Trye problems

John & Sandra, I have been using BFg All Terrains solely for the last 10 years or so. The set I have at the moment has done some 70,000kms (30,000kms offroad and outback) and still without a puncture. My car weighs around 3.1 ton (GU Patrol). In my experience, the trick is to drop your tyre pressures to suit the surface you drive on. On highway, I use around 40psi and drop it to 26-28psi on corrugations. Even further when I go offroad. You don't have to worry too much about sidewall temperatures on these lower pressures if you keep your speed down a bit. Hope this helps Ari

Almost all of our driving is on dirt roads. We use normal road pattern tyres on both our 4WDs (OKA and 2.8 litre diesel HiLux) and very rarely have tyre problems.

Agree with previous postings that it's best to keep tyre pressures are bit lower than for hard road use. This is fine at appropriate speeds. A good rough check is that if you can levae your palm agaisnt the tyre for more than ten seconds or so - should be OK. Another rough check is that pressure build up through heat should not exceed 4 psi.

Always adjsut pressure for when tyres are cold - and do not reduce when they heat up.

Can confirm that the forces involved with stone penetration tend to be more or less proportional to the square of the speed.
Collyn

G'day everybody, Thanks for the input on my question on tyres (correct spelling this time). John

Greetings all,

For the people new to towing heavy loads and for anyone else interested I'll expand on the
"4 psi" general rule for tyres.

After physical damage from impact tyre heat is quickest killer of tyres and is caused by underinflation. Overinflation usually doesnt cause the tyre to overheat it just reduces contact patch and wears the centre tread prematurely. It can make it less resistant to impact.

Because air expands when heated creating a higher pressure in a confined vessel we can use pressure differential as a measure of heat. A 4 psi increase from cold to hot for any given load at various speeds is a good guide to keep the tyre at a safe temp and get good wear for our dollar.

This can be a little hard to grasp as in a tyre goes up 7psi from cold it doesnt have enough air in and needs more even though the tyre went up 7 psi. Excess heat was generated from underinflation causing the pressure to rise above the 4 psi from cold to hot.

The great thing about the 4 psi guide is it works for any given load. My BT at about 2400kg likes 38 psi cold rising to 42 after about I hour down the highway at 100kph. At 2750kg it likes 40 psi rising to 44 after 1 hour. If I run full water tanks ,which I have not tried yet, it would probably like another 2-3 psi cold.

If a tyre is overinflated for a given load/speed it might only go up 2 psi from cold to hot. So drop the pressure 2psi next morning or when tyre is cold and drive for half hour at least and recheck cold to hot increase.

This works for the tow vehicle as well .... a great guide to get rear tyres at the right pressure with the BT on (ballweight) and loading of tow vehicle. Just as an example my rear tyres run at 40 psi cold vehicle empty and at 53psi BT on and tray loaded with gear.

Obviously there is a cut off here .... if a tyre is at say 15 psi there might not be enough air to expand above the 4 psi. Use the vehicle tyre placard or manufacturers recommendation as a guide to starting pressures and adjust from there. The max pressure (and load) allowed in a tyre is printed on the sidewall. It says in dual or single fitment .... dual fitment does not mean dual axles it dual tyres each side of the same axle so single fitment load is the one for
99 % of us.

This can be a pain when you first setup with loaded BT on but is well worth the time and effort. Once you get the best pressures you can stick with them until the load has a severe change. I only check the cold to hot diff occasionally now. Like the BT hubs get into the habit of getting used to the tyre temp by feel after pressures are right and when you pull up after a long stint you can feel tyres ... if one is extra warm do a pressure check.

Anthony

Anthony. Maaaate! Your understanding passes all understanding. Good stuff (suggest tag it onto the Hints & Tips). But listen - I'm excited. You didn't say so, but I bet you use a hand-held Pressure Guage. Yes? Well... I've got one, I've got one! Already! I don't have to buy one! The first and only thing! I'm on a roll - I can feel it! I'm Big Keved! Wow. What a relief - I thought I was going to have to buy everything. How wrong can a bloke be, huh? One of the reasons I've been told alloy wheels work better (apart from unsprung weight) is their superior heat dissipation characteristic. I gather though, for the hard case offroader, the tendency for them to crack under pressure, rather than bend like the steels, rules them out? I can feel a Show Pony set of road tyres with sexy alloys coming on (for tarmac-only excursions) with another set for the tough stuff. Lets see now, at, say, $500-600 per corner times 9 or 10 or 11 thats ...... Anyway, further to your info, as I'll be buying the vehicle second hand, and could get any old tyres (probably with quite a few thousand K's left in them), the question of what tyres to specify with the van raises its ugly mush. I'm inclined to wanting road tyres for my first set & think I would rather ditch the 4 (or 5) tyres on the vehicle up front if they were not what we want, than specify 6 of the same (wrongish) ones for the van & be faced with replacing 10 or 11 later on! A truely Ugly Thought! With this in mind, could I troll the gang for thoughts on a Whimpish/Macho tyre with sensational dry/wet grip on black top/bulldust & gravel/sand, fantastic wear & brilliant breaking right down to the ply? Seriously, a recommendation on a road/well graded, shortish track set is certainly of interest. Any bites? Griff

Griff,

Aluminium is one third the weight of steel ... what if the alloy wheel is three times the thickness. Aluminium conducts heat four and a half times better than steel ... what if the steel wheel is 1.8mm thick and the alloy rim is 8.1mm. I have alloys on the F250 because it came with them and steels on the van as I would rather have steels in the outback. I prefer steels in the outback because I'm the poor sucker who'll have to break out the tyrepliers, levers and rip a tyre off for repair. Taking a tyre off like this sure rips in to my shiny alloy rim so when we head out I'll have steels all round.

I have BFG all terrains on my van and other fourbies. I was wanting to put them on the F250 but they dont pass the load rating. They dont balance that well using up to 180g of weight depending on the tyre lottery given to you. These are all light truck tyres. Michelin light trucks balance consistently around 50g but are a bit more expensive. Nuffin wrong with road pattern tyres ... Bob has done some serious stuff with the standard F250 tyre.

The main thing would be to keep the same diameter and section wheels all round so the tyres are interchangeable from van to vehicle. If the stud patterns match all the better. Wait til you get 6 ton to drive I dont think you should be going so fast you bend or break rims no matter how bad the road.
I have very little outback experience and there are plenty in here who have and they might be able to tell of the specific tyre probs out there ?

Anthony

Griff, Bushtracker are currently recommending Bridgestone Duellers AT693 (I think). I had to resole the vehicle so I used these in order to have interchangeable spares. Can't speak for off-road performance or wear yet, but I can say they are one of the quietest tyres I've ever had on a 4WD Motley

Griff I have used BFG's on all the 80's I've had for some years now (on third set) and have got at least 100k out of the previous 2, tranferred from vehicle to vehicle. I use sunraysia style rims and have had no problems with them or the tyres whether it be in the Alps or across the Simpson. When I was in the "waiting phase" for the BT, Steve asked if I wanted the Duelers as they were supposed to be good, but at the time I stuck with the BFG. I would be interested to know how Peter's (Motley's) are wearing on both the BT and his truck as I was interested in their off road capability and longevity. It all boils down to what you want or what you like although how many K's you get for your buck can be a factor. Two things though, always carry a pressure gauge and a good air pump (ARB, Blue Tongue or Big Red - all the same basically) because you never know! Jeff

G'day Jeff,

I saw some time back the ad blurb for these duellers and I think they quoted a 30 -40% higher resistance to tread puncture "against a well known brand". They would probably balance better than a BFG also. Feedback from these in the outback will be interesting when it filters through. I have wondered why BTi changed .... better tyre or price point.
Time will tell .....

Anthony

Whatever you get don't get Yokahama Geolanders, I had them on my 80 series and got 2 punctures and 1 blow out on the gibber rocks of central Australia. The tyre service in Alice Springs recommended Bridgestone Duelers which we bought and then didn't have another puncture in the next couple of years on all types of roads. The Bridgestone wore well, were quiet but I changed to BFG and they are good also. A friend who has a tyre service in Hastings Vic, recommends road pattern tyres on trailers the same as truckies use, as they will wear better, and still be suitable to put on tow vehicle if required.

Brian A question? I can understand the reasoning behind road pattern tyres on the BT, but while this would be good on the black what about on the dirt? Do you think they would have the same "puncture proof" attitude as a dedicated off road tyre??? Anthony Thanks for the note. (I thought of an emoticon kiss here but Angie might get jealous) Jeff

They apparently have the same tread material, jsut a different pattern that doesn't have lugs to get caught when turning or stones caught in them. I recently changed one BFG damaged due to allignment problem and now have a highway pattern that is called a Radial Long Trail TA. That one is a spare until I wear the others down.

Brian Thanks for that. Will keep them in mind. Jeff

Thanks for the input. I will tread warily. Griff

Hello Griff, I have turned away from BFG AT tyres. After my initial moan I have had another two punctures and lost one tyre, replaced it with a Toyo AT tyre. Unfortunately I have 15" wheels. If I had 16" wheels I could have changed to Toyo Hyparadial F55 tyres. These are the favoured tyres in the Mareeba area, have seen a couple of farmers and locals efforts at destroying them. If I had treated the BFG ATs like that the tyres would have died in a couple of thousand kms. The locals seem to get about 80,000 km out of a set. I am considering kitting out the Patrol and BT with 16" wheels and the Toyo Hyparadials when we get bach to Brisbane in August. If you have not already purchased your tyres and wheels make sure you get 16" wheels. Heavier and sturdier tyres are at least available. Have fun John