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arb/truetrack in the front?


superfinder
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hello guys/ladies

I already have a rear arb locker with upgraded half-shafts and etc. But now I want a front "locker". Cost isn't an issue I just want to know what is best for my needs. I just do some serious greenlaning nothing more.

I'm thinking about truetrack or another arb.

when i put arb i will upgrade my shafts and cv's but i know you cant use always 100% lockers when you want and need traction in the front and with truetrack this isnt a problem its always working and it doesn't harm the weak mechanical parts of a defender. Now which one is the best option?

By the way i do every year 25000km's (20000 on road) a year with my defender.

Thanks for the replies

greets

Superfinder

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Manual of some kind, no contest. I run ARB's and they are great. If you put auto lockers in the first time you get in a sticky situation with a side slope, camber or a tight section through tree's on greasy ground you'll regret it. I spose it depends what your doing with them. If its just the odd occasion you need to cross a field or something the auto locking units might be O.K. but anything more serious go for something you can control. Ive seen many people making a bit of a tricky section a disaster because their auto lockers send em off in the wrong direction. With a manual unit its just a flick of a switch and your truck behaves like its on open diffs!

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I've said this before - the TruTrac isn't a locking or limited slip diff. It's an open diff with a torque bias, so it will work just like normal but will 'bias' torque across the diff according to the limiting torque on the wheel with least grip. It's hard to explain in text and even harder in pictures but it's a beautiful beautiful thing if you can grasp the concept.

I'd go for a TruTrac in the front, and indeed I have a TT in the back of my Ninety. It's transparent in normal use, but better when use is less "normal" :)

Edit: it's hard to explain but I'm going to anyway.

u.special1.jpg

The two cross-shafts in the picture are one piece with a spiral and a spur gear on each end. Inside the diff (not visible) is a helical gear which meshes with the spiral. These helical gears are splined to receive the ends of two halfshafts, and the crownwheel drives the red housing. In a straight line with plenty of grip, the whole assembly 'tumbles' and drives the two halfshafts; counter-rotating torques are generated at each cross-shaft but the spur gears mesh with each other and resist it. When one halfshaft has no resistance (wheel in the air), this torque isn't resisted so the cross-shafts turn, the spiral slides across the helical gear and the diff behaves as an open diff. HOWEVER, when one halfshaft has wheel slip but a resistive torque (one wheel on tarmac, one wheel on ice is an extreme example of this) then the angle of the spiral means that the wheel on tarmac receives (typically) three times the torque that the ice-wheel resists, via the involute spirals.

As I said, makes your brain ache but a clever bit of kit.

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I had a detroit and Truetrac in my 90 when I first got into offroading. Sold both of them to fund twin ARBs'. Best move I made in a long time. The problem was I went for 10spl and not 24. Now I'm getting more serious with my 90 I wish I had gone 24 spl route. Not a lot of kit to upgrade in 10 spl.

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I have to disagree here; many people cant use the front locker whenever there is a bend in an offroad situation and with the truetrac, it still allows you to do this. Also, to lock and unlock diffs while offroading is tricky, since you cant unlock them while under load.

The best thing about them is that there is less to worry about while driving offroad; they do pretty much what they need to do at any one time.

As for turning a tricky situation into a disaster: I havent found any situations like this due to my diffs. If someone is turning a tricky situation into a disaster it is Poor driving which isn't going to change with diffs really.

Strangely enough, the story about the detroit locker causing interesting steering effects is not really true: it is the truetrac in the front causing this (power understeer). it is noticeable, but not disastrous. The flipside is that you have to try really hard to break a CV: the truetrac never goes solid and is therefore much kinder on your drivetrain.

Looking back on it, I would go for them again because of beforementioned reasons, but I wouldnt recommend them for a daily driver.

Daan

Manual of some kind, no contest. I run ARB's and they are great. If you put auto lockers in the first time you get in a sticky situation with a side slope, camber or a tight section through tree's on greasy ground you'll regret it. I spose it depends what your doing with them. If its just the odd occasion you need to cross a field or something the auto locking units might be O.K. but anything more serious go for something you can control. Ive seen many people making a bit of a tricky section a disaster because their auto lockers send em off in the wrong direction. With a manual unit its just a flick of a switch and your truck behaves like its on open diffs!
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Personally I would prefer an auto locker, like a no spin for the rear and an lsd for the front. I like the simplicity. If I were using Land Rover axles then a Detroit Locker rear and Tractech Truetrac front would be my nirvana

Strangely enough, the story about the detroit locker causing interesting steering effects is not really true: it is the truetrac in the front causing this (power understeer). it is noticeable, but not disastrous.

Daan

I was under the understanding that it is the Detroit locker that provides the steering effect, due entirely to the way it works: like a ratchet that can allow one wheel to turn faster than the pinion and the other wheel but not slower. In an open diff the outside wheel powers you around the corner whilst the inside freewheels. Whereas in a Detroit Locker equiped vehicle the inside wheel is pushing you around the corner and the outside wheel does the freewheeling

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Personally I would prefer an auto locker, like a no spin for the rear and an lsd for the front. I like the simplicity. If I were using Land Rover axles then a Detroit Locker rear and Tractech Truetrac front would be my nirvana

I was under the understanding that it is the Detroit locker that provides the steering effect, due entirely to the way it works: like a ratchet that can allow one wheel to turn faster than the pinion and the other wheel but not slower. In an open diff the outside wheel powers you around the corner whilst the inside freewheels. Whereas in a Detroit Locker equiped vehicle the inside wheel is pushing you around the corner and the outside wheel does the freewheeling

It is what i was thinking; although in a normal diff both wheels do both exactly the same work, regardless of speed. The detroit will put torque on the inner wheel only while going round corners.

I did remove the front prop a while ago and all of a sudden the understeer had gone completely. so if you are driving the rear only, the effect is not noticeable (or at least in my setup).

daan

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