Lowering Tyre Pressures

Submitted: Thursday, Apr 04, 2013 at 19:39
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We are doing the Mereenie Loop and the Oodnadatta Track in the next three weeks with a Pajero and Off- Road Goldstream Caravan. We are wondering whether we need to alter the tyre pressures on both the vehicle and the caravan and to what pressures. Any advice would be greatly appreciated.

Regards Marty
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Reply By: Member - Mfewster(SA) - Thursday, Apr 04, 2013 at 20:26

Thursday, Apr 04, 2013 at 20:26
Lowering tyre pressures reduces the chances of punctures and also takes some of the shock off your vehicle. Your caravan and car will ride smoother. But. With lowered tyre pressures you must reduce speed. On that road I'd be running on around 28psi and I wouldn't be going over about 55kmh.
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Follow Up By: baz&pud (tassie) - Thursday, Apr 04, 2013 at 21:30

Thursday, Apr 04, 2013 at 21:30
Agree with above, but again it depends on the condition of the track, have been on the Oodnadatta track three times, twice very rough, and once you could drive at any speed you wanted to, therefore the saying, drive to the conditions applys.
Enjoy the trip.
Cheers.
baz
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Follow Up By: Member - Ed C (QLD) - Thursday, Apr 04, 2013 at 22:11

Thursday, Apr 04, 2013 at 22:11
Here's a quote from Mick Hutton >

"You can do a great deal to minimise the risk of a flat tyre. I’m not going to spend a lot of time on this as the forums and articles are chock-a-block with this sort of stuff. I’ll just list the main issues and the reality is pretty simple;

Speed
Tyre Pressure

For our commercial off-road tours we will not give a blanket tyre pressure figure at all for travellers. For radial tyres we ask that they put a little bit of belly in the sidewall of the tyre to start and adjust from there, by the end of the first or second day most folks have got it worked out for the tracks they are on at that time, if the corrugations are shocking we simply let a bit more air out. In the end it is a personal preference and you just have to experiment yourself.

The slower you travel the less flat tyres you will get, if you learn nothing else at least learn that."

(note the bottom line ;-))

lifted from > This article here


:)
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....Not necessarily mechanic!!"

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Follow Up By: Member - Mfewster(SA) - Thursday, Apr 04, 2013 at 22:12

Thursday, Apr 04, 2013 at 22:12
Agreed Baz however the Oodnadatta Track is a bit more variable than the Mereenie Loop which doesn't get the same frequency of grading. So Yeah, I was speaking in general terms and lots of rain or otherwise can change things real quick up there.
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Follow Up By: The Bantam - Friday, Apr 05, 2013 at 00:31

Friday, Apr 05, 2013 at 00:31
While I agree that there are times that reducing tyre pressure can be of considerable benifit.

Nominating any specific tyre pressure without knowing the vehicle, the particular tyres and the load they are carrying is completely sensless.

One poster says they would be running 28PSI......some of us would be running that as a highway pressure.
others would be running mid to high 40's on the highway.


you need to start with the correct highway pressures, for the tyre and the load they are carrying.

The only way of reliably doing this is from the load v pressure tables for your tyres, after weighing your vehice axle by axle as loaded to travel.

you should know this before you set off.

then you have a sensible start point from which to work.

Different tyres under different loads respond differently to pressure reductions.

Persoannly I run about 30PSI front and rear in my vehicle loaded as I travel not towing.
I carry as set of staun tyre deflators set to 24psi and another set set to 18psi.

Dropping to 24 eases the ride considrably on rough roads & I then limit myself to 80kph.
At 24 the tyres do not seem to squirm too badly and give a traction improvement on loose surfaces.
dropping to 18 works well for me in soft sand, but I limit to about 60kph....At 18 the tyres are starting to squirm noticably.....but the car squirms on sand anyway and you need the flotation.

You realy do have to work it out your self individually.

If I am driving fast dirt roads I do not deflate at all.......because over 80kph is close enough to highway speed.

remember if you are loaded rear heavy or towing you may need to run different tyre pressures front and rear.
the trailer is a different vehicle and may have different tyres and should be calcuated seperately bassed on its axle loading and the tyres it is fitted with.

Remember too pressure should match load...if I was running fully loaded in the tray...my rear highway pressures would go up to around 36psi, my aired down pressures would have to go up accordingly.

cheers
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Follow Up By: Member - PJR (NSW) - Friday, Apr 05, 2013 at 09:05

Friday, Apr 05, 2013 at 09:05
Ed

Who is Mick Hutton?

Our highway pressures are 35 - 40. Dirt road that is maintained 25 - 30. Tracks like Oodnadatta, Strez, Tanami and the development road on the Cape at 20 - 25. But that' a guide only. We may alter those pressures depending on the conditions. Dry sand it can be anywhere from 15 - 15 to 20 - 25 on wet sand.

I haven't been on the Mereenie Loop so at a guess it could be 20 - 25 mainly because I have heard it can be heavily corrugated. But I have a compressor to change as required.

We do it, formost for grip/traction then in decreasing importance, protect the tyres, make it easier for the car and last but not least to give a little comfort for the passengers.

Phil

Pressures given: PSI Rear - PSI Front.
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Follow Up By: Member - Duncan W (WA) - Friday, Apr 05, 2013 at 10:49

Friday, Apr 05, 2013 at 10:49
Phil, Mick Hutton is Connie Sue Beadelll's partner. Connie is Len's daughter. Mick & Connie run a tag-along tour company that specialises in very remote travel.

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Follow Up By: Member - Ed C (QLD) - Friday, Apr 05, 2013 at 12:50

Friday, Apr 05, 2013 at 12:50
Thanks Dunc :)

Phil,
As well as having a good deal of first-hand experience with tyres in off-road/off-track conditions, Mick is also a specialist tyre repairer (when not on tour)...

Mick Hutton / Beadell Tours

I think it is safe to say that he knows "a thing or two" about tyres....


:)
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Follow Up By: Member - PJR (NSW) - Friday, Apr 05, 2013 at 12:55

Friday, Apr 05, 2013 at 12:55
Okay. I have never heard of him that's all.
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Reply By: Off-track - Thursday, Apr 04, 2013 at 22:27

Thursday, Apr 04, 2013 at 22:27
Disagree with the belief that low pressures reduce punctures, it's a myth in my opinion and have seen no hard facts to support it. However lower pressures will certainly make the ride more comfortable and potentially prevent damage to the vehicle from vibration etc.

Flame suit on but hey keep your mind open to both sides of the argument.
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Follow Up By: Motherhen - Friday, Apr 05, 2013 at 00:05

Friday, Apr 05, 2013 at 00:05
Consider a tyre as being akin to a balloon - blow it up tight and press a sharp stone or object against it - BANG. Now half inflate it, and you can press the sharp object into it some way without it bursting.

My husband is a farmer, and many farmers say low tyre pressures will put you in danger of side wall damage, but over the years on road he has learnt the risk is the lesser of two evils with lower tyre pressures.

Motherhen

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Follow Up By: Off-track - Friday, Apr 05, 2013 at 01:05

Friday, Apr 05, 2013 at 01:05
One of the much touted but inaccurate analogies is the balloon theory. A balloon is constructed totally different to a tyre the similarity starts and finishes with a vessel containing air. A tyre also isnt inflated anywhere near its bursting pressure.
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Follow Up By: Aussi Traveller - Friday, Apr 05, 2013 at 09:40

Friday, Apr 05, 2013 at 09:40
I'm with you Off track the lowering of tyre pressure is a myth, however the lowering of speed and careful driving will make a world of difference.

Phil
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Follow Up By: The Bantam - Friday, Apr 05, 2013 at 12:04

Friday, Apr 05, 2013 at 12:04
There is a reasonably strong case that pressure reduction reduces certain types of tyre dammage...BUT ...in my view it is a minor factor...and a side benifit.

The major factors are traction, ride, and ground pressure.

Small reductions in tyre pressure do produce a clear traction advantage on loose surfaces...this is well known and proven by every off butumen motor racing competitor and easy enough to prove yourself very quickly.

Improvement in ride will become immediately obvious on rough roads you and your vehicle will benifit immediately from a moderate pressure reduction.

Reduction in ground pressure, a reduction in tyre pressure will most certainly allow you to traverse soft ground better and get out of plenty of bogs.

It is also known and proven that reductions in tyre pressure with a responsible reduction in speed considerably reduce wear & tear on roads & tracks.

High speeds and hard tyres make corigations and pot holes faster.
In proper off road conditions the improved traction and lower ground pressure dramaticaly reduces how much damage is done by every vehicle that passes.

believe the puncture reduction thing or not......reducing tyre pressures under the correct conditions with an appropriate speed reduction is smart and safer all round.

cheers
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Follow Up By: The Bantam - Friday, Apr 05, 2013 at 12:27

Friday, Apr 05, 2013 at 12:27
Further on the puncture matter.

Pressure reduction probably does not reduce reduce what most people know as "punctures".....tyres being penetrated by small sharp objects like nails & screws"

It IS proven to reduce gross tyre damage from large blunt objects like rocks & roots.

I have a copy of video somewhere that shows a vehicle being driven over a short blunt steel spike, that simulates a sharp rock or root.
It is clear that the tyre is easily penetrated at highway pressures and not at fairly modest pressure reductions....the behaviour of the ryre and the principle are clearly shown in the closeups......the balloon analogy holds.

But remember some things are going to poke a hole in ya tyres regardless.

I remember the one of Leyland brothers saying striaght to camera.....something like "we've tried it all, all sorts of tyres, tubed tyres, tubless tyres, tubless tyres tubed, tubed tyres tubless, all sorts of pressure combinations...we still get punctures" then the vid shows a tyre with a root the size of a crow bar thru a tyre.

Pressure reduction is proven to reduce tread chipping and chunking particularly on the edge of the tread...this I put down to improved traction....as the tyre rolls over objects rather than spinning over them with imperfect traction.

The rock strike on the rear tyres thing...I don't buy it.

the simple fact is most rear tyres are heavier loaded than fronts....and the front tyres may simply be digging up & turning rocks over that the rears run over.
These two facts alone would account for the rear tyre failures.
Reductions in pressure will still reduce the problem.

cheers
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Follow Up By: Aussi Traveller - Friday, Apr 05, 2013 at 13:08

Friday, Apr 05, 2013 at 13:08
Gee Bantam don't I feel patronised.

I have done my own test, I call it the reality test.

I have driven several different model vehicles ( they were all Toyota) with several different tyre makes on close to 1000000 km of dirt road, I have never let my tyres down from 41 psi, I have never had a puncture or blow out.

My secret as above lower your speed, use care with driving and make sure your suspension is up to scratch.

You are welcome to your opinion though.

Phil
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Follow Up By: Motherhen - Friday, Apr 05, 2013 at 13:18

Friday, Apr 05, 2013 at 13:18
As Off Track and others here have said, the main reason we reduce our tyre pressure on corrugated roads is to reduce damage - the basketball analogy. The lesson learnt by my husband was the irreparable damage to a caravan fridge. $2,000 was a dear lesson for one who was wary of side wall damage. On beaches and similar conditions the reasons are different and well known.

Mh
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Follow Up By: The Bantam - Friday, Apr 05, 2013 at 14:38

Friday, Apr 05, 2013 at 14:38
There are thousands of people who have persisted with out dated and ill informed practices for many years and have just been fortunate not to have had a problem..or simply are incapabe of knowing the difference.

If you have never reduced your tyre pressures how can you possibley know how it works ?

I am sure there are people who claim that seat belts are of no benifit because in over xyz years they have never been killed.

There are plenty of people that claim that smoking or sun exposure does not cause cancer, because they are not effected.

The fact is the practice of lowering tyre pressures off the butumen is well and truly tested and proven, both in formal documented research and peoples every day experience.

There is a very good reason it is included in the nationally approved and accredited 4wd training system.

There are plenty of situations where we should all slow down......but there are plenty of situations where less speed will help you not a bit, but reduced tyre pressure will.

Reducing tyre pressure WILL also reduce damage to the roads & tracks.

Aussie Traveler mate....there is no problem with being wrong......but failing to learn....when presented with good well proven information......well that is just willful ignorance.

how do you feel now.

cheers
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Follow Up By: Aussi Traveller - Friday, Apr 05, 2013 at 17:25

Friday, Apr 05, 2013 at 17:25
I still feel patronised, because you have not shown any published material to prove your argument, so you can shove your wilful ignorance comment were it fits.

I have had a quick look on goggle for some published information, but only come up with former EO posts that to me don't hold much credence as none of them have any published articles on the matter, well the hand drawn version from the pink road house is as good as it got, I didn't think much of that info either..

I had a colleague do an accredited 4wd training course and the driver under the exact instructions of the instructor, rolled the vehicle, injured 4 passengers and the vehicle was a right off.

My 4wd experience dates back to 1976 so I do know what I am talking about, give me some hard evidence, not some banter by those Monday experts.

You know what they say about experts don't you??, an ex is a has been and a spurt is a drip under pressure.

Now I'm going bush for the week end.

Phil
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Follow Up By: Off-track - Friday, Apr 05, 2013 at 22:33

Friday, Apr 05, 2013 at 22:33
Yet to see any proof to support your theory bantam. All it amounts to is personal experience both individual and collective which is no different to the other side of the argument. It is ignorant of you to say otherwise.

Maybe what it does prove is that the performance and reliability of modern offroad tyres isnt as affected by pressure variations as some may think.
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Follow Up By: BarryR1 - Saturday, Apr 06, 2013 at 00:00

Saturday, Apr 06, 2013 at 00:00
You know Phil (Aussie Traveller) it's a sad reality that you would be hard pressed to find one post on this forum where you have made a positive contribution. You are always on the attack, flaming people and generally debasing anyone whose opinion doesn't match your view of the world. No one chastised you, they simply offered an opinion that in know way diminished or debased your point yet you act like it's a personal attack. You seem to be out to make yourself the centre of attention by hijacking other peoples threads and deliberately inciting.

Perhaps you could find somewhere else to offer your anonymous "expertise"!

Enjoy the trip. I know the forum will breath a sigh of relief with your absence!

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Follow Up By: ModSquad - Saturday, Apr 06, 2013 at 00:05

Saturday, Apr 06, 2013 at 00:05
Thankyou Ladies and gents,

This seems to wandering to places it shouldn't. There is little value in continuing in this vein.

Enough.

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Follow Up By: Ozrover - Saturday, Apr 06, 2013 at 10:39

Saturday, Apr 06, 2013 at 10:39
Sorry ModSquad, but I can't let this one go!

"well the hand drawn version from the pink road house is as good as it got, I didn't think much of that info either.."

Aussi Traveller ,

So you would disregard the observations of a bloke (Adam Plate) who had well over 35 years of experience in driving the roads around Oodnadatta & Central Australia?

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Follow Up By: The Bantam - Saturday, Apr 06, 2013 at 16:35

Saturday, Apr 06, 2013 at 16:35
At the risk of labouring the point....there are plenty of people who have been " doing it wrong" for a very long time, there are also plenty of people who doggedly stick to ideas that while once accepted, have been supeseeded or proven erronious by good reserach.

After all half the world believed the earth was flat till some crazy joker sailed around it.....the other half always believed it was sperical.

Anyway back to the point......you would have to have had ya head under a rock or somewhere else dark & smelly for 20 years not to have seen the principles of pressure reduction in off road situations discussed at length in every corner of the 4wd community.

The matter of tyre pressures was also raised in the enquiry innto deaths and 4wd hire on Fraser island

As for cretitable references.

Cooper and Micky Thompson detal tyre pressure reduction is gloosy colour brocures ( possibly not as well as it could be) and have produced videos that show the results to be "dogs balls obvious"

The matter of tyre pressure reduction has also been canvased extensivly in formal reserach

here is one paper
Though not true "off road trucking", it deals with dirt & gravel roads like would be found in logging and mining.

http://road-transport-technology.org/Proceedings/5%20-%20ISHVWD/Part%201/EFFECTS%20OF%20TIRE%20INFLATION%20PRESSURE%20AND%20CTI%20ON%20ROAD%20LIFE%20AND%20VEHICLE%20STABILITY%20-%20Woodrooffe%20.pdf

this paper discusses the effects of tyre pressure on both the tyre and the road surface......if you have the ability to digest the extensive verbage

It relates to heavy trucks where the pressure reductions are very large in proportion to what we do...like 90psi down to as low as 30psi

It lists a range of truck tyre the US wheel and tyre assocaition have issued reduced speed, reduced pressure recomendations for.

they prove that rut development is reduced by as much as 90% on lightly graveled roads....under some sutuations running reduced pressure could have a "healing" effect reducing existing ruts.

They found in the test situation that tyre wear reduced by 15%.

Sandy road traction (not soft sand or beach) was shown to improve by 34% and clay road traction by 17%, with only a reduction of pressure from 100 to 65PSI.

Stopping distances where shown to improve.

Didn't take me long t google that one up, remember not all information is published on the internet....and ya have to know how to specify search phrases

If you want to read any of the wheel and tyre associaions material you will have to pay.

I have more but I think this one paper is enough to be going on with.

cheers
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Follow Up By: Off-track - Sunday, Apr 07, 2013 at 08:13

Sunday, Apr 07, 2013 at 08:13
Interestingly it didnt state anything about lowering pressure to reduce puncture, that is my argument that I find difficult to accept. Although it did cover decreased wear from high to low pressures.

I find it equally interesting that Dakar race teams running BFG increase pressure when in rocky terrain to reduce punctures.
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Follow Up By: The Bantam - Sunday, Apr 07, 2013 at 09:45

Sunday, Apr 07, 2013 at 09:45
If you look at table 2. Tyre durability results- number of occurances

you will see 4 different types of tyre damage tabulated, although only a fairly short test, all tyre faults examined reduced dramaticaly

Tread cut chunk outs reduced from 171 occuraces to 35.

This is one issue that is very commonly raised and reported among touring 4wders and caravaners in Australia on Australian roads.

Rip enough chunks out of ya treads and a puncture can not be far away.

As for the Dacar race teams......firstly this is a high speed race that reflects highway speeds ( and then some) much of the time.
Realy who knows what the individaul race teems and drivers do.

The pumping up, over high speed rocky terian idea has been arround for a very long time it was very a strongly held belief in the 70's and 80's and these days has fallen out of favour.

AND it comes from a time when there where a lot of problems with early steel belted radials, and lots of radials where being run underinflated.

there where so many "problems" with early steel belted radials that many manufacturers where selling textile belted radials like the Bridgstone RD102.....and the textile radials had a good following among those doing rough road work at the time.

Anybody seen a textile belted radial recently.

At the time the recomendation was to inflate higher in an attempt to solve some realy basic problems with the new fangled steel belted tyres.

The second reasoning is mainly lifting the sidewalls higher off the road surface to prevent rock penetration in the sidewalls.
Radials even when correctly inflated, belly out in the side walls more than crossplies.
In practice it probably just makes the ride so intolerably bad the drivers have to slow down.

I have not seen any research to this particular matter.....but the practice of reducing pressure and speed has been very well canvased and reserached.

cheers
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Follow Up By: Off-track - Sunday, Apr 07, 2013 at 12:35

Sunday, Apr 07, 2013 at 12:35
This is getting old really...

Some people believe lowering pressure reduces punctures and some people dont. There are many ways to support either argument as people generally look for ways to support their actions rather than disprove it, too often emotion and long-winded replies rather than hard evidence but I certainly havent seen anything substantial to change my opinion and I have been looking for ways to disprove it.

One day when I get punctures from running 40psi on gravel roads I might rethink it but it's been a long time and (distance) coming.
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Follow Up By: Aussi Traveller - Monday, Apr 08, 2013 at 10:24

Monday, Apr 08, 2013 at 10:24
Barry R1 let me break this down for you, even though I loath to have to defend myself I feel that in this case I must for fear of being labelled a troll, which by the way I probably the only thing I haven't been accused off in this thread.


BarryR1 posted:
"You know Phil (Aussie Traveller) it's a sad reality that you would be hard pressed to find one post on this forum where you have made a positive contribution."

Well Barry I have made many valuable contributions over the last 7 years and was regularly told so, not necessarily under Aussi Traveller I was a member once.


"You are always on the attack, flaming people and generaly debasing anyone whose opinion doesn't match your view of the world."

No Barry this is not the case, in fact it is the very opposite on this thread, I have stated my case and even told Bantam he was welcome to his opinion.

"No one chastised you, they simply offered an opinion that in know way diminished or debased your point yet you act like it's a personal attack."

After I said Bantam was welcome to his opinion, he came back with another long winded rant and the accused me of being wilfully ignorant and how did I feel about that. ( I would call that a personal attack)

"You seem to be out to make yourself the centre of attention by hijacking other peoples threads and deliberately inciting."

It is you that has hijacked this thread, as every thing I have posted in this and every other thread I have posted on has been relevant to the topic, however you have not contributed to this topic other than your personal attack of me.

"Perhaps you could find somewhere else to offer your anonymous "expertise"!

Enjoy the trip. I know the forum will breath a sigh of relief with your absence!"

Firstly let me say I have put my name to all post on this thread, I don't always put my name on posts not to be anonymous but probably because I couldn't be bothered, however Bantam has not signed any of his post, so to me this is what I would call anonymous,In fact I have met and made many personal friendships with people on this forum.

Yes you are right there are other forums out there where people respect others opinions without personally attacking people, but it will be me sighing with relief as I am going to spend more time out bush and less time on here wishing I was out bush like most people do on this forum.

Bantam

You have posted 5 long posts on the subject now, yet none of your post have any published peer revued papers on the subject, the link you posted comes up with a 404 error, to be fair nether have I, however I did not resort to any personal attack on you in fact I said you were welcome to your opinion.

Ozrover I to have done 37 years driving around this country on all types of roads and tracks, so I would believe that I have the right to have an opinion on this subject.

Finally ModSquad

If you think that I have offended anyone on this thread, please accept my apologies.

Phil
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Follow Up By: The Bantam - Monday, Apr 08, 2013 at 12:31

Monday, Apr 08, 2013 at 12:31
Phill mate. I have never signed my posts on internet forums and never will, I do not seek personal approval....or to promote myself or my business......... the vast majority do not......this is normal....just like bad spelling and grammar.
I like most other partisipate to share & learn.

My posts are what they are, however if you don't like em I expect you to produce a well constructed argument.
If I am wrong, show me the facts.
If proven wrong I will admit it...I did yesterday..and I thank Dennis Ellery for his robust exchange.

Not just repeating your opinion and saying it must be right and you are entitled to it.



As for this entitled to opinion thing.......I seem to see this posted on this particular forum a lot, and not just when I am involved.

The truth is, there is a very big difference between personal opinion and facts, proven methods, approved procedures and accepted practice.

Truth to tell, unless you are Alan Jones, personal opinion is not worth much, its very rarely accurate or reliable and changes over time.

Even Alan Jones' opinion is not fact.



As far as being peer reviewed.......hell what do you think this is and what do you think is going on.....the internet is one of the most vigourolsy peer reviewed environments there is.

besides......how much factual information and research work do you think is actually and formally peer reviewed.



As far as long posts......I do not resile from long posts when I think they are need to produce a well constructed argument.



Back to the subject......the concept of pressure reduction off highway has been well and truly canvased, the princliples have been informally proven and tested by thousands, and have been subject to several properly constructed independent scientific studdies.
And the details continue to be investigated and in understanding improved.

People running around off highway with tyres inflated to highway pressures, and experiencing problems, but, being totally oblivious to the problem or the cause....is so common, that it has reached the scale of a standard joke........some however know it is beyond a joke, because it could potentially cost a great deal.....it has been identified as a contributing factor to loss of life.

When major 4wd identities, people who run fleets of vehicles, make a living from dragging people's sorry asses out of the scrub or see the results of running tyres inflated to highway pressures when it is inappropraite every day...say that it is a good idea to lower your pressures under certain circumstances.....a prudent person will listen and try to understand instead of continuing to insist they are entitled to their own opinion.


The understanding of the role of off highway tyre deflation is possibly the single most important development in off road driving since the invention of the pneumatic tyre, it deserves proper explanation and robust discussion.

Many of us have learned a great deal about this matter from forum discussions about this matter....many have taken ideas out and tested them ourselves and proven or disproven many of the small details.....then reported back in discussions from our experiences.

The quality of the facts continues to improve......BUT there remains enormous volume of people with less than perfect understanding and clinging to proven incorrect and outdated personal opinion.
This is proven every time there is a thread on a forum about off highway tyre pressures.



If you come to forums to discuss, learn & share, I hope you will respect and value a robust discussion...I do.

But if you come to air an opinion and insist you are right, I and others will be happy to provide you with a deserving insult...and let the chips fall where they may.

cheers
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Follow Up By: Off-track - Monday, Apr 08, 2013 at 14:20

Monday, Apr 08, 2013 at 14:20
Sorry Bantam but the second half of that reply is full of emotive heresay that is being paraded as fact...it isnt.

"Single most important...", "standard joke", "quality of the facts..." - are you serious!?

Like I have said before, use what works for you, let others use what works for them without using forceful emotive opinion to drive the sheep into one paddock. Show the facts, offer your opinion and advice but dont berate people for choosing an alternative that others use with success. I couldnt care less what method people use but it does get my goat when people try to force one sided opinion.

Dont insist that you are right either.

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Follow Up By: The Bantam - Monday, Apr 08, 2013 at 18:27

Monday, Apr 08, 2013 at 18:27
As I say mate this is not a matter of opinion..and facts are facts....no hearsay...facts

It is a serious matter when a coroners inquest and a following government equiry identifies tyre inflation as an issue in deaths.

This IS a one sided argument...and not a matter of opinion.

Sorry I am right and not because it is my opinion, because the facts say I am right.


Say how about you try defalting your tyres as is current recommended and approved practice, before you say it does not work.

cheers

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Follow Up By: ModSquad - Monday, Apr 08, 2013 at 21:06

Monday, Apr 08, 2013 at 21:06
Thanks all, this isn't progressing anything further in a positive manner. The thread will now be locked.



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FollowupID: 786057

Reply By: ABR - SIDEWINDER - Thursday, Apr 04, 2013 at 22:34

Thursday, Apr 04, 2013 at 22:34
Hi Marty

A TPMS could be a good investment too, one saved tyre almost pays for the system.

Regards

Derek from ABR

AnswerID: 508208

Follow Up By: Ozrover - Saturday, Apr 06, 2013 at 10:28

Saturday, Apr 06, 2013 at 10:28
Good call Derek,

We run TMPS's on all of our vehicles, & have saved a few tyres from destroying themselves due to slow leaks usually caused by Tek screws/nails etc...

They are also a useful way of monitoring the rise & fall of tyre pressures during a trip, as well as the effects of loads in the vehicle on tyre pressures & temperatures.

1
FollowupID: 785812

Reply By: Mick O - Thursday, Apr 04, 2013 at 23:04

Thursday, Apr 04, 2013 at 23:04
Marty,

this link on Tyre Pressures should give you a bit of reading material.

Conventional wisdom says reduce tyres by at least 10% once travel conditions change from bitumen to gravel although I will go somewhat lower myself. Speed is everything so it is a matter of driving to suit conditions.

Yes I'd lower on both Van and Vehicle.

Another thing to watch is changing track. The central accumulation of gravel on outback roads and tracks causes a lot of the tyre issues due to people travelling across it at speed. Strangely enough it's where you'll find all the sharp stones etc! If the track looks a little bit better over there, resist the urge to move across until you have significantly reduced your speed.

Enjoy the trip.

Cheers Mick
''We knew from the experience of well-known travelers that the
trip would doubtless be attended with much hardship.''
Richard Maurice - 1903

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AnswerID: 508210

Follow Up By: Member - Salt grinder - Friday, Apr 05, 2013 at 00:02

Friday, Apr 05, 2013 at 00:02
Pretty much concur with all that has been said. But just a little bit more info . . . .

The graded road may look easy, however most tyres destroyed are usually the rear as the front wheels dislodge and flick up rocks that can have that potential to just have a sharp point or edge that can split a casing in the centre if caught at the wrong angle.

if there is a van behind then the chances of a blow multiply.

Then also there is that graded smooth shoulder on the LHS of the road that looks temptingly smooth away from the corrugations. That's where the graders hide all the bigger rocks that can tear open the sidewalls of a soft tyre, sometimes there may even be sharp tree stakes lurking along that ridge.

I had a 4WD overtake me in Nth Qld on a correguated road travelling about 90kph. At the curve ahead he made it about half way round before sliding off into the scrub, landed on his side (no one seriously hurt TG). The bend was corrugated and at speed he was just touching the tops of the bumps, airborne 50% of the time at best. The result was he had no steering to speak of, lost control and drifted sideways. Flip. We fortunately winched him upright, back on the road, and the vehicle was bashed but drivable. He could not understand how it happened so easily. There endth the lesson.

Ciao
Cocka
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Follow Up By: Off-track - Friday, Apr 05, 2013 at 01:09

Friday, Apr 05, 2013 at 01:09
Havent heard that theory before, Cocka, any proof/evidence to support it?
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FollowupID: 785664

Follow Up By: Member - Salt grinder - Friday, Apr 05, 2013 at 10:26

Friday, Apr 05, 2013 at 10:26
Not sure of which part of theory to which you are referring. The roll-over is factual.

Personally, over 30yrs across Oz outback have lost 2 rear tyres, no front tyres . . . one a rail spike on the Old Fink track, the other coming out of Arkaroola to Leigh Creek. Both occasions the casing had been split in the centre.
On the Gibb R Rd saw a guy who'd done 3 tyres on that one trip, one on the trailer and 2 vehicle rear . . . all separate incidents. The trailer one had the sidewall ripped open. He said "I'm buggard now" as we sat under a tree, I made him a cuppa. I asked what his tyre pressures were ? His answer, 40psi.

Also my accumulated knowledge talking to bushie tyre repair centres . . . they really know what goes on.

As to the theory of the accumulated gravel alongside the graded tracks . . . . I don't mean to imply the grader drivers get out and personally hide rocks in the scree. But it's easy to see that that is where the bigger stones finish up as the grader moves up the road. With a bulging side wall from lower tyre pressure . . it could become a marriage made in hell . . . . "cave ne emptor".

And incidentally it doesn't have to be a big rock to damage a tyre, it's about pressure, speed and luck . . . . . the first two you can control.

The trouble with common sense is that it is not always so common and is often only learnt in hindsight.

I don't pull a trailer these days, to much to look after and I prefer free camping in the remote. I always have the front of the tent facing the sunrise. But I ask this question, I wonder how many trailers have tyre pressure sensors to alert the driver that a trailer tyre is loosing pressure?? The answer is probably here somewhere in this forum.

Ciao
Cocka
I sometimes question my sanity . . . . and then it answers back.
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Follow Up By: Mick O - Friday, Apr 05, 2013 at 10:55

Friday, Apr 05, 2013 at 10:55
Whole heartedly agree Cocka. Excellent overview of your experiences which largely mirror mine....except that I’ve destroyed a lot more tyres lol. I destroyed my first tyres on fairly pedestrian tracks in the early days simply because of a basic lack of knowledge on tyre pressures (And yes speed was probably a factor as well). I was 19 so I’ll use youth and inexperience as an excuse. These days, a bit of pressure out of the tyres and a much easier going sees me make it there, and back with a minimal of tyre issue. Ironically, I’ve not destroyed one on an outback track since with the odd exception when hitting unseen obstacles at the edge of the track, usually where left by the grader a long time back and since covered in grass etc. That’s the luck part alright.

There was another good point made about ride comfort. On heavily corrugated tracks, we reduce much further to allow the tyres to do some of the work, thereby assisting the suspension and shock absorbers to cope. The trade off is heat in the tyres but again, this can be managed by reducing speed, cautious driving, and the odd stop for a cuppa or to stretch the legs. I’m of the firm belief that a good Tyre Pressure Monitoring System is an essential bit of kit these days, particularly if towing. Up front you are a long way from any potential tyre issue on a van or trailer often with dust to contend with as well. Nice to have the warning when the tyre is on its way down before a major issue eventuates or the tyre is destroyed.

Cheers Mick
''We knew from the experience of well-known travelers that the
trip would doubtless be attended with much hardship.''
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Follow Up By: Bonz (Vic) - Sunday, Apr 07, 2013 at 07:41

Sunday, Apr 07, 2013 at 07:41
Mick, I saw you'd stated the heat in your shockers (157 deg I recall) on one corrugated track, how'd you measure that?
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Follow Up By: Bonz (Vic) - Sunday, Apr 07, 2013 at 07:42

Sunday, Apr 07, 2013 at 07:42
It was in a vimeo clip by the way
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Follow Up By: Mick O - Sunday, Apr 07, 2013 at 10:36

Sunday, Apr 07, 2013 at 10:36
Bonz,

I carry a small digital thermometer in the glove box. Just point and shoot. You can pick them up at Jaycar for about $40. Very handy little item.

Digital point and shoot thermometer

Cheers Mick
''We knew from the experience of well-known travelers that the
trip would doubtless be attended with much hardship.''
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FollowupID: 785916

Reply By: Motherhen - Friday, Apr 05, 2013 at 00:09

Friday, Apr 05, 2013 at 00:09
If lowering car tyres pressures to go over loose sand, we lower caravan tyres to the same. Otherwise on rough roads we lower the caravan pressures more than the tow vehicle - and found 25 psi cold ideal on the Gibb River Road. My husband took them down to 27 psi for the Tanami and 25 would have been better - there was some damage.

Motherhen
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AnswerID: 508220

Reply By: KevinE - Friday, Apr 05, 2013 at 08:13

Friday, Apr 05, 2013 at 08:13
Hi Marty, as you've probably worked out by now, you get some very diverse answers to questions on an internet forum!

I last drove those 2 roads in Oct last year; yes, I would definitely lower your tyre pressures on both the tug & the van.

The late Adam Plate's guide to tyre pressures is absolutely definitive for the vehicle's tyre pressures on both of those roads! (& most other dirt roads!) Just work out what you're driving & how it's loaded & compare it to Adam's guide Adam Plate's tyre pressure guide.

Unfortunately, Adam hasn't mention caravans! We towed a camper trailer & had the tyres at 20 psi. with no issues whatsoever. You may need to have a tad more pressure in your van tyres though because of the weight!

We had 4 people in a fully loaded 4WD & the tyres pressures were; 20 psi in the front & 26 psi in the back, again with no issues whatsoever.

On those 2 roads our cruising speeds were around 80kmh on the Oodnadatta Track & around 90kmh on the Mereenie Loop. The car sat well on the road, steered well, braked well & was quite comfortable.

This was part of a bigger trip of over 5,000km of outback roads, including some very out of the way places - we didn't get a single tyre failure. We did see a few on other vehicles though! Strangely enough, the majority were on the passenger side rear tyre as Adam predicts. When quizzed, the drivers all had what they thought were low pressures, but I thought were too high.

Now all you have to do is sort out what you think will work for you lol!

Cheers,

Kevin :)

NB: if you go for a look at the Peake ruins, I'd leave the van somewhere, I wouldn't take it in there ;)
AnswerID: 508241

Follow Up By: KevinE - Sunday, Apr 07, 2013 at 08:52

Sunday, Apr 07, 2013 at 08:52
I should add that I started driving off road in the army (infantry) a long time ago & they never dropped their tyre pressures, ever back then (dunno if they do now?) I was in the HQ unit for 2 years & we drove everywhere the boys in the rifle companies walked or got driven in by by old inter trucks or APC's, behind them in an old series 2 Landrover. No roads, no track, just bush. On one jaunt, we went from Pt Augusta to Woomera without traveling on one single track. It wasn't much fun! (especially having the RSM sitting alongside me yelling at me about my driving lol!) My army experience caused me to resist advice from others to drop my tyre pressures for a long time. My theory being if the army did it that way, it was correct. I regret that, as a lot of my trips since then would have been far more comfortable, fun & cheaper had I listened.

Cheers again,

Kevin.
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FollowupID: 785899

Follow Up By: The Bantam - Sunday, Apr 07, 2013 at 10:03

Sunday, Apr 07, 2013 at 10:03
A lot of people point to "army practice" when referencing 4wds.

I have friends and relatives who have been in driving roles in the army at various times and the army outlook has always been very much different to 4wd practice outside.

In my older brotherinlaws day, NO army vehicle had freewheeling hubs, though they where common on civilian vehicles.
It was considered that a vehicle "was not in a state of readyness" if it had free wheeling hubs fitted and they where diseagaged.

Likewise deflating tyres unless absolutly necessary was considered a " vunerability", because the vehicle was not then in a "state of readyness" to travel at high speed.

Snatch straps where considered extreemly dangerous and not permitted.

Even today, my nephew constantly bemoans the fact that he is not permitted to use methods and techniques he knows work well and he would use in his own 4wd when in the bush in a green truck.

AND I could go on with issue after issue.

When you work on the idea that you may be being shot at.....different things become important...like being able to just get into a vehicle and drive it.

Then there is the army attitude to recovery....." mate if ya cant get it out easily......leave it there...we'll drag it out later with something bigger".....that is if the enemy have not blown it up first.

cheers
0
FollowupID: 785907

Follow Up By: KevinE - Sunday, Apr 07, 2013 at 16:49

Sunday, Apr 07, 2013 at 16:49
You clearly know a lot more about army practice than me mate. I was just in the army for 15 years lol! I certainly wasn't in the same army as your friends & relatives though, as a lot of what you've written is far different from the army I was in ;) (vehicles in a state of readiness??? They're either serviceable or they're not - weapons have degrees of readiness, not vehicles)

I wasn't in RACT, I was a grunt, during which time I was an RP for 2 years, so I drove the Landrover when we went bush for those 2 years. I also got to drive Inter Mk 3's & 5's at times & later Series 3 Rover's & Mog's when I left the reg's & joined the ARES (change of badge to RAE)

You might want to tell the guys driving the ration trucks, or the guys that used to drive Mini Mokes, VW Combi's, Falcon Utes etc about that theory of no freewheeling hubs on army vehicles lol!

The point I was making is that I wish I'd listened to people about dropping the pressures on my tyres on corrugated roads years ago & my previous experience made me resist that idea.

Cheers,

Kevin.
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FollowupID: 785948

Reply By: Member - TheFox3305 - Friday, Apr 05, 2013 at 09:11

Friday, Apr 05, 2013 at 09:11
Have a look at the Pink Roadhouse website - Adam's many years experience on tyre pressure is shown on a link on this page Adam's info
AnswerID: 508250

Reply By: Member - Andrew & Jen - Friday, Apr 05, 2013 at 22:11

Friday, Apr 05, 2013 at 22:11
Hullo Marty

As in many cases on this forum, there is a quite division of opinion on the matter of tyre pressure reduction. What to do?

In such cases I find it useful to listen and put more weight on advice from people who drive for a living in a wide range of conditions.

Two examples -

We spent some time yarning with a guy at Mutawintji NP last August - he is the fleet mechanic for a large trucking company that drives millions of kms over unsealed roads. What do they do? As soon as they leave the bitumen, they drop the pressures from 100 to 50 psi and lower their speed accordingly.

When we travel on the tracks with the guys who work up in the Vic High Country, similar story - pressures down to 18 or in some cases, lower when we leave the bitumen.

As has been said above, experiment and find what works for you :-)

Cheers
Andrew
AnswerID: 508298

Reply By: BluePrint Industries Pty Ltd - Friday, Apr 05, 2013 at 22:43

Friday, Apr 05, 2013 at 22:43
Hi Martin,

We have also written a blog on tyre pressures at

http://www.exploroz.com/Customers/49000.875/12/2009/4WD_TYRE_DEFLATION_TIPS_FOR_SAND_and_OFF_ROAD.aspx


It is a good starting point.

Regards

Kurk
AnswerID: 508304

Reply By: Echucan Bob - Friday, Apr 05, 2013 at 23:48

Friday, Apr 05, 2013 at 23:48
Something not mentioned so far is keeping the weight on the wheels to a minimum. The factors affecting puncture risk are speed, weight and tyre pressure. A sharp stone will puncture a highly inflated tyre driven fast enough. Think of a bullet hitting glass. If you slow right down the tyre will roll over the stone and avoid puncture. If you lower the pressure the tyre will envelope the stone and maintain contact with the road around the stone, again avoiding a puncture. If you are overloaded the tyre will overheat due to excessive side wall bagging. This will also expose the sidewall to sharp objects.

Not only will high tyre pressures increase the risk of tyre damage on rough roads, the suspension is forced to handle greater amplitude wheel travel which can destroy shocks and other bits of the car. A suitably deflated tyre absorbs a lot of the shocks, making the ride smoother and protects the sprung and unsprung parts of the vehicle. With pressures down the area of tyre in contact with the road increases and this reduces the localised pressure that a sharp stone can cause.

To reduce puncture risk: minimise wheel loading, keep speed down especially on bends when drifting further exposes the sidewall, reduce pressures on gravel roads, steer to avoid sharp rocks and stones. Use TPMS to detect problems before the tyre is destroyed.

Bob
AnswerID: 508311

Reply By: DiscoTourer - Saturday, Apr 06, 2013 at 02:30

Saturday, Apr 06, 2013 at 02:30
It's easy to see from these posts who assist with creating corrugations and those that assist with looking after our tracks.

The number of fellow travellers that I have come across with flats due to too high tyre pressures is amazing....but they do listen when the sun is belting down....they don't want to be changing another flat 10ks down the track.

Brett....
AnswerID: 508314

Follow Up By: olcoolone - Saturday, Apr 06, 2013 at 08:30

Saturday, Apr 06, 2013 at 08:30
Corrugations are formed by speed and suspension frequency, the only thing lower tyre pressures may help with is making hard suspension more compliant....... most suspension these days is long travel softly sprung type.

An old 70 series landcruiser will do more damage to the ground than a coil sprung 100 series landcruiser.

If you slowed down it would have the same effect.
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FollowupID: 785801

Follow Up By: DiscoTourer - Saturday, Apr 06, 2013 at 11:34

Saturday, Apr 06, 2013 at 11:34
Absolutely speed, suspensions etc are contributors, but the fact is, and well documented in studies, that tyre pressures do contribute to corrugations greatly!

Brett....
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FollowupID: 785818

Follow Up By: The Bantam - Saturday, Apr 06, 2013 at 15:10

Saturday, Apr 06, 2013 at 15:10
It has been proven that reducing tyre pressure does reduce the tendancy to create corrigations and other road damage.

Because.....reduction in tyre pressure reduces road pressure.

AND

the softer tyre tends to damp the resonant system that creates the corrigations.

This is a fundamental part of road surface engineering.

In any situation where the road surface is damaged or the road surface is not up to it road engineers will reduce speed #1 and reduce permitted load carrying #2

cheers
0
FollowupID: 785830

Reply By: Ozrover - Saturday, Apr 06, 2013 at 09:06

Saturday, Apr 06, 2013 at 09:06
You know what's best for everyone?

- Drive fast.
- Run your tyres at High Pressures.
- Overload you car to ridiculous levels.
- Tow Heavy Trailers.
- Fit large diameter rims with low profile tyres.
- Ignore the Road Conditions that your driving on.
- Ignore Local Advice from people who drive on those roads all of the time.
- Ignore anecdotal evidence that implies that you should maybe be lowering your tyre pressures.


You know why?

There are lots of tyre repairers out there that want your money & most make a pretty good living at repairing abused tyres.

Jeff running for cover with tongue firmly in cheek!
AnswerID: 508318

Follow Up By: DiscoTourer - Saturday, Apr 06, 2013 at 11:30

Saturday, Apr 06, 2013 at 11:30
Glad you chipped in Jeff. I also made a post on a previous article about what the tyre people in the bush know and their experience is invaluable to those in the city that think they know it all. Looking forward to dropping in and saying gday again
Brett
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FollowupID: 785816

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