Question for owners of single axle caravans

Warren-Pat_01 · Guru

Question for owners of single axle caravans

86GTS · Guru

The tyre on the drivers side of our single axle caravan wears out way faster than the other side.
I think that I may have a slightly bent axle which causes the tyre to scrub on the inside edge.
I swap sides & use the spare to even the wear out.
Its been like it for 11 years & I reckon that we've only got about another 3 years of caravanning left in us so I'm not worried about it.

DMaxer · Guru

I have just replaced the tyres on my single axle Windsor. The replaced tyres had been on since new in 2013 and although not worn out I was concerned about the age. I noticed on the old tyres that they were wearing a bit more around the edges more so than in the middle. I ran them on 40lb as recommended by the manufacturer.

When I had the new tyres put on the tyre dealer put 40lb into them and they seemed to have a slight bulge. He then put an additional 5lb to bring them up to 45lb and most of the bulge disappeared. He told me not to inflate them anymore as the valve was 50lb and they would increase pressure when moving.

My van has a tare weight of about 1900 and loaded up carries about 2.2 give or take a bit. He was of the view that my van was at the upper limit of a single axle weight wise that is why there was a small bulge when the tyres were cold.

the new tyres I have had fitted are light truck commercial tyres whilst the previous tyres were Goodyear ones which came with the van when manufactured. I could see the difference in the tyres especially the width in the walls.

Surprisingly, when I had the spare replaced as well he showed me the way that tyres deteriorate just from age. The spare has never been used and has had the cover over it at all times. However, looking inside the wall on the internal side I could see cracks starting to appear. This tyre had never seen the light of day let alone be used. He was of the view that if I had used it as a replacement for a flat tyre it would soon puncture.

Warren-Pat_01 · Guru

Thanks chaps,
A bit of history of my van - it was bought second hand & I was told by the dealer (runs a New Age yard) to put 46psi in the tyres (the VIN Plate says 250Kpa - cold). 250Kpa is 35psi, but the tyre itself shows for the maximum 1060kg a pressure of 450Kpa (64psi)!!

As the tyres were wearing irregularly, I spoke to a mechanic who was "old school" at Warrnambool about it - he did a wheel alignment using a sledge hammer on the straight axle (while checking his instruments). I recall Possum saying here somewhere about rebending jayco axles to fix alignments.

Why Jayco (& silly me, continuing their selection) chose luggy "4WD" tyres on a caravan (the Savero), I don't know. The wear on the RHS tyre, a Toyo Open Country is normal but with a much better tread pattern. I'll watch the new tyre as well as it has a similar pattern to the Toyo (beggars can't be choosers when you're in the bush - you take what you can get).

Of course Jayco in their wisdom, run everything at near maximum. The ATM of the van is 1980Kg, the tyres are rated at the 1040-1060kg, the wheels' maximum loading is 1000kg. At one stage when it was discovered that one wheel had a cracked spoke, I tried to get 16" steel wheels - an impossible task!! Mine are the alloy, flash looking 15x7JJ wheels at Jayco's premium price & made in the PRC!!

86GTS · Guru

I was wondering why my caravan has an ATM of 1700kg which exceeds the axle, rim & tyre maximum load rating.
Avan run everything to the maximum too, the same as Jayco.
My tyres look a bit flattish at 35PSI but sort of OK at 45PSI.
They have a maximum inflation rating of 65PSI!
Before I went away on my first trip after buying my caravan new I removed the solid cowling to check the pressure in the spare wheel.
My caravan has Sunraysia type rims.
I discovered that the spare was exactly the same diameter but had a different stud pattern.
I took it back to the Avan dealer & he swapped it, saying was mistakenly a Jayco rim.

watsea · Guru

86GTS,

You said that the ATM exceeds the axle, rim and tyre ratings. I hope that I am not telling you how to suck eggs. Have you accounted that the ATM also includes the weight held by the tow ball in the vehicle ie weight on the axle and wheels?
ie
weight of the axles and wheels = ATM - loaded TBW

Peter_n_Margaret · Guru

Warren-Pat_01 wrote:
TPMS squealed out a warning .....My LHS tyre had lost some pressure
the steel belt on the tyre ..... had started to protrude from within the tread.
wearing on both sides, with the centre untouched.
with 52psi of pressure,
the tyre itself shows for the maximum 1060kg a pressure of 450Kpa (64psi)!
____________________________________________________________________________________________

I have picked a few bits from your posts.

A critical piece of information seems to be missing. What is the actual weight on the wheels?

The physical evidence suggests the tyres are under inflated.

Cheers,

Peter

yobarr · Guru

watsea wrote:
86GTS,

You said that the ATM exceeds the axle, rim and tyre ratings. I hope that I am not telling you how to suck eggs. Have you accounted that the ATM also includes the weight held by the tow ball in the vehicle ie weight on the axle and wheels?
ie
weight of the axles and wheels = ATM - loaded TBW

Good post Ted, as 86 GTS (Why do so many seem not to have a name?) seems to have confused ATM with GTM, (Gross trailed mass) or total weight on wheels of van. Cheers

86GTS · Guru

watsea wrote:
86GTS,

You said that the ATM exceeds the axle, rim and tyre ratings. I hope that I am not telling you how to suck eggs. Have you accounted that the ATM also includes the weight held by the tow ball in the vehicle ie weight on the axle and wheels?
ie
weight of the axles and wheels = ATM - loaded TBW

Ball weight is 150kg, weighed it today before we take off for a month tomorrow.

yobarr · Guru

86GTS wrote:
watsea wrote:
86GTS,

You said that the ATM exceeds the axle, rim and tyre ratings. I hope that I am not telling you how to suck eggs. Have you accounted that the ATM also includes the weight held by the tow ball in the vehicle ie weight on the axle and wheels?
ie
weight of the axles and wheels = ATM - loaded TBW
Ball weight is 150kg, weighed it today before we take off for a month tomorrow.

If your van has an ATM of 1700kg, and you have 150kg on the towball, you obviously can have up to 1550kg on the van's axle, PROVIDED that the van's axle rating is 1550kg or higher. Cheers

P.S Fortuitous that you discovered that your spare wheel had the wrong stud pattern while you were still at home, and not in the back of beyond.

Peter_n_Margaret · Guru

yobarr wrote:
If your van has an ATM of 1700kg, and you have 150kg on the towball, you obviously can have up to 1550kg on the van's axle,

ATM is a rating.

Tyre pressures need to be based on the ACTUAL weight they carry. We still do not know what that is.

Cheers,

Peter

Ian G · Senior Member

Hi Warren What type of TPMS did you buy and does it read from your dash to the caravan wheels or did you need a booster ? Ian

Warren-Pat_01 · Guru

Good morning,
A sleepless morning after our trip back home from Capella yesterday! Never have I seen so much water in the creeks, rivers on the Gregory Highway/Development Road! And rough surface signs placed on sections of the road didn't tell the whole story! At least the signs warning of rough, deep edges were truthful! They would have chewed a tyre easily, let alone any skewing when the tyre when into the soft edges.

Back to the subject - the easy question (Ian G) - the TPMS is a Safety Dave unit for 6 wheels, no it doesn't require a booster but I'm now getting some strange effects from the caravan monitors - have to chase that up soon.

PnM, the load in my van, I don't know but we have been conscious on what we carry. Normally I travel with the water tanks empty (the wear has been all the time) but this time & during our Covid isolation at Cunnamulla for 10 days, I had to fill one tank. I took your advice about using the onboard water system rather than trying to get the mains pressure system fixed - I suspect an intermittent NR valve. We came home with about 20L of water in both tanks. We've also limited our clothing, using layers while we were down south & don't carry a lot of food - no jars, cans. I would have thought an overloaded van would result in irregular wear on both tyres.

jontee · Veteran Member

G`day Warren ,

I was having the same uneven tyre wear issues on my single axle Nova van . A neighbour in a caravan park suggested I have the axle alignment checked . I took the van to a truck alignment centre . The axle was just 2mm out of alignment . My tyres now wear evenly .

Cheers ,

jontee .

Stretch60 · Senior Member

Savero tyres don't age well. My van purchased second hand in 2018 had those tyres and had lumps and odd shapes all over the tread surface. Turned out they were 12 years old and not fully worn. Replaced with new tyres and no irregular wear. Tyres normally only good for about 6 years.

Peter_n_Margaret · Guru

Warren, you can not receive any credible advice or have any idea what tyre pressures should be, until you get the van weighed.
Each wheel needs to be weighed individually.
Cheers,
Peter

Warren-Pat_01 · Guru

G'day jontee,
I did mention that I had the wheel alignment done at Warrnambool on a visit prior to Covid.

Stretch60,
These Savero tyres have been on the van 3 years, as I said above I foolishly followed the previous choice of tyre brand, type. Where the steel belt came through on the tyre was between the tread pattern, indicating that the tyre had impacted something like the rough edges of our Qld "fantastic" rural roads.

Peter,
After we bought the van (4.5 years ago) and I became more aware of weights, we did a short trip to a farm at Inkerman. We had enough supplies for the weekend, only minimal clothing for October when it gets too warm for southern travellers. I deliberately filled all of the tanks & weighed the rig (our Nissan Patrol, then + the van) on the weigh bridges on the Port Access Road just south of Townsville. The car was 100kg over, the van also 100kg over (with 180L of water in the tanks). I had a GVM upgrade done on the car, from then on while we travel the less remote areas, I run with water tanks empty.
Since them. before we head either west or south, I always check the weights to ensure that I'm legal.

This last trip was the first time since then that we put water in the tanks - and only because we had to isolate at Cunnamulla. Yes we had more clothing on this trip but not a lot. After leaving Charleville, we had about 20L of water in the front tank, 40 in the rear (according to the gauges).

jontee · Veteran Member

Sorry Warren , I forgot about the old school mechanic with the sledge hammer .

Cheers ,

Jontee .

Peter_n_Margaret · Guru

Warren-Pat_01 wrote:
Since them. before we head either west or south, I always check the weights to ensure that I'm legal.
_____________________________________________________________________________________________________________
So exactly what are the weights on each of the van wheels?
Cheers,
Peter

Warren-Pat_01 · Guru

Hi Peter,
I didn't weigh each wheel at the time, just noted I was under the GTM (1907kg) of the van, as well as for the car's GVM (3050). I carry a sheet of figures in the glovebox for reference.
We had left home later than we had planned but knowing I was "legal" I felt I had no worries. Included in the car's tub were some boxes of china, table cloths, etc that were going to remain at Warrnambool.

I would have thought that had I been overloaded, the tyre wear would have been on the inside of the tyre, not on both edges of one tyre, the one that mostly travels on the rough sections of SW Qld roads - roads that often see triple road trains on them.
It is no use weighing the van now as it is now sitting in the drive at home, has been emptied & is being thoroughly cleaned, sanitised. It's my job tomorrow to clean the roof, soft sides of the lid as I can reach them.

Peter_n_Margaret · Guru

Warren, the GTM is of not what is important for the tyre pressure.
The other issue is that most vehicles are not loaded evenly. It is common for vans to be quite a bit heavier on the kitchen side.
I still feel that it is very likely that tyre was under inflated.
Cheers,
Peter