tyre pressure

Submitted: Wednesday, Jan 09, 2008 at 13:15
ThreadID: 53270 Views:2102 Replies:9 FollowUps:1
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Hoping to get some guidance re tyre pressures for sand travel. Have goodyear mtr's on wrangler and if at psi of 18 is it safe to travel at 30-40k/hr?. Would be a mixture of soft sand on beach and some sand/gravel over a goat track. Any thoughts would be greatly appreciated.
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Reply By: Peter 2 - Wednesday, Jan 09, 2008 at 13:20

Wednesday, Jan 09, 2008 at 13:20
That would be ok, especially if only going a few k's.
Your jeep is relatively light and the MTR's are a pretty stiff/strong tyre. On the sand you could probably go as low as 10lbs if you have to to extract oneself from the soft stuff. I run about 14 -15 lb and that gives me another 4 or 5 to let out if need be.
AnswerID: 280587

Follow Up By: Smudger - Wednesday, Jan 09, 2008 at 13:38

Wednesday, Jan 09, 2008 at 13:38
16-18psi is ideal for sand work. I've read of blokes deflating to as low as 8psi to play o the beach, but all the test results I've seen show that below 15psi there's a real risk of rolling the tyre off the bead. Ive also poken to roo hunters who swear the best bush tyre is a rag inflated to 70psi .."ride's a bit rough, but gidgee roots won't get through 'em.
Stick to 18psi if it's doing the job, just remember to reinflate when you hit the hardtop.
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Reply By: Member - Coyote (QLD) - Wednesday, Jan 09, 2008 at 13:31

Wednesday, Jan 09, 2008 at 13:31
it pretty much comes down to speed and corners where you will coe unstuck with low tyre pressures. Like inthe previous post, you can get down to some reallylow pressures as long as you are driving in a straight line and not going too fast (too fast dpeends on how low you go) The issues at stake are the tryes will roll off the rim if you try and turn to hard for te pressure you are running.. eg at 10PSI. don't trun.. just drive out of bog ad inflate to say 15-20 PSI, then if youhave to tturn make them gentle and be aware that if the beach/dune is slopingthen you have even less turning ability before the weight of the vehicle on one side means you roll out of your tyres. The other factor is speed.. the softer the tyres, the more flexing they are doing.. the more flexingthey do, the more they heat p.. if you start driving along a for example a hrd beach at 80km at say 15PSI.. you are likely to blow a tyre (let alone what would happen if you tried to swerve for a creek wash out etc etc... ) FWIW the details you provided, say 18PSI at 40km/hr sounds like something I wouldn't have a problem doing, just no severe swerves/ driving across dunes...
AnswerID: 280590

Reply By: Member - Stephen L (SA) - Wednesday, Jan 09, 2008 at 13:32

Wednesday, Jan 09, 2008 at 13:32
like Peter said above, will be no problems at all. If the sand is dry and soft, go lower until you find what works for you.

If you go lower than say 10psi, do not do any fast and aggressive turns, or you may pop your tyre from the rim.


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AnswerID: 280591

Reply By: Member -Signman - Wednesday, Jan 09, 2008 at 13:33

Wednesday, Jan 09, 2008 at 13:33
As a rule of thumb- irrespective of vehicle/mass/tyre etc.- you should try to achieve a 'footprint' of about 300mm long in sand.
Then again- it could be a 'Jeep thing'....

AnswerID: 280592

Reply By: _gmd_pps - Wednesday, Jan 09, 2008 at 13:40

Wednesday, Jan 09, 2008 at 13:40
It very much depends on the tyre size vs rim size
a 255/85 on a 6.5" rim will get problems at 18 psi even on a light vehicle a 285/70 on a 8" rim will handle it much better.
You did not mention your tyre size so all answers will be specualtions and mostly useless. And then again if you use beadlocks the scenario changes. Trial and error is one way to explore things ..

good luck
AnswerID: 280598

Reply By: Member - Kiwi Kia - Wednesday, Jan 09, 2008 at 15:59

Wednesday, Jan 09, 2008 at 15:59
I go along with the 'you will be ok' crowd on here. As already mentioned the problems come with speed and hard turns. Also, the faster you go the more heat build up in the side wall as it flexes. This is one of the reasons you should reinflate on the hard top or keep your speed well down.
AnswerID: 280619

Reply By: splits - Wednesday, Jan 09, 2008 at 20:01

Wednesday, Jan 09, 2008 at 20:01
I have only ever had one experience with sand driving and nobody paid any attention to pressures at all. It was in late 1972 and early 73 on Stockton beach near Newcastle. I spent three months living and working there as part of an RAAF team that was clearing the top end of the beach of unexploded ammunition. We had two swb soft top three speed Cruisers that were stock standard except for smooth rounded looking tyres that had a couple of straight narrow groves around them. They could have been aircraft tyres for all I know. I don't remember what pressures were in them but they did not look underinflated.

The entire operation lasted for two years and those cars were driven regularly on the blacktop back to the base at Williamtown, they hit maximum speed along the sand near the water line countless times, they carried heaps of equipment plus six or seven men to every square inch of the sand hills during that period and were used as dune buggies on weekends. All of this was on the same pressures. I don't remember every having trouble with them and we never rolled one off a rim.

That was enough beach driving for me and I have never been near one since but, after that experience, if I did try it again I would be inclined to use near smooth and only just legal street tyres with factory recommended pressures.

AnswerID: 280656

Reply By: Member - Ed. C. (QLD) - Wednesday, Jan 09, 2008 at 21:46

Wednesday, Jan 09, 2008 at 21:46
I reckon Jol Fleming has a pretty good handle on the issue of tyre pressures...........

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AnswerID: 280689

Reply By: Derek from Affordable Batteries & Radiators - Wednesday, Jan 09, 2008 at 22:40

Wednesday, Jan 09, 2008 at 22:40
Drive to conditions.

Here is the extract from our instructions included with our PSV please take care on soft tyres.

"Use extreme caution when driving with partially deflated tyres. Traveling too fast while turning with deflated tyres you
may break the tyre’s seal and peel the tyre off the rim which may result in your vehicle rolling over or loss of control
causing death, bodily injury and / or property damage. You are responsible for your own safety and the safety of
those with you.
ABR – SIDEWINDER is not responsible for any liability or incidental damage, injury or inconvenience as a result
of use or misuse of the PSV. "


AnswerID: 280700

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