Any value in switching tyres for our trip?

Submitted: Friday, Dec 19, 2014 at 10:29
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Hi all,

We recently bought a 99 105 series cruiser for a trip around Australia next year. Presently the vehicle runs 33s with BFG mud tyres that have a fair bit of tread left on them.

Our trip will take us clockwise around oz and we're planning on doing mostly sand driving across beaches/deserts in SA/WA, as well as the Gibb River Road and back across Channel Country. We'll spend plenty of time on the tarmac for our trip and I'm wondering whether as part of our pre-trip fitout we swap out the muds for a set of all-terrains?

We're pretty new to 4wding so won't be doing anything extreme on this trip and yes I know tyre pressure and not driving like a wingnut are more important than what tyres you're running. The question is do you think it's wise to replace the muds (that probably have 20k left in them) pre-trip or just stick with them? Road noise doesn't bother us but safety and effectiveness does.

Thanks.

Duncbot
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Reply By: rocco2010 - Friday, Dec 19, 2014 at 11:32

Friday, Dec 19, 2014 at 11:32
Gidday Dunc

I think you know part of the answer ...

You will probably nudge 20,000km on a trip around the country. Better to start on new tyres.

whether they are muds or A/T is a personal decision that others with more expertise than me can deal with.

Cheers
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Reply By: Member Kerry W (WA) - Friday, Dec 19, 2014 at 11:43

Friday, Dec 19, 2014 at 11:43
Hi Dunk,
Personally I would keep with the BFG muddies especially in they are the newer KM2s or KMs (ditch anything older than 6 years of age for a trip like this)
Just watch the muddies in the Wet never push it on wet bitumen, otherwise they are ideal for the extremes you may need them for. I personally run muddies on my Patrol all the time and put up with whatever inadequacies they may have on the bitumen. There is always a compromise with what ever tyre you run on a 4X4 that does bitumen and offroad work.
An advantage with the BFG muddies is their performance in sand and mud when aired right down they have a softer sidewall which allows them to bag out well at lower pressures than one would expect - without popping off the rim when other harder walled tyres will.

2 points I would like to make, if you are new to 4WDriving it is unlikely that you will test the vehicles limits and really test those tyres, see how you go and adjust the type of tyre you buy next according to what you want to do with the vehicle. All Terrains will do everything you want.

Secondly as the BFG Muddies come with 18mm of tread when new they can still look servicable with 5-8mm of tread so have a closer look at them you can get up 90,000 out of the BFGs if they are a good size and treated OK they will wear faster and perform worse as they get low on tread.

Just my 2 cents worth you will find others will give you their experiences and many, -rightfully so, - will say to go for a less aggressive tyre for the trip. Either way enjoy it.
Kerry W (Qld)
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Follow Up By: The Explorer - Friday, Dec 19, 2014 at 20:57

Friday, Dec 19, 2014 at 20:57
"An advantage with the BFG muddies is their performance in sand and mud when aired right down they have a softer sidewall which allows them to bag out well at lower pressures than one would expect"

Hi

No advantage in width ("bag out") for sand - its the length of the footprint that counts. Width, by itself, provides no advantage for drive tyres on sand.

A common misconception discussed many times on the forum. A large diameter, bald, skinny tyre would perform as good on sand as a wide, brand new, deflated "muddy"..in fact standard road tyres are fine, just let air out (to increase footprint length).

Possibly some advantage in getting "muddies" for some applications. Think most people get them for looks but I could be wrong :)

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: Peter_n_Margaret - Friday, Dec 19, 2014 at 22:30

Friday, Dec 19, 2014 at 22:30


Cheers,
Peter
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Follow Up By: gbc - Saturday, Dec 20, 2014 at 07:13

Saturday, Dec 20, 2014 at 07:13
might want to reassess your terms the explorer. Tyres don't get any longer unless their sidewalls bag. On balance just because they bag doesn't necessarily mean the footprint gets any wider. Photos above show it perfectly.
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Follow Up By: The Explorer - Saturday, Dec 20, 2014 at 09:42

Saturday, Dec 20, 2014 at 09:42
Never passed comment on how tyres do or don't "bag" when deflated. My point was that the apparent increase in width created by "bagging" (as suggested by a previous poster) provides no advantage to driven tyres on sand, its the length of the tyre footprint that counts, as perfectly illustrated by the photos (and yes, in this case the "bagged" out part of the tyre isn't even touching the ground i.e. there has been little increase to on ground width anyway).

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: AlbyNSW - Saturday, Dec 20, 2014 at 11:24

Saturday, Dec 20, 2014 at 11:24
Agree with Greg, wider tyres give you a bigger "bow wave" of sand in front of your tyre which adds to the resistance, length of tread is where you get the most traction.

Whilst deflated standard road tyres work fine on sand I suspect that side wall failure would be a lot higher with their lighter duty construction.

Oh and how good does a nice set of muddies look :) isn't that the most important consideration in the whole debate! LOL
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Follow Up By: The Explorer - Saturday, Dec 20, 2014 at 11:36

Saturday, Dec 20, 2014 at 11:36
Hi

My reference to "standard road tyres" was to indicate that, on sand, wide, aggressive tyres are unnecessary. However, as you indicate, there are indeed other factors that need to be considered. In some cases muddies may well be the best choice for one persons intended application.

Cheers
Greg
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Follow Up By: Member Kerry W (WA) - Saturday, Dec 20, 2014 at 12:10

Saturday, Dec 20, 2014 at 12:10
I only speak from personal experience on this forum, and I have to comment further on this "misconception" which seems to relate more to older tyre choices and individuals own opinions or limited experiences in correctly optimising the use and choice of tyres in sand.

I should mention I was always an adventurous soul and learned to drive on sand and mud in 2WD vehicles as a kid so I have a bit of experience behind me.

There is no question that the length of the tyre alone - adds substantially to the tracton available - this is why tracks are so effective on earthmoving equipment - but a dozer on narrow tracks will still sink well before the same dozer on wide tracks.
The way I commonly use to explain, to novices, the effect of deflated tyres when looking for extra traction is to view them as being 4 mini Caterpillar tracks on your vehicle. This makes sense to them when visualising how the tyre should look for soft sand.
The "bag out" I refer to actually includes tyre length and width ...and yes, with the extra surface area, "width" does assist greatly in sand despite opinions to the contrary.


The "bag" depends on a lot of things but I was referring to a 33' BFG MT which as I stated has soft walls and "bags" well when needed. The Photos above are quite correct but are not the type of tyre we are discussing on this post.
The aired down length available is directly proportional to the available height or diameter of the tyre and the overall volume of the tyre determines how low a pressure the tyre can be reduced to before the weight of the vehicle is no longer effectivey supported by the tyre. IE A low profile small diameter tyre needs to maintain a higher pressure to keep its shape for a given weight than a high profile larger diameter tyre. simple physics as 10 PSI over 10 sq in will carry more weight than 10 psi over 5 sq In.
In essence a 33" Muddie has 1/ height - for a longer deeper footprint, 2/ Width - extra volume (allowing even lower "let down" pressures) and of course extra cm2 for extra traction. 3/ Pliability to allow the side wall to hang out a bit wider when the pressure is low and take pressure of specific points on the bead so the tyre is less prone to popping off the rim.

When driving on soft dry sand (or any surface for that matter), until the tyre sinks into the sand, this bulge is irrelevant. However if climbing a sandy hill or towing another vehicle in soft sand and the vehicle begins to sink into the sand and this bulge sinks below the surface it becomes something like a paddle and provides extra surface area and obviously extra traction. Albeit only marginally extra traction but as the vehicle is still moving this marginal amount of traction AND surface area is often enough to keep the vehicle from sinking further AND in motion. Many aggressive tyres have protective lugs in this bulge area which also help.
From my experience - a similar diameter thinner tyre has little or nothing left - the vehicle stops.

The other issue relates to the driver who controls the throttle. It is also said MT tyres are useless in the sand - this is untrue. They are very effective if they are not forced to dig themselves onto a deep hole by an unskilled driver.
EG
A few years ago at the first cutting on Noosa North shore, I came across a 4X4 Wagon towing a small caravan bogged 1/2 way up the cutting in soft dry sand, below it were two other 4x4s bogged - facing down the cutting - they were both hooked onto the 4X4wagon and caravan and all three 4X4s had become hopelessly bogged. As I had a horse trailer on and was escorting my daughter and friend on a beach ride I had no interest or time to intervene. However, eventually money was offered and the kids encouraged me to assist. So I unhitched the horse float and dropped my tyres till they looked right for the job - so somewhere around 10 PSI. Much to the disbelief of the gathered crowd I pulled in front of the Prado and said "we do this once - we go up the beach not down". (I had better things to do - honestly) I gave them a shovel and tyre guage and insisted on 15 PSI in all tyres and they needed to get the sand away from the front of all their tyres. I had 2 Maxtrax and a front Difflock in my vehicle with 33" BFG MTs. I gave him a handheld 2 way and talked him through the revs we needed to maintain - I.E. when to ease off and when to apply throttle.

Needless to say - It Worked - Once we got moving I actually pulled them all the way to the top without stopping once. At times barely moving but still making progress.

I did know from experience how resilient the MT tyres on my vehicle were to bogging is sand because of all the above factors. Unfortunately we didn't record the recovery on video.

I would like to see how (to quote the Explorer) "A large diameter, bald, skinny tyre would perform as good on sand as a wide, brand new, deflated "muddy""


Consequentially you may forgive me as to why I dispute the "misconception" regarding wide (aggressive) tyres being for "looks" alone.

Maybe I am wrong and any vehicle with 10m psi in their tyres will do this, (if they can go that low and still support the vehicle and stay on the rim) I have recovered quite a few vehicles over the years and personally I have not seen anything else do it yet.


Why do desert racers use wide tyres and not bald skinny ones?
Kerry W (Qld)
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Follow Up By: The Explorer - Saturday, Dec 20, 2014 at 12:59

Saturday, Dec 20, 2014 at 12:59
Hi

Firstly we are just talking dry sand here. Different physics involved when other substrates encountered e.g. A bulldozer with "narrow" tracks is not more likely to sink in dry sand - narrow or wide tracks neither will come close to "sinking". Different story in mud and the reasons why something will sink in mud are different to why a 4WD can get bogged in sand (i.e. wheel spin - you dont actually "sink"...but dig yourself a hole).

There are probably several reasons why you would not use bald, skinny tyres in a desert race car, but they are not related to what we are discussing. I was just using it to illustrate that tread pattern and width of a tyre are not the primary characteristics that determine the ability of a normal vehicle to travel over sand without getting bogged.

There may or may not be some benefit in traction on dry sand created by the increase in width caused by reducing a pressure in a tyre (or by using a wider tyre to start with) but point is the lengthening of the footprint is where almost all of the benefit is obtained...the fact that a tyre may also widen a bit (i.e. "bag") plays little part either way.

Fact of the matter is that you dont need "wide" tyres for sand (what is a wide tyre and what is a narrow tyre anyway?) - end of story..but you are free to use "wide" tyres if you wish - there maybe other characteristic of the tyre that are of benefit.

Cheers
Greg

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Follow Up By: Member Kerry W (WA) - Sunday, Dec 21, 2014 at 23:37

Sunday, Dec 21, 2014 at 23:37
I originally said Dunkbots current tyres had an "advantage" at lower pressures than harder walled tyres.

Fact of the matter is - he already has wide tyres.

My balanced reply was not promoting MTs or espousing superior sand performance.

I do however live and work in a remote area and rely on my vehicle being set up for both mud and dry sand. When the seasons dictate - I like to get home at night. So I put up with my tyre choices for a valid reason.

This forum exists to share information and experiences. ...

Just reminding...




Kerry W (Qld)
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Follow Up By: The Explorer - Monday, Dec 22, 2014 at 13:05

Monday, Dec 22, 2014 at 13:05
Hi

You seem to have taken this discussion somewhat personally and gone off track (no pun intended) - not my intent. Was just pointing out that the benefit of decreasing tyre pressures (wide or skinny, any brand, your car, my car, anyone's car - doesn't matter who they area, how much experience they have had or where they choose to live) is directly related to a lengthening of the tyre's contact foot print. Some comments provided were suggesting otherwise.

It wasn't about any particular type of tyre or anyone's own particular choice for their specific circumstances, including yours or the OP's.

Yes, the value of the forum is indeed related to the combined knowledge/experiences of everyone, though keep in mind not everything you may read is true/factual...just reminding :)

Cheers
Greg
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Reply By: pop2jocem - Friday, Dec 19, 2014 at 13:06

Friday, Dec 19, 2014 at 13:06
G'day Dunc,

I think you have already got a handle on the importance of tyre pressures and speed. Tread pattern IMHO more important if you were planning on more extreme off roading.
Obviously the muddies will howl a lot more on bitumen surfaces than AT's.
Personally I would give it a go on what you have. If you need to replace them through what you experience in your travels I'm pretty sure most significant sized towns will have a tyre outlet. Carry an extra spare tyre even if it isn't mounted on a rim and practice at home repairing punctures and fitting tyres to a rim. 2 tyres and rims are ideal but of course more weight.
We just completed a 6 month lap around the block including the GRR. I punched holes in 2 tyres going through rock strewn creek crossings. Too much weight the main problem. I bought 2 replacements on the GRR.
I had 10.5x 15"'s which were great for every other part of the trip but in hindsight not the greatest choice for the GRR. Your muddies would be much better but certainly not essential.

Enjoy

Cheers
Pop
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Reply By: 671 - Friday, Dec 19, 2014 at 17:14

Friday, Dec 19, 2014 at 17:14
You current tyres should get there but so will a lot of others. I have driven to the top of Big Red and back down again on 205 x 16 muddies without the slightest bit of trouble. I have driven over the Oodnadatta Track on 205 x 16 street tyres. I have a done a lot of soft sand driving with the Armed Forces on 7.50 x 16 muddies. A long time ago I took a pocket size sedan down the then unsealed and very rough track from Mt Isa to Boulia on 5.20 x 10 street tyres without any problems. I even successfully crossed a 500 k unsealed section of the Nullarbor five times in the 1970s on street tyres.

The key to the whole thing is don’t overload the car and don’t drive like a bat out of hell. If you do that then you will go just about anywhere on anything.

There is a bit of information here about 4wd tyres.http://www.outbackcrossing.com.au/FourWheelDrive/Truth_About_4WD_Tyres.shtml I agree with what he says about wide verses skinny. A 235 will certainly do the job and it makes a much smaller target for anything capable of causing a puncture.
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Follow Up By: Peter_n_Margaret - Friday, Dec 19, 2014 at 18:12

Friday, Dec 19, 2014 at 18:12
"A long time ago I took a pocket size sedan down the then unsealed and very rough track from Mt Isa to Boulia on 5.20 x 10 street tyres without any problems."

One like this? :)



Cheers,
Peter
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Follow Up By: 671 - Friday, Dec 19, 2014 at 21:17

Friday, Dec 19, 2014 at 21:17
Now that brings back a few memories. Looks a bit like Evan Green, Jack Murray and co. back in the mid 60s.

I did not have a roof rack but I did have an S badge at each end.

If only the road down from Isa had been that good.

Here is another mob that forgot to read the magazines and did not realise that they needed lifts, lockers, huge muddies with white letters, super you beaut shocks, twin overhead electronic roo repelling bull bars and heaven only knows what else before you can even think about driving in those areas.

https://www.youtube.com/watch?v=BoQYM7TOnLI

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Follow Up By: Peter_n_Margaret - Friday, Dec 19, 2014 at 22:17

Friday, Dec 19, 2014 at 22:17
Gelignite Jack Murray and Evan Green were my heroes.
The pic above was the Stuart Highway north of Coober Pedy in 1967 on the way home from Darwin on our honeymoon.
We had a roof top tent that went on the pack rack.
No "S" badge, just a 1963 850.

Cheers,
Peter
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Follow Up By: Peter_n_Margaret - Friday, Dec 19, 2014 at 22:22

Friday, Dec 19, 2014 at 22:22
The tyres, by the way, were Pirelli rag radials. They said we were mad using radials on that road.
They performed faultlessly.

Cheers,
Peter
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Follow Up By: Crusier 91 - Saturday, Dec 20, 2014 at 09:38

Saturday, Dec 20, 2014 at 09:38
Come on 671, that video is bollocks!!!!!!!!!!!!!!!!!!!things were built to last back then, opposed to today's manufacturing.
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Follow Up By: 671 - Saturday, Dec 20, 2014 at 14:18

Saturday, Dec 20, 2014 at 14:18
Peter_n_Margaret posted:
The tyres, by the way, were Pirelli rag radials.

Mine were standard issue Dunlops. I think from memory they were called SP 141 or something like that. They worked well on sandy surfaces and the rock covered dry creek beds did not damage them.

The thought of reducing pressures back then (1967) never occurred to me and I very rarely do it today. I usually need a Big Red sized sand hill before I even think about it.

I just drove to the conditions and worked on the theory if you are going to hit something underneath then do it at half walking speed. Despite having near zero ground clearance, there was no damage under the car except for a polished aftermarket sump guard that had lost its paint from the grass between the wheel tracks.

“No "S" badge, just a 1963 850.”

That was all you needed. You were just following the same route traveled by Austin Sevens and T Fords decades earlier and they got through ok.

Crusier 91 posted:
things were built to last back then, opposed to today's manufacturing.

Please don’t tell me they don’t make them like they used to. I posted that DVD mainly to show where they went in those days on skinny tyres.

As for the cars: I worked on the *&##@^|! things as an apprentice starting in ’61. All day it was valve grinds, diff overhauls, worn king pins, rusted suspension or steering ball joints and uni joints, riveted brake linings that seemed to wear out in record time leaving the rivets to wear groves in the drums and so the list goes on.

On one customers car, I had to change the oil in its multiple plate clutch every time I changed the engine oil.

There was none of that when I left the trade in the mid 1980s and everything seemed to last twice as long.

Those Redex trials certainly exposed a few structural problems with Australia’s own. I have a book listing the reasons each car lost points in the 1955 trial. Half the Holdens failed to finish and between them there were around 60 body and sub frame cracks.

Of course we still get a bit of that today with overloaded 4WDS fitted with heavier aftermarket suspension. There seems to be no shortage of cracked chassis, axle housings and shock mounts along with collapsed wheel bearings and broken wheel studs.

One consolation though is the aftermarket suspension always comes through unscratched.
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Reply By: get outmore - Friday, Dec 19, 2014 at 19:02

Friday, Dec 19, 2014 at 19:02
no value changing tyres - bfg muddies would be a very good tyre for what your doing
- id keep my eye on them and budget and aim to get them swapped out in a major centre or city as the need dictates
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Reply By: AlbyNSW - Friday, Dec 19, 2014 at 22:10

Friday, Dec 19, 2014 at 22:10
Another point to consider is that muddies use more fuel than AT's
If you were starting again is sounds like AT's would be better suited but MT's would be fine just the same.
You wouldn't have any trouble selling them on eBay etc and could put that money towards new rubber which would be a good start to a big trip like you have planned
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Reply By: jacent - Saturday, Dec 20, 2014 at 07:54

Saturday, Dec 20, 2014 at 07:54
Save your cash and wear them down, replace while away if need be plenty of tyre shopsin australia! Have fun!
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Reply By: Athol W1 - Saturday, Dec 20, 2014 at 14:37

Saturday, Dec 20, 2014 at 14:37
Duncbot
If you are towing a caravan on this trip I would be more concerned about running the 33" tyres rather than if they be mud or all terrain tyres, as the extra diameter can have an adverse effect on your ability to tow (greater load on engine can contribute to overheating issues, and will effect fuel consumption, also can lead to some transmission related issues).

Mud tyres also have far less grip on paved road surfaces, and especially if those surfaces are wet.

As you are not intending to do any serious off road driving the I would suggest that you fit a good quality All Terrain tyre as close to the original TOYOTA outside diameter as you can find. Whilst BFG's have a good reputation my preference, and the tyre that I have had the most success with, would be the Bridgestone 697.

What ever you decide on have a great trip (I may see you on the road)

Regards
Athol
AnswerID: 543193

Follow Up By: jacent - Sunday, Dec 21, 2014 at 04:38

Sunday, Dec 21, 2014 at 04:38
I have 33's on my cruiser Bf Goodrich km2 muddies towed a 2 tonne van round australia no issues at all, very good in the wet, plenty of grip in any condition, been on the beach, gravel etc no dramas don't listen to ppl telling you to change them, once worn down if you wish to go down a size or different tread pattern do it then! Sit on 90-95 should keep your fuel use down a bit towing!
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Follow Up By: Duncbot - Monday, Dec 22, 2014 at 09:16

Monday, Dec 22, 2014 at 09:16
Hi Athol,

Thanks for your reply. We're not towing anything on our trip so should be right I hope.

Cheers,

Duncbot
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Reply By: Duncbot - Monday, Dec 22, 2014 at 09:20

Monday, Dec 22, 2014 at 09:20
Thanks everyone for your input - helpful and informative as always.

I think we'll stick with the muds for the time being and see what our mechanic reckons when we get our pre-trip inspection done. When we replace I'd say we'll go to ATs as it'll probably suit our driving needs a bit better but until then we'll just take it easy in the muds. We're pretty sedate drivers anyhow so hopefully we won't strike any issues.

Thanks for your help everyone, your input is really helping us prepare for our trip next year.

Cheers,

Duncbot
AnswerID: 543249

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