Caravan Tyre Pressure; what should you be running?
Tyre pressures are super important, and if you get them wrong the results can be catastrophic. If you aren’t sure what Caravan Tyre Pressure you should run, this post covers everything you need to know, including a way of calculating exactly the right pressures.
The right tyre pressure is critical for good braking, stability and tyre wear. So, how much air should you be running in your Caravan Tyres?
The answer is simple; it depends, and on a number of different factors, which we go into below. Once you understand them, its pretty straightforward.
Where do you start?
Understand that tyre pressures change
The first, and most important thing to know is that your tyre pressures change all the time.
If you measure them at the start of a cold day, before you’ve done any driving, and then at the end of the day when you arrive at your destination after several hours on the road, you’ll see that they will have changed by at least a couple of PSI. You might start off at 40 PSI, and end up at 48 PSI at the end of a hot day.
This is important to know, because depending on when you check your tyre pressures, you might not actually get an accurate reflection.
When you drive along, tyres generate heat and this increases the internal temperature, which makes the air expand, and thus the tyre pressure increase.
Ideally, you want your tyres to rise about 4 – 6 PSI from their cold pressures, and this works on any terrain.
The more flexing of the sidewalls that is being done (turning or corrugations) the more the tyres will heat up, and the greater increase of pressure that will be had. Something to be aware of.
The caravan nameplate
If you check the nameplate, which is usually on the drawbar of your caravan, it will have a tyre pressure listed. There are a couple of variations though; it can be the maximum cold pressure, or the recommended tyre pressure, so read it carefully.
If it displays the maximum cold tyre pressure, this should correlate with what is written on the sidewall of your tyres (if not on one side, it will be on the other), and this is not the recommended tyre pressures.
If you pump it up to the maximum cold tyre pressures, it will be too high and cause you other issues.
The more weight, the higher the pressure needs to be
Caravan tyre pressures are actually quite simple, and they follow the same rules that a car tyre, or 4WD tyre would too. The more weight you are applying to each tyre, the more air pressure that is needed.
This is an important concept to understand, especially when it comes to comparing single axle to dual axle caravans.
If you have 2500kg spread over two tyres, then the air pressures need to be higher than if they are spread over 4 tyres. The difference is simple; you have 1250kg on each tyre in the first example, and only 625kg on each tyre in the second example.
My folks generally run about 65 PSI in their tyres with a single axle van that weighs around 2.7 tonnes. If it was dual axle though, you’d get away with less air in each tyre as its spread over a greater surface area. Twin axle caravan tyre pressures are almost always less than their single axle counterparts.
The bigger the tyre, the less air you need
Likewise, if you are running big tyres on your caravan the air pressure won’t have to be nearly as high as the tiny on road caravan tyres that are common on different vans.
In combination, this means that a caravan with big tyres, and dual axles can run significantly less air pressure than a van of the same weight on single axles and small tyres.
Monitor the tyre wear
Longer term, you can easily work out if you are running the right tyre pressures simply by seeing how the tyres are wearing. If you are getting wear in the centre, and not on the outer edges, your tyre pressures are too high. If you are getting wear on both outer edges and not the centre, your tyre pressures are too low.
If you are getting wear on one side of the tyre only, or scalloping (one lug worn and the next not) then you have a different problem that needs some suspension attention, wheel balancing and more regular caravan wheel alignments.
Calculating the right tyre pressures
There are a couple of ways to calculate the correct Caravan Tyre Pressure, but take them as a guide and make sure you are happy with how they are wearing and handling too.
The formula is simple; find the maximum cold tyre pressure (written on the tyre) and divide it by the maximum load of the tyre (also usually written on the tyre), then multiply it by the weight of the van, and divide it by the number of wheels on the road.
Please know this refers to the cold tyre pressure, and it will increase as you drive along.
The best way for this tyre pressure calculator to work is if you know the exact weight of your van or vehicle, which you can find by getting mobile weighing done, or using a weighbridge.
If you don’t know the weight of the van, you can use the ATM divided by the number of wheels on the road, but this is less accurate as it includes weight that may or may not be there, and the tow ball weight (which isn’t on the tyres).
Yes, that sounds difficult to follow, so we’ll do a practical example using our Reconn R2
Maximum tyre pressure – 80 PSI (as per the tyre sidewall)
Maximum load of the tyre – 1550kg (please note its only 1400kg if you have dual tyres (two tyres on the same side, like a truck) from the sidewall of the tyre.
Side note ; the reason the dual rating is lower is to allow for the vehicle to continue if one fails. For example, if a truck with dual wheels has one tyre fail, the one right next to it will support the load until you can pull over safely.
ATM of the van (on your caravan nameplate) – 2600kg
Number of wheels – 2
Then, do the below:
80/1550kg = 0.051613~
0.051613 x 2600 = 134.2
134.2/2 wheels on the trailer = 67.09 PSI.
Now, that seems high, and it is, because it includes the tow ball weight, and we aren’t actually running it at 2600kg.
I know we are running around 1050kg on each wheel, so we can do it again, more accurately:
80/1550kg = 0.051613~
0.051613 x 1050 (one wheel weight) = 54.19 PSI, which is very close to what I have been running in the past, and is working well.
Compare the tyres to your vehicle
A good way to wrap your head around this is to consider the tyres on your vehicle, and the weights that it would run at.
For our Isuzu Dmax, we are running about 650kg on the front tyres (each), and 900kg on the rears (each). That’s a total of just under 3100kg over 4 tyres. Our Dmax runs 40 PSI on the front, and 45 PSI on the rear, and we generally get pretty good wear.
On our Reconn R2, we are carrying around 1030kg on each wheel, and its exactly the same tyre size. You’d expect to need to run higher pressures on the Reconn than the Dmax due to the extra weight, and as a result we keep it somewhere between 50 and 60 PSI.
According to the calculator above, we get the below:
80/1550kg = 0.051613~
0.051613 x 650 (one front wheel weight) = 33.5 PSI, which is quite a bit lower than the 40 PSI I’ve been running
And for the rear – 0.051613 x 900 (one rear wheel) = 46.45 PSI, which I’ve been running at 45 – 48 PSI.
Our Hybrid Camper tyre pressures
Our Lifestyle Reconn R2 weighs in at about 2300kg, on a single axle setup. We are running 265/75/16’s, with each tyre ultimately taking around 1100kg each (and the remaining weight on the tow ball). When we are covering a lot of distance on the bitumen we’ll run the tyres between 50 and 60 PSI.
If we come to rough gravel, we’ll let them down to about 30 PSI, and sometimes even lower if we are going slowly.
I’ve not actually spent much time on the beach with it, but would imagine we’d end up around the 20 PSI mark in order to drag it through soft sand.
Tyre pressure monitoring systems (TPMS)
Today, there’s a number of TPMS’s that you can purchase for your 4WD, or van, or both, which monitor the real time pressure of your tyres. These used to be quite uncommon, but with how much cheaper they’ve become, and people starting to see the value in them, they are becoming a more regular fitment.
Not only can you watch your tyre pressures rise from when you first take off in the morning and get to their running pressures, but you know the moment you have an issue, and you can usually set alarms if the pressure changes suddenly, or drops below a certain point.
One of the most common tyre failures is when you get a small puncture, and the air leaks out slowly, causing the tyre to get hotter and hotter, until the sidewall fails.
If you’d known about the small leak not long after it occurred, you’d have pulled over and potentially been able to fix it instead of having to buy another tyre, and deal with the hassle of swapping it out in the middle of a hot day.
What Caravan Tyre Pressures do you run?
How much air do you run in your caravan tyres? What have you learnt over the years works? Have you tried the Caravan Tyre Pressure Calculator above?
Yep, its a bit confusing. The discussion in these comments relates purely to the markings on a tyre that show max load single 1550kg, and max load dual 1400kg.
They lower the dual axle max weight rating to ensure that it can carry the weight if one fails
If you had a dual axle caravan though, running these tyres you could put 1550kg of weight on each tyre, as they are running in a single application (end to end, not side by side).
You’ve got me thinking a bit though, as on a dual axle caravan if one tyre fails the entire weight on that side of the van is going to be supported by one tyre, in the same scenario as if it was dual wheel. Interesting.
All the best
Interesting comments, especially as all my tyres, car, van and camper, each explicitly state dual axles, so they definitely do not mean dual wheels.
Thanks for raising an interesting point, and one that I misinterpreted. You are correct – the dual rating refers to two tyres run together on one corner, like a dual wheel truck.
I’ve made amendments to the article, and really appreciate your comment.
In your article about tire pressures you have stated that the dual rating shown on the side of the tire is in respect to two axles I believe. My understanding of it (and its just that) is that the lower rating is for dual tires as in two wheels together, such as found on vehicles with four wheels per axle. If I am wrong and you are sure of your facts then please disregard this email (just trying to help).
Otherwise a great and helpful article.
Best regards, Colin.