I think my biggest prob was tyres 16 x 7.5 even at 10psi they looked like road pressure, they just didnt want to pull me on to the sand just bulldoze through it:D
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I think my biggest prob was tyres 16 x 7.5 even at 10psi they looked like road pressure, they just didnt want to pull me on to the sand just bulldoze through it:D
Tyre size will not be the problem - but very stiff sidewalls or belt may well be! The theory is that the area of tyre spread out over the sand is inversely proportional to pressure, but this ceases to be accurate if the tyres are very stiff.Quote:
Originally Posted by THE BOOGER
(I spent nearly two years driving over the Simpson on 7.50 x 16 tyres)
John
Agree with the general points about hi range in sand, but low range has its places too, for example in tight, twisty inland tracks or when doing anything at slow speed. For example why stress your clutch in high range during a 3 point turn in a tight area, use low. And if your speed isn't going to get much beyond say 25kmph on some track, use low range so you have a wider choice of gears (2-3-4 low), in effect a close-ratio gearbox, rather than just first with occasional grabs to second.
But so much depends on the situation, and the car's gearing and torque. Some cars can lope along in second with barely any revs, whereas others need their engine high in the rev band to go anywhere.
dm_td5 says driving on sand is not an exact science. Spot on.
JD also makes a good point about stiff sidewalls. A classic example is a Suzuki Sierra on 35" Simex JT2s, the car doesn't have the weight to flatten the tyre for a larger contact patch.
The big problem with using low range compared to high range is that the lower the gear, the easier it is to produce enough torque to break traction. How much of a problem this is varies with both the vehicle and the driver, but given an unskilled driver, the highest possible gear for the circumstances is the one least likely to get the driver into trouble on sand.
The other important point in sand driving is to avoid changing gears as much as possible, especially when going up hill.
John
When it comes to tyres you really need to play with it and work out what your safe to run them at and look out how much they belly out giving you a longer foot print in the sand, ive found my MTRs on both my trucks are alot stiffer in the sidewall then most other tyres so i run them a little lower, but you have to be carefull you dont go so low you pop the off the rim.
when i first got the 37x12.5 on my county i started running them at 14, that my almost no difference to road pressure so i droped to 10, still no good it wasnt till 8 they started to sit well and going a little lower makes it feel like a tractor :)
in my old disco i had BFG MTs they were perfect at 12-14 when i changed to MTRs i had to drop down closer to 10, same with the MTRs on my prado (265-70-17s) they are crap on the sand at anything about 12, 10 is the the sweet spot for them.
I have run on old bar treads 7.50 16s in my mates old SIII, they were VERY stiff and we had to drop them very low to make them handle the sand well, i dont remember exactly how much it was several years ago.
They were crossplies probably. When radials first became available they made a big difference in sand, mainly because the sidewalls were so flexible. Modern offroad radials though have much stiffer sidewalls, and for this reason you are better off in sand with road type tyres as a a general rule.Quote:
Originally Posted by cal415
John
Do that in WA and you will look like this :pQuote:
Originally Posted by cal415
[IMG]http://photos-d.ak.fbcdn.net/hphotos..._5222710_n.jpg[/IMG]
Photo courtesy of Klappers having fun in the Lancelin Dunes // Yes he was running reduced tyre pressure & CDL
Mike
:)
\Quote:
Originally Posted by isuzurover
Sorry but complete crap.
If that was the case then how can drive around in High without the CDL in .Same as driving in low as far as the center diff is consered
I think you are confused ,Driving on the road with the CDL in will bugger the center diff in no time
As a Trained land Rover Off road driving instructor. Land rover say to engage CDL when the terrrian looks bad and traction may be lost. In other words when you see a bad bit or are about to climb a sand dune than engage it and when you are finished then disengage it . They say just because you are not on tarmac does not mean you should engae CDL
This is the reason you can put a land rover in and out of CDL whilst on the move and don't need to stop or engage the clutch to engage or disengage it
I didn't read it that way (IZUZUROVER quote) .... He was referring to "off road" ... In Perth it is either "Pea gravel" roads or Sand as per the photo aboveQuote:
Originally Posted by Reads90
Mike
:)
I think that the reason for engaging the centre diff on rough roads comes from the effect of driving on severe corrugations. The problem is that on every corrugation, with the centre diff unlocked, front and rear axles are alternately clear of the ground so all power is transferred to the axle with no traction, via the centre diff. a moment later, the axle regains grip, giving an impact type load to the gears. This can go on for hours or even days. How severe the effect is depends on how bad the corrugations are and how fast you are going (but bear in mind that the normal way of driving on corrugations is to go fast enough that the wheels don't drop right into every corrugations, and you have very little overall traction!). Traction control will greatly reduce the effect (Discoverys without diff locks for example).
It is certainly a problem with corrugations, but whether it is a problem with a lot of other offroad, I doubt. (This has nothing to do with whether you are likely to get stuck, just whether you are likely to damage the centre diff by not locking it offroad). One of the problems with Landrover's instructions on the matter is that as far as I know it is quite rare to find roads with corrugated gravel for hundreds of kilometres at a time. In Australia it is quite common, although perhaps not as much as it was thirty years ago.
John