Tyre pressures

[Tentman]

O K - Ive got my MT's fitted to my Safari (used Kumho 834's 285/75r16's on 8" blaktrak rims) and they are pretty well mannered on the road.

When I start "having adventures" its going to mostly be by myself I.e. only one truck so I don't want any excitement of the losing a bead variety.

I've been out with a couple of guys who reduce their tyre pressure but both of them went straight down to 16 psi. I forgot to ask if that was based on experience or just "what they'd been told".

So based my rim tyre combination is there any rule or guide as to what is a sensible minimum pressure??

Thanks

[dutchy]

as a guide i run 33x12.5r15 on 8" rim on 10 psi with problems. have even hit my rim on a couple of rocks and bead stayed on.

[LR90NZ]

O K - Ive got my MT's fitted to my Safari (used Kumho 834's 285/75r16's on 8" blaktrak rims) and they are pretty well mannered on the road.

When I start "having adventures" its going to mostly be by myself I.e. only one truck so I don't want any excitement of the losing a bead variety.

I've been out with a couple of guys who reduce their tyre pressure but both of them went straight down to 16 psi. I forgot to ask if that was based on experience or just "what they'd been told".

So based my rim tyre combination is there any rule or guide as to what is a sensible minimum pressure??

Thanks

Did you fit tubes when you got the tyres?
Do you friends have tubes in their tyres or run beadlock rims?

Generally you get a longer foot print with the tyre pressures reduced and therefore better traction/grip off road. Also you get a better (softer) ride off road.
However unless you have beadlock rims or have fitted tubes then much below 15-18 psi and you are more at risk of popping the bead off.

[zukmeista]

Popping the bead off usually isn't a problem anyway if you have a reasonable 12V compressor and tubes. They pop back on easy enough, just need to clean any mud out of the area and it's sweet.

[Tentman]

Thanks Guys

I don't have tubes in them, so it looks like I should run them at about 18 psi for a start and see how I go, maybe drop them a bit further when I have some latitude to experiment.

I suppose I should have mentioned that we will be primarily in Canterbury heading up riverbeds and farm tracks towards Tahr country - does that make any difference ??

[callum007]

Id happily go 15psi any day of the week in any country/conditions. yes you have a heavy truck but they are a big tyre on a good rim width.
I run my trials truck at 3-5psi, no beadlocks, only ever had one flat in 6 years of trials

[Dannz71]

id go straight to the nearest tyre shop and throw tubes in mate best thing ever, then if worst comes to worst, (which it will, trust me) then the bead will pop off and then straight back on, and ya probly wont even know about it.
Theres not much worse than poping a couple tyres off the bead and filling the rim with mud at night on your way out... previous exp...

[dutchy]

I run my trials truck at 3-5psi, no beadlocks, only ever had one flat in 6 years of trials

what size tyre? i assume 8" rim with tubes?

[Mehrts]

I've seen too many guys have issues with tubes being spun on the rim and ripping the valve stem out at lower pressures. Therefore, I'm a tubeless fan myself. Even if the tyre spins on the rim a little, it won't do anything except throw the balancing out of whack.

Never had any issues with my dual cab Hilux running tubeless 33x12.5 Wranglers on 15x8 steel rims at 15 PSI. Just had to be mindful where your tyres end up while driving.

Now have 35x11.5 Silverstones with Staun internal bead locks on 15x8 steel rims for the tougher stuff.

[callum007]

I run my trials truck at 3-5psi, no beadlocks, only ever had one flat in 6 years of trials

what size tyre? i assume 8" rim with tubes?

35*10.5 on 7" rim tubed

[buried]

i've spun the rim inside the tyre on 18psi, usually stick to 20-22 offroad which is all good

[mudlva]

Some thing to consider is
New steel rims will spit tyres for the first half dozen trips

Wash the detergent that the tyre installer uses off as soon as you get home with hot water. You will need to fully deflate the tyre first and get the hot water to flush as deep as posible

Older steel rims with worn paint and slight amount of surface rust hold real good

Tubes are good and you are able to run lower preasure but when you throw a tyre it will generally take the valve off at the same time

Tubless will not go as low generally but you can reseat the tyre when it does come off. Problem here is that once the tyre has turned off the bead it will full up with crap and generally not hold air well afterwards.
Also with the river crossings and what not rocks will be your biggist concern and could well dent the rim. This will affect tubeless set ups worst

[Lchundy]

All valid points above
Another thing to consider when running real low pressures is you lose diff clearance,which will cancel out any traction advantage from running low pressure

[Tentman]

Hmmmm - rims are new, hadn't figured on that being an issue but will manage it now I'm aware of it. Thanks for all your advice.

[mud_slinger]

prob with tubes if you get a puncture they will go flat straight away vs tubeless which depending on hole and if anything still stuck in there will seal the hole so will leak slower. also with tubes if there is any crap in the tyre it will rub against the tube causing pitting and eventually lead to a puncture.