BFG AT's, tread chipping off

[goingbush]

Have a bit of a curly one.

My current tyre of choice is BFG AT 235/85R16

I'm running them tubeless on 130 rims, all round on my 110 and caravan.

the tyres are at about 20,000 klm , on the highway I pump the front to 35, rear to 45 and van to 50 , on the dirt I use 28 front 32 rear and 35 van

for the last 5000 klm its been 85% dirt , mixture of black soil, gibber , corrugations , etc the usual outback mixture, but come off the dirt to do about 150klm on bitumen & I did not pump them back up .

If I was going to do a long haul of course I would increase pressure.

I just noticed my rear tyres all chewed up , the fronts and the van are fine,
if it was by running low pressures surely the fronts & the Van would have similar issue ?? not even sure if it wasn't like this before the blacktop.

any ideas ??? pics below

FRONT
https://www.aulro.com/afvb/images/imported/2013/06/896.jpg

REAR
https://www.aulro.com/afvb/images/imported/2013/07/1306.jpg

VAN
https://www.aulro.com/afvb/images/imported/2013/06/897.jpg

[alien]

Only time I've had that sort of chipping was on a recovery in the Victoria high country.
I had high pressures and the tyres where slipping/spinning as they struggled for grip on a rocky surface.

More for my own curiosity when you deflate the tyres are the length on each axle foot print the same?
When driving did the rear of the 110 feel stable or was it wandering/twitching at any stage?

I'd like to know what the end result is so please keep us updated with what you find.
Cheers, Kyle.

[LowRanger]

Most of the times that I have seen this on the rear tyres,it has been caused by running rear tyre pressures too high,and the tyres are destroyed by rocks flicked up by the front tyres.A lot of people used to blame another well known brand of tyre for doing a similar thing to the rears,until cameras were mounted to the underside of some vehicles and they were driven at different pressures,and the differences noted.

[DeeJay]

I wonder if putting in 4wd ( locking the centre diff) on gravel, especially towing, would make a difference, The damage is not like that of wrong pressure on hard surfaces..

[goingbush]

I wonder if putting in 4wd ( locking the centre diff) on gravel, especially towing, would make a difference, The damage is not like that of wrong pressure on hard surfaces..

Yes I always lock the center diff on loose surfaces !



Most of the times that I have seen this on the rear tyres,it has been caused by running rear tyre pressures too high,and the tyres are destroyed by rocks flicked up by the front tyres.A lot of people used to blame another well known brand of tyre for doing a similar thing to the rears,until cameras were mounted to the underside of some vehicles and they were driven at different pressures,and the differences noted.

I thought that could be happening, but if so the caravan would be getting pummelled too, the tyres perhaps may have been a little high but speed relative to the conditions.


Only time I've had that sort of chipping was on a recovery in the Victoria high country.
I had high pressures and the tyres where slipping/spinning as they struggled for grip on a rocky surface.

same here, that sure was not the case



More for my own curiosity when you deflate the tyres are the length on each axle foot print the same?
When driving did the rear of the 110 feel stable or was it wandering/twitching at any stage?

I'd like to know what the end result is so please keep us updated with what you find.
Cheers, Kyle.

footprint very much the same on all tyres, as is the amount of percieved bulge on the bottom.
no twitching , except perhaps for a few sections where it felt like I was driving on marbles, but not sustained enough to account for any tyre damage

should also point out I have truetracs front & rear so the truck is pretty stable

At first I thought it may be a dodgy batch of tyres on the rear axle, but I do rotate tyres & the odds of that axle being a pair of the same faulty batch (if that is the cause) are pretty slim,( between the 4 on the car, 2 on the van and the 2 spares )

Also keep an eye on my TPMS and the pressures / Temps have all been normal.

[rangie ute on 38'']

we had the same set on the old mans rangie and they all chipped up like that but we never really got to the bottom of it , we assumed it was a soft compound on hard gravel roads. they were 31/10.5

[scarry]

I have had a good few sets of the same tyres on D2s(different size) and never had them as badly chipped as yours.
Sure one set did get chipped after around 15K on dirt roads,but nowhere near as bad as yours,and i can't remember the rears being worse than the fronts.
I don't think pressures are the issue,more than likely stones thrown up from the front wheels.
i would talk to the supplier.they may have some ideas as they are supposedly the tyre 'experts' or contact BFG directly,they may want to see those pics.

My son has done a lot of K's on BFG KM2 on dirt roads,they are badly chipped,nowhere near as bad as yours,i don't think the fronts are worse than the rears.

Good luck.

[goingbush]

Thanks Scarry

have sent email to BFG
will await reply with interest.

[yt110]

Is the back of the 110 loaded up? If so I would try the rears at say 40 may be 38 on the dirt.

Why? well the others seem to have been rolling along nicely but the rears have been flexing too much.

I can't wait to get shot down for this idea,its just my experience from having used these tyres for over 200,000 kms on my county,but each to their own.

[Vern]

Last set of bf a/t's I had in the same size as yours chipped badly, and come to think of it the set I had before in a different size didn't really chip that much at all(mainly road use). Have known a lot of people to run bf a/t and they all seem to chip easily. Got coopers next, no chipping, just war out a bit quick.

[ramblingboy42]

rear tyre pressures too high...

[weeds]

My AT's chipped badly on my desert trip years ago......esp. On the strezleckie track. I tried different pressures but put it down to the size of the rocks and maybe the compound of the tyres.

I switched to MT's After noticing all the tag along operators using MT's

[roverrescue]

Looks like classic stone throw from the fronts for mine.
You say:
for the last 5000 klm its been 85% dirt

Van less affected as you most likely have rear mud flaps and the distance from the rear axle to the van axle is greater.

Try a set of proper front flaps and also rear axle leading flaps.

BFG AT and the new KM MT are bad for it on fast broken dirt. Most BFG fanbois and girls dont do 4000km of dirt in every 5 ;)

Steve

[rovercare]

Rubbish tyre, that's why

[roverrescue]

But Matt,
They are just the bestest. So soft and supple - fantastic grip in the wet, nice cornering at $1.25 in air conditioned comfort. ;)

Personally I dont think they are rubbish, I just think they are meeting the market -
The "market" is a tyre that is essentially a high performance blacktop / wet weather tyre for new 4wd with a zillion torques and a billion horses powers. Oh but they have to look tough and at least stand up to some dirt roads three weeknds a year.

S

[goingbush]

OK thanks for responses

If the stones are coming off the front tyres causing that chipping, well I'll have to look for another 235/85R16 AT

Any suggestions, bearing in mind I want a tyre thats going to be easily sourced.
pity Michelin XZL's are impossible to get !

What tyres are the Army G-Wagens running ??

[weeds]

What tyres are the Army G-Wagens running ??

could be wrong but i think they are running BFG's

[DiscoMick]

When I had BFG ATs on the D1 they seemed to work best on sealed roads at 28 front and 32 rear, and were lowered on gravel roads, so I think your pressures may be too high.

[goingbush]

When I had BFG ATs on the D1 they seemed to work best on sealed roads at 28 front and 32 rear, and were lowered on gravel roads, so I think your pressures may be too high.

Thats what I normally run, but we are all loaded up for an extended trip.
The tyres are wearing evenly across the pattern (apart from the chipping) which to me suggests they are not over or under inflated,

however I did lower them to 28 Front & 32 Rear yesterday, will keep them at that & will keep an eye on the temps on the TPMS.

[scarry]

could be wrong but i think they are running BFG's

What else would they run.....

The ADF has no $ limit so they can afford the best:p

:wasntme:

[Graeme]

Duratracs are available in that size but may be noisier.

[goingbush]

Duratracs huh, never heard of them but just did a bit of googling and they are looking good, a bit of extra noise I can live with,
all reviews seem good so I might even give them a run when I wear down the rest of my BFG's (all 8 of them) at the current rate that will be about 6 months !

[Bearman]

Don, have a look at goodyear wrangler silent armour. They do one in 235/85/16 that seems to be a good allrounder. The tread is not as aggressive but they seem to be long wearing although I haven't done much offroad/gibber style running with them so can't give a good recommendation on that.

[Graeme]

I recently switched to 245/70-17 Duratracs on my D4 for winter. I'm hoping they're a tough go-anywhere tyre but in this size they only have 2 sidewall plies so will have to see how they last. Great grip in sloppy stuff.

[goingbush]

Looks like classic stone throw from the fronts for mine.
You say:
for the last 5000 klm its been 85% dirt

Van less affected as you most likely have rear mud flaps and the distance from the rear axle to the van axle is greater.

Try a set of proper front flaps and also rear axle leading flaps.

BFG AT and the new KM MT are bad for it on fast broken dirt. Most BFG fanbois and girls dont do 4000km of dirt in every 5 ;)

Steve

I accept that this is what the damage is from but ....

Ive been thinking about this,

How is a stone/rock hitting a tyre in the air, any different from the tyre hitting the stone/rock on the ground

Its not as if the front wheels are spinning causing the rocks to be thrown backward, I think the rocks just rise into the air & the rear tyre hits them,

but I cant see that would chip the rear tyres any more than the front tyres would be chipped, which is zilch !!




I have had a good few sets of the same tyres on D2s(different size) and never had them as badly chipped as yours.
Sure one set did get chipped after around 15K on dirt roads,but nowhere near as bad as yours,and i can't remember the rears being worse than the fronts.
I don't think pressures are the issue,more than likely stones thrown up from the front wheels.
i would talk to the supplier.they may have some ideas as they are supposedly the tyre 'experts' or contact BFG directly,they may want to see those pics.

My son has done a lot of K's on BFG KM2 on dirt roads,they are badly chipped,nowhere near as bad as yours,i don't think the fronts are worse than the rears.

Good luck.

No reply from BFG
perhaps now that they have the ADF Contract they don't care about the little fish.
A polite reply would be all that was required to stop me switching brands, but as they say Loyalty means nothing nowadays

[roverrescue]

I dont think i can give you an answer GB but it is just what i have seen an experienced.
Perhaps as a test. Put on some good front flaps and leading rear flaps and swap front to rear and test the theory!

I guess the confirming factor for me is the scalloped out leading flaps on my 130.
I really need to replace them but anways after 5 or so years of me flogging them oncape roads the conveyor rubber is now worn down from front ot back on the leading flaps of the rear axle. They seem to wear way more than normal flaps and I dont really know why... Stones fly from tyres even if they are not spinning ;) Then the tyre behind hits them at 100!

S

[goingbush]

Thanks Steve,
its probably here somewhere, but what tyres are you running ??

My front mudflaps are about 6" off the ground but don't show any signs of pummelling, they are probably too high. hadn't thought of leading rear flaps.

[jon3950]

Its not flicking them in the air thats the problem. The front wheels disturb the rocks, exposing the sharp edges. At speed the rear tyres then run over them before they have settled back down.

So the rear tyres see a rougher surface than the fronts.

We see this a lot in rallying. The Oberon area is notorious for tyre damage with its shale roads. We see a lot of punctures and always the rear tyres, as sharp stones go through the tread after being sat up on edge by the front wheels.

Cheers,
Jon

[LowRanger]

I accept that this is what the damage is from but ....

Ive been thinking about this,

How is a stone/rock hitting a tyre in the air, any different from the tyre hitting the stone/rock on the ground

Its not as if the front wheels are spinning causing the rocks to be thrown backward, I think the rocks just rise into the air & the rear tyre hits them,

but I cant see that would chip the rear tyres any more than the front tyres would be chipped, which is zilch !!



We went to a tyre distributor,for a club meeting a few months ago,and one of the things they showed was a video,taken with a camera mounted under a vehicle,and showing the impact of stones thrown up from the front wheels,and the subsequent tread damage to the rear tyres at different tyre pressures.
Was quite an interesting video,and it wasn't aimed at any particular brand,but was just intended to highlight proper tyre management.

[Iain_B]

I experienced the same thing with my BFG KM2's - it happened on our last big trip in late October last year. It happened on a 450km drive between Lawn Hill National Park and Normanton and pretty rough and corrugated roads and it was around 38-40 degrees.

My fault really, we had the tyre pressures too high as we had pumped up the tyre for a sealed section of the road so we could drive fast, and since the centre diff lock used to jam and I would have to jack up the front axle and manually unlock the diff. When we hit the dirt road again, I decided not to lock centre diff or deflate the tyres as it was only a short distance to the sealed section according to the map, as few detours and some backtracking due to forgetting a SPOT GPS device on the side of the road and we had done over 400km on the dirt.

By the time we stopped for the night, rear tyres had quite a bit of damage. Front tyres had no damage at all.

The damage is not as bad as the AT's in OP's photo, but is it worth buying a new tyre and using the new spare, and using one of the damaged ones as the spare? We have a 10 week 20,000km trip in August/Sept/Oct this year.

Anyone got any actual experience of how quick a tyre deteriorates once chipping starts, or if you remove the cause ( i.e. put them on the front) then they would be fine.

[vnx205]

Its not flicking them in the air thats the problem. The front wheels disturb the rocks, exposing the sharp edges. At speed the rear tyres then run over them before they have settled back down.

So the rear tyres see a rougher surface than the fronts.

We see this a lot in rallying. The Oberon area is notorious for tyre damage with its shale roads. We see a lot of punctures and always the rear tyres, as sharp stones go through the tread after being sat up on edge by the front wheels.

Cheers,
Jon

It is quite likely that this is the answer.

I believe that the vast majority of punctures on the Gibb River Rd are rear tyres for the very reason you mention.

That means that the extent of the chipping and the likelihood of punctures depend to a very large extent on the characteristics of the gravel or rocks. Smooth, round ones would cause few problems. Square ones would be OK while they were lying flat, but if they tilted just a little, the sharp square edge would be exposed.

[goingbush]

I experienced the same thing with my BFG KM2's - it happened on our last big trip in late October last year. It happened on a 450km drive between Lawn Hill National Park and Normanton and pretty rough and corrugated roads and it was around 38-40 degrees.

My fault really, we had the tyre pressures too high as we had pumped up the tyre for a sealed section of the road so we could drive fast, and since the centre diff lock used to jam and I would have to jack up the front axle and manually unlock the diff. When we hit the dirt road again, I decided not to lock centre diff or deflate the tyres as it was only a short distance to the sealed section according to the map, as few detours and some backtracking due to forgetting a SPOT GPS device on the side of the road and we had done over 400km on the dirt.

By the time we stopped for the night, rear tyres had quite a bit of damage. Front tyres had no damage at all.

The damage is not as bad as the AT's in OP's photo, but is it worth buying a new tyre and using the new spare, and using one of the damaged ones as the spare? We have a 10 week 20,000km trip in August/Sept/Oct this year.

Anyone got any actual experience of how quick a tyre deteriorates once chipping starts, or if you remove the cause ( i.e. put them on the front) then they would be fine.

Iain,
Normanton to Camoweel is where the damage happened, that would include the same section of road that you took to Lawn Hill,

We have to go to Sydney for two weeks in Aug, then back on the road, so will wind our way down there from Mt Isa, (the odo just clicked over 185,000 . the damage occurred in the last 500 or so Km, ) I'll leave them on the rear and see how they fare in the next 5000 or so, if they get much worse I'll swap them for the spares.

[Graeme]

I would be surprised that the damage is caused by the front tyres exposing sharp edges because the fronts encounter those rocks exposed by other vehicles' rear tyres. I suspect the cause is that the rocks from the front tyres are hurled at the rear tyres at speed causing the rear tyres to encounter them at a much faster speed than the speed the front tyres encounter stationary rocks. Sharper rocks would do more damage.

[transtar]

We've found the BFG AT's Manufactured in USA are better than those made in Asia for tread life and chip resistance. Don't know what the difference is but is quite noticeable on vehicles working side by side

[vnx205]

I would be surprised that the damage is caused by the front tyres exposing sharp edges because the fronts encounter those rocks exposed by other vehicles' rear tyres. I suspect the cause is that the rocks from the front tyres are hurled at the rear tyres at speed causing the rear tyres to encounter them at a much faster speed than the speed the front tyres encounter stationary rocks. Sharper rocks would do more damage.

The way it was explained to me (by a friend of a mate of someone I knew :D), is that on surfaces like the BRR, the front tyre tilts the rock without necessarily lifting it.

Before the rock has time to settle back down under its own weight, the rear tyre hits it while it is still teetering on its edge.

That seemed to make more sense to me than the idea of rocks being hurled through the air fast enough to damage a tyre.

I had no problems myself on the GRR, but I was running crossply retreads which performed faultlessly. So I am simply being an armchair expert. :D

[goingbush]

If this was the case I would expect the van tyres should show damage caused by the rock edges left exposed by the rear tyres .

(The van track is slightly wider about 50% overlap )

[jon3950]

The way it was explained to me (by a friend of a mate of someone I knew :D), is that on surfaces like the BRR, the front tyre tilts the rock without necessarily lifting it.

Before the rock has time to settle back down under its own weight, the rear tyre hits it while it is still teetering on its edge.

That seemed to make more sense to me than the idea of rocks being hurled through the air fast enough to damage a tyre.

I had no problems myself on the GRR, but I was running crossply retreads which performed faultlessly. So I am simply being an armchair expert. :D

That's it exactly. I don't think its the speed the rock hits thats the problem, its the fact that a sharp edge is exposed and is then squashed between the ground and the tyre causing a chip or puncture if sharp enough.

Tyre pressures are going to have an effect on the severity, but in my example with rally tyres at Oberon it doesn't seem to help - its mostly down to luck.

Back to the BFG problem, I had a set of rears do this many years ago on my D2. Went to buy some replacements and they were replaced under warranty - apparently they had a bad batch.

Cheers,
Jon

[vnx205]

If this was the case I would expect the van tyres should show damage caused by the rock edges left exposed by the rear tyres .

(The van track is slightly wider about 50% overlap )

Not according to the way it was explained to me. The distance between the front and rear tyres is much less than the distance between the rear tyres and the van tyres.

The rocks only balance at a dangerous angle for a split second. At the speed a lot of people drive, there isn't time for it to fall down before the rear tyres hit, but there is time for it to fall back flat before the van tyres hit.

if that theory is right, then I would expect that people who drive much more slowly have fewer problems with the rear tyres as their lack of speed allows more time for the rocks to fall back flat.

[Graeme]

if that theory is right, then I would expect that people who drive much more slowly have fewer problems with the rear tyres as their lack of speed allows more time for the rocks to fall back flat.I can't possibly believe that rocks somehow magically fall back in such a way that they settle to not show a sharp edge. Travelling more slowly means that the front wheels don't propell as many rocks and those that are thrown are not as quickly so the rocks either are no longer flying or are barely travelling by the time the back tyres get to them.

[Bearman]

I don't think it is anything to do with rocks flying or settling, more to do with the fact that the rear wheels have the most weight on them and will suffer the most on sharp surfaces. I have driven that Gregory Downs to Camooweal road through Thorntonia Station many times and the rocks are very sharp and with a loaded vehicle the rears cop the most damage.

[vnx205]

I can't possibly believe that rocks somehow magically fall back in such a way that they settle to not show a sharp edge. Travelling more slowly means that the front wheels don't propell as many rocks and those that are thrown are not as quickly so the rocks either are no longer flying or are barely travelling by the time the back tyres get to them.

There is no magic involved.

Some of the rocks are fairly flat, a bit like a pancake or a thickish coin. Their natural tendency is to sit flat so that the edges don't present a problem. It is only when they are momentarily tilted a bit that the edge is a danger.

[jon3950]

I don't think it is anything to do with rocks flying or settling, more to do with the fact that the rear wheels have the most weight on them and will suffer the most on sharp surfaces. I have driven that Gregory Downs to Camooweal road through Thorntonia Station many times and the rocks are very sharp and with a loaded vehicle the rears cop the most damage.

No doubt true for a heavily laden 4wd, but not for a well set-up rally car. As another example, we did 2 rear tyres on the the Freelander we use for recce up at Oberon earlier this year. It was unladen and I'm sure its weight is biased to the front.

Cheers,
Jon

[jon3950]

I can't possibly believe that rocks somehow magically fall back in such a way that they settle to not show a sharp edge. Travelling more slowly means that the front wheels don't propell as many rocks and those that are thrown are not as quickly so the rocks either are no longer flying or are barely travelling by the time the back tyres get to them.

Picture a conical shaped rock with a sharp point, lying on its side. The front tyre passes over it and flicks it enough to stand it on its base. Before it has a chance to fall back on its side, the rear tyre passes over it. Because it is standing upright the point of the rock is pushed into the tread of tyre.

Obviously a simplification, but that's the principle. This was the type of rock we dug out of the Freelander's tyres in my example above.

Cheers,
Jon

[scarry]

So now i have worked out why i usually get nails and screws more often in the rear tyres,flicked up by the fronts...maybe?

[vnx205]

Picture a conical shaped rock with a sharp point, lying on its side. The front tyre passes over it and flicks it enough to stand it on its base. Before it has a chance to fall back on its side, the rear tyre passes over it. Because it is standing upright the point of the rock is pushed into the tread of tyre.

Obviously a simplification, but that's the principle. This was the type of rock we dug out of the Freelander's tyres in my example above.

Cheers,
Jon

I was thinking of the sort of shape that might cause the chipping in the original photos. A sharp edge on a disk shape would do that but wouldn't cause a puncture.

I can picture the shape you describe causing a puncture. Obviously the one you saw did.

[vnx205]

So now i have worked out why i usually get nails and screws more often in the rear tyres,flicked up by the fronts...maybe?

So do you subscribe to the theory that these screws are flicked up by the front tyre and fly through the air fast enough to puncture the rear tyre?

Or do you lean more towards the alternative view; that the front tyre disturbs a screw that is lying harmlessly on its side and before it has time to settle, the rear tyre runs over it while it is still fairly vertical?
:)

[jon3950]

So now i have worked out why i usually get nails and screws more often in the rear tyres,flicked up by the fronts...maybe?

Funny, I was just thinking the same thing. I can't remember ever getting one through a front tyre. A couple of weeks ago I put an M8 capscrew through one of my near new LTZs on the rear. It would a very big bolt to get stuck in a tyre if was just lying in the road. We may be on to something!

Cheers,
Jon

[roverrescue]

All very interestting discussion and likely we will never actually get the final answer!!!!

All I know is my old D1 with a 100" wheel base was evil for rear tyre wear - It had no real front flaps and no leading rear flaps

I upgraded to a 130 which has shown much better tyre wear front to rear and has lots of flaps!!! Interestingly I got savage rear tyre wear when one of my front flaps was torn off on the OTL
I drove for many months flap less. In that time the leading rear flap got flogged and that rear tyre chipped out like your pictures above.

All this is evidence enough for me that it is more than stones turning on edge but then again what would I know!

And to answer your question GB. I run Bridgestone 762 muds which wear better than the Toyo muds which wear light years better than BFG KM2 muds (all side by side comparison of mates vehicles on these roads).

Wet road bitumen handling are not a high priority for me, actually bitumen road handling is largely irelevant!!!

But all this is changing fast and soon I will sell the defender and just use the mrs commo wagon to get around the cape considering all the bitumen and billard table smooth dirt that is getting placed at tax payers expense ;)

Steve

[scarry]

So do you subscribe to the theory that these screws are flicked up by the front tyre and fly through the air fast enough to puncture the rear tyre?

Or do you lean more towards the alternative view; that the front tyre disturbs a screw that is lying harmlessly on its side and before it has time to settle, the rear tyre runs over it while it is still fairly vertical?
:)

Maybe the one in red is the go;)

But the other thing is it always seems to happen to me when the tyres are newish.Possibly the greater tread depth helps keep the nail/screw verticle for a good penetration:(

So the only way to clear this up is maybe someone can strap a go pro under a vehicle and see what exactly happens.

[Bearman]

No doubt true for a heavily laden 4wd, but not for a well set-up rally car. As another example, we did 2 rear tyres on the the Freelander we use for recce up at Oberon earlier this year. It was unladen and I'm sure its weight is biased to the front.

Cheers,
Jon

Not sure what you mean about a rally car, I don't think Goingbush is using his as one. I know that country very well and it is mostly rocky and very hard and just for an example I was operating a D9 dozer not far from there and I could not get a single tyne ripper to dig into it. Going one way you could jack the rear of the D9 off the ground and the ripper wouldn't go in but just smoke and slide over it, turn around and try the other way and it would go right in and stop the dozer. We had to drill and blast before we could work it. That Camooweal to Gregory Downs section is some of the hardest rock I have ever seen and is murder on tyres.

[Bearman]

All very interestting discussion and likely we will never actually get the final answer!!!!

All I know is my old D1 with a 100" wheel base was evil for rear tyre wear - It had no real front flaps and no leading rear flaps

I upgraded to a 130 which has shown much better tyre wear front to rear and has lots of flaps!!! Interestingly I got savage rear tyre wear when one of my front flaps was torn off on the OTL
I drove for many months flap less. In that time the leading rear flap got flogged and that rear tyre chipped out like your pictures above.

All this is evidence enough for me that it is more than stones turning on edge but then again what would I know!

And to answer your question GB. I run Bridgestone 762 muds which wear better than the Toyo muds which wear light years better than BFG KM2 muds (all side by side comparison of mates vehicles on these roads).

Wet road bitumen handling are not a high priority for me, actually bitumen road handling is largely irelevant!!!

But all this is changing fast and soon I will sell the defender and just use the mrs commo wagon to get around the cape considering all the bitumen and billard table smooth dirt that is getting placed at tax payers expense ;)

Steve



Steve, I remember years ago when all the rage was to do the Bloomfield track, the tourists were all 4WD, diff locks etc, half way up the inclines they would be overtaken by locals from Wujal Wujal in their Falcon or Holden wagons with the tribe on board:D

[goingbush]

<snip>

Anyone got any actual experience of how quick a tyre deteriorates once chipping starts, or if you remove the cause ( i.e. put them on the front) then they would be fine.

The first pic (from original post) of the Damage when I noticed it at Mt Isa, @ 185,000 Klm, Have determined It happened about 250km prior on the Gregory Downs - Camoweel Road

Took the second pic thisarvo.
The speedo is now on 186988, so basically 2250km later and the tyres are stuffed. The Front Tyres & Van tyres are still perfect.

https://www.aulro.com/afvb/images/imported/2013/07/1306.jpg

https://www.aulro.com/afvb/images/imported/2013/07/1307.jpg

I'll need to swap the spares onto the Defender, Got better life out of my old Dunlop Super Grippers, probably try KL71 or RT03 next time !

[Tank_JR]

I have the same tyres have not that happen, bad batch maybe?

[TerryO]

Did you ever check if your A/T's were made in the US or Asia?

I know through motorcycle racing that there is big differences in tyre quality and performance depending on which country each batch of same model tyres is made.

My guess is to higher pressure and rear load bias with a rough surface chucked in for good measure. Sure stones get tilted and or thrown as a vehicle drives over the surface but as Graeme said the vehicle before you had already dislodged the same stones often only minutes, some times seconds before. Its not like it is virgin road, however just like everyone else on this topic I'm just guessing.

No matter what even on a 4wd rear tyres get a harder time than the fronts, so its not that surprising that in harsh conditions they would be the ones to deteriorate faster than the fronts if some thing isn't quite right for what ever reason.

I must admit I think BFG A/T's are a great all rounder and mine have taken a real bashing and still are in great condition.

If my new KM2's on the D3 last a third of the instance the A/T's on the D1 have I'll be rapt.

[goingbush]

All 8 of my BFG's are made in USA, Not sure where to find the batch number.

Had a discussion with Jim (yt110) re the problem and think the pressures were too low (33psi cold) the flex of the tyres over those sharp rocks causing the damage more likely than the front tyres presenting the pointy rocks to the rear tyres. And the fact that BFG AT's have so many facets.

40 psi would be better, Too high a pressure and risk a puncture, too low & tread damage, 33 gives a better ride because of the flexing , think I'd prefer a harsher ride & less tyre damage.

quick look around the Caravan Park , about 30% of vehicles are fitted with BFG AT's and none appear to have any damage at all - its just me so no need for the masses to be concerned but still have decided will now go with Toyo M-55 next time round

[scarry]

Did you ever talk to BFG(michelin) yourself to see what they said?

[goingbush]

Did you ever talk to BFG(michelin) yourself to see what they said?

Here is a respons from BFG, similar response from BFG Facebook


Hi Don,

Thanks for your enquiry.

On some surfaces ( typically sharp crushed rock), tread chipping is almost unavoidable.
This type of tread damage is common place for Forestry and mining service vehicles, regardless of tyre make.

Tread chipping is most common on the rear axle because the vehicle is often left in 2H.
Also, towing places additional load on the rear axle.

The non-driven tyres in simple terms pass over the abrasive surface suffering little damage.
Whereas the driven tyres apply torque to the crushed rock forcing the sharp edges of the crushed rock into the tread rubber.

Adjusting pressures can help but, reducing your speed will be more effective in preserving tyres on abrasive surfaces.

Hope that this helps to explain .

Also, we can provide pressure recommendations for various conditions especially if you know your axle loads.

Kind Regards,
The BFGoodrich Australia Team

Guilty on all counts except I don't / can't drive in 2H :confused:

[scarry]

Here is a respons from BFG, similar response from BFG Facebook



Guilty on all counts except I don't / can't drive in 2H :confused:

Send them back something.

Maybe

Thanks for your response but my vehicle is permanently in 4WD bla bla.
And with my axle loads and tyre sizes/type of bla bla,what pressures do you suggest,on this type of road surface.

Their answer would be interesting.:p

[PAT303]

The chipping you have is typical when driving on hard rock,all the tyres I ran in the Pilbara,MTR's,Maxxis,Michelin,Continentals chipped,most people use thier 4wd as mums taxis and do one trip a year or two and find thier tyres and added on bling don't live up to the hype the mags make them up to be,the only tyres that don't chip are the LT truck style like Hercules or Michelin. Pat