Caravan wheel nut torque; what’s the correct figure?
After my folks very nearly had a caravan wheel come off their van (it was literally holding on by a few loose nuts) I started looking very carefully into Caravan Wheel Nut Torque, and trying to make sense of once again, what seemed like a total shambles of information.
Start with the OEM recommendations
We always recommend that you start with the recommendations from your original equipment manufacturer. If you buy a Jayco Caravan, you’d go back to Jayco for information, and they will either give you a figure, or pass on the relevant information to get it.
For us, I went to the Cruisemaster website as this is the brand of suspension and hubs that we are running, and you get a table which gives you a heap of figures, depending on what size studs you have.
This means you need to measure the diameter of your studs (which is harder than you might imagine without removing a wheel, and having Vernier’s. Ours appears to be 1/2″ BSF, which they state should have a maximum torque of 200nM. OK – so what’s the minimum, and the recommended torque?
What is the wheel manufacturer’s recommendation?
I did more research, and found that the torque specifications often come from the wheel manufacturer. Many alloy wheels on big, off road caravans are recommended to have their wheel nuts torqued to 135nM. So, do you do it to 135, or somewhere between that and 200, or the full 200nM?
A document from AOR Campers online suggests its literally somewhere between those two figures, which seems ludicrous to me. I hate vague information, and you can’t get more vague than that; somewhere between 135 and 200nM!
Steel vs alloy wheels
There appears to be a fairly big difference in torque levels for your wheels, depending on whether they are steel or aluminium. Whilst this makes sense logically, I bet there’s a heap of people who don’t know this, and just use one figure in place of both.
Check your wheel nuts with a torque wrench
Regardless of what tension you do them up to, in my mind the major importance is that they are all equal. You cannot do them up equally without a torque wrench, and that means it should be part of your kit. Do it in the correct star pattern, and then go around and around until they are all at the desired tension.
I’ve been borrowing my Dads torque wrench for the start of our big lap of Australia, but have since gone out and bought my own 1/2″, 40 – 200nM Teng torque wrench for about $150 as I like my hybrids wheels staying attached.
Check them often
The next part, which would have likely prevented the issues my folks had is to check your wheel nuts often. When we had our camper wheel bearings serviced by Ken Peachey’s in Perth, they left a sticker on the drawbar stating to check the wheel nut tension after 50km, and you should do it at regular intervals after that.
This is going to depend on what you are doing with the van, but if you are using it full time I reckon once every two weeks is probably pretty reasonable. It takes a few minutes of your time, and gives you peace of mind that a wheel isn’t going to come off, that you aren’t going to sheer studs and you’ll get to your destination of choice without any further issue.
I make a habit of checking our Isuzu Dmax wheel torque too, which is 120nM, and really easy to do.
What torque do we go to?
On our Reconn R2, I’ve been doing the 6 studs up to 160nM, as this was a figure we were told by a Caravan place a long time ago, but perhaps its marginally too high. With Steel wheels I’m less concerned about damaging them, and more concerned about not having nuts come loose!
What torque do you do your caravan wheels to? Does it match the wheel, and hub manufacturers recommendations?
I picked it up at a tool shop when we drove through Adelaide. This is the unit, but there are lots of decent ones around. You can spend a lot of money; I wanted something mid range.
Hi Aaron, can you share a link to where you picked up your Teng torque wrench?
Thanks for your constructive, and interesting comment. You are probably right about the firmly comment, but I bet Toyota would have a recommended torque specification on file somewhere. I’ve seen it for some of their other vehicles, and it is wheel dependent (and number/size of studs).
Interesting about the structural bolt torques; as a mechanical fitter I’ve had some experience with structural stuff, but not a huge amount. I can completely understand why there are so many variables, and why it would be hard to get the same each time.
When you check wheel nuts without a torque wrench, I find myself often nipping them a bit more, and I have no doubt that doing this over and over results in a slightly higher pressure, which is where a torque wrench gives you good peace of mind. You know that you’re not stretching the studs or doing them tighter than they need to be.
On that note, I’d expect having them all done to equal amounts of compression would be very helpful, or you’d end up with some nuts being far more likely to come loose first, and the overall pressure on the wheel being uneven.
Cheers again, and all the best
As an aside. The owners manual for my 2006 Land Cruiser does not state a torque, rather something like “tighten firmly” or similar.
Makes some sense given the time most will look for this information is at the road side changing a wheel without a torque wrench. Still an exact spec might be nice.
Now putting my engineer’s hat on I can tell you that no structural bolt is ever done to a toque spec but rather an amount if stretch, or elongation. The reason is there are too many uncontrollable variables such as age, material, corrosion, lubrication etc. and the same torque on a range of bolts results in a range of compression. It is my guess to the reason why there is a given range which as you point out is quite wide. In this case, close enough is good enough backed by regular checks as you advise.