TC V Diff Locks

[Aussie]

Is it worth fitting Difflocks if you have TC? also to ppl who have TC in their vehicles, Wot are your thoughts on it?.

[rrturboD]

given that TC functions when wheels are moving at different speeds, and seeing a TC vehicle FIGHT its way up a steep hill, with diff lock, TC would not sense spin of wheels at different speeds etc, so progress should be little less dramatic. Also, consider when TC locks say left wheel, tailshaft is spinning at same speed, so right wheel drives at double the speed to accommodate the stationary left, and is much more likely to spin, TC cuts in, breaks right, releases left, left spins ... and so it goes on.
I'd go for locking diff great for off road and let TC handle tarmac driving.

[Rosco]

given that TC functions when wheels are moving at different speeds, and seeing a TC vehicle FIGHT its way up a steep hill, with diff lock, TC would not sense spin of wheels at different speeds etc, so progress should be little less dramatic. Also, consider when TC locks say left wheel, tailshaft is spinning at same speed, so right wheel drives at double the speed to accommodate the stationary left, and is much more likely to spin, TC cuts in, breaks right, releases left, left spins ... and so it goes on.
I'd go for locking diff great for off road and let TC handle tarmac driving.

I think you've missed the point a wee bit. When TC is activated, it is through the ABS, hence it's not a case of merely locking up the wheel. It's more a case of on/off on/off on/off etc in the blink of an eye.

As for which is better I'd have to say IMO a diff lock would be more definite, but I can't speak from experience, not having experienced one. But I do know for a fact that TC works very well on loose steep ascents and slippery spots.

Cheers

[Aussie]

But I do know for a fact that TC works very well on loose steep ascents and slippery spots.

From my limited experience with TC I would have to agree with this. I took a mate out who has a 94 Land Cruiser, we went up a very steep loose track, I got up it quite easily and watched the LC come up, he had a bugger of a job, took the same line up as I did but had to work very hard to make it up, I put it down to the TC.

[Jamo]

Depends what you want to do.

To some extent TC is retrospective, whereas a positive locking diff is already operating.

Both have their benefits. If you're into extreme stuff, then the difflock is probably better.

In my car the diff locks are controlled by the management system, so they actually form part of the TC system.

[Captain_Rightfoot]

My summary ... they are heaps better than nothing, but not as good as a physical difflock.

The advantages are that they are always on which can be good if you get suprised by a change in conditions. They are quite effective too. They don't interfere with steering the car.

The downsides are they only work for a little while (couple of minutes) and then they overheat and switch off. They are also hard on the braking system if used heavily.

Lockers are slightly more effective (how much depends on the conditions). The only dowsides with them are cost, and if a f&r are fitted steering can be problematic :D :D

[Rosco]

They are also hard on the braking system if used heavily.



Hang about ... we're talking 'bout a Landie here right?? No reason why they should be needed for more than a few mo's or so. :p:p

[gghaggis]

The new TC systems are very effective - look at a current model Defender or D3. They will however, place a heavier burden on the braking system, and are probably not quite as effective as difflocks. On the other hand, difflocks can easily overload your drive train, especially when one wheel in the air comes down to earth rapidly. And I'd rather change brake pads than half-shafts or CV's. So if you don't need that extra 15% ability, TC is probably far more cost-effective in the long run.

Cheers,

Gordon

[JDNSW]

Just looking at it from a theoretical point of view - if the need is because a wheel has lifted off the ground, either a locked diff or traction control will be equally effective, at least in theory. However, if the need is because you are operating very close to the limit of adhesion, and one wheel has less grip than the others, the locked diff will have the advantage over traction control that the wheel with less grip will still provide some drive, where the TC will do nothing until that wheel loses grip. Depending on how good the traction control is, the difference may be almost nothing.
It seems to me that in theory at least, if the traction control operates perfectly, the locking diffs will have only the advantage that all the power is used rather than dissipated into the brakes - as almost all vehicles with TC have plenty of power compared to the amount that can usefully be applied to one wheel, this advantage may not be real. It comes down to how good the TC is in doing what it is claimed to do, and annectdotal evidence is that the Landrover system is pretty good.
Two other observations -
If you have all three diffs locked, then traction control will do nothing. (but if your e.g. front diff is not locked, it will help even if the rear diff and centre diffs are locked).
The major drawback of locking diffs is that it enables you to apply 100% of power and torque to one wheel - unless done with care or you have upgraded axles, expect something to break.

John

[rangieman]

The new TC systems are very effective - look at a current model Defender or D3. They will however, place a heavier burden on the braking system, and are probably not quite as effective as difflocks. On the other hand, difflocks can easily overload your drive train, especially when one wheel in the air comes down to earth rapidly. And I'd rather change brake pads than half-shafts or CV's. So if you don't need that extra 15% ability, TC is probably far more cost-effective in the long run.

Cheers,

Gordon

sorry but who has the 06 D3 here
i have been in a Defender with TC and at slow speeds the TC was useless compared to my none TC Defender but rear diff locked

but get a bit of momentum up with TC and wow it would go any where
so my thoughts on this difflocks on nice and slow :D
TC on you need some get up and go and speed = danger+damage not good:angel:

[tempestv8]

It's best to have BOTH systems then!

:p

Diff lock for treacherous conditions, and ETC for when it's just mild offroading.

My DII is super capable with diff locks, except when I bottom out on my diff due to very deep ruts.... ;)

[Jamo]

The TC system in the D3 is far more sophisticated than that in previous models.

I does not need speed to activate. It will activate at speeds lower than you can probably physically drive the car!

And, as far as I'm aware, the diff lock system in the D3 is capable of 100% lock up.

I've got both TC and centre and rear diff locks; so as tempest said, best of both worlds!

[cmurray]

difflocks can easily overload your drive train, especially when one wheel in the air comes down to earth rapidly. And I'd rather change brake pads than half-shafts or CV's.

Gordon,
I tend to disagree with this. While the wheel is in the air, greater stress will be put through the axle/CV on the ground while the diff is locked, but when the other wheels comes back to the ground, it is more likely to be spinning at a slower rate and closer to the ground speed than an unlocked diff, as the opposite wheel on the axle is transmitting power to the ground, thus less of a shock load, as only half of the power is going through it. An unlocked diff could have 100% of the power going to the axle/CV when it lands, this power will be instantly transmitted through the diff to the other axle as soon as the wheel gets grip, meaning more chance of breaking either of the axles/CVs or even the diff as the change in power distribution is transmitted through the spider gears.

Either way, you just need to remember the golden rule, bouncing equals braking!

[Tusker]

TC is reactive. If you need to keep a bit of momentum, the delay in TC kicking in can be your undoing.

Difflocks are proactive, in that you need to anticipate the need & engage beforehand. Useless if half way across &....

Actually I'm surprised how often the light comes on in "normal climbs". You don't know how often you lift a front wheel.

One thing I don't like about TC is it changes your driving style - it goes against the grain to keep your foot in it when traction is lost.

Regards
Max P

[waynep]

Watching a 4WD with good traction control work its way up is slippery or rocky slope is quite amazing ( well to me anyway ). You can see it working - one wheel will spin a bit, it'll take a think, try another wheel and so on until its gets forward motion. I would presume TC and an auto would be a good comb.
I'd have to think seriously about the need for difflocks in my next car with the TC systems around now.

Heres's a bit of video that give a comparison ( although it's a bit doubtful if the TC in the Disco was working )

http://www.youtube.com/watch?v=elU2e7ZnNz8

[rovercare]

Also, consider when TC locks say left wheel, tailshaft is spinning at same speed, so right wheel drives at double the speed to accommodate the stationary left, .

:eek: No it doesn't, differential action doesn't half/double the wheel speed

[JES]

In my experience TC works well at slow speeds, but not too well at high speeds. The link below shows how it works at slow speeds.
Note the on/off pulsing.

I was travelling with 2 Patrols on the day, one open diffed GQ, and one front and rear locked GU. After picking lines a little better the GQ got up, but the GU made very easy work of it with front and rear lockers on.

http://www.youtube.com/watch?v=D4-E6R0uXLQ

John

[isuzurover]

:eek: No it doesn't, differential action doesn't half/double the wheel speed

Yes it does! - lift one wheel of the ground and the ratio it turns at is about half that when both are on the ground (e.g. 2.35:1 instead of 4.7:1).

So much for your "practical" experience... Never noticed that when a 4x4 with an open diff lifts a wheel that that wheel spins faster???

[cmurray]

:eek: No it doesn't, differential action doesn't half/double the wheel speed
Rovercare,
If one wheel is stationary, the other wheel will spin at twice the speed. If both axles are doing 50RPM with the prop shaft doing 100 RPM, if one axle starts doing 0 RPM but the prop shaft remains doing 100RPM, where does the 50RPM that the now stopped axle go? Out the other wheel, ie double the wheel speed.

[Redback]

Watching a 4WD with good traction control work its way up is slippery or rocky slope is quite amazing ( well to me anyway ). You can see it working - one wheel will spin a bit, it'll take a think, try another wheel and so on until its gets forward motion. I would presume TC and an auto would be a good comb.
I'd have to think seriously about the need for difflocks in my next car with the TC systems around now.

Heres's a bit of video that give a comparison ( although it's a bit doubtful if the TC in the Disco was working )

http://www.youtube.com/watch?v=elU2e7ZnNz8

Wayne that's excactly how the TC works in a Disco, it keeps the car going even with 1 or 2 wheels off the ground, made that hill look easy.

I love the TC in mine.

Baz.

[Jamo]

Yes it does! - lift one wheel of the ground and the ratio it turns at is about half that when both are on the ground (e.g. 2.35:1 instead of 4.7:1).

So much for your "practical" experience... Never noticed that when a 4x4 with an open diff lifts a wheel that that wheel spins faster???

Maybe I'm ignorant, but that doesn't make sense.

The drive shaft drives both axles in an open diff setup. It doesn't split the drive in half. The revs of the driveshaft should be altered by the gearing ratio so it should only half if the ratio says so.

If, for arguments sake, the ratio is 1:1, then if the tailshaft is rotating at 100 revs, then both axles should be rotating at 100 revs.

If in an open diff setup, the wheel in the air spins faster than when on the ground, it should only be because there is no longer the frictional retardation of the ground itself, thus reducing the load on the engine.

[tombraider]

Is it worth fitting Difflocks if you have TC? also to ppl who have TC in their vehicles, Wot are your thoughts on it?.


In a word...

YES



:D

[isuzurover]

Maybe I'm ignorant, but that doesn't make sense.

...

If in an open diff setup, the wheel in the air spins faster than when on the ground it should only be because there no longer the frictional retardation of the ground itself this reducing the load on the engine.

The reason it happens is because of the gears in the diff. When both wheels are turning at the same speed, the pinion turns the crownwheel, but the side and spider gears in the diff remain stationary compared to one another. When you lift one wheel, the side gear on the axle (halfshaft) that is connected to the wheel on the ground now remains stationary (or rolls along with the speed of the vehicle), while the diff centre revolves around it... The change in ratio comes from the fact that the internal diff gears are now turning.

[waynep]

Wayne that's excactly how the TC works in a Disco, it keeps the car going even with 1 or 2 wheels off the ground, made that hill look easy.

I love the TC in mine.

Baz.

The posts on diff ratios and spinning wheels is making my head spin :angel:
specially on a Friday nite !

Anyway ..Baz ... yes I agree ...I've personally experienced much the same situtation as in the video ...my car with rear difflock (as per the Rangie in the vid ) and a jap car with TC ( as per the Disco in the vid ) ..I got up with a bit of scramble and fuss but the TC car got up with much less "fuss". Mind you my driver skills ( or lack thereof )might have been a part of that too !!

[Jamo]

Oh well, as I said, I've got both.: TC and two diff locks. I think I'll keep up with the rest off road, but I'm not sure if they'll keep up with me!;)

[rovercare]

Rovercare,
If one wheel is stationary, the other wheel will spin at twice the speed. If both axles are doing 50RPM with the prop shaft doing 100 RPM, if one axle starts doing 0 RPM but the prop shaft remains doing 100RPM, where does the 50RPM that the now stopped axle go? Out the other wheel, ie double the wheel speed.

I'll eat my words, the joys of posting when you haven't slept after night shift:(

[rovercare]

Yes it does! - lift one wheel of the ground and the ratio it turns at is about half that when both are on the ground (e.g. 2.35:1 instead of 4.7:1).

So much for your "practical" experience... Never noticed that when a 4x4 with an open diff lifts a wheel that that wheel spins faster???

Now Now Ben, this isn't OL:D

[Slunnie]

Is it worth fitting Difflocks if you have TC? also to ppl who have TC in their vehicles, Wot are your thoughts on it?.
It depends on the type of driving that you're doing.

ETC is totally under rated in my opinion, even in sand.

I drive a disco2 with ETC, centre diff lock, front and rear diff lock. My thoughts are ETC is better than no ETC. ETC is better than a LSD. ETC with CDL is better than ETC without CDL. ETC with CDL with 4 wheels on the ground is better than No ETC, but with CDL and a rear locker. CDL and a rear locker is better than ETC and CDL with less than 4 wheels on the ground. ETC with CDL and rear locker is best for climbing offset and angulated terrain and steps. Twin lockers with CDL is the best for crawling extremely difficult terrain but can induce front end movement if wheelspinning. Twin lockers with no CDL is stupid.

[isuzurover]

Now Now Ben, this isn't OL:D

I know, there is no finger:Dfinger icon :D - but it was on here you had a go at me for saying that an LT230 CDL was vacuum operated :p

[953]

I'd have to think seriously about the need for difflocks in my next car with the TC systems around now.




I have front&rear lockers & love them but,financially speaking the above quote makes alot of sense 2 me.

Cheers Dean.

[rovercare]

I know, there is no finger:Dfinger icon :D - but it was on here you had a go at me for saying that an LT230 CDL was vacuum operated :p

:angel:

[D110V8D]

"In true Outer Limits style"


F%$K TC. Toyotas rule!

[isuzurover]

"In true Outer Limits style"


F%$K TC. Toyotas rule!

No - Nissans rule

\toyotas

nissans...

and so on add infinitum like all the threads over there... :D

[Aussie]

Quite a lot of different opinions on this subject, I may settle for a winch and leave the lockers until a later date.

Oh- One question I have is in regards to a Centre Diff lock, can someone explain why would I need a CDL if I had my front and rear Diffs locked. (prob a very easy answer..lol)

[Pedro_The_Swift]

of course,, the OTHER reason TC is better,,

west to east.
Mt Glorious.
in the rain.
towing a camper.

difflocks?!?!

[Redback]

Quite a lot of different opinions on this subject, I may settle for a winch and leave the lockers until a later date.

Oh- One question I have is in regards to a Centre Diff lock, can someone explain why would I need a CDL if I had my front and rear Diffs locked. (prob a very easy answer..lol)

Because the CDL allows for a 50/50 distribution between the front a rear diffs, instead of 70rear/30front or 60/40 i'm not sure of the ratio front to rear power delivery.

The CDL is basicly replacing the old way of locking in the front hubs and selecting 4H or 4L.

Your basicly selecting 4WD from inside the cab.

Baz.

[Ruslan]

Quite a lot of different opinions on this subject, I may settle for a winch and leave the lockers until a later date.

Oh- One question I have is in regards to a Centre Diff lock, can someone explain why would I need a CDL if I had my front and rear Diffs locked. (prob a very easy answer..lol)
I might be wrong, but imagine you sitting on top of sand dune (on rocks, etc.), front wheels of the ground, on back wheel just in touch of the top of the ground, so 3 wheels out of action. If no lockers, no TC, you in trouble. Even with lockers and TC could be not a lot of torque on last wheel. CDL can be helpful here, because 50/50 power goes to axels and "grounded" wheel has more chance to move car from current position :)

Cheers,
Ruslan

[Aussie]

Because the CDL allows for a 50/50 distribution between the front a rear diffs, instead of 70rear/30front or 60/40 i'm not sure of the ratio front to rear power delivery.


Well this raises more questions for me then..lol Does my RR NOT have a 50/50 split front and rear? Also shouldnt a CDL be the 1st thing ppl buy instead of Front and Rear diff locks? My reasoning for this question is surely you would want 50/50 split before you then fit diff locks?

[Redback]

I think your mixing up the D2 with other landies, the reason owners of D2s are getting a CDL is because they weren't in the D2 until 2003, your Rangie on the other hand will have one, if it doesn't then it has a Viscous setup instead.

Depending on what model Rangie you have, will depend on what setup it has, but you won't need a CDL unless the one on the Rangie doesn't work.

Baz.