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General => General Discussion => Topic started by: McGirr on May 04, 2015, 09:38:11 PM

Title: Tyre Pressures for dirt roads.
Post by: McGirr on May 04, 2015, 09:38:11 PM

Just curious on tyre pressures.

Did some exploring around Warburton and got home washed the dirt off the car and the next morning a flat rear tyre, first flat in 7 years. Any way put a plug in it today as there is no tyre repair place here. There was a sharp rock that went through the tyre in a lug in the main tread. The tyres are reasonably new.

The tyres had 37 psi in the rear and 34 psi in the front.  Being based here all I do is drive on dirt roads with the occasional Rocky track. What would be the ideal psi for the front and rear tyres. The tyres are hankook all terrain tyres. You can see the tread slowly being worn traveling on the dirt roads with the odd lugs being chipped here and there.

Once these tyres have done their job I will look at upgrading to some tougher tyres.

Mark
Title: Re: Tyre Pressures for dirt roads.
Post by: Mik01 on May 04, 2015, 09:41:47 PM
Did the same on my first off-road dirt driving. Now deflate to around 24. But that's for dirt, rock and mud etc
Title: Re: Tyre Pressures for dirt roads.
Post by: broncos11 on May 04, 2015, 09:43:15 PM
Just watched Your4x4 tonight and they were doing the GBR and they all put 24 psi in and had travel speed around 80kmh to best cope with corrugations. Probably a but more severe then your average driving around home, so maybe high 20's????
Hope your going well

Dave
Title: Re: Tyre Pressures for dirt roads.
Post by: Kelvo on May 04, 2015, 09:43:33 PM
I normally run 20% less than my road pressure.

Remember different vehicles have different 'starting' pressures so a universal pressure will not suit all.
Title: Re: Tyre Pressures for dirt roads.
Post by: Steffo1 on May 05, 2015, 08:34:10 AM
Just watched My4x4 tonight and they were doing the GBR and they all put 24 psi in and had travel speed around 80kmh to best cope with corrugations. Probably a but more severe then your average driving around home, so maybe high 20's????
Hope your going well

Dave
Did the GBR, Gunbarrel & some in '05 & ran 28 front, 26 rear. On the GBR I found 80-90 kmh was the best suspension harmonics for my vehicle & the Gunbarrel was anywhere from 2-70+ kmh  ;D
Steve
Title: Re: Tyre Pressures for dirt roads.
Post by: KingBilly on May 05, 2015, 08:41:26 AM
28 cold all round for dirt roads.  Try to stay under 85 kph

KB
Title: Re: Tyre Pressures for dirt roads.
Post by: fishfinder on May 05, 2015, 08:56:38 AM
28 cold all round for dirt roads.  Try to stay under 85 kph

KB
aqgree
Title: Re: Tyre Pressures for dirt roads.
Post by: Redcherokee on May 05, 2015, 08:57:45 AM
What's that old rule?  Measure the pressure cold, and then again when they are hot.  Someone will be able to confirm the desired difference. Is it 5?.  Anyway, that sort of methodology sounds good.

Title: Re: Tyre Pressures for dirt roads.
Post by: KingBilly on May 05, 2015, 10:17:43 AM
What's that old rule?  Measure the pressure cold, and then again when they are hot.  Someone will be able to confirm the desired difference. Is it 5?.  Anyway, that sort of methodology sounds good.

Difference of 4 psi between cold snd hot but that is more applicable to black top and vehicle loads

KB
Title: Re: Tyre Pressures for dirt roads.
Post by: chester ver2.0 on May 05, 2015, 10:26:44 AM
Mcgir

On the mines which are all dirt roads about the same quality as you experience 2 to 30 depending on loaded or not was the normal numbers
Title: Re: Tyre Pressures for dirt roads.
Post by: rossm on May 05, 2015, 11:00:01 AM
Gidday

I have been in that country on a tagalong and out very experienced guide recommends a minimum of 10 per cent below normal highway cold pressure. If it is very rocky and you are not heavily loaded 15 per cent is not ruled out.

Just have to watch the speed . But from experience you are not likely to barrelling along.

I envy you, there is some great country out in that region.
Title: Re: Tyre Pressures for dirt roads.
Post by: austastar on May 05, 2015, 11:29:27 AM
Hi,
    For me, highway is f 60, r 70.  I halve that for gibber and corrugations.
Cheers
Title: Re: Tyre Pressures for dirt roads.
Post by: Pog on May 05, 2015, 11:39:37 AM
Hi,
    For me, highway is f 60, r 70.  I halve that for gibber and corrugations.
Cheers

Are you talking psi?
Title: Re: Tyre Pressures for dirt roads.
Post by: Azz on May 05, 2015, 12:47:34 PM
28 psi for out on the bush, extended gravel touring.

Will drop to less when its muddy.
Title: Re: Tyre Pressures for dirt roads.
Post by: swanny on May 05, 2015, 12:53:51 PM
26 to 28 psi for me depending on weight, I think terrain is also a factor, if the road is nice and firm (gravel type road) then I run what is mentioned or even a touch higher, however if its a bit sticky, wet, and muddy I tend to lower them a touch more and back my speed off.

I reckon dropping your speed is pretty important when lowering tyre pressures....

Swanny
Title: Re: Tyre Pressures for dirt roads.
Post by: jk on May 05, 2015, 09:40:46 PM
As said above weight is always going to be a factor, but on the Cape York Trips we ran about 25 to 26lb front and rear all the way from Laura to the tip and back.

After two trips to the top and back to Brisvagus the tyres showed no sign of unusual wear and we had no flats or punctures, in fact someone commented that they didn't look like they had done much off road work, to which I replied..............nah, only about three to four thousand km worth  :cup:

Cheers
Johnno
Title: Re: Tyre Pressures for dirt roads.
Post by: dales133 on May 05, 2015, 09:53:46 PM
So what do you do with your camper trailer/van tyres? What pressures do you usualy run them at on and off road?
I'd imagine weights a factor but generaly
Title: Re: Tyre Pressures for dirt roads.
Post by: KingBilly on May 05, 2015, 09:57:19 PM
Normally run the camper at the same pressures as the tug. Particularly important in sand.

KB
Title: Re: Tyre Pressures for dirt roads.
Post by: jk on May 05, 2015, 09:58:38 PM
Usually the same as the 4x4, if the 4x4 is approximately 3t loaded over 4 tyres at 25psi then the camper is approximately 1.5t over 2 tyres at the same pressures ! But that's just me  ;D
Title: Re: Tyre Pressures for dirt roads.
Post by: edz on May 05, 2015, 10:32:28 PM
This vid might help https://www.youtube.com/watch?v=9Kz8mmLkeks (https://www.youtube.com/watch?v=9Kz8mmLkeks)
Title: Re: Tyre Pressures for dirt roads.
Post by: V8CRSA on May 05, 2015, 10:39:53 PM
On the trip we just did we ran 25ish in the front and 28ish in the rear,and all tyres have come out of it in great condition.
Kamper was also around 25psi

Matt
Title: Re: Tyre Pressures for dirt roads.
Post by: dales133 on May 05, 2015, 10:50:14 PM
Cool thanks guys
Title: Re: Tyre Pressures for dirt roads.
Post by: grafy82 on May 05, 2015, 10:50:47 PM
We ran 28psi all round, including camper on our last trip to Weipa. They were already old tires but did not show any bad wear and no punctures after about 2000 kms of off road.
Title: Re: Tyre Pressures for dirt roads.
Post by: fuji on May 06, 2015, 01:34:30 AM
aqgree



X50
Title: Re: Tyre Pressures for dirt roads.
Post by: GanG on May 06, 2015, 09:00:39 PM
When I was working in arnhem land 2013 and on our road trip in 2009 up there I ran 22psi all round with a moderate load on the vehicle and towing a light trailer
Title: Re: Tyre Pressures for dirt roads.
Post by: McGirr on May 06, 2015, 09:05:28 PM

Had a chance today to drop tyre pressures to 26 front and 28 rear. Will see how it goes otherwise may drop a little lower.

Thanks for the replies.

Mark
Title: Re: Tyre Pressures for dirt roads.
Post by: theins on May 06, 2015, 09:09:49 PM
How does the Tyre profile effect the psi? Given that a low profile tyre only has limited sidewalls, should you still drop the pressure?
Title: Re: Tyre Pressures for dirt roads.
Post by: letsgoplaces on May 06, 2015, 09:26:36 PM
Hi Mark,

We ran 24 all round for our time out there.
You should have a much softer ride by dropping your pressures by 10psi.
But the roads in WA are so much nicer than the NT and SA

It's been good to see that Warbuton is treating you well :D

Cheers
John
Title: Re: Tyre Pressures for dirt roads.
Post by: timneva on May 06, 2015, 10:11:47 PM
Here's a handy little sheet I picked up from from the pink roadhouse years ago, which gives some rough tyre pressure guides for various vehicles/conditions.

(http://gallery.myswag.org/gallery/d/50086-2/tyre-pressure-pdf.jpg)
click on the image and it should expand to full size......

Cheers
Title: Re: Tyre Pressures for dirt roads.
Post by: SteveandViv on May 07, 2015, 01:36:52 AM
As we are always around dirt up here I leave mine at 20psi front and 24psi rear. That works best for me up Cape Leveque road as it is quite strait those pressures work well. I think people are to hang up on the 4 PSI rule as as mentioned it works for the black top but no really the dirt. Every Tyre brand is a little different but all of them are able to run at low pressures so using them to soften the corrugations is a must. 
Title: Re: Tyre Pressures for dirt roads.
Post by: Moggy on May 07, 2015, 06:34:18 AM
This vid might help https://www.youtube.com/watch?v=9Kz8mmLkeks (https://www.youtube.com/watch?v=9Kz8mmLkeks)
It did!
Thanks.
Think i know what my next tyres will be now
Title: Re: Tyre Pressures for dirt roads.
Post by: Bird on May 07, 2015, 09:40:52 AM
Way too many variables to give an accurate answer...