Tyre pressures for lower profile tyres.

Submitted: Monday, Aug 29, 2016 at 00:54
ThreadID: 133327 Views:3699 Replies:5 FollowUps:24
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Hi folks. I haven't visited Exploreoz lately, but when you need some information or advice it's a great forum. I have had Hiluxes for quite a few years and always let my tyres down to suit conditions. Sand about 14psi, off road 24 to 30. I have a Ford Everest now with 18" rims. Do the same pressures suit?
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Reply By: Malcom M - Monday, Aug 29, 2016 at 06:53

Monday, Aug 29, 2016 at 06:53
I think low profile tires in an off road situation are pretty stupid.
You do not have the tire sidewall volume to flex and act as a shock absorber, you are basically already on the deck.
You'll be more prone to punctures and carcass destruction let alone being bogged.

Good luck
AnswerID: 603929

Follow Up By: vk1dx - Monday, Aug 29, 2016 at 09:22

Monday, Aug 29, 2016 at 09:22
I would say also that the low profile side wall would be easier to tear on rocks, fallen timber or those very sharp and sturdy stump stakes. May even tear the side walls on an oyster shell.

Sorry Malcom - not a good idea to go off road with them.

I certainly wouldn't and if you saw what a rock, up on the tracks near Mt Buller did to one of our tyres, (265/75/16) you wouldn't either. FYI that was the first flat in 40+ years.

Phil
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Follow Up By: Malcom M - Monday, Aug 29, 2016 at 09:44

Monday, Aug 29, 2016 at 09:44
Why sorry Phil? pretty much exactly what I'm saying.
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Follow Up By: vk1dx - Monday, Aug 29, 2016 at 09:55

Monday, Aug 29, 2016 at 09:55
It happens with the electronic media mate. Everyone has to be so bloody politically correct and if not then they get accused of something that they didn't mean. I know!!

Catchya

Phil
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Follow Up By: Malcom M - Monday, Aug 29, 2016 at 10:07

Monday, Aug 29, 2016 at 10:07
lost me...
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Follow Up By: vk1dx - Monday, Aug 29, 2016 at 10:50

Monday, Aug 29, 2016 at 10:50
It was meant for Twinkles, the initial poster.

Phil
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Follow Up By: CSeaJay - Monday, Aug 29, 2016 at 11:50

Monday, Aug 29, 2016 at 11:50
The OP never mentions LOW PROFILE unless he edited his post. Why do you have to say he is stupid?
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Follow Up By: vk1dx - Monday, Aug 29, 2016 at 12:01

Monday, Aug 29, 2016 at 12:01
Read the title of the thread again and I did not say he was stupid.

I did however agree with comment "low profile tires in an off road situation are pretty stupid". Learn to read english.

Phil
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Follow Up By: Gramps - Monday, Aug 29, 2016 at 12:51

Monday, Aug 29, 2016 at 12:51
Hahahaha this is almost as good as the Marx Bros movie I watched yesterday.

Regards
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Follow Up By: vk1dx - Monday, Aug 29, 2016 at 13:23

Monday, Aug 29, 2016 at 13:23
It's bloody annoying from my side Gramps. I would love to share your humour. Why can't people simply learn to read.

A good idea mate cheers

Off to chemo treatment. Want to swap. Been 6.5 years so far.

Phil
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Follow Up By: The Explorer - Monday, Aug 29, 2016 at 14:03

Monday, Aug 29, 2016 at 14:03
Hi

The OP said his new vehicle came with "lower profile" tyres i.e lower than the ones he had before....these are not necessarily "low" profile tyres.

The Ranger in question comes with 265/60R18 tyres. Are these "low" profile?

Personally I think not, but I could be wrong as I do not know what the accepted threshold between low, not so low and normal profile is..

Cheers
Greg
I sent one final shout after him to stick to the track, to which he replied “All right,” That was the last ever seen of Gibson - E Giles 23 April 1874

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Follow Up By: garrycol - Monday, Aug 29, 2016 at 16:35

Monday, Aug 29, 2016 at 16:35
God you silly old farts carry on.
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Follow Up By: Tony F8 - Thursday, Sep 01, 2016 at 17:22

Thursday, Sep 01, 2016 at 17:22
This sounds so much like a faceache forum, seriously some of you need to take two panadol and have a sleep
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Reply By: Michael H9 - Monday, Aug 29, 2016 at 06:55

Monday, Aug 29, 2016 at 06:55
I run those sorts of pressures on 17's. A mate in a Disco on 19's tends to run about 5psi more to protect the rims. You'll be experimenting a bit but around 3psi more might be a good starting point. It depends on whether your tyres are standard size or a little larger.
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Follow Up By: CSeaJay - Monday, Aug 29, 2016 at 11:52

Monday, Aug 29, 2016 at 11:52
Michael
I would suggest the pressures would be approx. the same as what you are mentioning. There are several profiles becoming available for 18's in LT construction and several vehicles are going down that route.
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Reply By: garrycol - Monday, Aug 29, 2016 at 16:41

Monday, Aug 29, 2016 at 16:41
I have 255/60R18's ATs on my RRS and have not had any issues airing down. I have been down to 12psi to get out of trouble but I would not recommend going down that low for any extended period.

Sand - not below 15psi, and any slower offroad normally in the low 20s - remembering you can always go a little lower if needed.

Remember you do not have the tyre height of the good old days and the main issue will be hitting a rock or a hole a bit too fast - there is little give in the side wall.

Don't be too taunted andjust drive with care being aware of your lower profile.

Garry
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Reply By: Ron N - Monday, Aug 29, 2016 at 22:00

Monday, Aug 29, 2016 at 22:00
All - The definition of Low Profile, with regard to tyres is constantly changing,

In the 1970's, anything below an 80 series was regarded as "low profile".

In todays world, 55 series and lower is regarded as "low profile".

One has to keep in mind, that lower profile tyres are designed specifically for paved roads, and to improve roadholding and handling, on paved roads.

IMO, a 60 series tyres (as in the 265/60R18 fitted to the Everest) - is first and foremost, a road tyre.

If I had a vehicle fitted with these size tyres, I certainly would not be contemplating too much off-roading with them.

IMO, a 70 series tyre is a far preferable choice, if much off-roading is planned.

Cheers, Ron.
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Follow Up By: garrycol - Monday, Aug 29, 2016 at 22:29

Monday, Aug 29, 2016 at 22:29
You need to google 265/60R18 LT in MT and AT tread patterns and you fill find plenty of proper offroad tyres including the iconic BFG AT KO.
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Follow Up By: Ron N - Monday, Aug 29, 2016 at 22:59

Monday, Aug 29, 2016 at 22:59
Just because a company is producing a particular tyre size, doesn't mean it's ideal as an off-road tyre.

If you look at the picture gallery below (bottom of webpage), of the Colorado 7 on test (fitted with the standard 265/60/18 Bridgestone Dueler HT's), you will see how little flex there is in the relatively low profile sidewalls.

The testers never even tried it out in sand, nor did they even mention letting the tyres down at any time. The reason being, they'd gain little advantage, because of the relatively narrow, stiff sidewalls.

Vehicles fitted with these size tyres indicates the designers are working on 99% highway use, and 1% pussyfooting around on a few dirt firetrails, with no serious off-roading.

/http://performancedrive.com.au/wp-content/uploads/2013/03/2013-Holden-Colorado-7-LTZ-underneath.jpg]Colorado 7 on test

Cheers, Ron.
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Follow Up By: garrycol - Monday, Aug 29, 2016 at 23:27

Monday, Aug 29, 2016 at 23:27
I agree a HT tyre may not be suitable but you said a 60 series tyre is first and foremost, a road tyre.

That is just not true as there are plenty of 60 series light truck, mud terrain and all terrain tyres that are good offroad and are far from being a road tyre.
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Follow Up By: gbc - Tuesday, Aug 30, 2016 at 18:36

Tuesday, Aug 30, 2016 at 18:36
That being said, a 60 series tyre is never going to be able to run the deflated tread length a 70/75 series can run so by default cannot be as good off-road. No matter what the construction or tread pattern, a straight line says the rims are going to hit early and often when the tyres are lowered a little. Not only that, simple physics requires tyres with a lower volume to require more air pressure to hold up any given weight than a tyre with a larger volume so they are at a disadvantage off the bat.
I'm not saying they won't make it, but I'm surely saying they are going to put more strain on a car off-road than high profile tyres in the same situation.
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Follow Up By: garrycol - Tuesday, Aug 30, 2016 at 19:38

Tuesday, Aug 30, 2016 at 19:38
Following your logic - a 70/75 tyre by default cannot be as good offroad as 85/100 series tyres - and so one - where do you stop. Maybe but for everyday offroad use they are fine.

I can remember when we first went from 15" to 16" radial offroad tyres and the same argument was about. Likewise when we went from 85 series and went to 70 series - the same argument as made.

Improvements in tyre technology negate many of the old arguments on sidewall height. My 60 series tyres on one vehicle work pretty well offroad, as do the 100 series I have on another vehicle.
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Follow Up By: gbc - Tuesday, Aug 30, 2016 at 20:11

Tuesday, Aug 30, 2016 at 20:11
No doubt they work pretty well. My other 'suv' runs 255 55 r 18's. I don't care what tyre technology does, they'll never work in sand anything like the dirty boring 265 75 r 16's I have on the ute - and nor will your 60's. Small profile rubber performs well on road, conforms to extreme speed/load requirements and saves fuel on modern vehicles and that's nice, but unless overall diameter increases it is a retrograde step in terms of off-road options and is well masked by the better than average vehicle they are usually found on. Stick them on an old athsmatic 70's tech diesel and see how far you get up a beach ;)
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Follow Up By: Michael H9 - Tuesday, Aug 30, 2016 at 23:32

Tuesday, Aug 30, 2016 at 23:32
I saw an interesting video of a pretty standard Disco 4 doing Baboon Pass in South Africa. It's a very tough rocky track. The driver was concerned about the low profile tyres so pumped them up instead of deflating them. He went up to 3 bar which equates to 43psi, the aim being to protect the rims and sidewalls at the expense of traction. The video is here -

https://youtu.be/a81JPyo7J50

It wouldn't work on sand, that's for sure.
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Follow Up By: Member - Boobook - Saturday, Sep 03, 2016 at 17:43

Saturday, Sep 03, 2016 at 17:43
Errr, to just talk about the profile, eg 60 , 70 etc is completely meaningless.

For example which tyre has more rubber on the sidewalls?

A 245-70 17 or a 265-65 17 or a 285-60 17?

None, they are all the same. ( to within a mm or two.)

The 60, 70 etc by its self is just a ratio, not a thickness and gives no idea of the sidewall height.





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Follow Up By: Ron N - Saturday, Sep 03, 2016 at 19:15

Saturday, Sep 03, 2016 at 19:15
From the Goodyear website ...

"The two-digit number after the slash mark in a tire size is the aspect ratio. For example, in a size P215/65 R15 tire, the 65 means that the height is equal to 65% of the tire's width. The bigger the aspect ratio, the bigger the tire's sidewall will be."

Goodyear Tire - How to read tire sizes

The specific intention of low-profile tyre design is to reduce the height of the sidewall, to reduce sidewall flex - the exact opposite of what you want in an off-road situation, where you are seeking substantial sidewall flex, to gain in footprint area, and to give the tyre more ability to distort, and therefore absorb impact, and to reduce rock and stake damage.

Cheers, Ron.
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Follow Up By: Member - Boobook - Saturday, Sep 03, 2016 at 19:56

Saturday, Sep 03, 2016 at 19:56
Exactly Ron, so you can't say a 60 is any worse than a 70 profile if you don't also state the width. It's nonsense otherwise. In fact a 60 profile tyre could have a lot more sidewall height than a 70.
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Reply By: Member - Paul B (WA) - Saturday, Sep 03, 2016 at 11:25

Saturday, Sep 03, 2016 at 11:25
A couple of years ago we came upon a new 200 series Toyota stuck on the beach at Esperance which had uber flash shiny alloy rims and really low profile tyres, maybe 45 or 50 profile, but about 2" rubber between tread and rim at most. Leaving aside my incredulity at such an arrangement, it was incredibly difficult to do anything other than snatch him along over and over until all the snatch straps were seriously in need of an overnight rest. It wasn't even particularly soft sand.
An old bloke came along after an hour or so in an old stock standard series 3 Landy and gave the bloke with the 200 series a real bollocking and told him he wouldn't be helping him if he was that stupid as to render a wonderful 4wd totally useless with such stupid tyres and suggested he call a recovery truck. I must say by then, we were all pretty much all fed up with the whole exercise as well and insisted he do exactly that. I was delighted to later discover it had cost him about $500 to be recovered professionally.
His excuse for the tyres: "I thought they looked good!"
Paul B Kalgoorlie

Do your best, have fun & s/he with the most friends wins!

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Follow Up By: Ron N - Saturday, Sep 03, 2016 at 12:17

Saturday, Sep 03, 2016 at 12:17
I've never forgotten the 1st Lancelin Dune Buggy races, held about 1966 or '67, I think, in the mighty sand dunes of Lancelin.

It was real free-for-all - bring what ya liked, and put it up against all comers! LOL

There were blokes with smart-looking VW conversion buggies - blokes with hunking great homebuilts with rear-mounted V8's that threw sand spectacularly for 50M - and blokes with carefully-engineered, mid-mount engine jobs.

Then there was the bloke who turned up with a bog-standard SWB petrol S2 Landrover, fitted with wide sand tyres!

Guess who ran rings around the whole field, V8's and all - and won the race, hands down!
Yep, it was that unimpressive-looking, little old Landrover fitted with sand tyres!! LOL

Cheers, Ron.
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