlling how my vehicle acts (guess that is why I own a jeep wrangler). I can see a distinct advantage of the electronics on non-technical terrain with a few easy to moderate challenges. The systems are improving, but I would not want one on a technical trail. When I want my axles locked, I want them locked...not have the brakes applied on one side or the other with one tire turning and the other not....that is the purpose of a locker..to ensure that neither tire turns slower than the ring gear. The downside of this is tire wear, and even trail damage. For example, with a locker engaged during a tight turn, the inside tire will spin, or the outside tire will drag...there is no way around it. With the electronic controlled stuff, this isn't the case....but you don't really know when the electronics are doing their job or not.

As for the center diff locks.....well, IMO, there is no need for them. Real transfer cases shakin: ) are either in 2wd, 4wd, or neutral. There is no "kind of in 4wd", or other crap like that. on-off. Reliable, predictable, ain't gonna make you wonder...don't have to push a button to go between sorta-4wd and real 4wd.....just like a mechanical locker....on or off....off or on. You choose where you want it...not some engineer who isn't anywhere near you or have a clue about your situation.

All that said, the electronic junk is probably good for 90% of the drivers out there. The casual user who ventures off road occasionally, but doesn't spend time on the technical trails, or doesn't want to have that much direct control over their vehicles...the casual users....nothing wrong with this....just not my cup-o-tea, and not effective for the trails I spend time on. I imagine it will also create alot of problems as people begin to heavily modify their vehicles (re-gearing, different tire sizes, etc). That is just a guess though....as both of my 4x4's have manual control of pretty much everything....again, it comes back to the types of trails I spend my time on.

 

[Brian McVickers]

Wow, what a difference. Almost looked like you were standing still there for a while.

 

[goodtimes]

4. Traction control requires wheelspin to activate, so it is harder on the trails and the vehicles tires.

Interesting you mention that Scott, I think it would be the other way around (see my last post for reasoning). It would be interesting to put the two systems side by side, on the same lines, and see the differences in how the vehicles react.

 

[Brian McVickers]

I'll volunteer for testing, sounds like fun!
Brian, if you are going on Secret Pass next weekend we could find a suitable trail and maybe video tape it.
I'll even let you pick the trail and lines!


Um, wait, maybe "suggest" the trail and lines!! Although I may be willing to follow you almost anywhere!

 

[goodtimes]

No "trail" so to speak. Something a little more scientific. More like the "manufacture" of conditions that will exploit the advantages of each system, to highlight the differences between them. This could easily be accomplished on specific parts of a trail like Box Canyon...not the trail as a whole...just specific spots where conditions are right for accomplishing the task.

 

[ShottsCruisers]

Here is a video BEFORE I installed the CDL on my Discovery II. It is kind of hard to see the tires spinning, but the vehicle had to work very hard to clear the obstacle.

http://www.expeditionswest.com/vehicles/ewvehicles/Land_Rover_Discovery/ricepeakLR.WMV

Speaking of that trip....here's a 100-series Crzr in that same spot. It's a '99 and has it's rear and center locked but no TRAC. Notice when it climbs the twisted spot, the rear slides to the side? Another advantage of TRAC is in off-camber situations. A locker will slide ya and TRAC will not.

http://shottscruisers.smugmug.com/photos/26756767-O.mpg

 

[ShottsCruisers]

With the electronic controlled stuff, this isn't the case....but you don't really know when the electronics are doing their job or not.

***You can hear the systems operate and on some vehicles (like my 2001) an indicator lights up.

As for the center diff locks.....well, IMO, there is no need for them. Real transfer cases shakin: ) are either in 2wd, 4wd, or neutral. There is no "kind of in 4wd", or other crap like that. on-off. Reliable, predictable, ain't gonna make you wonder...don't have to push a button to go between sorta-4wd and real 4wd.....just like a mechanical locker....on or off....off or on. You choose where you want it...not some engineer who isn't anywhere near you or have a clue about your situation.

***Depends on vehicle. For safety, the advantages of a Full-Time 4WD system are notable. For off-road trail running though it is essential to lock the CDL.

All that said, the electronic junk is probably good for 90% of the drivers out there. The casual user who ventures off road occasionally, but doesn't spend time on the technical trails, or doesn't want to have that much direct control over their vehicles...the casual users....nothing wrong with this....just not my cup-o-tea, and not effective for the trails I spend time on. I imagine it will also create alot of problems as people begin to heavily modify their vehicles (re-gearing, different tire sizes, etc). That is just a guess though....as both of my 4x4's have manual control of pretty much everything....again, it comes back to the types of trails I spend my time on.

The combo of TRAC and lockers is the best possible setup in my opinion (and experience). When a rear locker alone isn't enough and you lock the front your turning capability is limited and that's when breakage can occur. (ala 80-series) With the 100-series I can lock the rear and TRAC can operate on the front. This gives me full turning capability and added traction. Rarely do I ever need to lock the front. (not the case in the 80)

And believe it or not, I recall many obstacles over the past years where 80's where triple-locked and stuggling while the TRAC 100 crawled right up (and visa versa of course...depends on the situation...though my point is that you're better off having it.). I'd never give up TRAC.

 

[ShottsCruisers]

Interesting you mention that Scott, I think it would be the other way around (see my last post for reasoning). It would be interesting to put the two systems side by side, on the same lines, and see the differences in how the vehicles react.

The results will vary depending on the obstacle. It is fun to watch different vehicles. One of my favorite reasons for wheeling with various model/brand-names.

From my experience...if you compare on the same vehicle model:

Best: Triple lockers (easier on the tires too)
2nd place: TRAC and rear locker
3rd place: TRAC only (CDL only)
4rd place: Locked Center and Rear/Open front (Yes, on the 100-series especially I'd take TRAC over a rear locker model and without question)
Last place: CDL only