Thread: Additional Traction - at cross roads with options.

Originally Posted by rangieman

Another positive on Slunnie`s point is with selectable you have the choice of engaging going down steep hills which i do often with the chance of lifting a rear wheel and loosing traction down hill

The technique I use in that sutuation, with ATBs front and rear, is to preload the driveline a little by applying a little brake and driving through it (don't touch the clutch) when its likely to lift a wheel.

I do the same uphill too and manage to surprise myself how well the ATBs work in some pretty difficult situations.


BUT!....
If you are hitting really serious hard core situations, you'll need a fully locked diff, and HD half shafts, flanges, drive shafts etc. ATBs will just make you work too hard, and perhaps hammer the vehicle too hard in such extreme situations.


Different topic....
I have had the detroit style "unlocker" in a vehicle the past. With these units:
- when you are doing the office commute or school run on tarmac, at ANY time other than a dead straight section of road you are only driving one wheel, the inside wheel. (The outer is on overrun).
- often when on a straight section of road, after coming out of a bend in the road, you can still be driving just one wheel. The ratcheting mechanism in the diff linked to the previously outer wheel half shaft may be half a ratchet tooth ahead of being properly engaged even though turning at the same speed as the other side of the diff - its being driven by the roadwheel not the driveline.
- of course, when the (one) driven wheel gets driven to the point it loses its grip on the road surface, then the ratchet mechanism catches up with the lazy freewheeling wheel and it gets drive.
- this is where oft observed "handling oddities" comes from

Conversely, if on a soft or slippery surface where there is room for a lot of wheel slippage almost constantly (sand, mud, ice etc):
- in these circumstances the detroit "unlocker" will basically always be acting like a spool. (or like a selectable locker in locked mode)
- in some situations like this a "locked" diff is not the most effective option (e.g. slippery side slopes)
- unfortunately there is no "unlock" option with the detroit "unlocker" type system
- admittedly getting side-on traversing slippery side slopes are something we would all sensibly avoid.

I haven't driven the ATB's on soft sand but I'm betty they are to the vehicles ability in those conditions. I also.read that they improve braking. Cheers

Originally Posted by tact

The technique I use in that sutuation, with ATBs front and rear, is to preload the driveline a little by applying a little brake and driving through it (don't touch the clutch) when its likely to lift a wheel.

I do the same uphill too and manage to surprise myself how well the ATBs work in some pretty difficult situations.


BUT!....
If you are hitting really serious hard core situations, you'll need a fully locked diff, and HD half shafts, flanges, drive shafts etc. ATBs will just make you work too hard, and perhaps hammer the vehicle too hard in such extreme situations.


Different topic....
I have had the detroit style "unlocker" in a vehicle the past. With these units:
- when you are doing the office commute or school run on tarmac, at ANY time other than a dead straight section of road you are only driving one wheel, the inside wheel. (The outer is on overrun).
- often when on a straight section of road, after coming out of a bend in the road, you can still be driving just one wheel. The ratcheting mechanism in the diff linked to the previously outer wheel half shaft may be half a ratchet tooth ahead of being properly engaged even though turning at the same speed as the other side of the diff - its being driven by the roadwheel not the driveline.
- of course, when the (one) driven wheel gets driven to the point it loses its grip on the road surface, then the ratchet mechanism catches up with the lazy freewheeling wheel and it gets drive.
- this is where oft observed "handling oddities" comes from

Conversely, if on a soft or slippery surface where there is room for a lot of wheel slippage almost constantly (sand, mud, ice etc):
- in these circumstances the detroit "unlocker" will basically always be acting like a spool. (or like a selectable locker in locked mode)
- in some situations like this a "locked" diff is not the most effective option (e.g. slippery side slopes)
- unfortunately there is no "unlock" option with the detroit "unlocker" type system
- admittedly getting side-on traversing slippery side slopes are something we would all sensibly avoid.

In some down hill situations brakes are not advisable .
The way i drive is engine braking and foot brakes are a last resort and with that abs does not help in these situations
Im like the majority with no ATB experience like ive said all along they all have their plus and negative`s .
I don`t get it why it is such a hard choice maybe for the newbie with no experience but for me it is selectable and no i have never had a compressor die when needed nor a air line or any other part of the locker and i have had ARB , and Ashcroft locker`s across 3 car`s over the year`s all with out issue .

Just to add to this database

The badass Pajero evo (Dakar all time record holder with 12 wins) has center open diff but front and rear torsen (another AT diffs.

Also the US military humvee has a similar setup. Open center and torsen front and rear

And this is the same setup I will get for my defender......

P.s. Prado, although I know not many of us acknowledge it's off-road capabilities, has torsen center diff. It is equivalent to the ashcroft ATB in a defender.


Cheers
Martin

They all have pros & cons , for me it was simple is best , the detroit locker is probably the cheapest option , it is probably the strongest & most trouble free option , they are bullet proof and when you need it the most , it is right there , and the additional traction is about as good as it gets for most circumstances .
It was a chioce I made , and getting close to a million k's later , I still love it .

Originally Posted by rangieman

In some down hill situations brakes are not advisable .
The way i drive is engine braking and foot brakes are a last resort and with that abs does not help in these situations
Im like the majority with no ATB experience like ive said all along they all have their plus and negative`s .
I don`t get it why it is such a hard choice maybe for the newbie with no experience but for me it is selectable and no i have never had a compressor die when needed nor a air line or any other part of the locker and i have had ARB , and Ashcroft locker`s across 3 car`s over the year`s all with out issue .

It's not a simple choice even for experienced off-roaders. There is a sound reason why Dave Ashcroft sells so many ATBs. I would be in 2 minds and I have a bit of experience. It's not a simple choice for many. Some people find it a simple choice so more power to them hey.

Cheers

Originally Posted by ozscott

It's not a simple choice even for experienced off-roaders. There is a sound reason why Dave Ashcroft sells so many ATBs. I would be in 2 minds and I have a bit of experience. It's not a simple choice for many. Some people find it a simple choice so more power to them hey.

Cheers

Ditto for my D2.

For what I do with it I think atb's all round are the best compromise and will probably be going that way.

I love selectable, but my thinking is that atb's plus the more aggressive tc that the CDL'less D2 appears to have will be 90-95% as capable as a fully locked set-up anyway.

Anyone that used to be on Outerlimits years ago might remember Sam Overton's 'Lockless' comp buggy?
Instead of being locked all round they fitted it with TruTracs and their own TC.
That thing was impressive!

So...Overlanding has now become rock climbing and you need twin lockers and a whole new driveline HD everything? Ive been overlanding all over this continent in my stock Defenders for 20 years and never needed any lockers. I’ve towed Tojo’s, Nissan’s, Hiluxs out of many gnarly, rocky, hilly, boggy spots without issue. By all means get fully locked and loaded, but I’d be spending my money on a new radiator, new water and fuel pumps, filters, bearings and good tyres ...for Overlanding, which is generally understood as an extended journey.