Off-Roading Know-How – Preparation

Part one – Preparation

In the last few years, there has been an enormous increase in the popularity of off-road vehicles. More than ever in our environmentally-conscious world, all those who own or use any off-road vehicle must have a better knowledge on how, when and where to drive them off tarmac.

In this section, David Bowyer, who, incidentally started his school in 1986 in Devon, begins by going back to basics. The next chapters will cover all aspects of off-road driving. In this part David covers the first part of preparation. ‘Preparation’ is contained within three sections: Preparing your vehicle, preparing yourself and passengers and preparing the route you intend to take. Remember those three ‘P’s’.

Nick Dimbleby joined David Bowyer with his Range Rover to spend a few days driving some of the many delightful vehicular rights of way in Wales for this feature. The third member of this small convoy is David Spreadbury, from Dorset, who brought along his Discovery 300 Tdi.

David Bowyer, naturally, took along his well-known red V8 90. Don’t be fooled by the Tdi decal on the offside front wing. The wing was a second-hand replacement and he left the decal on it to fool his friends. But most of you know David is a V8 man!

Preparing Your Vehicle

It is so essential to prepare in all respects before tackling your off-road journey ahead, whether that is simply crossing a muddy, hilly field, greenlaning across the moors or driving up into the mountains – or about to embark on a major expedition across a continent. Obviously the amount of preparation depends on where, when and what you are going to do.

Know Your Vehicle

For starters it’s important to know your vehicle. No I’m not joking! Let’s say you bought, only a week ago, a little old Land Rover. Can’t wait to driver ‘her’, ‘him’ or ‘it’ (they always have nicknames, don’t they?) along that muddy track and up onto ‘that’ hill.

Before going off-road, get to know the vehicle in all respects. For instance does it steer nicely, do the brakes function properly, is the suspension in good order? Is the transmission working perfectly, i.e. the main gearbox and transfer box? The last thing you want when descending your first steep hill off-road is for either the main gearbox or transfer box to drop into neutral. Oh? It happens to even the tidiest little Land Rover purchased.

Read the Manual

If the vehicle is new to you, I suggest you give it a thorough going over from top to bottom. And a good way to go about that is to purchase from the LRe Bookshop (if it is not in the vehicle) the appropriate driver’s handbook. In it there will be at least two sections. The controls and operation of them, and maintenance together with servicing schedules.

The first section should tell you everything you should need to know about your new acquisition. What operates what, and why. The second section will lead you through what adjustments should be made to the mechanical side of the vehicle, what needs topping up or changing and above all, what needs checking throughout.

When driving off-road, especially in quite rough conditions, the strain on most of the vehicle’s components is enormous by comparison with driving on the tarmac. So without doubt for the sake of safety and reliability, your vehicle must be in first-class working order in all respects.

Perhaps the vehicle you have just bought is only seven or eight years old. But if that vehicle has, to your knowledge, been used for most of its short lift, off-road, then the same thing applies as our little old Land Rover. Simply get to know the vehicle.

Check for Rust

All Land Rover vehicles have a chassis. Don’t take it for granted that what the towing hook is bolted to is solid.

The rear crossmember could be terribly rusted through, which could cause unbelievable problems if the back of the vehicle parted company when being recovered backwards or when you are recovering someone else forwards, or you may have badly rusted dumb irons on the front at the point where the bumper attaches to the chassis.

Imagine being stuck up to your axles in mud and being recovered forward. The vehicle in front takes off, the rope tightens with a jolt, and then there’s a bang and a lurch. You sound the horn to stop your friend from continuing with the impossible. He stops; you both get out and look at the front of your beloved Land Rover. The bumper has moved a good three inches forward taking the front leaf springs and axle with it. The chassis has snapped behind the front spring hangers, the front prop shaft has fallen apart, the axle being connected only by the now horizontal rear spring shackles. And the whole of the front of the vehicle has dropped alarmingly. Even worse, you are stranded miles from anywhere.

Believe me, it is in your interest to make sure every square inch of that chassis is rust-free. If there is a problem, have it repaired professionally. It’s better to be safe than sorry.

Or perhaps you have recently taken delivery of a brand new vehicle. Well, still read and digest the handbook thoroughly and get to know the vehicle well before going into the rough.

Have it Serviced

Whatever vehicle you use, and whatever its age, the best way to ensure that it is ready to be taken off-road is to have it serviced regularly.

If you are to do a lot of off-road driving on a regular basis, i.e. most weekends, then expect to tighten up the servicing schedules enormously. As a rule of thumb, at least halve the mileage between each service, if not more! Especially if you enjoy driving muddy water areas.

Whilst I am on the subject of water and maintenance, consider the following: if you are an off-road enthusiast or simply enjoying using your Land Rover to its limit, when driving consistently through deep water, especially stagnant water with much mud in suspension, you may enjoy it, but your vehicle certainly won’t.
Quite simply muddy water destroys vehicles! Think about it. The mud simply eats brake disc pads, drum linings, suspension bushes, oil seals, their flanges and bearings. The poor chassis’s life could be affected as well as any metal parts of the body. And if the mud does get in past the bottom door seals it won’t do the carpets, if fitted, any good either.

Driving your vehicle through such areas occasionally, probably will not do much harm, but on a regular basis, expect problems and expensive maintenance.

Now, depending on what make or type of vehicle, and if it is petrol or diesel you are using, there are the following points to consider.

Having checked all fluid levels, i.e. engine oil, water, brake and clutch fluids, power steering and washer bottle, waterproofing is next, especially if you know that there is deep water to cross during the journey ahead.

Wading Plugs

All Land Rovers, Defenders, Classic Range Rovers and Discoverys have either one or two wading plugs to be fitted. Every one of the above has a threaded hole at the lowest part of the clutch ball housing. This hole should be left open for all normal on-road driving conditions.


Bell housing plug position on newer vehicles


Flanged timing case wading plug behind the crankshaft pully

The reason for having this hole in the first place is to allow any oil to escape that may be trapped in the bell housing coming through from either a poor crankshaft seal to the front or a poor gearbox primary shaft seal to the rear. Also, should the clutch slave cylinder fail, hydraulic fluid may be dumped into the bell housing.

On Td and Tdi there is a 'keep' for when the plug is not in use

On Td and Tdi there is a ‘keep’ for when the plug is not in use

So, if we intend to cross, and therefore wade though, deep water, we must plug this hole first with the appropriate wading plug. Until mid 1992, or thereabouts, this took the shape of a tapered threaded plug with a square head. On newer vehicles use a parallel thread plug, which has a flange to stop it being screwed into too far. This flanged type has a traditional hexagonal head.

On all later four-cylinder diesel engines including the Tdi, there is a threaded hole also in the bottom of the timing case cover that is there to allow any oil to escape from a poor front crankshaft seal. This is only applicable to engines fitted with a timing belt as opposed to a timing chain. The plug which we always install here is the parallel threaded type with a flange and hexagonal head.

Both these plugs must be inserted before wading to stop the ingress of muddy water that could seriously affect either the clutch or timing belt. We must not, however, leave these plugs installed because, when wading constantly through deep water, water can still get into these housings through surrounding poor gaskets and the last thing we want to do is to trap water, or come to that oil or clutch fluid, should there be a problem.

It is, therefore, essential to remove the bell housing wading plug, and timing case wading plug (if fitted on your vehicle) on the return journey from every off-road journey. If water does run out you know that you have a poor gasket, probably because the engine or gearbox has been removed, or timing case cover refitted without using Blue Hylomar sealer. No problem, but just remember it. If oil comes out, one day soon you could be having the oil seals replaced! 

Axle Breathers

Whilst under the vehicle inserting the wading plugs, cast your eyes about. Firstly, if the axles are fitted with remote breathers are they both there? Or hanging off? These remote breather tubes should be securely installed with cable ties to both the axles and up into the bodywork.

Their function is simply to allow the axle casings to breath. If you knew no differently and you took the vehicle into deep water with either broken or missing breathers, water would soon be sucked into the axles! Within a few hours of the offending water mixing with the axle oil, the differentials and bearings would be destroyed.

On earlier Series I, II and III vehicles there is a brass valve fitted to the top of each axle. Inside the unit is a ball bearing which stops water from entering down into the casing, but still allows breathing to take place. The problem is, if the ball gets gunged up and sticks closed, the only way the casing is going to breathe through the pressure built up from the revolving differential, is out through either the pinion seal or hub seals. Not good!

If the ball sticks open, then water will be drawn in. In fact it makes a lot of sense to change these old-type breathers for later remote ones if you are going to use your Series I, II or III off-road seriously. Better still, fit a set of raised remote axle breathers along with remote gearbox and transfer case breathers to roof level for serious off-roading. These are available from Mantec Services (tel: 01203-395368)

Assuming the vehicle is well serviced and regularly looked over, there shouldn’t be anything else to check for underneath, but cast your eyes around and make sure everything is in order, including the exhaust system.
One thing worth mentioning here is if your vehicle is absolutely covered in oil underneath around the engine, gearbox, diffs and swivel housings, remember this. If oil is escaping easily, what’s to stop water entering?

When driving through deep water, generally speaking, the pressure in all the housings will stop water from being taken in. But, if your engine stalls in deep water, almost instantly the pressure becomes a vacuum being aided by the cold surrounding water. The housings – with their components still – will simply suck the water in. And if that happens you could have a major problem, very quickly! I will elaborate more later in the series.

Having clambered about under the vehicle, it’s now time to check around outside. Check the tyres for condition. Are the sidewalls in perfect order? Beware of cuts, bulges and damage from previous off-roading forays.


Generally speaking, for Classic Range Rover and Discovery, the standard 205×16 Michelin XM+S244, Pirelli Akross or Goodyear block pattern tyres are quite sufficient for normal off-roading activities in the UK. The standard fitments are a compromise as most travelling is on the tarmac.

You can, however, fit a more aggressive tyre to make an already very capable vehicle even more capable. Tyres that spring to mind are the BF Goodrich Trac Edge. They fit the standard rims and are radial, so, therefore, are speed-rated and come in 225x75x16 size.

There are many makes and types of compromise and outright off-road tyres on the market, but for Classic Range Rover and Discovery I would stick to a narrow section tyre which fits the standard rims and so does not stick out from the side of the vehicle.

As soon as you fit wider tyres on wider rims, which are normally offset, you will not only run a great risk of wheel arch body damage, but you also expose the brake discs and associated guards to possible damage when in deep ruts. When driving through mud or simply on filthy roads, the wider offset tyres also make the sides of the vehicle disgustingly messy for normal use.

In any case, wide tyres of 9.5 inches or more across the tread rarely work well for you when driving off-road in wet hillside climbing situations. Okay, a wide tyre may give greater floatation properties on flat, boggy type ground, but for climbing or descending they don’t cut through the surface and bite as well as they could.

Now, if you are using a Land Rover then you have a greater choice of tyre sizes. Land Rover’s own choice has a job to be bettered; 6.50/205×16 on swb and 90 and 7.50×16 for lwb/110/130.

On swb and 90 vehicles, the Michelin radial 205×16 M&S (Mud and Snow) is a superb radial compromise tyre giving long life, nice gearing and comfort by having flexible sidewalls. It has very good road manners in all weather conditions. If you want additional tyre benefits giving greater ground clearance, then fit any number of a range of tyres that is standard optional fitment on the 90’s larger brother.

The general-purpose tyre for lwb, 110 and 130 is the Avon Rangemaster, with an option of Michelin XZY. If you want a tyre for off-roading rather than for on roadwork, settle for the Michelin XCL pattern. XCL tyres were used on all Camel Trophy events up until 1995 – in various sizes to suit the vehicle being used.

BF Goodrich All-Terrain BF Goodrich Trac Edge BF Goodrich Radial Mud-Terrain T/A

BF Goodrich All-Terrain BF Goodrich Trac Edge BF Goodrich Radial Mud-Terrain T/A

Michelin M&S (Mud & Snow) 244 Michelin XM&S Michelin XZY

Michelin M&S (Mud & Snow) 244 Michelin XM&S Michelin XZY

Michelin XCL Michelin XZL O/R Michelin XS

Michelin XCL Michelin XZL O/R Michelin XS

Camel Trophy vehicles now use a new tyre from Michelin – the XZL O/R. This new off-road tyre has caught my eye with interest.The well-spaced tread blocks look ideal for serious off-road work. The footprint is nice and narrow for biting into a wet greasy surface and the sidewalls are reinforced with rubbing strips to protect the tyre from sideways knocks. Finally Solihull recommends for Sand driving the Michelin XS. All the above tyres are radial.

For swb and 90 you might try BF Goodrich Trac Edge. Use either their 225x75x16 (similar in size to 6.50×16/205×16) or 750×16 giving a greater ground clearance, or for lwb/110/130 use 235x85x16 or 750×16. Trac Edge are Q speed rated to 100mph.

While mentioning BF Goodrich, it recommends for either Classic Range Rover or Discovery the following alternative tyre fitments:

As a general purpose compromise tyre, use its All-Terrain and for vehicles used with a definite lean to off-roading, fit Mud-Terrain. Both are radial and are S speed rated to 113 mph. Many people do, in fact, fit Trac Edge as an alternative to standard tyres, but do bear in mind that they are Q speed rated – fine for Tdi, but not really Efi.

Tyre Choice
Original Tyre Fitment
SWB (short wheel base) 80, 86 & 886.00x16
Land Rover Series I, II & III6.50x16
Land Rover/Defender6.00x16
Note for reference: 205x16 is similar in size to 6.50x16 and 225x75x16
LWB (long wheel base) 107/1097.50x16
Land Rover Series I, II & III7.50x16
Land Rover/Defender 110 & 1307.50x16
After market maximum sizes
SWB Land Rover Series I, II & III7.50x16
Land Rover/Defender 90, 110 & 130235x85x16
Discovery & Classic Range Rover225x75x16
Always ensure the tyre pressures are correct for the weight, load and type of vehicle, and for the conditions that you are going into. Check with your vehicle's handbook.

The BF Goodrich range of tyres are available direct from its main UK Distributors, Southam Tyres Ltd, Southam Drive, Southam, Warwickshire, CV33 OJH, (tel: 01296-813888), or their appointed dealers.

Finally, my personal choice as purely an ultimate off-road tyre is the SAT look-a-like remould ‘Super Mud Plugger’ in 7.50×16. The tread is incredibly aggressive, biting well in muddy conditions, especially when climbing, and obviously grips well when descending. They are also very reasonably priced, but they have a maximum speed rating of 74 mph as the original casings are ‘L’ rated and unfortunately they create much road noise and vibration on the tarmac. But for all that, they are brilliant.

The Mud Plugger Remould

The Mud Plugger Remould

From time to time these Super Mud Pluggers are available in radial as well as the normal cross-ply versions.

You must remember, however, that when purchasing a set of five directional tyres like the Super Mud Pluggers or Michelin XCL, you will have to decide which side of the vehicle the spare will be fitted for. I favour the nearside for a right-hand drive vehicle, as if you are going to damage a tyre, it is usually a front nearside wheel striking a rock in a rut out of view of the driver’s eye.

Grey modular wheels on David Bowyer's 90

Grey modular wheels on David Bowyer’s 90

I’d suggest that if you really are going to catch the off-roading bug on a regular basis using your main vehicle, your best option is to purchase a spare set of five rims and have a set of more aggressive off-road tyres fitted to them. If you are running a Land Rover, changing all the wheels won’t take too long using a high lift jack with a bit of practice.

If you purchase a spare set of five off-road tyres, have them ready fitted and balanced on a set of grey steel modular rims. These rims are very strong and, I feel, look better on the vehicle than white eight spokes.

Remember that both modular and eight-spoke steel rims are made of solid steel rather than shaped steel like a standard Land Rover/Dunlop rim. It is therefore important not only to tighten the nuts after lowering the tyre to the ground, but to re-check the torque a few miles later as there is no ‘sprung action’ of the concave stud hold. Always use a torque wrench to check tightness of nuts.

Right Gearing

Sometimes when you change the tyre size, you can affect the gearing of the vehicle. For example, you could purchase a 90 which comes fitted as standard with a set of 205×16 tyres. After reading this series you may decide to go for a set of larger 7.50×16 or 235x85x16 tyres. Great, lots of ground clearance now. But why is the speedo reading incorrectly? And you find that fifth gear only gets used on a level road with a following wind!

As regards the speedo inaccuracy, simply obtain from your Land Rover dealer a 110 part numbered speedo cable drive unit which replaces the original one on the transfer case output shaft.

As to the over gearing problem, again your Land Rover dealer can change the three gears in the transfer case to match those in a 110 which, of course, comes standard on 7.50×16 tyres. My V8 90 had ‘no go’ at all when I changed to the larger tyres but having changed the transfer gears, it’s back to that brilliant machine!

As regards tyre pressures, having spoken to several tyre manufacturers and importers, use the same pressures off-road as on road. Only reduce the pressures if you have soft ground to cross. Lowering the pressure to 15/18 psi will, of course, give the tyres a larger, longer and wider footprint, giving slightly better flotation. What you must remember, however, is that when back on the tarmac you must re-inflate to the correct pressures to become legal and to save damage to sidewalls through over flexing. The other thing to remember is, of course, when you lower the pressure, the diffs get closer to the ground!

Further Preparation

If you consider that there is a danger of losing your mud flaps, you should tie them up using cable ties, cord or bungey straps. The only time that you can have a problem is when the vehicle has been fitted with aggressive and large tyres. If the mud flaps are in close proximity of the wheel and you need to reverse back through a gully or back to the bottom of a steep bank, you could trap the bottom edge of the mud flap between the tyre and the ground possibly tearing it off its mounting. You have been warned!



This towing hook is too low so will need altering

Rear low-mounted foglights ought to be removed, too, as they won’t last long. Likewise, low front-mounted fog or driving lamps are going to get caught up very quickly even in mild off-road situations.

The front mounted spoiler on the Efi 1985-onwards Classic Range Rover should also be taken off, complete with driving lamps. I know, driving very carefully in mild conditions, you can get away without busting it, but if you are going to tackle any serious off-roading you will be best advised to take it off first when within the confines of your nice clean garage or driveway.

The lamps have plugs and sockets, and the latter simply locates into a spring clip to keep it out of the way. The spoiler itself is fixed with only a few bolts, leaving the number plate bracket in position. Take my advice, if you want to enjoy your off-roading with a Classic Range Rover fitted with a spoiler, take it off first.

Many people think that having a rear towing plate is a hindrance when driving off-road. This is only partially true. The standard drop plate fitted to all Land Rover products is fine. In fact, in the case of Classic Range Rover and Discovery, having this unit fitted actually serves to protect the vulnerable fuel tank from being clouted on the ground should the rear wheels land heavily both together in a cross ditch. The best drop plates are in fact the type with a curved underside, which acts as a shield and skid plate.

After the vehicles have had a thorough inspection and the routhe has been planned, our convoy is now ready to venture off road

After the vehicles have had a thorough inspection and the routhe has been planned, our convoy is now ready to venture off road

The main problem is when a vehicle is fitted with a non-standard ‘lower than normal’ drop plate, which can easily foul the ground when driving in rutted areas, especially when driving down and out of gullies. Another problem when you have a ridiculously low mounted towing point is if you are climbing a steep bank and don’t make the top and there’s no gentle run out at the bottom. You can easily bend the drop plate up into the tank as you land heavily back at the bottom, bending the rear crossmember, too, to make matters worse.

In arduous terrain, the standard drop plate also protects the rear bumper, especially the end caps which can foul on the ground. Another problem, in the case of the Discovery, is if the rear of the vehicle lands heavily in a hole. The bumper can be bent up under the rear door causing further damage. 

The answer here, if you have a standard drop plate, leave it fitted. If you have, on the other hand, a unit which is very low, then either consider removing it, or be prepared to pick your route carefully so as not to let it ‘plough’ the ground.

Whilst checking this area, it’s not a bad idea to make sure the trailer electric socket is installed as high as possible to avoid damage. Apart from being fragile units, if one gets ripped off, you will have live wires hanging down at the back. You will either blow fuses or cause sparks near the fuel tank! If you are going to do some serious off-roading why not tape over the hinged cap to keep the mud and water out. This will save you a lot of problems later when you go to connect up the trailer or caravan electrics.


Wherever the battery is, make sure that it is installed correctly using its battery clamp. Now I know we are considering the worst, but if you did turn turtle, you do not want the battery falling downwards, welding its terminals on the underside of either the seat box or bonnet! Fuel, oil and sparks are a recipe for disaster. So wherever the battery is, secure it. Even using some cordage to tie it down is better than nothing.

173707If the battery is under the seat, as on a 90/110, check it regularly, too. Bouncing around off-road often causes the standard clamp to come loose. And if there are any metal objects floating around in this compartment, remove them. In fact, as this area is far from being a dry area, I would tend to remove everything else, because if you are wading deep water this area will quickly flood.

In the next part ??.. David continues with further preparation and where you are going to, including marking up your maps.

Telephone: 01363 82666


Goodwinch Ltd, Oakleaf Way. Gunn. Barnstaple. Devon. Ex32 7NZ

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