Thread: ATB Diffs

Originally Posted by komaterpillar

I know the guys with 1 or 2 ATB's will disagree and defend savagely their decision but this was how I decided on the setup I have. I would have liked the onroad benifits of 2 ATB's but I wanted at least one positively locked diff and the ability to just put her in bog cog and crawl over an obstacle like a twin locked setup lets you do. No input from ABS or driver just lockers in, 1st low and let it do its thing.

Absolutely no disagreement or savage defence coming your way from me.

You made a perfectly valid choice - you value "crawl over an obstacle like a twin locked setup lets you do" over a liking for "the onroad benifits of 2 ATB's" and that is a perfectly valid choice. ATB's will never quite work as well as full lockers in the situation you you care more about. Good decision.

Originally Posted by Slunnie

IF the ATB does "90%" of what a locker does as some claim then it has to be nearing the forces of a locker, except that it also has the shock forces of the wheel spin required to make the ATB work and the ETC working on it. If the ATB isn't adding much additional stress to the driveline then its not doing much additional at all. Its not the general loading of the axle the breaks them, its the impact loading of when it grabs traction while spinning.

Thats the thing. In the few places where a full locker reigns absolutely supreme, nothing else really will come very close. In steane's ranking ATB (with TC) may be No.2 - but its not necessarily a close second in my view.

To get an ATB equipped vehicle to be half as good as a locker, when staring up a steep rutted climb with a wheel or two hanging in air - one would have to be brutal on the drive line. (whereas, all things going well, fully locked may walk up). The key here though is the term "half as good" which:
a. is just my opinion related to just the scenario described
b. is why risk of breakage is less with an ATB. Your own turn of phrase is applicable here: If its 90% as good as a locker then it has to be nearing the forces on driveline as seen with a locker. I dont reckon its anywhere near 90% thus nowhere near the kinds of driveline loads that are seen with a locker.
(As always acknowledging: one can still break stuff running ATBs or open diffs if you try hard enough)

Then factor in reality: In this situation the ATB equipped vehicle may try a few times and not succeed, then its time to break out the tow strap or winch. A bother but you still get to the campsite eventually.

depends what you use your 4wd for.
i do many touring. so a locker is not needed 99.999% of the time.
if your a mud freak who only does offroad travel, a locker might be cost effective

Just something I would like to add.
One of the things that make an ATB more effective as well as open diffs I guess is suspension travel most notably articulation.
I had an Quaife ATB in the front of my RRC and I would remove the sway bar when I was planning a long dirt trip like Cape York. The added articulation would ensure the dropped wheel had some ground contact and energise the ATB.
If I ever have enough dosh to put one in my D2 I would get front swaybar disconnects as well as the front swaybar is humungous.
Please can the complacent" I have ACE" comments. I have nice reliable springs unlike the poor bloke I met outside of Mildura topping up his ACE oil every couple of ks to get to a workshop. LOL
Regards Philip A

Part of the fun of ETC or ETC with ATB's is being honestly able to tell onlookers "No mate she hasn't got lockers fitted" when you go places most 4wds can't go unless locked front and rear...

Cheers

Even if that is something of an untruth

Originally Posted by ozscott

Part of the fun of ETC or ETC with ATB's is being honestly able to tell onlookers "No mate she hasn't got lockers fitted" when you go places most 4wds can't go unless locked front and rear...

Cheers

hehehe I hear ya! Guilty of that too. (and its COMPLETELY true, Disco Muppet. they aren't "lockers").

One trip in particular comes to mind - the first trip into the Malaysian jungle for my barge was to a trail I hadn't travelled before. The vehicle was only a year old and had been treated with kid gloves til then. The group I used to hang with told me the trail is not hard at all, and not to worry about my stock standard Defender making it. They lied. It was a set up.

We hit the first serious obstacle about 15 min after leaving the tarmac. It was about 1am. I was in the middle of a convoy of 7 vehicles (none of the others were land rovers). Couldn't see the obstacle but could hear the screaming engines and chatter on the radios as the three big lifted and locked trucks ahead of me struggled and thrashed about trying to get through. Was parked up for about 30 min waiting blindly for my turn.

Then the radio crackles "Land rover next - all come look!". The crews of the three vehicles behind me all ran forward past me to join the three crews ahead of me at the obstacle. I idled forward in low 2nd til the obstacle came into view. Oops! That section is affectionately nicknamed "The rock garden". Big rocks, gullies, side slopes and plenty of ways to get cross axled. Selected low 1st, feet off. Focus only on picking line. Idled through it entirely. Disappointed the entire convoy who were evidently hoping to see the Landy perform hopelessly.

Of course it wasn't the ATBs that got me through. Pure driver skill and excellent lines, not to mention my greatest virtue - a modest and unassuming demeanour.

And the point of the story: I felt no grief or guilt at all in rubbing it in that my STOCK STANDARD(!) Defender shamed all their rigs with their 35" or 37" tyres, lockers, and horsepower.

Much like Tact the thing i love most is my standard height 110 on 33s fully locked idling over almost everything whilst patrols and cruisers on 35 amd 37 inch tyres struggle. The standard articulation complimemted with my lockers makes for an excellent all round set up.

The front and rear lockers allow me to have a extremely capable offraod vehicle that can tackle any track and the centre diff atb allows it to be an excellent tourer offering the added safety of locking in slippery fast terrain. Persoanlly i think my setup offers the best of both worlds and thats what i set it up for.