The Only Part That Touches the Ground

If you have money for exactly one upgrade to a travel vehicle, spend it on tyres. They are the only component in contact with the ground, they determine what surfaces you can cross, they are the most common cause of a trip-stopping failure, and they are the one part that cannot be compensated for by skill or by anything else you bolt on.

Reading the sidewall

A marking such as 265/70 R17 121/118 S tells you almost everything. 265 is the section width in millimetres. 70 is the aspect ratio, so the sidewall height is 70 percent of 265, about 186 millimetres. R means radial and 17 is the rim diameter in inches. 121 is the load index, here 1,450 kilograms per tyre, with the second figure applying in dual fitment. S is the speed rating, 180 km/h.

The number that matters most for a loaded travel vehicle is the load index, and it needs to comfortably exceed the axle weight divided by two. Fitting passenger-rated tyres to a vehicle loaded to its limit is one of the quiet, common and genuinely dangerous mistakes in the overland world.

Construction beats tread

Sidewall construction is what survives a rock edge, a pothole at speed on a corrugated road or a kilometre driven flat. Look for reinforced or three-ply sidewall constructions, often marketed as light truck or LT, and for a tyre designed for load rather than for comfort. The trade is a harsher ride and more weight, and it is worth it.

Tread pattern then decides the surface bias. An all terrain tyre with reasonably closed blocks is quiet, long-wearing, safe in the wet and competent in sand, gravel and light mud, which is more than 90 percent of what any travel vehicle meets. A mud terrain has wide-spaced blocks that clear themselves in deep clay and grip sharp rock, at the cost of noise, wear, wet braking, aquaplaning resistance and fuel. Choose mud terrains only if your route is genuinely dominated by mud.

Tread pattern decides how a tyre looks in a car park. Construction decides whether you get home.

Size: bigger is not automatically better

A slightly taller tyre gains ground clearance under the axles, which is where clearance matters, and a longer contact patch when aired down. Going too large costs you gearing, brakes, fuel, speedometer accuracy and often the ability to turn without rubbing, and can overload wheel bearings and steering components.

Width is a genuine trade rather than an upgrade. Wide tyres float better in sand. Narrow tyres cut through mud and snow to firmer ground beneath and put more pressure on rock for grip. If your travel is mostly mud, snow and rock, narrower and taller is often the better choice, which surprises people who have only ever seen wide tyres in photographs.

Pressure is a tool you carry with you

Set pressure for the actual load, not for the sticker in the door frame, which assumes an empty vehicle. On a loaded travel vehicle, that usually means more pressure on the rear axle than you expect. Then adjust for terrain: down for sand and rock, moderately down for corrugations where it improves both comfort and component life, back up for tarmac. A quality gauge, a deflator and a real compressor turn one set of tyres into four different tyres.

Repairs and spares

Learn to plug a tubeless tyre and carry a proper kit with a reamer, plugs and glue; it fixes tread punctures in ten minutes at the roadside. Sidewall damage cannot be plugged and needs a replacement, which is why a full-size matching spare is not optional on a remote trip and why serious expeditions carry two.

Carry a valve tool and spare valve cores, which fail more often than the tyres do, and check pressures weekly, cold. On a long trip, rotate tyres regularly and inspect the sidewalls every time you air up, looking for cuts, bulges and the fine cracking that says a tyre is aged rather than worn. Rubber ages out at around six years regardless of tread depth, and an old tyre with perfect tread is the classic cause of a sudden failure at speed on a hot day.

Questions we get asked

All terrain or mud terrain?

All terrain for nearly everybody. Mud terrains only when the route is dominated by deep clay or sharp rock, and even then many experienced travellers choose a heavy-duty all terrain for its road manners and wear.

Tubes or tubeless?

Tubeless for speed of repair and lower running temperature. Tubes for spoked wheels and where rim damage is likely, since a dented rim still holds a tube. If you run tubes, carry two spares and the tools to fit them.

How old is too old?

The four-digit code on the sidewall gives the week and year of manufacture. Beyond six years, treat a tyre as suspect for remote travel however good the tread looks, and beyond ten replace it regardless.