TUBES VS TUBELESS
Tyre design has come such a long way since I first went off-roading and I have come to the conclusion that tubes tyres, for all but highly specialist applications (don’t ask me what these might be) tubeless is the only way to go. As a general rule, tubeless tyres are: as tough, easier to repair (in most situations), are far safer, give better grip, better braking, use less fuel and suffer far (FAR!!!) fewer punctures and are altogether the better choice for overlanding.
Up until ten months ago (mid 2010) if someone had to ask me, what is the best tyre for overlanding use, I could not give a definitive reply. This is no longer the case. During my TV shoot for Take A Deep Breath, season-2, I travelled ±27 000 kms through Namibia, Angola and Botswana. Before this, I had done a trip through Mozambique and crossed the Kalahari. I did all this on a single set of tyres and did not suffer a single puncture or had a single issue with my tyres. I have never known such fantastic service from a set of tyres. The tyres were BF Goodrich, ATs, 265/75R16 on a Toyota Land Cruiser 105 wagon.
The question of tubed or tubeless is much debated.
Tubes versus Tubeless
• A tubed tyre running at reduced pressures for long periods generates more heat and is more prone to damage and punctures.
• A tubed tyre is easier to repair in the bush than a tubeless, when on a split rim or rim with narrow flange because they are easier to remove from the rim. However, tubeless tyres can often be repaired with a simple plug, not usable with tubes.
• Tubes do not strengthen the tyre or help prevent punctures, if anything, the reverse is true.
• If a tubeless tyre is deflated for use in heavy sand conditions that require excessive throttle, the tyre may move on the rim. The result is total deflation.
• Blowouts occur less often to tubeless tyres. In tubed tyres, sudden deflation can be caused by excessive heat that is aggravated by friction between the tyre casing and the tube. This is especially serious if the tyre is under-inflated or overloaded where tyre distortion increases this friction tenfold.
• Damage to tyres is common in outback travel. If you use tubeless tyres, carry a suitable tube to enable you to effect a repair should the damage be sufficient to render the tyre useless for tubeless operation. It is very unlikely that you will find the tube of the correct size when you need it and even if you do not intend to go into very remote areas, carry a spare tube.
• Blowouts can tear a tube to pieces rendering it useless, so if you use tubed tyres, carry several spare tubes.
Fitting inner tubes
When fitting tyres with inner tubes it is imperative that once the tyre is inflated it should immediately be deflated and then re-inflated. This will remove twists in the tube. If a twist remains, the tube may split. Evidence of tube failure of this nature can be detected as the tear begins at the point of highest stress, normally the valve. Many tyre fitting workshops do not know this, so you should keep and eye on the fitting operation and make sure that this operation is carried out correctly.
RADIALS VS CROSSPLIES
Radial
Radials are superior to cross-plies in almost every respect except price. They offer superior traction, safety and comfort, both on a paved surface and off-road.
Radial tires are made by laying strips from flange to flange (the flange is the point where the tire meets the rim). The advantage of this design is that flexing of the sidewall does not affect the tread. They flex independently of each other. So, decreasing pressures will flex the sidewall and tread area, while keeping the tread pressure evenly spread and increasing the tire contact area with the ground, thereby decreasing the ground pressure and the tyre penetration.
Cross-plies
These are constructed by laying strips of fabric over each other at 90° angles, forming a wafer effect. These strips are called plies and the more plies a tire has the higher its load carrying ability will be, while its flexibility is reduced. They were first used in the 1860s and apart from improvements in the materials used they have changed little in design. When the side wall of a cross-ply expands with deflation, the ground pressure in the middle of the tread decreases. At the same time the ground pressure on the outside of the tire increases. The lower the inflation pressure the more marked the effect.
When the tread bar of a cross-ply meets the ground it bends. This causes the weaker area of casing behind to distort, allowing the tread bar to move backwards. As the tire rotates and the tread leaves the ground, it flicks back to its original position. This movement, combined with the distortion of the tread described above, causes trauma to the surface over which the tire is passing. In sandy conditions, this trauma, exaggerated if the cross-ply is under-inflated, will cause the tire to dig in. Cross-plies are therefore unsuited to heavy sand conditions.
Cross-plies also have a higher rolling resistance than radials and this will affect fuel consumption. Perhaps the only time that cross-ply tires could be advantageous is when the vehicle spends most of its time carrying heavy loads at low speeds over hard rocky ground that could cause damage to more expensive radials.
