Tips for choosing a tyre, maintenance and repair

In this sixth instalment of our Unsealed Guide to 4×4 tyres series, we’re going to chat about choosing a tyre, maintenance and repair.

If you’re reading this, then I’m going to assume you’re using a 4×4 for offroad touring and towing and want a tyre to suit.  Your first stop is your vehicle’s tyre placard, which will tell you the standard sizes.  Contrary to the belief of some tyre shops, it is not a legal requirement to fit only the tyres on the placard (we covered that in the previous article), but it’s your starting point.  First, we’ll look at tyre specifications, then consider tread pattern, construction and manufacturer.

Tips for choosing a set of tyres

Tyre diameter

You’ll probably want to increase the tyre diameter a little as that will give you better ground clearance, better ability to climb over obstacles, and even better approach, ramp and departure angles.  All good, but there are drawbacks – cost, fuel consumption, handling, and effect on the driveline of extra mass.

Limit the increase

You could run 37” tyres, and they are amazing offroad, but do you really want the compromise?  For the average 4×4 tourer, the answer is no, and my suggestion would be to limit the increase to 50mm or less than the placard diameter, which means it’s legal without special engineering, and you get a little lift without needing drastic modifications such as replacing suspension arms.  A popular standard size is 265/65/17, and 265/70/17 is a common upgrade and, indeed, what is on my own 4×4.

Should you go wider?

As for width, well, I don’t see any point in going wider. However, you can, and if you do, remember that you may need aftermarket wheels to fit the wider tyres and flares.

The problem with low-profile tyres

We also need to talk about low-profile tyres, and while there is no fixed definition, anything below 60-series profile is suspect.  The problem with low profiles is the proximity of the rim to the ground when aired down and flexed up offroad, which limits how far down they can be aired.  They are also difficult to swap rims on in the field, not to mention expensive.

Consider going smaller

Generally, I would not suggest the average tourer needs to swap wheels, despite the fact all the influencers do (awesome, maaate). But if you run say 20” wheels, and can run 17s, I would suggest what dealers consider a “downgrade”, as the 17s will perform better offroad, the tyre/rim combination will be lighter, the tyres will be cheaper, and you won’t notice anything onroad.

Typically you can pick up a set of smaller rims secondhand and defray that cost against the cheaper 17” tyres compared to 20”, and sell your 20s or keep them for your coffee shop runs.

Load and speed rating

Ratings are next, which is load and speed rating. See our previous article on tyre regulation for that, as your tyre must be compliant to be legal.

Tread pattern

So with the specifications sorted, we’re now into the decision about tread pattern, construction and manufacturer.  Your tread pattern choices are, roughly: road, all-terrain, rugged terrain, mud and extreme.  We’ll discount the extreme tyres, which are really just for dedicated offroad vehicles and not intended for tourers.  The choice between the other four patterns is the balance between road and off-road performance.  The better a tyre is at one, the worse it is at any other, and don’t let the tyre marketing people tell you any different. 

The road pattern tire in passenger construction will be quieter, use less fuel, handle better and ride smoother than a mud terrain in light-truck construction…but the muddie will grip better anywhere other than the road, take a load better and resist punctures.  The all-terrain and rugged-terrain are somewhere in between the road and the mud, and arguably, the ‘rugged-terrain’ doesn’t need to exist as it’s really just an all-terrain, but here we are.

It’s interesting that over time, the all-terrain now performs as well offroad as the mud terrain of old, and the mud terrain of today is as ‘streetable’ as the all-terrain of old.  I would say that a good set of all-terrains can handle every terrain you’d encounter in Australia, but there is no question that in terrains such as difficult mud, snow and rocks, mud terrains would be an advantage.

You’d still get there with all-terrains, though. I’ve been up and around the High Country for years in all terrains and never had to turn back due to tyres. If all I did were High Country tracks, then I’d use muddies, but as I do a mix of terrains and long-distance driving, all-terrains work for me.

Are two sets of tyres necessary?

Back in the day, many people ran two sets of tyres, one road, one offroad. I think there’s much less need to do that these days given how well modern all-terrains perform, and the danger is the offroad set of tyres age-out, not wear-out, so it becomes expensive. It’s also an effort to swap the wheel on and off depending on the terrain, but it would be worth it if, say, you’re driving Melbourne-Brisbane return on bitumen and don’t want 6000km of wear on your expensive mud terrains.

Consider light-truck construction tyres

There is a lot of talk about tyre plies, which are layers of material in the tyre, but I wouldn’t get too hung up on it.  Humans do have a mindset of “more the better”, but that mindset only goes so far, and that’s the case with plies. Just make sure the tyres are LT construction for their puncture resistance, and that should be all you need.

Directional vs asymmetrical tyres

You will see some directional and asymmetric tyres. The idea here is that the tyres are designed to work in a specific direction or facing in/out, so performance is improved compared to a symmetrical tyre. For 4×4 tourers, the performance delta is tiny and not worth it compared to the cost, and more importantly, the ability to switch a tyre from any corner of the car to any other.

Which brand of tyres should I buy?

Now for brands.  Tyres are very difficult to test as you need to test across several environments and precisely control the environment, which is tough in 4×4 conditions.  It’s also expensive as you need to buy or be given the tyres.  So, objective evidence is hard to come by, and you’re forced into anecdotal. 

My first advice would be to stick to the well-known brands such as Kumho, BFG, Cooper, Yokohama, Falken and others as these companies rarely produce bad tyres.  I would avoid the cheapest tyres as usually they are cheap for a reason.  Then, ask on forums. Get a general sense of a tyre, see if there are consistent comments. For example, I’ve seen 4×4 tyres develop a deserved reputation for de-beading. 

It’s also worth looking at the design age. For example, the BFG KO3 is quite new, so expect that tyre to perform well compared to others as the tread design, construction, and compound have all improved over time.

Tyre maintenance

Tyres don’t require any active maintenance aside from pressure checks – we’ve covered which pressures to run in a previous article – but they do need regular checking. If tyres are under-inflated, they will wear at the outside; over-inflated, they will wear in the centre. If you spot uneven tyre wear across the tread, that’s probably a wheel alignment problem; always get your alignment done when you buy new tyres.

You do need to check your tyres for damage such as missing tread chunks, tears in the sidewall, bulges and cracks. Any of these could be the prelude to an expensive failure.

Tyres can also be ‘rotated’, which is swapping them from say front-left to rear right. The reason you do this is because each tyre on a car has a different wear rate, and the rotation evens it out over time. Get it done at every service.

Tyres can only be repaired if a puncture is in the tread area, not the sidewall. You can, and should, practice in-field repairs with tyre plugs using an old tyre, and carry an air compressor which can keep you going in the event of a slow leak.

Happy driving, and remember, you get the best from your car if the tyres are the only part of the car that ever touches the ground!

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