Thread: Hill decent and slippery stuff

Originally Posted by gghaggis

I've only observed chains being used in clay/mud twice, both times by rather, er, boisterous lads. They certainly worked, but the condition they left the track in had a lot to be desired. Perhaps a more contained driver would have done less damage.

Cheers,

Gordon

Chains are used by the farming community here quite a bit. It is true that they can be used without ripping the ground apart but in general they cause a hell of a lot more damage than rubber. I have chains but I would not use them on a public track, and many clubs will not allow drivers to use chains on club runs although I have seen it done.

The correct chains (there are different types of course) on a vehicle makes a huge difference in traction, mud or clay.

Originally Posted by gghaggis

I've only observed chains being used in clay/mud twice, both times by rather, er, boisterous lads. They certainly worked, but the condition they left the track in had a lot to be desired. Perhaps a more contained driver would have done less damage.

Cheers,

Gordon

Thanks for your comments Gordon.

My observation of chains being used in a situation that involved a mixture of mud and half buried tree roots was to see a number of vehicles fitted with MT tyres (no chains), spinning wheels, sliding and bouncing around before in most cases, eventually having to be snatched or winched over the obstacle. Then along came a guy with AT tyres fitted with chains and he just idled through with complete control and no more than about half a revolution of wheel spin. It was a most impressive demonstration of how effective, and when used sensibily, less damaging to vehicle and environment the chain equipped vehicle was.

I agree though, that if not used with restraint, they would do extreme damage to tracks.

It is interesting that there are many threads on very agressive, oversize MT tyres but very few, if any, on the use of chains in mud.

Originally Posted by Xtreme

It is interesting that there are many threads on very agressive, oversize MT tyres but very few, if any, on the use of chains in mud.

Well, in many public areas, chains are illegal. MT's are not.

Cheers,

Gordon

As Extreme has said chains used sensibly in mud give amazing grip and do far less damage than spinning agressive muddies. They are absolutely awesome on slippery hard packed clay hills such as our CREB track up here. Cheers Rob

Hi,
in about 1964, the track into Blanket Bay (Cape Otway, Vic) was clay, and rutted with longitudinal grooves.
In an FX Holden, I was stuck with the front wheels in one groove and the rear wheels in the adjacent groove and going nowhere.
Ladder snow chains got me going again, even with a hill start.
Yes, driven conservatively you can get traction with little track disturbance.



cheers

In my view HDC is a waste of time for any trained driver (and yes I'd love an explanation as to why it isn't). All it does is apply the brakes for you, and you can do that yourself. ABS works in low range on the D3, so I'm not seeing any advantage whatosever. HDC is of course only applying the brakes for you and does so to a set speed, it can't see the likes of a washout or spoon drain coming and slow things down more or less depending on the terrain and the manual control isn't as quick to react as foot pressure.

One technique that will help is driving through the brakes, ie holding the brakes on with your left foot and applying accelerator to force the wheel to turn slowly. That'll keep the wheels rotating whereas just applying brakes or using HDC is constantly trying to slow the wheel, not force it to rotate slowly. That makes quite a difference.

Also, HDC can be a little rough and jerky and it is not difficult to be smoother by braking yourself.

If the rear locker could be manually locked that would be nice as then you wouldn't lose engine braking on an axle should one wheel slip. But we can't.

HDC works in reverse too, FWIW.

Totally agree with Gordon re chains in mud. Also, trying to fit the buggers....not very nice! At least snow is just cold!

Originally Posted by rmp

In my view HDC is a waste of time for any trained driver (and yes I'd love an explanation as to why it isn't). All it does is apply the brakes for you, and you can do that yourself. ABS works in low range on the D3, so I'm not seeing any advantage whatosever. HDC is of course only applying the brakes for you and does so to a set speed, it can't see the likes of a washout or spoon drain coming and slow things down more or less depending on the terrain and the manual control isn't as quick to react as foot pressure.

There has been plenty of discussion on these forums about these. Just do a search if you really want that explanation. No one else has said one is better than another. What has been said is that a specific technique is required when using HDC. That was not what the OP was asking for anyway.

Oh, and there are not many "trained" drivers off-road. Are there even many on this forum, you know, that have been formally trained?

Originally Posted by rmp

One technique that will help is driving through the brakes, ie holding the brakes on with your left foot and applying accelerator to force the wheel to turn slowly. That'll keep the wheels rotating whereas just applying brakes or using HDC is constantly trying to slow the wheel, not force it to rotate slowly. That makes quite a difference.

Umm, frankly. That's a recipe for disaster. No way are the reactions of your one brain going to be faster than the computers controlling the various vehicle functions.

And by the way, that is exactly what HDC is doing. Engine turn wheel, brake control slippage.

Originally Posted by rmp

Also, HDC can be a little rough and jerky

So? So is the ride on rough tracks.

Originally Posted by rmp

HDC works in reverse too, FWIW.

Said that.

The one main advantage I can see with HDC is that it can apply braking to select wheels depending on lock-up - ie it will release/partially release a wheel that has locked up. A driver-controlled braking technique could never enforce that fast enough to make a difference. You can 'drive through' the HDC too, balancing the car between braking and forward momentum with the throttle. This is a technique best done in GGS mode, so that you have greater control over the throttle and diff lock-up.

It's not the solution to _all_ descents, but it can be pretty impressive when used correctly.

Note that the HDC in the 2010 models is much smoother and quite unobtrusive.

Cheers,

Gordon