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**JohnFromPerth** · 22-11-19, 02:14 PM

Hi Purdy
Thanks for the tyre information. Very useful.

I have heard mixed opinions of Mickey Thompson tyres, but cannot quote from experience.

Some people suggest that you are getting an average tyre but paying a premium for the name.

Mickey Thompson was a well known American racing car driver who also chased land speed records. As well as driving in the Indianapolis 500, he drag raced and raced off road.He was murdered by a business associate in 1988.
He started a specialty tyre company carrying his name, but who actually makes the tyres is not clear.

Back to replacement tyres.
Someone on this forum recommended Hankook Dynapro AT-M RF10 XL construction tyres. The XL stands for Extra Load.
I have had Hankook Dynapro (but not the AT-M) on another vehicle and found they gave exceptional tyre life. Around 60,000km of highway and off road driving.

Cheers
John

**old Jack** · 22-11-19, 02:18 PM

Hi Purdy,

All good in theory but you need to consider a few other things.

1. Factory rims are 18"x 7.5"" so you would need to check if 285 and 305 are an approved rim width for 7.5"wide rims. 265 are standard so 275 would be ok on 7.5"wide rims but once you jump up to 285 you may need to go to 8"wide rims..

2. You must also ensure the tyres do not touch any part of the body or suspension at any point in the steering and suspension travel range. I have true 32"/813mm diameter LT235/85R16 on my Challenger and they only just clear on the front. Certainly I could not fit snow chains to he front tyres.

The Pajero Sport already has a wide tyre fitment at 265mm so jumping up a profile will give you an extra 13.25mm of ground clearance and raises the ride height by the same.
Increasing width to 275mm and going up a profile gives you a 20mm increase in ground clearance and ride height.

You need to be careful of the combined ride height increase of both suspension and tyre diameter increase and what is the resulting change in ride height.

In Qld and NSW you can go up 25mm by tyres and up to 50mm by suspension as long as tyres do not rub at any steering or suspension angle and you have maintained at least 2/3's of the original suspension droop travel.
Vic, WA, NT & Tas it is up to 50mm ride height increase in total using both tyres and suspension changes.
SA is no legal changes because they are still thinking about the adopting VSB-14 the National Code.

You also need to remember that when doing a suspension lift and maintaining 2/3's of the suspension droop travel will only allow you a 30-40 mm lift on the front and a 40-50 mm lift on the rear suspension.

OJ.

**Purdy** · 22-11-19, 03:43 PM

Hi guys,

Thanks for responses.

Yes I checked and the 275/65/18 can fit on these rims: 7.5-9.5.

So Im ok there.

After some research, everybody who is currently running 275/65/18 with standard suspension is reporting no rubbing at full suspension travel and lock. Also the spare fits with MM tow bar. So Im ok there.

As I dont do heavy 4WDing (just a 12 acre hobby farm) Im satisfied with the ride height from suspension. I need new tyres for rego and the highway ones just dont cut it on the farm, so I may as well get an extra 20mm lift with new tyres was my thinking.
I dont tow anything heavy either so standard suspension has been fine.

Thanks again

**Pego** · 30-01-20, 09:48 PM

Smaller Wheels

Has anyone gone down to a 16 inch rim for maximum sidewall? I'm just thinking about it in regards to clearance for the brake disks and whatnot.

**old Jack** · 30-01-20, 10:03 PM

Originally posted by Pego View Post

Has anyone gone down to a 16 inch rim for maximum sidewall? I'm just thinking about it in regards to clearance for the brake disks and whatnot.

When the Pajero Sport was first released we tried 16" Challenger alloys, the rear fitted but the front did not because the brake calipers are too big.

OJ.

**Pego** · 09-02-20, 08:36 PM

Dang. Thanks OJ.

**orthodoxs** · 14-09-23, 05:37 PM

I had swapped the factory standard HT Tyres to Coopers ST Maxx 265-60-18, They have indeed performed very well, 110K of mostly Highway, towing and relatively little off-road use. The Tyre power dealer at Darwin, reminded me periodically with SMS for rotating and balancing my tyres every 5000km, this was done free of cost as part of the Tyre care package (Not sure if its by coopers/dealer?) offered when the Tyre was purchased, fitted and aligned at the outlet. The tyre noise was not so bad either because i am little hard of hearing and as the dealer says, rotation every 5000km doesn't allow scalloping of the tread and thus reduce the noise? (Not sure if this explanation is correct)
Now, i am thinking of changing to coopers 265-65-18 all 5 tyres, just in case one of them becomes nonsalvagebly damaged mid-life, its 1 size up from standard. Has anyone here been using them, are there any problems at all? Does the spare fit without trouble?
The tyres are very expensive, quoted at $540 in brisbane, also the dealer here seem to feign ignorance about the tyre care package and says he can charge anywhere upto $100 per rotation, have any of you also got the Tyre care with the free 5000km rotation deal from coopers?

**old Jack** · 14-09-23, 06:50 PM

110,000km from a 5 tyre rotation is 88,000km a tyre so the tyre exceeded the Cooper mileage warranty.
No argument that $540 a tyre is expensive so 5 tyres will cost $2700 but when this is divided by 110,000km this is a total 5 tyre cost of 2.45 cents per km or $2.45 per 100kms.
$100 a tyre rotation is good value if it includes tyre balancing and wheel alignment, but with 21 rotations over the life of the tyre that adds up to another $2100.

A LT265/65R18 has an OD of 808mm and will fit in the spare tyre position as it is only 27mm larger in diameter than the LT265/60R18 which is 781mm in diameter.
If you have an external mounted factory towbar there will not be an issue but in you a concealed towbar like a HR then you will need to push the tyre forward a little as the tyre get winched up.

Do you really need to go up a profile, as the tyre is heavier and there is an effective change in gearing so fuel consumption will increase, if this is 1 litre per 100km and Diesel in $2.50 a litre then over the 110,000km you get from a set of tyre the extra fuel cost in $2750 which is another set of 5 tyres! If fuel consumption increases to 2 litre/100kms then that is an extra $5500 if fuel over the life of the tyre.

Do you really need to use a heavy duty hybrid AT/MT tyre since you do very little off road driving would a 10ply AT be more a sensible choice?

Do not get me wrong, I have run Cooper ST Maxx for 12 years and 205,000kms on my PB Challenger and I will not use anything else because of the traction, toughness and reliability these tyres provide off the bitumen. But the I pay a premium price at purchase and more again in extra fuel consumption for these attributes. I do my own 5000km tyre rotations and only get the balances and alignment done when I feel or see a problem, but I do only get 70,000kms from a 5 tyre set of LT235/85R16 ST Maxx, running at GVM and 1/3 of the kms off bitumen.

OJ.

**orthodoxs** · 14-09-23, 09:02 PM

Thankyou OJ for your prompt and your usual wise comments,
The offer of free tyre rotations from cooper contains balancing, it does not include alignment, which i have never done during the tyres life, however i keep a careful eye on uneven wear or drift while on even road surface, to do an alignment if needed. The free rotations was very valuable to me and saved me a lot of money, however the last few rotations were paid for, as i had moved to Brisbane.
To me the tyre is attractive because it is a real all-rounder, its longevity is astounding, its reliability off road, especially in remote locations is very reassuring, for some strange reason it also seems to be puncture resistant, never had one. The side walls are more resilient than i imagined, only a few superficial damages to the side studs on the rocks. i chose this tire exactly because it has an AT/MT capability, even if i go offroad occasionally it matters a lot, as each trip can potentially end with difficulty, as i offroad alone for gold fossicking with only some recovery gear and a Sat phone for emergency, need to have very very reliable Tyres, not very keen to changing damaged tyres on uneven ground in the wilderness. I if had anything more road oriented i probably wouldn't venture out there even for a single day.
I have a HR internal tow bar but i got the point that the Tyre can be moved forward and winched up, should not be a problem.
This tyre by its very function has very thick studs and deep grooves, i think the OD has changed quite a bit from while it was new as it has worn down significantly over the years, it also looks physically and quite obviously much smaller in circumference now, i think that the Tyre is manufactured with the correct OD and progressively becomes smaller, so my reasoning of fuel consumption is opposite to what you have mentioned.
If the gear changes are governed by engine RPM, and as the computer reads Tyre rotations in its computations, not actual ground speed, the diesel consumption will be more as the OD comes down, as the gear changes will be sooner however there will be more torque provided with a smaller OD Tyre. I may be wrong on this, also in my mind i find that my diesel consumption has increased as the tyre has worn away over the years. By installing a larger tyre OD i think my diesel consumption will be improved not increased, with a slight loss of torque, but since diesels have a good torque power band it wouldn't matter anyway. What do you think?

**old Jack** · 15-09-23, 09:46 AM

Hi Orthodox,

For remote outback travel off the bitumen I do not think there is a better tyre than the Cooper ST Maxx.
Light Truck construction tyres are sized by the rim diameter, carcass width and the sidewall profile, so a LT265/65R18 fits an 18" rim, has a 265mm carcass width and has a sidewall height of 65% of the carcass width so 172.25mm. It is the tread depth that varies across tyre size, brands and models, a ST Maxx has one of the deepest tread of all the hybrid AT/MT tyres in this size at 14.7mm, may other hybrid AT/MT 10 ply rated LT tyres have tread depths between 10mm and 13mm. Therefore the ST Maxx reduces in diameter more than most other tyres as the wears the tread down.

The vehicle odometer calculation is based on the revolutions of the gearbox output shaft and the rolling circumference of the factory specification tyres so when you fit oversize tyres the odometer will under read by the percentage difference between the fitted tyre rolling circumference and the theoretical rolling circumference of the factory tyre, and the rolling circumference changes as the tread wears down.

When a ST Maxx is new the tyre diameter is larger than the theoretical standard.
ST Maxx LT265/60R18 is 781mm but the theoretical is 775mm so the ST Maxx is 3.3% larger.
ST Maxx LT265/65R18 is 808mm diameter but the theoretical is 803mm so the ST Maxx is 3.6% larger.

But since the tyres have a 14.7mm tread depth the tyre tread can legally wear down to 1.6mm so there is 13.1mm of tread wear which reduces the tyres diameter by 26.1mm which is 3.3% on both tyres. So both ST Maxx tyres are at the theoretical diameter when worn down to the legal limit so the odometer will under read the most when the tyres are new.

The weight of a tyre has a significant impact on fuel consumption because you have increased the rotational mass forces of the tyre.
A factory HT265/60R18 weighs about 16kg but a ST Maxx in LT265/60R18 weighs 23.18kg, go up a size to LT265/65R18 and the weight is 25.45kg!

The rolling resistance of a tyre also effects fuel consumption, aggressive tread patterns and lower tyre pressures increase fuel consumption.

OJ.
.

**orthodoxs** · 27-10-23, 08:40 PM

Hi OJ,
Thanks for the details, i dropped out of the conversation as i fell sick. In reality, what does happen to fuel consumption after changing to new tyres or size up in dia only?

**old Jack** · 28-10-23, 01:26 PM

Originally posted by orthodoxs View Post

Hi OJ,
Thanks for the details, i dropped out of the conversation as i fell sick. In reality, what does happen to fuel consumption after changing to new tyres or size up in dia only?

Increasing overall tyre diameter always increases fuel consumption to some extent, increase the weight of the tyre and or wheel, increase the tyre rolling resistance (aggressive tread patterns) , increasing the aero dynamic drag with a roof rack roof rack load, lifted suspension and or increasing the vehicle weight all compound and the cumulative increase in fuel consumption can be significant.

OJ.

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