Whoops - Got the Yeti stuck!

[Joel SHOEMARK]

Joel, not all 4x4 Yetis have the Off-road button.

Yeah mate, it's an option here in Australia. The Brochure for Australia lists EDS for the "off road tech" but not for models without "off road tech".

In this situation the diff is operating like any normal open diff. EDS (Electronic Diff Lock) is the electronic program that brakes the spinning wheel and caused drive to go to the wheel that's still on the ground. As the normal version is not listed to have EDS I wouldn't expect any more to happen.

[r999]

In both videos it is noticeable that as soon as the wheels start spinning the driver eases off on the throttle, so I go back to my comment at #14; keep the power on!!

Thanks for that. I think it fully explains the Octavia Scout video. Initially the driver is tentative with the power because he is inhibited by being so close to the wall and fence. When he uses more power, the car climbs.

[BossFox]

Offside rear is in the air, nearside front is spinning noisily, other two wheels are taking all the weight, and the car is going nowhere.

But you can't clearly how much power is being sent to the wheels.

Without a bit of power the car won't start using it's electronic system to look for grip.

It doesn't look like much, which is why it's going nowhere. But hard to be sure.

So you're never going to get a conclusive answer from a very short couple of seconds of video.

[VWD]

Usefull bit of advice I got in the wilds of Africa, when I made a comment on how great LR were in mud. "It's not WHERE it will take you, that you worry about ,but WHERE it won't.

[r999]

Some may still be interested in this thread from 2010: http://www.briskoda.net/forums/topic/159259-4x4-systems-tested/

As Johann said then, the first video in that thread, the roller test, is fascinating. It makes me wonder why the 4WD community has not come up with a few simple, standard, consistent tests for 4WD capabilities. The roller test would be an obvious one to start with. Instead, 4WD vehicle reviews rely on the vaguest comments about off-road abilities, comments that are subjective, impressionistic, and unverifiable. "The deepest sin against the human mind is to believe things without evidence" (T.H. Huxley)

[Llanigraham]

Because every system is different, so there can be no one test, plus what one person expects from a 4x4 is different to anothers.

[r999]

I didn't say one test. I said a few simple, standardised tests. Like the tests done for fuel consumption, or rolling resistance, or acceleration times, or any other objecively measureable attribute of vehicle performance.

[Ootohere]

The wheel on the side with the least resistance is always going to spin when it is an open diff, & it does not matter if you can give drive to the front and rear, its still going to end up with the wheel with least resistance spinning at each end and this can be no drive to the wheels solidly on the ground.

The electrics can slow the wheel down to try and allow it to get traction, but its still not providing drive to the other wheel.

You need to lock the axle by locking the diff (axle one & centre one) or Limiting the slip in the diff, that can be mechanical, hydraulic or electrical, but you need something or AWD, Part time 4WD etc easily becomes 'no wheel drive'..

Then the tyres still need to grip, its better if its at least one front and back.

so its horses for courses really.

george

It not rocket science, if at least one of the 4 wheels has positive drive,

& it helps if the tyres can stay on the ground & the tyre can bite.

[James I]

The Yeti does this by applying brake pressure to the wheel that is spinning, by default the drive then has to go the other way to the other wheel, in principal acting along the lines of a limited slip diff. Hence the need to keep your foot on the accelerator until the magic is done.

[Llanigraham]

I didn't say one test. I said a few simple, standardised tests. Like the tests done for fuel consumption, or rolling resistance, or acceleration times, or any other objecively measureable attribute of vehicle performance.

How?

So are you going to use the same set of tests for the Yeti, a Impreza and a Defender?

Sorry, but that is like saying that EVERY car has also to be done the same way.

It isn't possible.

[Ootohere]

Within a 7th of a revolution of the wheel it is applying the brake on off like abs & slowing the wheel.

As you well see and the point of the thread is you are still not getting drive to the other loaded wheel.

Good if you were.

george

[Llanigraham]

George,

what your Suzuki does bears no relationship to how the Yeti (or Freelander) copes with a cross-axle situation. With them the electronics senses the wheel is spinning and applies the brake on that wheel, locking it solid. The remaing wheel then takes the drive through the diff, and you drive away. It does NOT go "on & off".

When I did my course with LR we drove a Freelander where 3 wheels were mounted in roller skids, and all the drive was through 1 rear wheel. The Yeti system would allow the same.

[Ootohere]

I know it doesnt resemble, & neather do may suzuki jimny's resemble a standard Jimny system, but neither of them systems are getting gets stuck.

I had Freelanders td4 autos.

I drove a few Yeti 4x4's when they first went to Dealers and took them off road & then had one for a week.

It did what it can do & tyres help.

Soft Roader tho & thats it really.

I like them, but you would not go anyplace serious with one. Well i would not,

to expensive and to easily cross axled.

george

http://www.en.wikipe...Haldex_Traction

http://www.en.wikipe...el-drive_system)

http://www.borgwarner.com/en/Heldex-AWD/default.aspx

[yetifabia]

I hadn't really intended to start a debate. I just wanted to share a bit of news and maybe get some sympathy

For what it is worth:

- I do have an off road button and it was on.

- The brakes did seem to go on - off, but I believe that was because the other wheel started spinning when they were applied.

- We have had torrential rain and the ground off-road is basically slime.

- There is no way that I would have put any car into that sort of position deliberately. I would not expect anything even vaguely usable as a road car to get out of it.

I am still entirely confident that my Yeti will do what I need as long as I refrain from silly mistakes

[BossFox]

The electrics can slow the wheel down to try and allow it to get traction, but its still not providing drive to the other wheel.

You need to lock the axle by locking the diff (axle one & centre one) or Limiting the slip in the diff, that can be mechanical, hydraulic or electrical, but you need something or AWD, Part time 4WD etc easily becomes 'no wheel drive'..

Then the tyres still need to grip, its better if its at least one front and back.

so its horses for courses really.

george

Agreed on the horses for courses bit.

Yet is a softroader and less compromised for daily use than a hardcore 4x4.

But the spinning wheel is not braked to allow it to find grip.

It is braked to force the torque to go from the spinning wheel with no traction through the open diff to the wheel on the other side to try and get the vehicle moving.

If this does not get you moving it's because you are not giving it enough power to get the system working or there is just not enough traction available to get the vehicle moving.

Various vehicle manufacturers have used this system for some time now.

When the Discovery mk2 came out in the late 1990's Land Rover thought that because it had this it didn't even need a locking diff in the centre. And it worked!

Just too many people moaned as they couldn't see a Land Rover without a big lever to move cogs around or wanted more precise control of the 4x4 system so a difflock was added back as an option extra. But the fact is that the system of using the vehicles brakes to simulate a rudimentary locking axle and centre diff worked well enough.

[Peter a Proud Yorkshireman]

Graham and Richard you are spot on! Been a bit wet this "summer" and several times in sticky muddy and very wet situations on the decidedly non off road racing Pirellis. Yorkshire Show early July in lots of mud with cars and horseboxes stuck everywhere (some for two days), went into no mans land to try and get round, got suck for a few seconds and as wheels spinning went in reverse a bit then put my foot down and apart from a bit of left and right slewing got out no problem! Yorkie really shi-ten up though !

Cheers :beer:

Peter

Not an off road specialist but has come in several times since then is`nt technology wonderful! When to put on the goodyears is the next thought.

[BossFox]

Nice pics of your Suzuki playing George.

Here are some of mine.

Disco is one of the ones with no centre difflock I took across the Sahara desert, relying on it's electronic traction control.

[Ootohere]

I use a Jimny in rear wheel drive all the time now and took the rear lsd out of it last winter after being in for a few years.

I am happy enough with vehicles with electrics and had a few,

its just worth understanding their limitations and the advantages.

? Reading the various Australian Yeti reviews, is there a LSD in the rear & is it mechanical or electrical.?

Is the front working by using the EDL?

george

[Joel SHOEMARK]

My Australian Yeti doesn't arrive until Jan/Feb next year but I haven't read anything about a LSD, just EDL.

[Joel SHOEMARK]

Sorry EDS, what Skoda abbreviate their EDL as. I don't know what EDS stands for.

[Ootohere]

http://www.motorbar.co.uk/yeti20tdi4x4_0210.htm

[Joel SHOEMARK]

Funny they say pushing the off road button changes the LSD. I always thought a proper LSD was a mechanical device. Unless they mean it changes the EDL program.

[Norry]

Funny they say pushing the off road button changes the LSD. I always thought a proper LSD was a mechanical device. Unless they mean it changes the EDL program.

Having had a "proper" LSD in a previous car I think the Yeti system that uses the brakes to divert the torque from the spinning wheel to the other one is far superior. With the LSD mechanism inside the diff housing the lubricating oil became very burnt and contaminated with swarf from the clutch discs and caused problems wearing the bearings and causing the clutches to grab etc.

I suppose this can still happen in the Haldex unit though?

[Joel SHOEMARK]

This really looks like the rear wheel is being braked (EDS), not like LSD.

[Joel SHOEMARK]

But this doesn't show the front wheel being braked much at all, if any. It just seems to spin free and they use mometum to get through not and traction control.

I'm wondering if it's the differance in vehicles with "Off Road Tech" and those without. I have specified "Off Road Tech" ($790) on mine.