Time for a (tyre) change

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01 Nov 2012 12:21 - 01 Nov 2012 12:22 #1 by dandjcr
dandjcr created the topic: Time for a (tyre) change
Forum Home > OKA Maintenance > Time for a (tyre) change

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From Tony Lee:

Mentioned previously that the markings on the 123's air filters show they are the originals fitted during manufacture in 1995.
After a very successful maiden voyage in the (almost) completed refurbishment - mostly through some pretty wet forest tracks NW of Bulahdelah during which the winch got a pretty good workout - I figured it was time to make some plans for the central Australian trip planned for when we get back from the US in July.
Checked the tyres out with a view to getting a new one to replace the odd spare plus an unmounted case as backup.
Tyres are Michelin XZY 285/70R19.5 with no damage to side walls and heaps of tread on them so I figured just getting the two new ones would be OK. Clevers Tyres said they are superseded and the new ones are not nearly as versatile as the ones fitted.
Rims are 19.5 x 7.5 fitted in 1996 and the date code on the tyres is 276 - week 27 in 1996 - so the tyres are FOURTEEN years old.
Guess it is time to get some new ones!
Pity about all the unused tread still on the tyres.
I know Peter_n_Margaret uses 305s on 8.5" rims, but what are the recommendations for my 7.5" rims? Not interested in optimising for mud, but need an all-rounder for bitumen plus the unsealed/rocky/sandy conditions in the centre and the north during the dry season.
April 11, 2010 at 11:09 PM Flag Quote & Reply

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From Peter_n_Margaret:

Tony, I can't advise on the 285s. No experience at all.
I do have a little exposure to 265s, and it was not good. They were very hard and I reckon the vehicle would have been shaken to bits in a few 000ks of corrugations.
My vehicle came with 7.5" rims and I sold them and bought the 8.25" and 305 tyres.
How heavy are you going to be?
You could probably go back to 16" splits and 255/100 tyres for a similar cost as new 285s. The 255/100s give a great ride and perform well over most terrain.
I still have plenty of 16" rims.
Cheers,
Peter
April 11, 2010 at 11:11 PM Flag Quote & Reply

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From Tony Lee:

Weighed it a couple of days ago as part of the shakedown trip - full water and fuel tanks, tools, and most provisions plus two people and it was 5400kg so by the time I add the high-lift jack and more food it will be right on the 5500kg. More good luck than good judgement but the result was OK.
April 11, 2010 at 11:14 PM Flag Quote & Reply

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From David Ribbans:

Tony
I've got two Michelin 285 XDE2 tyres and they're great, long lasting and good on all surfaces. (Same as Peter's but a bit thinner and fit the 7.5 inch rims and a bit cheaper if you stake one). They can be difficult to find and are quite expensive.
From memory the XZY's have little lateral tread so they are not so good in sand/mud but tough for rocks and bitumen.
On the other end of the scale, I also had some old Hankooks retreaded with a block tread which was quite cheap. I know some people frown on retreads for outback work but we did half the CSR on them and they've been fine but wearing faster than the Michelins. No signs of delamination, even after long distances at low pressures.
April 11, 2010 at 11:16 PM Flag Quote & Reply

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From Peter_n_Margaret:

I have only run the drive tread XDE2s Tony. I have pulled a couple of blocks off, but they have been brilliant. I do always run them in the "correct" direction, but Peter Clarke, Michelin's now retired tech advisor suggested that I would not know the difference after 10,000km of use.
I reckon the all position (steer) tread would probably last even longer, but loose a bit of "bite".
Cheers,
Peter
April 11, 2010 at 11:17 PM Flag Quote & Reply

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From Seamus Campbell (earlier thread, June 2009):

Hi
This is in response to some tyre notes in the latest newsletter.
I have 285/70 AH11 Hankook tyres on 19.5 X 7.5 rims. According to a tyre dealer I rang up, that width tyre is fine on 7.5 rims.
The Hankook tyres are a highway truck tyre and do not bag out very well on sand.
Robin from Kalgoorlie recommended never running them below 30psi, and Hankook recommended 60psi as the lowest pressure to run on gravel or sand!
I've blown one tyre by driving at about 60kmh for about 10 kms when it was about 30psi.
I find the Hankooks not very good on thick sand but I'm not sure whether I'm expecting too much from an OKA on sand?
I'm loath to lower them below 30psi so they do not bag out at all. According to Robin Wade (who knows these things) running them at below 30psi weakens the sidewall which will sooner or later result in a blow out.
One thing the dealer said re the Michelin XDE2 tyres is that they are a drive tyre and should NOT be used on the front as steer tyres.
I'd be interested to know how those who have them on all four wheels go ?
Seamus
June 13, 2010 at 11:51 AM Flag Quote & Reply

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From David Hallandal:

I have had the Michelin XDE2 tyres on for over 30000km with only one damaged due to a large stake through the side wall (my fault not the tyres). I run my tyres at 40-50psi on the road and as low as 20psi in sand. I would have the 305/70R19.5 in sand any day, the side wall bellows well. You need to run a 8.25" wide rim to be legal with these tyres although there are plenty of OKAs out there on 305s and 7.5" wide rims. There is also a couple of other tyre brands with good 305 alternatives to the Michelins that are not uni directional and would look at these as well.
David
June 13, 2010 at 11:54 AM Flag Quote & Reply

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From Seamus Campbell:

I was told it was quite bad to put these tyres on the front as they are drive tyres only.
Have you had any problems with them on the front.
According to the tyre dealer I rang - you would have real problems steering with these tyres.
Ta
Seamus
June 13, 2010 at 11:55 AM Flag Quote & Reply

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From Joe Baz:

Hi all
I was a Goodyear dealer for more than ten years in the Kimberley area. We tested and recorded data for Goodyear while we had tyres on a trial basis, and the data collected was sent to head office in the USA. One of the reasons we trialled some tyres in the area was because the same tyre was a durable and good seller in the USA and the contrary was happening here. Talking with the technicians at the time about drive and steering tyres (as we had 6x6 trucks working in the desert) the response was that using a drive tyre on the steering, especially over a hard surface, will promote uneven wear and this will make balancing very very difficult and some times impossible. This was more to do with the pattern design than with the tyre construction. If drive tyres are used all around one has to be prepared to rotate tyres quite regularly to avoid the rounded shoulder and uneven wear, after all the OKA is a 4wd.
Cheers
Joe
June 13, 2010 at 11:58 AM Flag Quote & Reply

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From David Ribbans:

Seamus,
I've used 285/70 AH11 Hankooks and they are good on bitumen, rocks and gravel but not good in sand and mud (no lateral tread pattern). However any tyre will give better traction if the pressures are low enough.
We also have a pair of 285 Michelin XDE2s which are very good and I've never heard of them only being drive tyres. Ours spend most of their time on the front, steering is fine and the wear is fairly even.
I had the Hankooks retreaded with a block pattern and they are now much better in soft sand (and much cheaper than new Michelins). We did the CSR on them with no problems and sand doesn't get much sandier than that.


Good clearance on the way to Desert Queen Baths, Rudall River NP.
The rear tyres are expensive Michelins. The front tyres are old Hankooks which were economically retreaded with a block tread pattern. Both did pretty well.
FYI we run 55-60 psi on bitumen, 40 on gravel/rocky tracks and 30 (or whatever it takes) on deep sand.
It's good practice never to run soft tyres at high speed on hard surfaces, they can overheat and blow out, not to mention increase fuel consumption.
June 13, 2010 at 12:00 PM Flag Quote & Reply

Hal Harvey
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Seamus, I can see you're really looking for tyres to go on 19.5s, but the following is an abbreviated version of what I wrote for the newsletter before the May 2009 newsletter - but that newsletter isn't currently on the site:
... Our LT OKA was purchased with the standard 19.5” wheels, fitted with Michelin XZY 285/70s. This was a fairly popular setup on late 90s OKAs, and while they serve the purpose, they are really nothing special. The 19.5” size is uncommon, and while not unobtainable, the choice is very limited. Picking one up when you need one at short notice is unlikely to happen. Worse still, they’re not designed for off-roading; reducing tyre pressure to get flotation over sand required some pretty low pressures at times, and 19.5” truck tyres were never designed to be trundling around at 40psi, let alone 14psi. We tried to stick to 65psi on the highway and 25psi on sand, but it was a telling tale as we destroyed tyres one after another – almost one every serious trip, a nerve-wracking scenario when you know you have no chance of finding a 19.5” tyre anywhere within 3000km.
The final straw was having yet another tyre disintegrate on the highway, and trying to get it replaced back in Perth only to be presented with a ‘new’ tyre that, by the date code, was already two years old; so to all intents, 1/3 of its way through its useful life, and of course at full quid...
So to cut a long story short, we swapped to wide 16" rims, put on real off-road tyres (355/80) and now run around at 45psi on bitumen, and have had them as low as 12psi on super-soft sand (normally 18psi is all that's required). OKAs are great on sand if you have the right tyres!
--
Hal

June 13, 2010 at 12:01 PM Flag Quote & Reply

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From Peter_n_Margaret:

Hi Guys,
I have been running 305 XDE2s on 8.25" rims for about 130,000km now and have no wish to change to anything else.
I have staked three tyres during that time and worn every tyre out that I have scrapped.
We have done plenty of sand work, rocks and all other surfaces and stick STRICTLY to the Michelin weight/speed/pressure data.
Today I ran them at 20/30psi (3.5T on the rear) for 15km through soft sand north of Weipa.
They do have very flexible sidewalls and bag out well (although not as good as a big 16" would).
The biggest problem with these tyres is that the compound is fairly hard and they chip quite badly on gravel roads at cruise speeds. Notwithstanding that we are getting 60-70,000km on the road for every tyre.
Rex Ellis has been running these tyres on his OKA successfully for many years.
Cheers,
Peter Wright
June 13, 2010 at 12:07 PM Flag Quote & Reply

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From David Hallandal:

One thing that is not bought up when talking about OKA tyres is the fact the Michelin 900/16 tyres have a 99km/h speed rating. Not sure on their 255 replacements but many people are blowing their 16" tyres on the black top as they're running them at or above their maximum rated speed.
June 13, 2010 at 12:09 PM Flag Quote & Reply

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From Tim Forsyth:

Hi all,
I installed a tyre temp/pressure sensor system in all my wheels. I have Toyo M608Z which are way too hard for off road. Due to the constant tyre monitoring I have run these tryes at low pressures and stopped to increase pressure when temps get over 65 deg. So for short times I do run low pressures, the heat generated on corrugations is amazing and would soon blow the tyres. So far all I have had is one puncture, which I pulled over and repaired in situ well before low pressure caused damage. The system's alarm activated, giving me early warning. I strongly recommend getting this fitted to everything running expensive pneumatic tyres.
Henry at Pro Comp in Melbourne has mags and tyres for the OKAs. To date none of us are running the Pro Comp size that he recommends. Hal in WA is running oversize for beach work which are prone to wandering problems on highway. Hal can run his tyres at very low pressures and climb sand dunes as easily as regular light 4x4.
Tim Forsyth
June 13, 2010 at 12:12 PM Flag Quote & Reply

Hal Harvey
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Actually with the 355/80R16 tyres I have, wandering problems are theoretical, but not evident in reality. She drives fine.

I too have tyre pressure/temperature monitoring installed. It works well and apart from being able to have a constant eye on things as Tim says from the driver's seat, another benefit is that - and I'll bet you never thought of this - while you're pumping your tyres back up and it's raining/windy/mosquito-ridden/fifty degrees outside, you can sit inside drinking coffee or savouring the air conditioning... Just glance at the monitor every once in a while to see when the tyre's up to pressure; then jump out to change the hose on to the next tyre, and back in with barely a pause of the DVD. There have been times when that has been much better than doing it like the unwashed have to.
--
Hal

June 13, 2010 at 12:13 PM

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Last Edit: 01 Nov 2012 12:22 by dandjcr.

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