Tyre Presures? rock & Mud
Submitted: Sunday, Jul 30, 2006 at 16:42
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Jack 2000
Gday,
I was wondering if someone could inform me on tyre pressure for rock work, I have reasonably fat tyres and I am not sure if deflating them a bit would make sense on rock climbs, (power line track,
Perth hills).I mostly do beach work and in the past all rock work was done with narrow tyres. Also letting your tyres down on slippery surface what is the general concessus. (4X4 area Kwinnana,
Perth)
Also I spotted an exploroz wheel cover on the back of a Prado in West
Perth on Tuesday.
Reply By: ross - Sunday, Jul 30, 2006 at 17:04
Sunday, Jul 30, 2006 at 17:04
Hi Jack There are no hard and fast rules re tyre pressure.
It does help on rocky surfaces by wrapping around
the rock for traction.
It also decreases the risk of have a sharp rock pierce your tyre.
Too much defltion and you run the risk of pinching the tyre wall or losing the seal around the bead.
On the poweline I use about 25psi+ from memory but mainly for a more comfortable ride.
For slippery surfaces choosing the right tread/rubber compound is maybe more important but a little deflation helps.
At the end of the day its all trial and error based on the vehicle ,its weight,tyre type and anything Ive missed;)
AnswerID:
186077
Follow Up By: MP - Sunday, Jul 30, 2006 at 17:35
Sunday, Jul 30, 2006 at 17:35
I've quite often wondered about the theory behind lowering pressures off the bitumen. The only time I have ever let the tyres down is in sand. I would have thought lowering pressure on dirt only makes the sidewall venerable.
Mark
FollowupID:
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Follow Up By: Voxson (Adelaide) - Sunday, Jul 30, 2006 at 19:09
Sunday, Jul 30, 2006 at 19:09
If you were to look at your tyre in slow motion going along a dirt road,,, you would see your sidewall being struck by the same amount of sharp objects,, whether it be at 25psi or 40psi.....
How the pressure makes a difference is ,,, with less pressure in your tyre there is less chance of one of these shaft objects piercing your sidewall.....
Pump a balloon up really hard and push the bottom of a match into it and try and pop it and then half blow one up and try it again...
Same theory with tyres...
FollowupID:
443133
Follow Up By: D-Jack - Sunday, Jul 30, 2006 at 19:12
Sunday, Jul 30, 2006 at 19:12
Not to mention it's not really fun travelling on severe corrugations with 40psi in the tyres!
FollowupID:
443134
Follow Up By: Member - Tim - Sunday, Jul 30, 2006 at 19:45
Sunday, Jul 30, 2006 at 19:45
Even more than that, if the tyre pressures are too high the steel belts can actually be bleep tered by the impact of a rock. If the pressure is not so high they can bend around it.
Tim.
FollowupID:
443143
Follow Up By: Member - Tim - Sunday, Jul 30, 2006 at 20:09
Sunday, Jul 30, 2006 at 20:09
Actually on more thought I should qualify that last statement - In the situations like rock crawling or other slow work that were initially asked about you will not damage a belt. In order to do that you need to be running higher pressures on dirt roads at higher speeds.
Tim.
FollowupID:
443147
Reply By: Truckster (Vic) - Sunday, Jul 30, 2006 at 18:08
Sunday, Jul 30, 2006 at 18:08
Trial and error.. try it and see what you think. it wont hurt.
AnswerID:
186095
Reply By: Nick R - Sunday, Jul 30, 2006 at 22:24
Sunday, Jul 30, 2006 at 22:24
watching the guys scramble over rocks and loose dirt at the winch challenge yesterday, they seemed to have their tyres down a bit, not as much as for sand but they definitely had a fair amount of give and indeed bounce at times. If I had to guess I'd say they would have had their tyres in the low to mid 20s for psi.
One would hope they know a little about what they are doing.......
NickR
AnswerID:
186174
Reply By: srowlandson - Monday, Jul 31, 2006 at 10:46
Monday, Jul 31, 2006 at 10:46
i ALWAYS drop to 25psi when i hit dirt when going 4 wheeling.
Lower pressures save my fillings falling out,and stops the tyres getting cut up etc.
When the going gets tough, i start dropping the pressures more and am happy to go down to 18psi.
I carry a pair of air compressors, and often air up and down a few times a day.
STeve
AnswerID:
186232