diverae
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Post by diverae on Mar 20, 2004 9:22:22 GMT -5
What tyre pressures do everyone use out there, and on what size tyres?
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Saliya
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Post by Saliya on Mar 20, 2004 10:14:45 GMT -5
Hi there,
The way I see there are a number of key points you need to consider before deciding the tyre pressure. Some of them are; weight of the car, size of tyre, type of terrine, ground temperature (specially when you drive in soft sand), more importantly your driving style and so on.
I drive a Land Cruiser and as a general rule I try to drive at 18psi. You surely can change it by 2 - 3 psi up or down but you need to then change your driving style too. You can drive fast and hard when you are on higher air pressures whilst you need to be extremely careful on hard turns and hard drops when you drive at lower pressures. Both has pros and cons and at times I change my air pressure based on my mood!!
A medium weight four wheel like a Prado or a Pajero could be driven at say 16 -17 psi
Then a small four wheel like a RAV 4 can be driven at even 14 -15 psi
If you start in a morning say at 18 psi, with the ground temperature going up, automatically the tyre pressure too tend to climb up and its best that you have a quick check say after 3-4 hours. Once I started at 18 in the morning and I ended up around 24 - but this was in Liwa and more importantly during mid summer
Hope I hadn't confused matters but its reality in my car and my style of driving!!
Cheers,
Saliya
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Post by Fouad Berjaoui on Mar 21, 2004 5:15:32 GMT -5
exactly what Saliya said, also vehicle load plays a role and tyre thread plays a role.
A vehicle loaded with 5 people should not be deflated below 12 as a vehicle loaded with only the driver.
Aggressive tyre thread, you can go down to 8 PSI but smooth tyre thread, do not go below 14.
Fouad
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Saliya
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Post by Saliya on Mar 21, 2004 7:10:11 GMT -5
Hi Fouad,
I didn't know the effect of aggressive tyre thread vs smooth tyre pressure - so I learn today.
I drive on BFG - Macadam, this I guess could be considered smooth thread.
Thanks,
Saliya
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Bryan
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Post by Bryan on Mar 22, 2004 5:05:10 GMT -5
Fouad, How do you differentiate agressive from smooth? I'm still learning  . I have Michellin Synchron. I guess that is smooth and maybe the BFG All terrain is aggressive. Am I right? Regards Bryan |
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diverae
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Post by diverae on Mar 22, 2004 6:03:50 GMT -5
Nice one. I didnnt know about the difference between aggressive and smooth. Like Brian I have michelin synchrones but on a Patrol SWB. Used to have a Jeep Cherokee which I ran at 15 psi, changed recently to the nissan, which I also run at 15 in the sand. Hopefully afetr payday I'll change to BFG ATs. Foaud, what pressure do you run on yours (in soft sand)?
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Klaus
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Veteran Club Member
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Post by Klaus on Mar 22, 2004 13:40:16 GMT -5
This issue is about tyre pressure, right?!
Don't understand, it's easy; put gas(CO'2) instead of air, no change of pressure hot or cold. I did it all the years(35) I had a car, also back home (NL) summer or winter no pressure change.
Consider this.
Klaus
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Bryan
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Post by Bryan on Mar 24, 2004 3:55:39 GMT -5
Klaus,
Where can u fill your tyres with gas here. All the pumps offer only air. But you still need to deflate in the sand right.
Bryan
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Post by Fouad Berjaoui on Mar 25, 2004 6:05:14 GMT -5
Aggressive threads are the ones found on few Yokohama, BFG, Interco and Mickey Thopmson Interco Tyres (aggressive): uae4x4.com/images/trips/trip0301/trip0301-14.jpgYokohama Tyres (aggressive): uae4x4.com/images/trips/trup0401/trip0401-01.jpgBFG : notice the two ZR2, they both have BFG tyres, the black one still has the OEM BFG "Longtrail" (Smooth) whereas mine (white one) has the BFG "KO" thread (aggressive) uae4x4.com/fouad/zr2-tyre.jpgHope this helps the explanation. Basically the smooth tyres are good in sand but very vulnerable to punctures in rocky roads like Hatta. The aggressive tyres are invincible in Hatta but on soft sand you have to deflate down to 10 or 8 for them to work properly. The Michelin, Pirelli, Bridgeston Dunlop and all the rest are considered as "smooth" tyres. Note that some of these manufacturers do have Aggressive tyres but are not imported to the Arab world. Except Michelin (French Company), they do not have an aggressive tyre, instead of developping their own aggressive tyre, they went and bought BFGoodrich (American company) and now they market BFG as their own under BFG brand. Just like Nissan is owned by French company Renault. So although BFG does make good passenger car tyres, but you dont see them here, instead you see Michelin tyres for passenger cars. It's all in the policy making. Fouad |
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Ghanem
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Post by Ghanem on Apr 27, 2004 9:57:01 GMT -5
I run my jeep at 15 on sand , 20 on rock
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Bryan
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Post by Bryan on Apr 28, 2004 2:22:24 GMT -5
Gr8 explanation fouad. The pictures really say it all. Now I know and understand . U the man. Thanks once again for helping out. |
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Post by Fouad Berjaoui on Apr 28, 2004 10:30:56 GMT -5
Ahhh Shucks, I am blushing now  hehe not really, it's just this is the whole purpose why this club was created : to share our experiences and knowledge. I am sure there is something you know that I dont, and one day by pure coincidence you will share your experience with me and I would have learned something new Fouad |
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stupot71
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Post by stupot71 on Apr 29, 2004 1:04:17 GMT -5
Like Fouad said the type of tyre make a big difference. tyres with harder sidewalls will need to be let down lower to increase the foot print so a 3 ply side wall is tougher than a 2 ply
i run Mickey Thompson MTX on sand i run at 10psi 8 if its really soft or to get out of a stuck. on rocks i lower my tyres to 20 it helps when crawling over objects I cant even drive my jeep on sand with tyres at 15!!!
also bear in mind when you reduce your pressures they will go up a few psi in the sand
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Post by Fouad Berjaoui on Apr 29, 2004 12:32:14 GMT -5
Stu is right about the the psi going up in the sand due to two factors :1- the sand pushes them upwards and 2) the sand temperature heats the tyre air.
HOWEVER, this is on NORMAL vehicles, ALL vehicles EXCEPT Stu's vehicle. His tyres are so BIG that when he steps into the sand, the SAND LEVEL goes up, hehehehe
Man you have big tyres, 33s or 32s ??
Fouad
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Prasad
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Post by Prasad on Apr 30, 2004 13:29:56 GMT -5
When I first started out I ran at 18psi on my dunlop grandtreks 275/70R16, after the last liwa trip I experimented at 15psi and found it to be the best. I once popped a tyre at 17psi purely driver error. I find that running at 15psi is easier and less of a strain on the engine as well.
I have since changed to BFG A/Ts same size and run these at 10 psi. Havn't yet been on rocks with them. I guess I'll go down to about 25psi.
My main concern was what pressure to use on tarmac. I have now found out that the ideal pressure to use on road is, first check cold tyre press: then drive for about 30/40 mts and check again. The pressure should have increased by 4psi, if so the cold tyre press: was correct. Experiment till you end up with a 4psi increase, works for all tyres.
Cold tyre pressure for my tyres is 35psi.
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. I have Michellin Synchron. I guess that is smooth and maybe the BFG All terrain is aggressive. Am I right?
hehe not really, it's just this is the whole purpose why this club was created : to share our experiences and knowledge. I am sure there is something you know that I dont, and one day by pure coincidence you will share your experience with me and I would have learned something new 