Thunderbolts Way

Hendo · Guru

Thunderbolts Way

watsea · Guru

A bad outcome for those concerned. Hope there was no injuries or worse.

I travelled that way once from Brisbane to the Hunter Region when the main coast highway was impacted by flooding. Steep, yes, some parts of Thunderbolts Way were damp, but at no time did I feel that I would lose control. I guess that I drove to the conditions .

-- Edited by watsea on Wednesday 3rd of December 2025 06:40:47 PM

Rodsvan · Veteran Member

I've no idea what caused this but I drive on the Brown Mtn road every few weeks, and I've noticed a surprising number of caravaners who clearly have no idea how to drive on steep hills. A lot of them leave their foot on the brakes for the entire descent, and their brakes are overheating terribly. I think a bit of education wouldn't go astray on using gears (especially using them manually in automatic cars) and using brakes properly so they don't overheat.

Peter_n_Margaret · Guru

And caravan owners need to fully appreciate that pig trailers (caravans) are inherently unstable.
You might think they are stable, but they never are.
Cheers,
Peter

Possum3 · Guru

Moombi Hill, Must have vehicle in low gear - if 4WD also select low range or hill descent.
See; www.ozroads.com.au/NSW/RouteNumbering/National%20Routes/15/moonbi.htm

Peter_n_Margaret · Guru

You may have noticed a sign that says "Heavy Vehicles must use low gear" at the top of some hills.
That means that every vehicle with a GVM of 4.5T or higher must use engine braking to control the speed. ANY use of the primary brake is a FAIL and the driver can be fined.
Even if the vehicle is un-loaded and only weighs 2T this applies.

That should also apply to towing vehicles and ANY vehicle combination that weighs 4.5T or over, in my view.
Cheers,
Peter

Steel Dog · Veteran Member

What I do when I'm towing our caravan down Steep hills

I find that it's best to avoid using cruise control or relying heavily on engine braking. If you do, the caravan tends to push the tow vehicle because the van's brakes are not being engaged, which can reduce stability and control.

Instead I rely on the tow vehicles brakes and slightly increase the caravan brake controller setting. This way when I press the brake pedal, the caravan brakes activate just enough to keep the outfit running straight, with the van pulling itself into line rather than pushing the tow vehicle.

In my experience, this method provides better control and a safer, more stable descent.

Safe travels

Are We Lost · Guru

Your advice is contrary to most. The engine should provide all (or almost all) of the braking effort. Choose a sufficiently low gear so that is achieved. At least we agree on not using cruise control. That would not enter my mind as an option. Anyway, in my vehicle, cruise control only activates above 30kph and I would probably be travelling more slowly than that.

With your brake controller setting, do you mean the van is braking slightly harder than the tow vehicle? That is the way I set mine but for a different reason. I am not concerned about the need to use the van brakes to keep it in line because the speed would be slow enough that there would be no chance of that happening. I tweak the setting a little as I want to keep the best brakes in reserve ... those on the tow vehicle. If needed, maybe a touch on the brake controller button on occasions to only apply the van brakes. If speed starts to build despite that, then a quick stab on the footbrake and slow to a crawl. Then, if I sense fade beginning, or the transmission is getting too hot, the tow vehicle brakes will still be sufficient to stop.

Thunderbolts Way is one of the steepest main roads in NSW with 2 x 12 degree long descents. There are limited opportunities to pull over, making it a bit more challeging.

I went down there a couple of years ago on a 38 degree day. I had planned to stop at a clearing about half way down to let things cool while looking at the view. But it was busy with parked vehicles so I kept going. By the time I reached the bottom the transmission temperature had risen above my safety margin and I could tell brake fade was close. It really works hard with a heavy van behind.

4WD with low range was the next option but I prefer to avoid that on sealed roads due to lockup.

-- Edited by Are We Lost on Thursday 4th of December 2025 09:03:23 PM

watsea · Guru

The day that I travelled down Thunderbolts Way was slightly rainy and some fog. I engaged low gears and applied some manual activation of the trailer brakes as I considered appropriate. No excessive heating for me, though not a hot day. I think the lookout that Are We Lost refers to is Carsons Pioneer Lookout.
I have stopped there for view once while travelling uphill, not towing, nice spot. On the day, towing downhill, no stopping, as the fog blocked any view.

Ineedabiggerboat · Senior Member

Last time I drove it it was raining, incredibly thick fog and there had been a storm go over it which left huge amounts of largish branches and a leaf covering which made it incredibly slippery to boot. To top it off, there was a truckload of solar panels strewn over the road. Enjoyed every minutes. Not!

WindyHill · Member

Peter_n_Margaret wrote:
You may have noticed a sign that says "Heavy Vehicles must use low gear" at the top of some hills.
That means that every vehicle with a GVM of 4.5T or higher must use engine braking to control the speed. ANY use of the primary brake is a FAIL and the driver can be fined.
Even if the vehicle is un-loaded and only weighs 2T this applies.

That should also apply to towing vehicles and ANY vehicle combination that weighs 4.5T or over, in my view.
Cheers,
Peter

Just love the engine braking, but in reality 99% of the vehicles out there towing caravans, camper trailers, boats, horse floats do not have it.

Ineedabiggerboat · Senior Member

Why, no compression?

Cupie · Guru

I agree ... good post ....

Whilst my old analogue GQ Patrol can't tell me of transmission temperature and the like ...

What I have always done is get into the slow Transport' lane and just wind it down in the lowest appropriate gear occasionally touching the breaks to slow the engine revs.

I have been known to pull over into a rest area and have a refreshing drink to admire the view and let thing cool ... while having a giggle at the gin palaces racing down in the fast lane leaving behind the distinctive smell of over heating bits!!! $200,000 + rigs looking for a place to self destroy.

I typically have minimal pad wear on both the tug & van and have travelled >240,000 km with the van on back.

ps. I would never consider using 4wd H or L, on good bitumen surfaces because of the risk of 'transmission lockup'.

-- Edited by Cupie on Sunday 4th of January 2026 09:14:34 PM