Tyre options for caravans

Submitted: Thursday, Jul 02, 2015 at 18:52
ThreadID: 119371 Views:1702 Replies:4 FollowUps:12
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good evening all,
just to be a pain and probably bring up a subject that has probably been done to death a thousand times before I joined this web site forum, and it is only a small query about tyres on Caravans.
At the moment we are having a caravan built for us, and we have been given the option of 15 " 16" and 17" wheels now my only experience I have with caravan wheels is 15" wheels, would some one like to explain to me what if any would be the advantage of having a larger wheel on the van apart from the obvious of ground clearance. the van we are having built is going to be supposedly dirt road capable, but not bush bashing like the Gall Boys do.
Your opinions are eagerly awaited upon and also your responses thank you. we only have a couple of weeks to make a final decision, that is why the Question.
Thank you
Broodie H3
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Reply By: disco driver - Thursday, Jul 02, 2015 at 19:00

Thursday, Jul 02, 2015 at 19:00
The logical thing to do is to use rims and tyres with the same specifications as your towing vehicle.
That would give a degree of interchangeability and an extra spare for either the tug or the van if required.

Disco.
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Follow Up By: Sand Man (SA) - Thursday, Jul 02, 2015 at 19:07

Thursday, Jul 02, 2015 at 19:07
Yes, agree with Disco's comments.

A van will take a variety of wheel sizes and offsets.
Select the same size rim as your tow vehicle, with the same offset and stud pattern and you can interchange the two spares between both the vehicle and the van.

Tyres also need to be the same specs to enable changeability.
The brand is not so important but makes sense if possible.

Bill


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Follow Up By: snow - Thursday, Jul 02, 2015 at 20:31

Thursday, Jul 02, 2015 at 20:31
Sweet, 36" mud terrains it is ;-) just kidding.
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Follow Up By: Member - PhilD_NT - Thursday, Jul 02, 2015 at 23:00

Thursday, Jul 02, 2015 at 23:00
Sand Man, the answer may or may not be as simple as that. As well as stud pattern and offset there is also hub diameter. In my situation I have a Ranger PX and a Jayco van. It appears that the stud pattern and hub size are the same but the problem is therefore offset. The car is +55 offset and the van is zero. Car rims/tyres on van is impossible as rim/tyres would jam up against chassis. Van rims/tyres on car would be illegal as to increase in track and hang a long way out of the guards. I think that I got that all right. Any compromise would seem to require changing van axle lengths at least. This could even require engineering approval.
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Reply By: Nomadic Navara - Thursday, Jul 02, 2015 at 20:31

Thursday, Jul 02, 2015 at 20:31
The following only applies if you are not going to match your tugs wheels.

Are the tyres fitted all the same aspect ratio? The bigger the aspect ratio the more the tyres will cushion the shocks to the van. The other thing is the larger the diameter overall the better the wheels will toll over bumps and sharp edges in bitumen roads. The negative is the brakes will all be 12" units and the larger the diameter of the wheel the less effective the brakes will be.

Another thing to consider is to check what tyres are on each wheel. Go for one that will more easily replaced when outback. Don't worry about off road treads, you only need those for driven wheels and not un-driven wheels. Good heavy duty truck tyres is all you need.
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Follow Up By: Frank P (NSW) - Thursday, Jul 02, 2015 at 20:49

Thursday, Jul 02, 2015 at 20:49
G'day BroodieH3

I agree with everything PeterD has said, except that there is more to "Good heavy duty truck tyres is all you need" than meets the eye.

Heavy duty truck tyres with stiff sidewalls can transmit more shock load and vibration to the suspension and body than the van was designed to accommodate, even when running reduced tyre pressures. This is particularly relevant on corrugated dirt roads which you will encounter while not doing Gall Boys stuff.

My van manufacturer is quite specific about that and excludes some brands and sidewall construction from the chassis warranty.

You should check with yours as to what is suitable.

Cheers

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Reply By: 671 - Thursday, Jul 02, 2015 at 23:22

Thursday, Jul 02, 2015 at 23:22
I would have thought your van manufacturer could have given you a bit more advice than just suggesting three different wheel diameters. The tyre should be an integral part of the suspension design. It is with cars but I often wonder if the word "design" means anything at all to some caravan manufacturers.

My 4wd ute for example comes with a 15 and a 16 inch tyre as standard equipment. Both are the same diameter although one is a lot wider. The construction is not the same and the pressures are different.

Matching van wheels with the car is not always without problems. Wheel off sets have an effect on weight distribution between the wheel bearings. Some wheels may cause problems while some may not. It would take someone with a better knowledge of suspension design than me to advise you in that area.

One thing that I would do in your situation is discuss the problem with a tyre manufacturer, not a tyre dealer. They usually have a customer information number on their web site. If you can give them details of the van size, weight, type of suspension etc, they should be able to suggest a type and size tyre and the correct pressures to use.

If I had to make a decision myself without asking anyone I would most likely go with a 205R16 LT. Of course I don't know the size and weight of your van so they may be too small. They were the standard size off road tyre on the lighter weight range of utes like the Hilux, Navara etc for decades. The load rating is 112 which I don't think is high enough to shake the van to pieces and they should be readily available in the bush.

The factory recommended pressures look far too low but they work perfectly both on and off road. There has never been any sign of under inflation wear or excessive heat build up when driving on Outback roads.

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Follow Up By: 671 - Thursday, Jul 02, 2015 at 23:27

Thursday, Jul 02, 2015 at 23:27
I should have added in that post that I use two different types of 205 tyres on my ute depending on where I am going. The comment about the low factory pressures are for the LTs.
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Follow Up By: Nomadic Navara - Friday, Jul 03, 2015 at 13:56

Friday, Jul 03, 2015 at 13:56
Quote "The tyre should be an integral part of the suspension design. It is with cars but I often wonder if the word "design" means anything at all to some caravan manufacturers."

Forget your first statement. Your second statement is more to the point. They don't design. They simply select an axle and springs from the manufacturers that is sufficient to carry the load and order the bits. Forget any sophisticated design from van manufacturers. Even with independent suspension the manufacturers of them just supply a few different weight carrying capacities and the van manufacturer selects one of sufficient carrying capacity.
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Reply By: Member - Andrew W14 - Friday, Jul 03, 2015 at 09:39

Friday, Jul 03, 2015 at 09:39
The other thing you need to be aware of is that caravans require a minimum load weighting for the tyre (I am not certain but I think its 900 kgs). When I tried to change to 17" tyres for the van I found it impossible to get some with sufficient load rating of 900 kgs.

Andrew W
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Follow Up By: Member - Broodie H3 - Friday, Jul 03, 2015 at 11:53

Friday, Jul 03, 2015 at 11:53
thank you all for your valuable input, the weight of the van should come in at around 1850 kg when completed, it will have a simplicity suspension under it and when fully loaded she should weigh around 2500 kg hopefully a bit less depends on the red wine and books being stored for recreation and medicinal purposes only.
so reading the consensus hear it would appear that a highway pattern l/t tyre should be the preferred option, and discuss with the van builder the tyre specs prior to signing off on the contract. does that sound feasible to you all
thank you
Broodie H3
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Follow Up By: Member - Andrew W14 - Friday, Jul 03, 2015 at 13:56

Friday, Jul 03, 2015 at 13:56
Best thing you can do for your van (and tyres) is to ask them NOT to put Simplicity suspension in. Heavy, crude, Leading arms, shake your van to bits etc. Speak to Vehicle Components and others to see what else is available.
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Follow Up By: 671 - Friday, Jul 03, 2015 at 19:50

Friday, Jul 03, 2015 at 19:50
Member - Broodie H3 posted:
thank you all for your valuable input, the weight of the van should come in at around 1850 kg when completed, it will have a simplicity suspension under it and when fully loaded she should weigh around 2500 kg


In that case a 205 x 16 LT could be ideal providing you can get them in highway pattern.

My little ute weighs 1600 kg.The handbook says it is considered to be empty with a load of two people and up to 100 kgs of luggage. I thought a couple of average size people would weigh about 75kg so with another 100 of whatever on board the car would weigh 1850. GVM is 2500kg. This means I could add another 650 kg to it.

Factory pressures are 25 psi front and rear when empty and 25 to 34 rear depending on load. This gives a variation of 9 psi.

The tyre manufacturer gave me a lot of information about them including a 1 psi increase would support an additional 70 kg.

650 kgs divided by 9 equals 72 kg which ties in with each additional psi supporting an additional 70 kg.

Those pressures and that adjustment at the rear depending on load have worked perfectly over the last seven years everywhere from remote sandy Beadell roads to coastal mountain tracks.

I think it would be worth your while choosing your favorite brand of tyre then ringing the manufacturer. You have to start somewhere when making your final decision so that would be as good a place as any.




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Follow Up By: Member - Broodie H3 - Friday, Jul 03, 2015 at 20:54

Friday, Jul 03, 2015 at 20:54
Hi Andrew,
in regard for your remark about the simplicity suspension system, I am a bit dumb founded, and if you could expand on your reasoning for your thoughts I would be glad to hear yours and anyone elses comments on the simplicity system. we have simplicity under our current van which is a 22' Roadstar, and have towed the van all over the place including the Oodnadatta track and most of the W.A mid west country dirt roads and I honestly can't think of a better suspension system for a caravan, especially on dirt roads no shocks to brake down on corrugated roads or coil springs like I have seen on numerous caravans, that have the new coil spring and shock system, the simplicity has never let us down that is why we are going with this suspension this time, and to be fair I have not researched any other suspension system so if you have or anyone for that matter has information that could sway my view I would be only too happy to hear it and consider the information so received.
Broodie H3
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Follow Up By: Member - Andrew W14 - Friday, Jul 03, 2015 at 22:23

Friday, Jul 03, 2015 at 22:23
Brodie - I guess its a matter of my personal experience plus that of many others who have changed from Simplicity to Control Rider, VC Air or similar. A search with Google will find many many posts of people who have changed away from Simplicity to their satisfaction.
My previous two vans (Scenic 23', and Compass 21' both had Simplicity suspension and were classed as 'semi off road'. I found they literally shook the van to pieces. I am not an engineer but the principal of a leading arm suspension, that needs to move towards the obstruction before moving upwards has me baffled!
My current Van (custom built 19' full off road) has VC CruiseMaster Air which to be honest is so superior it has to be experienced to be believed! Mind you it is bloody expensive!.
Have a look at the weight of Simplicity and justify why you are carrying around 100 kg extra weight. Try leaving items out on benches when driving on corrugated roads with Simplicity -all over the floor when you stop. Try storing glass plates and glasses next to each other with no protection and see if they stand the conditions on Simplicity.
Don't get me wrong - I am not against Simplicity - the sheer numbers fitted prove me wrong, and it is a good system, but it is simply not the best available by a long way - which is what you should be aiming for in a new van.
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Follow Up By: Legendts - Saturday, Jul 04, 2015 at 21:08

Saturday, Jul 04, 2015 at 21:08
Never had a thing come off the bench with our Simplicity in over 12 years except once under severe braking when the guy in front hit the anchors after diving in front of me and it actually happened today! Yes there are better systems available now and all at a cost, together with their own issues. The Simplicity is a tried and relatively free of issues. I have not had any problems with ours and the van gets used. When we had our van built we had a 100 series cruiser so I opted for 16" Toyota mags the same as the cruiser with BFG AT tyres as I had on our vehicle too. I now run a 200 series with 18" tyres so that put paid to all the same size scenario. Good luck with your decision and it will be right for you. That's what counts.
Safe travelling.
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