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As for what speed you can be travelling when the CDL is engage, it doesn't matter, there will be no limit, all you really need is that the front and rear axles are travelling at the same speeds.
I've been known to slip it in and out at 100km/h :angel:
As for gravel road speeds, it all depends on the road surface, tyre type, tyre pressures, your skillset, run off, etc, etc.
The old 'drive to the conditions' comes to mind and use your common sense.
Well I've been wondering about cdl on my d2 myself, I've engaged on the move lots now, any where from 2kph to 60kph but was wondering if I'm ment to be engaging on the fly? As I've never heard a crunch grind or even had any trouble engeging it I'm starting to think that it's ok to do? Also with TC I've had engage at around 80kph I was on a dirt road near the farm (hargraves) and hit some corrigations that made the car skip a little ( was around a corner that dropped away aswell!!) and traction control flashed on but it didn't seem to noticeable what ever it did, so I'm not 100% I was doing over 80kph but I know I was doing 90kph when I first hit the corrigations but soon as I felt the car start to skip/slide a little I was to focused on the road/car to look at the speed and i didn't look down until after and the speedo said 75ish and the TC light was still on for another 2 or so seconds
As long as you are travelling in a straight line and the wheels aren't spinning you can engage/disengage the CDL
(and if you can spin your wheels at 100km/h plus, can I have a drive, please ? :D)
As rick130 says, it doesn't matter what speed you're going. What matters more is to engage the centre diff before you loose traction - you don't really want the front & rear wheels rotating at wildly different speeds when you lock the diff.Quote:
Originally Posted by disco2_dan
So - bottom line - if you're on a loose(ish) surface and you're not sure, better to lock the diff than not.
Sorry, but I can't get my head around the idea that braking distance at a given speed will be shorter for a 4wd vehicle when 4wd is engaged. If each wheel has a brake, then applying those brakes will reduce the wheels' tendency to turn and by so doing reduce the vehicle's speed. How will the fact that all 4 wheels are under drive (or when in 2wd, only 2 wheels) affect brake performance?
I thought the same when I read that...but then I was thinking silicon hoses must be some sort of performance upgrade too so hopefully someone can clear this one up!
All to do with weight transfer the rear wheels can lockup and skid not good:(
With the center diff locked the rears maintain the same speed as front as long as you have a rear locked diff[ not the best;) ditch the front tailshaft lock the center diff and drive it like you stole it:angel: not recomended but fun just the same:D
Brake lock is caused by a lack of traction - if the tyre looses grip when braking then the brakes stop the tyre from spinning, hence the lock - if I understand correctly. So then, a tyre under drive will have more traction than a tyre carrying vehicle weight only (the 2 undriven tyres of a 4x2), so the risk of brake lock on a 4x4 would be less than on a 4x2. That makes sense - thanks for the clarification!
Interesting one this! Ok, first, the CDL... As everyone before has said, no problem engaging it when on the move on dirt when in a straight line. Just don't do it when going around corners or when you are stuck with the wheels spinning!! If you are traveling in a straight line, both axles are covering the same distance.... so the center (transfer box differential is rotating as one lump and the bevel gears within this diff are stationary). If you are turning in a circle, the front axle is traveling in a greater arc than the rear... This means that it it is going marginally faster than the rear axle... (The longer the wheelbase, the greater the speed difference between the two axles). At this point, the small bevel gears in the center differential are rotating within the housing (which is also rotating!). All very confusing, but this means that the two interlocking halves of the center diff lock are rotating at different speeds so must not be engaged... Hope that made sense and helped a bit!!
Re braking hard, yes you are right in thinking that all the wheels should be braking the same amount, BUT, they never really do.... As said before, when you stand on the anchor pedal, you get thrown forward and upward.. You can't see it, but so does the rear of your Land Rover.. (unless you are driving a series vehicle!!:D) Stand on the brake pedal hard enough, and there can be very little weight on the rear wheels... meaning they lock (becoming fairly ineffective..). This is made worse on dirt because the left wheel is usually on the looser gravel, so is also loosing traction.... if it does, and your rear wheels are locked, suddenly the only wheel with any grip and being of much use is the front right. When this happens, your rear end suddenly decides to overtake your front end in a clock wise direction!! All great fun if you are expecting it, but not so much if you are in a 130 with an overloaded roof in a foreign country. (Just ask my SWIMBO)!! Sooooooo, by having the center differential LOCKED, when you do plant your foot on the STOP pedal, you are lessening the chance of the rear wheels locking as they are directly locked/linked to the fronts, and if you do manage to press hard enough and get all four wheels locked, at least you are still traveling in a reasonably straight line!! Also, with the center diff locked, you WILL have to stall the engine to lock all four wheels, whereas with it unlocked, if you lock the rears and manage not to stall the engine, it will try and drive the fronts and keep going!
Turned out a bit longer than planned but hope it makes sense and helps!!!! :)