Put New Tyres On the Sprayrig...

Submitted: Thursday, May 07, 2009 at 17:24
ThreadID: 68611 Views:2473 Replies:5 FollowUps:7
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....last week, two anyway. So What???. Well they are the first tyres I have replaced due to wear in 15 years in the game. The rest were destroyed in action. The post below prompts me to tell
you this amazing bit of trivia. Not one puncture or sidewall
disaster in the last 5 years. Why,...?? Running 50 psi, thats why.
Load is between half a tonne & one & a half tonne, speed around
15kph, 2nd low range, conditions from good to 30% rock cover,
sticks, steep, rough, the whole range. Yes, I know this flies in the
face of most of the accepted advice on pressure, but I can only say ever since the increase my problems have gone. I took this
experience to the Kimberley & back at 40psi & had no worries.
The job yesterday was extremely rocky, bloke sowing same ground
destroyed 2 tyres & rims on airseeder on first round. "I let them down to 25psi" says he. Wrong way says I. He operated all day today at 50psi without incident. So it will come as no surprise that
I dont subscribe to the lower pressure/less damage theory, & I
doubt any on the forum do more offroad low range k's than I do.
The choice,however, is always yours.......oldbaz.
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Reply By: Willem - Thursday, May 07, 2009 at 17:38

Thursday, May 07, 2009 at 17:38
G'day Oldbaz

Ummmmm....reducing tyre pressures is for taking the strain off the suspension and giving the vehicle occupants a better degree of comfort when on endless corrugations.

However, if you are comfortable in your vehicle with whatever tyre pressure you are running and it works for you, then thats good.

There is no hard and fast rule and different vehicles travel differently. It all depends on load etc and the way it is driven.

AnswerID: 363711

Follow Up By: Member - Oldbaz. NSW. - Thursday, May 07, 2009 at 17:53

Thursday, May 07, 2009 at 17:53
G'day Willem, I quite agree. My operating conditions may be a bit
different, but I was advised that lowering pressure would decrease
impact damage..it is rubbish. That is exactly what the tyre dealer
who advised 50psi said to me. The comfort factor may be true..
the Hilux rides like a dray with that pressure & uprated springs,but
a tyre a week was too hard to take. cheers...oldbaz.
FollowupID: 631394

Follow Up By: Member - Pesty (SA) - Thursday, May 07, 2009 at 19:02

Thursday, May 07, 2009 at 19:02
Well olbaz, I too have 20 years of spray rigs in all conditions, and i dont think you can compare the same as driving a 4wd on tracks.
I think the speed factor plays a very big part, at 15k you are not going to fracture a tyre like hitting a rock at 70 k plus.
Personally i will continue to use lower pressures on my 4by for track work, and mid range pressures on my sprayrigs, as the only tyre problems i have seem to be crap on the gravel roads inviting themselves into my tyres..

Cheers Pesty
FollowupID: 631398

Follow Up By: Member - Oldbaz. NSW. - Friday, May 08, 2009 at 14:12

Friday, May 08, 2009 at 14:12
Hey Pesty, pleased to hear of another sprayer out there. I wasnt
comparing spraying to general track work although the really
rough slow stuff is very similar. I had no damage at 40psi on the
likes of the Ood, Tanami, Mereenie, GRR etc. Interestingly every
one I stopped for with tyre problems was running lower than I was, about 5 vehicles I think. Anyway I'll stick with it as it seems to
work for me. cheers...oldbaz.
FollowupID: 631504

Reply By: Member - G N (VIC) - Thursday, May 07, 2009 at 19:08

Thursday, May 07, 2009 at 19:08
Hi Olbaz

Many thanks for your post.
I have read SO many who have stated that "you must lower psi or will have trouble"

I thought i must be loosing it as I have dropped psi lower one time with BAD results and have run high psi ever since with NO issues at all !!!!!!!!!

You get my vote of confidence.


ps i think if you heading were more like "high psi is the best way for minimal damage" you would get dozens of hits.
I almost didnt open this thread as i thought is was about spray cart tyre. I am busy and often only open what the ones the preview sounds interesting.
AnswerID: 363729

Follow Up By: Member - Oldbaz. NSW. - Friday, May 08, 2009 at 14:19

Friday, May 08, 2009 at 14:19
Hi GN, while I am convinced my theory on pressures is right for me in my operations I dont say it is right for all conditions. But after
running 40 psi in the outback without incident I will continue to do
so until comvinced otherwise. You are wise to use your own
experience I reckon rather than blindly following the sheep.
cheers..oldbaz. ps..I was expecting a bigger "spray" than I got !!
No pun intended...:))).
FollowupID: 631506

Follow Up By: Member - G N (VIC) - Saturday, May 09, 2009 at 13:01

Saturday, May 09, 2009 at 13:01
Hi Olbaz

actualy i read on a post once that the correct psi can be determined by checking the pressure difference from cod to hot and i think from memory if it is 6psi or more then the tyres are under inflated.

I think that seems to make good sense and stops you over inflating but also under inflating which i think leads to issues due to too much side wall flexing and heat biuld up.

FollowupID: 631668

Follow Up By: travelguy62 - Sunday, May 10, 2009 at 07:35

Sunday, May 10, 2009 at 07:35
Hi Oldbaz,
I have read a few threads were travellers let there tyres down to travel on rough roads.I have always kept my pressures high (42fr/46r & 42trailer)I have done 6 trips to the cape and a trip to Stuarts Stoney Desert to name just a few with no tyre issues.I have always used good quality tyres and used there recommended tyre pressures for the load I am carrying at the time.
Cheers Guy
FollowupID: 631787

Reply By: OzTroopy - Thursday, May 07, 2009 at 22:30

Thursday, May 07, 2009 at 22:30
Put me down down as a low pressure sceptic too.

AnswerID: 363776

Reply By: Motherhen - Thursday, May 07, 2009 at 22:35

Thursday, May 07, 2009 at 22:35
Hi Oldbaz

That's a really good run - reports on the forums recently have indicated that tyres (car and caravan) should be replaced if older than five years, as they are subject to blowing.

It took me a long time to convince my husband to lower tyre pressures on the rig. His stubbornness came from the sidewall damage theory that works differently on the farm. It took a $2,000+ lesson when we broke a gas line in the caravan fridge to change his thinking. Last trip we kept the tyres low on dirt roads, and in over 15,000 kms mostly on roads such as Gibb River, Tanami, Mereenie Loop and Great Central with no tyre problems whatsoever on the caravan or tow vehicle. Smoother ride all round too. It is different to in the paddock and at lower speeds.


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AnswerID: 363778

Follow Up By: Member - Oldbaz. NSW. - Friday, May 08, 2009 at 17:02

Friday, May 08, 2009 at 17:02
Hello Motherhen, Strange you should raise the tyre age issue,
another theory I dont subscribe to. I still use original splits on the
Hilux over summer when it takes on a fire unit capacity & the
Roadgrippers date from 1988...not a lot of tread on them but
they perform fine & show no signs of deterioration. I just fitted two brand new Michelins to one of my Peugeots, both were original unused spares off my 405s, cars made in 1994. Tyres
perform perfectly & no sign of ageing. I think there is a lot of luck involved with tyres & many theories on what is right & wrong. I
follow my own experience & will stick with high pressure as long
as it works for me. I did a test on my Jack at 30psi & again at
40psi, the fuel difference was about 15%. Add that to a 30%
gain if you stay under 100kph & the savings are huge. I've put
the Peugeots up to 35psi for 10% better economy & no sign
of abnormal tyre wear. 405s now do 16k to a Litre if held under 100kph, not bad for 2L autos & as good as most diesel cars.
An issue there will always be opposing ideas on, I guess, as long as
you're happy with your choice...happy travelling.....oldbaz.
FollowupID: 631542

Reply By: get outmore - Friday, May 08, 2009 at 14:56

Friday, May 08, 2009 at 14:56
yep I dont think there is any question especially at low speeds doing track/off trackwory higher pressures protect the sidewalls

Ive wrecked a few sidewalls running low pressures and other punctures have been in the sidewalls (wrecking them)
I have had 1 tread puncture in 5 years and that was a tech screw all the others have been sidewalls. When off track driving for work i ran 40psi and only had tread punctures and wrecked no tyres
AnswerID: 363856

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