Toyo 285/70/R19.5 M608z

gait

Explorer
silly question ....... are the 305's part of the engineering cert for the 19.5 rims or is more work required,

I ask because I need a new set of tyres and of course my imagination starts to work
 

DIPA

New member
Canning Stock Route 2009

/Users/grayville/Desktop/M2U00045.MPG


/Users/grayville/Desktop/M2U00066.MPG

The CSR in 09 was starting to get heavy use each year and the sand hills really cop a flogging but taller tyres aren't the answer tyre pressure is.
I had Hankook AH11s highway tread in 09 the following year i fitted Toyo mz 608s to the rear axle and that improved our traction and allowed us to proceed at slower speeds on the hills as the smaller 4wds with coil suspensions seem to dig holes which make the track extremely rough so slower is better for us.
The in cab clip the tyres had 40psi rear axle and 30 in the front and we had several attempts at that hill before we succeeded after that the pressures were reduced to 28psi rears and 22 fronts,we did the rest of the trip at those pressures and had very little problems from there on.

Cheers DIPA
ps,
My tyre man told me for him to fit 305s the rims would have to be 8inch width min for the tires to be warranted.

Fingers crossed I got the attachments correct this time.
 

SkiFreak

Crazy Person
Fingers crossed I got the attachments correct this time.

Nope, you didn't. :(

I am not sure, but this site may not support the MPG video file format natively.
You might try converting the videos to a more standard format, like MP4 or AVI or host the file on a remote site, like YouTube, then link to it.
 

engineer

Adventurer
Sorry Dipa, i disagree
If you don't have rolling diameter, reducing tyre pressure won't help in my case, but what would i know, I've only been driving FG's off road for 23 years
 

DIPA

New member
My apologies Engineer i have no wish to put assertions on your 23 years driving FGs ,I have no experience at all with FGs which I understand are a very capable unit but I do have 30 odd years of driving many various vehicles in the northern deserts of Aus from 3 trailer road trains to 4x4 utes and rolling diameter isn't a factor as we have let grader tires down to maintain traction and they have pretty big diameter.
From the photos you posted it looks to me like your tires are digging rather than rolling, the pressures you quoted on the first photo said to me they are to high but are you in an industry which makes lowering your pressures outside the tire companies recommendations puts your insurance at risk if so you have a problem that I fear won't be solved purchasing conventional tires.
Cheers DIPA
 

gait

Explorer
footprint ..... ?

the larger the diameter the longer the footprint,

the lower the pressure the longer the footprint

and a little harder,

the greater the difference between tyre diameter and rim diameter the longer the footprint (at same pressure and tyre diameter).

Then of course there's a few limitations on lowest pressure without breaking bead which is also tyre and rim dependent. To say nothing (well, perhaps a smidgeon) about load. The above would all be comparisons at the same load.
 

engineer

Adventurer
so there it is, the mechanics and the boss, who have never done what we do, telling us how to do it with inadequate equipment.
I simply do not have time to be inflating/deflating tyres on an impossible itinerary
if we go lower than the pressures i mention, then i am changing tyres too frequently
i need more rolling diameter ON THIS PARTICULAR VEHICLE to achieve the desired outcome,
each FG is different. depending on build, suspension etc etc etc.......
or NPS in this case... and BTW, it is really gutless ;-)
I know nothing of deserts Dipa, but I've been driving on Fraser Island since i was 7, and i now have grey hairs
 

DIPA

New member
Thanks Gait quite right your explanation I do understand what you say but also Engineer you have a problem that is quite normal for the age we live in "pressure of the dollar", i regret i have no answer to your problem other than a tyre that is made to give you flotation over soft terrain which will have a speed restriction on the hwy or an in cab system that allows you to reduce or increase the tire pressures as requiewd neither is a cheap fix.
Good luck with your quest,I also have a few grey hairs, few is the word lol,desert sands aren't that much different to the sands of Fraser island just the texture and as I have found over the years on a cool day or the night air the tire foot print can be vastly different to a day which is hotter where ever you are.

Just an observation ,on the in cab video we had had a couple of goes at that sand hill and during a walk around I picked up a handful of sand from the wheel ruts it was very fine in texture like flour, multiple vehicles chewing their way over,the virgin sand was quite coarse i would probably have done better just trying a run at the virgin sands.


Cheers DIPA
 

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