Wheel bearing grease and hub temps: the outback check most people skip

I lost a hub on the Gunbarrel in my second year of full-time touring. Not catastrophically — I caught it before the wheel came off — but close enough that I've never driven past a fuel stop since without putting the back of my hand on every hub within thirty seconds of pulling up. That's the whole trick, really. It costs nothing and takes less time than filling the water jerries.

This isn't the article about how to actually pack a bearing or set preload with a dial gauge. Plenty's been written on that, including our own piece on spotting trouble before it costs you a hub. What I want to talk about is the bit that happens between services — the daily, unglamorous habit of checking grease condition and hub temperature while you're out bush, a long way from anyone who can help if it goes wrong.

Why hub temperature is the canary, not the diagnosis

A hot hub doesn't tell you exactly what's wrong. It tells you something is wrong, and that's enough to act on. Bearings running normal preload and correct grease will get warm on a hot day of towing — that's expected, friction does that. What you're checking for is the hub that's noticeably hotter than its neighbour on the same axle, or too hot to keep your palm on for more than a second or two.

I do this every fuel stop and every lunch break, without exception, on gravel or corrugations. On bitumen I'll check morning and evening. It sounds obsessive until you remember that a failing bearing can go from "slightly warm" to "seized and smoking" within fifty kilometres on a rough track, and out past Warburton or on the Tanami there's no NRMA truck coming. You're the recovery plan.

What normal actually feels like

The honest answer is that "normal" varies by van, by load, by ambient temperature, and I'd argue anyone who gives you a single number in degrees is guessing unless they've actually put a thermal gun on it. What I do instead is build a baseline in the first week of a trip — checking all four hubs (or six, if you're running a tandem) at the same intervals and getting a feel for how warm they run on your rig, loaded, on your tyres, at your usual pressures. After that, you're not comparing to a textbook number. You're comparing to your own van last Tuesday.

If you want a number anyway, a cheap infrared thermometer is worth the $30. I carry one specifically because "feels hot" is subjective and a differential of even 15-20°C between hubs on the same axle is the kind of thing worth pulling over for immediately, even if neither one feels alarming by hand.

The grease check nobody does until it's too late

Hub temperature tells you something's wrong after the fact. Grease condition is the thing you can actually inspect before it becomes a problem, and it takes five minutes with the wheel off — something I do before any serious remote leg, not just on a service interval.

What I'm looking for: colour, consistency and contamination. Good grease is smooth, holds together, and hasn't gone grainy or milky. Milky or foamy grease means water has got past the seal, which happens more than people admit after a deep water crossing or a caravan park hose-down that got a bit too enthusiastic around the hub. Grey or black grit in the grease means metal-to-metal wear has already started, and that hub needs attention before you go anywhere near a place like the Anne Beadell or the Gunbarrel Highway.

If you're running sealed bearing units rather than traditional taper roller bearings, you obviously can't do this visual check the same way — that's the trade-off with sealed hubs, and it's worth knowing which system your van has before you're four hundred kilometres from the nearest town wondering if you can even get the cap off.

Corrugations are the accelerant, not the cause

Bearings don't usually fail because of one bad day. They fail because heat cycles and vibration have already broken down the grease's ability to do its job, and corrugated roads just accelerate whatever weakness was already there. That's why I'd argue the pre-trip check matters more than the on-road one — the on-road hand-on-hub routine is a safety net, not a substitute for doing it properly before you leave bitumen behind.

If you're heading somewhere like the Gibb River Road or the old Telegraph Track, I'd get bearings packed or at minimum inspected in the fortnight before departure, not "sometime this year." Our pre-Kimberley service checklist covers what a workshop should be doing at that point, and it's worth reading alongside this one because the two jobs — professional service and your own daily hand-check — aren't interchangeable. One doesn't excuse skipping the other.

What I actually carry for a bearing failure a long way from town

Even with good habits, bearings fail. I carry a spare set of bearings and seals matched to my van's hub, packed grease, a few basic tools to get a hub apart, and enough understanding of the process to limp to the next town rather than sit and wait. On tracks like the Anne Beadell Highway or the Gunbarrel Highway, "the next town" can be a very long way off, and satellite communication — not just a UHF — is non-negotiable. I run a satellite messenger permanently, and I'd say the same to anyone doing the Simpson Desert's French Line or similar; check current conditions and access requirements with the relevant park authority before you go, because permit and track status changes and nobody wants that surprise on top of a bearing failure.

I'll admit the first time I repacked a bearing roadside, it took me nearly two hours and I got grease absolutely everywhere including in my hair. Practising the job at home, in the driveway, before you actually need it under pressure is worth the Saturday morning it costs you.

A small contrarian note on sealed bearing units

There's a push in the off-road van world toward sealed, maintenance-free bearing units, and I understand the appeal — no more crawling around with grease under your nails at a roadhouse. But out where I travel, I'm not sold. A traditional taper roller bearing you can inspect, repack and diagnose with your own hands and a thermometer. A sealed unit you mostly just trust, right up until it doesn't work, and then you're often looking at a full unit replacement rather than a $40 grease and reseal. For touring the Kimberley or the Western Desert tracks solo, I'd rather have the ugly, serviceable option than the tidy one I can't get into.

Building it into the rhythm of the day

None of this needs a special stop. I fold hub checks into the same break where I check tyre pressures and glance at the coupling — the same habit loop, just a different hand movement. It becomes automatic after a few weeks on the road, which is really the point. The vans that get into trouble on remote corrugated routes are rarely the ones where someone was checking hubs every stop. They're the ones where nobody thought about it until the wheel started wobbling.

Next time you're rolling into a roadhouse on the Savannah Way or pulling up on the Oodnadatta, give the hubs thirty seconds before you reach for the fuel nozzle. It's a small habit, and it's the cheapest insurance you'll ever carry.

— Bec Harmon, Free Camping & Remote Travel