ATRAC damage, discussion.

REDrum

REDrum

Aventurero de la Selva
Stop messing around, sell the Lexus and buy a 98 or 99 UZJ100 with factory F & C lockers. Then add an ARB front and on-board air and be done with it. I'm not against IFC. But, ATRAC is for light wheeling, snow, and wet grass on the soccer feild, not for real wheeling. Its a very good product, but it, and the AHC, are for girly-man trucks. Every truck at VOT with only some type traction control pained thru a lot of the tricky stuff. Those with selective lockers used them discretly and effectively.
 
Ace Brown

Ace Brown

Retired Ol’ Fart
REDrum said:
Stop messing around, sell the Lexus and buy a 98 or 99 UZJ100 with factory F & C lockers. Then add an ARB front and on-board air and be done with it. I'm not against IFC. But, ATRAC is for light wheeling, snow, and wet grass on the soccer feild, not for real wheeling. Its a very good product, but it, and the AHC, are for girly-man trucks. Every truck at VOT with only some type traction control pained thru a lot of the tricky stuff. Those with selective lockers used them discretly and effectively.
Click to expand...

Are you serious? A-trac is for "wet grass and girly-man trucks". There is no trail in Moab that has not been run with A-trac with assist from rear lockers. Now I'm not going to say it can conquer the trails that are buggy only like in BFE but it has run everything offered at Cruise Moab, even Pritchett Canyon more than once. Maybe you ought to take a ride in an A-trac equipped rig with a competent driver and get your eyes and mind opened.


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S

shmabs

Explorer
ATRAC

From what I have seen in of ATRAC in action I will offer my two cents, and what I have seen in action is a bone stock FJ Cruiser TT on 265/75/16's in moab with a competent but fairly inexperienced driver.

ATRAC Seems to do a very, very good job of keeping forward progress happening. Is it always the smoothest thing? no, but rarely would I think that it is so 'unsmooth' to cause breakage (the gm gov-lock comes to mind). Transient mechanic brings up a very good point from a purely mechanical standpoint, and it makes perfect sense. But I have also seen in action the above mentioned FJ hanging a front wheel, with one rear wheel in a whole, and the other on a solid surface, able to maintain forward progress coming up very steep, long climb on kane springs in moab. Myself and a few gentlemen with some large buggies were quite surprised. But at this point, the driver had enough experience to know how to drive using the a-trac.

As far as it being for girly man trucks and wet soccer fields, I can't say I agree. I was amazed at what it was doing a fairly difficult trail, with a mild rig. The driver and all those watching were VERY impressed with "a traction control that actually works on a real trail"

My experience is certainly limited, but from what I have seen of ATRAC, I don't feel as though it could cause axle breakage in the instance of excessive wheel speed suddenly stopped by traction. But then again, transient mechanics logic seems to really make sense to me......

Mike

Edit:upon reading, REDrum...were you joking? I suck at forum sarcasm
 
RobRed

RobRed

Explorer
I've used ATRAC a lot. It's very capable when used properly and will get you most places a locker will. Most. There are significant caveats when using a ATRAC and if used improperly will create damage. In a 100 series LC that damage is the ring gear in the front diff. In this example is the classic ATRAC oops... Bouncing the front end.

http://youtu.be/v1QqHZ7Sme0
 
proper4wd

proper4wd

Expedition Leader
One of the big differences in perspective is from the terrain that you drive.

REDrum and myself are here in the northeast... where I can affirm that because of muddy/rutted/slippery situations, a locking front diff will get you much farther than any traction control. This is because a lot of our technical driving requires a certain amount of momentum to be carried through. By the time traction control reacts to wheel spin, the vehicle has already lost forward progress and there isnt enough traction to get it moving again.

With a locking diff, the driver has the advantage of being able to read the terrain ahead, recognize the additional traction will be required, and engage. When the vehicle reaches the challenging terrain, it does not have to react to the changing conditions on the fly like traction control does.

Much of this is dependent on terrain... on perfectly dry slickrock yes traction control may get you 95% of the distance a front locker does because it is all very calculated and slow movements. In the middle of the woods, in 2' deep ruts, climbing a twisting trail over rocks and stumps, its a different ballgame.
 
RobRed

RobRed

Explorer
Thats a good data point. As you may note I said "most" of the same places. I shared the above video to show that damage can occur when using ATRAC, referencing the OP posts. That happens to be dry slick rock. We've seen reports of ATRAC blowing a diff on ice as well.

I live in California and we have a variety of surfaces and environments to drive on. There are times when ATRAC's near instant, momentary response will keep forward momentum when you can't see or judge every nook or crevice. This response wouldn't be possible with the locker. There are advantages.

In this example of a mixed slippery surface we demonstrating the do's and don'ts on ATRAC. It works well.

http://www.youtube.com/watch?v=R9-CxmH_9ng

In this example ATRAC is useless and lockers were used:

http://www.youtube.com/watch?v=tRx-nbAjz5s




If you read my posts on this topic I like having both ATRAC and air lockers
 
Ryanmb21

Ryanmb21

Expedition Leader
Should all ATRAC be considered equal? Toyota has been using it for about 12 years and I'm sure (hoping) they are making improvements. What may be true of one truck, of a particular vintage, may not be true of another.

Or, is it all the same?
 
RobRed

RobRed

Explorer
There will be nuances to each iteration of ATRAC and TC from other makers. The 200 series Crawl Control is updated ATRAC and more.

I find these threads amusing as they become ATRAC vs Locker. The best solution is both systems. That gives you a choice when to use which traction aid. It's sort of like asking which is better... MaxTrax or a Warn 10k Winch? Each have valuable uses and neither one is best all the time.
 
zimm

zimm

Expedition Leader
REDrum said:
Stop messing around, sell the Lexus and buy a 98 or 99 UZJ100 with factory F & C lockers. Then add an ARB front and on-board air and be done with it. I'm not against IFC. But, ATRAC is for light wheeling, snow, and wet grass on the soccer feild, not for real wheeling. Its a very good product, but it, and the AHC, are for girly-man trucks. Every truck at VOT with only some type traction control pained thru a lot of the tricky stuff. Those with selective lockers used them discretly and effectively.
Click to expand...

one cannot rile me thru mere words, although i fully encourage the attempt.
 
zimm

zimm

Expedition Leader
while im being persuaded that a system that includes atrac isnt always benign, id like to point out, that the potential damage stated has to do with a rapidly spinning tire... which means the atrac at that time isnt engaged, which means more often than not its being driven poorly by an inexperienced or impatient driver, and the truck is operating as an open diff. i know, as ive done it. BUT this is no different than heading into an obstacle, in a locked truck, unlocked, which i see happen ALL THE TIME. so, apple to apples, one has the chance of misusing the systems, and causing damage in that manner. whereas, the locked diff has ample opportunity while engaged to cause driveline carnage, not possible while atrac is engaged.
 
zimm

zimm

Expedition Leader
transientmechanic said:
Here's the issue,

Traction control of any kind (not just "ATRAC"), works by applying the brakes to a wheel to equalize the resistance between the two wheels, in order to try to make both wheels turn at the same speed.

If wheel A is on solid rock and needs to pull the vehicle forward, it may take 1000 ft lbs of torque to turn.

If wheel B is in midair, it will take essentially 0 ft lbs of torque to turn. So traction control will apply the brakes to wheel B until approximately 1000 ft lbs of resistance is achieved and both front wheels will turn.

You are now putting 2000 ft lbs of torque through the front driveline and differential to move the vehicle forward, with 1000 ft lbs to each wheel.

With a locked diff, the vehicle would move with just 1000 ft lbs of torque through the front driveline and differential. With just 1000 ft lbs to wheel A and 0 ft lbs to wheel B.
Click to expand...

"thru the front driveline" is an obfuscating statement. you will NEVER get 100% of the total output of the engine to one wheel in an atrac system, whereas you will EASILY do that in a locked truck.

thats what breaks driveline hicky-ma-doodles. a brake frozen wheel in an open diff is not the same as a spool.

also, the atrac disengages at a high rate wheel spin, and a locker never does.

i understand the advantages of a locker, i just dont see why there are those that act like lockers dont also have the highest risk for that reward.
 
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