[DB-101]

Hi people, read a lot of stuff on here about tires, so I am assuming (a dangerous habit) that some of you know what you’re on about. Currently I have stock 2006-ST rims (Ali) with 275-65-17 factory tires.

Have not had the truck long and took it down the beach for a bit of fishing and the bloody things cut into the sand like a hot knife in butter with 25psi inflation, had to drop them to 15 to keep going.

The beach is open to the southern ocean, so is not hard, or even firm, packed sand, quite the opposite in fact. I have seen snakes getting bogged down in it…

My old 2002 4.2TD GU had 285-70-16 BFG RT-TA’s that loved the sand, prior to that my 80 series 4.2TD cruiser had Long Trails and even those hi-way warriors could deal with it, but these buggers hate it.

I don’t want to go with pure off-road skins as I also tow a 3.4t boat up and down the west coast, so hi-way wear is my main concern and I don’t want to change the stock ST mags. Was going to swap over my 4.2TD rims & tires, but the aftermarket rims don’t clear the calipers.

What I want to find out is what is the maximum width of tire I can squeeze on to the rims. My local guy says he can put 285’s on them easy, but I was wondering if I can squeeze a set of 305-60-17 BFG RT-TA’s on to the factory mags (did not ask him about 305’s and I am overseas at present so cant at this time).

This would make them almost the same diameter as the stock, but wider for the sand (and still within WA law i.e. still inside the ) and therefore the speedo would be out by only 0.5kph or so.

Wadda ya reckon ???

 

[hank-70]

A friend of mine has 305's on his zd30 ST and seems to be ok, think they are Mickey Thompson MTZ.

 

[the evil twin]

You don't want to chase width... you want to chase "length" IE a bigger diameter narrower tyre is better than a smaller diameter wider tyre. Altho everyone refers to "bagging out" you actually end up with more flotation from the increased length of footprint than the width...

Why?. Because the rolling resistance in sand is from the "bow wave" of sand built up in front of the tyre so the wider the tyre the wider the bulldozer blade effect of the sand piling up in front of the tyre

Anyway, I digress. In your case I reckon your pressure is waaay to high

If you are running factory Duellers I would say that 25 PSI is too high for Whitehills etc. I would start at about 18 PSI and see how you go. I've seen conditions down there when 12 to 14 is needed.

By far the most common tyre in my Club is 285 and noone has any hasles at all on the Whitehills to Myalup or Wilbinga runs we do.

 

[truckster]

TET is correct. You want length. 285's have for me alwyas been more than enough for beach/sand driving.

Also whats wrong with dropping them to 15psi? I usually drop to 15-18psi as soon as I arrive at Beachport/Robe for the long weekends beach/sand driving.

I will say DDRs 17in Coopers @18psi looked like they had 50psi in them side by side with my 285/16 mtr's - they hadnt changed at all. Not sure if this is normal for 17in tyres.

 

[skamme]

TET is correct. You want length. 285's have for me alwyas been more than enough for beach/sand driving.

Also whats wrong with dropping them to 15psi? I usually drop to 15-18psi as soon as I arrive at Beachport/Robe for the long weekends beach/sand driving.

I will say DDRs 17in Coopers @18psi looked like they had 50psi in them side by side with my 285/16 mtr's - they hadnt changed at all. Not sure if this is normal for 17in tyres.

Yeh, but if I understand correctly, 285 will likely make the set up illegal, hence he was asking about 305's which wont be too big in diam??

The issue raised about sand driving and tyre width verses tall skinnies is a hotly debated topic where I come from, with tests inconclusive either way. It would seem to depend on the actual sand being experienced, baby powder soft sand...the wider tyres (in my experience) seemed to keep the show afloat better than tall skinnies. Course wet shelly grit sand, the wider tyres sucked, and the tall skinnies shone. Some will have other opinions no doubt

Either way, get em down if you need to. I run 265 75 17 silent armour. As stated above, 25 is near useless is soft sand. The tyres need 18 or less to get them spreading the footprint. They have fairly stiff sidewalls, and I have been down a number of times to 8 psi, (which is about 6 cold). No problems so far with sand in the bead or pushing/slipping tyres off the rims, and have towed the CT at these pressures in some pretty soft predicaments, sand hills etc. Regularly go to 12 which is generally excellent.

 

[DB-101]

Thanks for the feed back guys,


Just going on past experience, the 25psi was fine on the 285’s of my 2002 GU, but they were "bagged out" on the rims anyway. I do put them down to 15psi on a lot of occasions, especially in summer when the weekend warriors have been chewing up whitehills, tims thicket etc, I look at the beach and adjust accordingly. Most of the time I am on the south coast (Denmark – Walpole) and those beaches don’t get a 10th of the traffic as beaches south of Mandurah and the tracks are not ripped up. I make sure that they are at an inflation pressure where I am not tearing up the beach and tracks. All the sand I am usually on is medium course shell grit, not wet, that gets packed down via rain fall (with a little wind driven lose stuff over the top).

I am after a bigger foot print (via width), true, but I think the main issue with the factory stocks are that the sidewalls are at right angle to the tread, and it’s close to 90degree, and this is what I think is the driver for the tires slicing straight down (that and the overall narrowness under a heavy truck), and I agree that the usual 25psi I got away with on the 285-70's is not going to work on the 265-65's. I understand what you’re saying about the wave effect, just watch a 4bee go past on the beach and you see it every time. I was thinking that with a wider track, and therefore less pounds per square inch on the tires from weight, would go some way to alleviate the issue.

There is a big difference in diameter between 285-70 and 265-65, but I am trying to keep away from the speedo issue, and the motor is still under warrantee so I don’t want to endanger that. Stepping up in diameter will put more load on the motor when towing the boat, I had better talk to Greg at Brunswick on that score. I can order in 305-65’s from the states (don’t know why you can’t get them on Oz (at least not where I have looked)) and that will bring them up to close the diameter of 285-70’s, but again, I will need to talk to Greg on that issue. Besides, fatties look so cool!!!! haha

Skamme, 285-70-17’s are legal in the west on a late model patrol, the main rule here is that they cannot protrude outside the wheel arch. There is a law on diameter versus max factory size, but it's the outside of the guard that will get you busted. Even then, on my 2002 patrol I nailed some rubber flares on the guard to keep the 285’s inside and got them over the pits with no problem.

 

[CQCraig]

I had 16" rims on the old car (265/75R16 tyres) and went everywhere at 25 PSI.

I got the new patrol with 17" rims (275/65R17) and promptly got bogged straight away at 25 PSI. At 20 PSI it pulls like a train and I've never been stuck since.

I put it down to the difference in footprint when the tyres are deflated due to the different sidewall heights.

And I agree with the length vs width argument. The longer footprint is better.

Cheers
Craig

 

[benno77]

Im running 305/70/17s on my ST alloys . There Maxxis Bighorns. The patrol is lifted 2 inches and I had to take the mudflaps off but with the ST standard flared gaurds theres no protrution but spedo is out about 8ks. Ive never had two many problems in the sand in the patrol even with the old smaller bridgeston duellers that I used have in it. Its all about tyre pressure with sand driving and in actual fact I found the old duellers which where a more road orientated tire running at low pressure (as low as 12-13 PSi) performed better in the sand thatn what the big chunky beasts that are on there now do.

 

[DB-101]

OK,

From this I can see;

1. Yes you can fit 305’s to the stock 06-GU rims.

2. 305-70’s may hit the mud flap (and would not let me get under the garage door, which would put my insurance up).

3. It is better to have a slightly longer tread.

4. 285-70’s will fit, give a longer track (and they will fit under the garage door)

5. The 305-60-17’s will be a tad smaller than the 285-70’s, would not put my speedo by much and still to the business.

6. 305-65-17’s would give me give me the slightly longer track, knock out my speedo by approx 3kph (which I could live with, or should I say my kids will not get pinched for speeding all the time)and still let me get under the garage door.

I can’t find 305-65-17’s in Oz, but they are readily available in the states.

Therefore, I guess the economy will have to live with it, and I import the tires from Uncle Sam.

Cheers all.

 

[Mic]

Who makes these 305-60/65-R17s?

 

[DB-101]

Sorry for the slow reply, I’ve gotta do some work sometimes…

Quite a few makers supply this size, including BFG – AT (see links) which is what I am after.

Best price so far I have found is US$255.00, with a quote for shipping of $230 for 4. Now if I can just find them for US$192 each, and the Oz $ stays at parity, then with the shipping it’s less than AU$1000 and I escape the GST and Import duties.

Even so, at US$255 this comes to US$1250 with the shipping (could take 2 months by boat) and adding 10% Duty, and then 10% GST it comes to +/-$1513, it is close to the $375 a pop the local quoted me for 285-70-17’s.

When I imported my boat from the US there was another ~$260 in landing and fumigating costs, so that needs to be factored in, but hey, it’s only money and you can’t take it with you.

Looked on Oz websites and find nothing much, sent inquiries to those that do say they can supply, and the reply is that they have to bring them in from the states and that will be extra (of course) with prices between $420 and $500 each, before adding the extra costs (all ways get the fuzzy feeling I am getting ripped off in Oz).

 

[DB-101]

Tried to add links via the track back and it does not seem to add them. Not sure why, but look up BFG in the US as a starter.

 

[truckster]

How do you go with legalities and insurance on tyres that are not ADR approved?

"Stepping up in diameter will put more load on the motor when towing the boat, I had better talk to Greg at Brunswick on that score"

Your talking about a V8 Diesel 6.5 here not a 138 grey motor. Roachie ran 315's for years in his 4ton patrol towing his 2-3ton trailer without a problem what so ever. It wouldnt even notice the difference in 285's to 305's

 

[DB-101]

"Stepping up in diameter will put more load on the motor when towing the boat, I had better talk to Greg at Brunswick on that score"

I agree, not going to do much to load up the motor, however, It’s a warrantee thing Truckster, motor is still under warrantee and we all agree it is best not to give the warrantor any ammo to knock back a claim.

 

[DB-101]

The ADR is not an issue, as long as the tyres are a recognised brand with and the maker has an ISO9001 or better.

The tyres on the boat trailer are firestone that come in with the boat and my insurer and the DPI passed them with no issues knowing that boat, trailer and tires were imported from the states.

Now converting the trailer to Aust standards is a whole different thing, took two weeks and $5000 to make it legal in Oz.

 

[walkal]

Best price so far I have found is US$255.00, with a quote for shipping of $230 for 4. Now if I can just find them for US$192 each, and the Oz $ stays at parity, then with the shipping it’s less than AU$1000 and I escape the GST and Import duties.

Even so, at US$255 this comes to US$1250 with the shipping (could take 2 months by boat) and adding 10% Duty, and then 10% GST it comes to +/-$1513, it is close to the $375 a pop the local quoted me for 285-70-17’s.

When I imported my boat from the US there was another ~$260 in landing and fumigating costs, so that needs to be factored in, but hey, it’s only money and you can’t take it with you.

To get around the duty tax and gst make two transactions so it's under the $1000.

Wayne

 

[Chambo Off To Work We Go]

TET is correct. You want length. 285's have for me alwyas been more than enough for beach/sand driving.

Also whats wrong with dropping them to 15psi? I usually drop to 15-18psi as soon as I arrive at Beachport/Robe for the long weekends beach/sand driving.

I will say DDRs 17in Coopers @18psi looked like they had 50psi in them side by side with my 285/16 mtr's - they hadnt changed at all. Not sure if this is normal for 17in tyres.

I'm with these 2 guys.
So a lot of sand driving (on a weekly basis in summer).
The whole deal is about tyre pressure.
I too start at 18 and work it from there.
If sand is hard, then not really a drama.
But in soft sand 18 is the starting point for mine.

A set of tyre deflators makes it the quickest way.

Your duellers would almost be the best thing for sand I reckon.
That's what I had on mine initially.
Got Cooper STs now which are a little more aggressive but work equally well too.
But like I said that is more about tyre pressure than rubber.

 

[DB-101]

Totally agree with dropping to a lower pressure, as stated in the start of this thread

“had to drop them to 15 to keep going” and

“the 25psi was fine on the 285’s of my 2002 GU, but they were "bagged out" on the rims anyway. I do put them down to 15psi on a lot of occasions, especially in summer when the weekend warriors have been chewing up whitehills, tims thicket etc, I look at the beach and adjust accordingly”

A little further down on in the discussion.

All depends on the track and the beach in question. I was in Broome last year and the sand is so hard packed you could drive down it in a fully loaded patrol dragging 3t behind you running on bike tires and not get bogged down. No wave action, just rising and falling tides, which makes for a hard beach. Even sticking 305-65-17’s on the rig there will be times that the pressure has to come down to the absolute minimum, that’s a given.

I haven’t got deflators as yet (no sure if I need them), always just use my pressure gauge that has a deflation valve on it. Now if I could hook up tire deflators and my air supply to the tires permanently and plumb them into the cab so I can just sit and drop / increase pressure as I go I would be in hog heaven…..

Walkal,

to ship them in two lots to escape GST and duty, you have around $600 on shipping and landing costs for each shipment, not sure you will save much there from getting a local mob to import the whole lot in one go and pay the extras as mentioned.

 

[Morejandal]

Hey there,

Do you have a backup set of tyres?
What if you damage one bad enough that it cannot be repaired? Especially if you were away on a trip. No one will be able to find a matching tyre. Spose you could get something a similar rolling diameter in a different size?

 

[DB-101]

Do you have a backup set of tyres?
What if you damage one bad enough that it cannot be repaired? Especially if you were away on a trip.

Yeh, I have thought about this, would be pretty unlikely that I would on beach and beach access tracks, but you never know.

That's why I am starting to lean towards Micky T's 4 rib x 10ply 305-65-17's. No exactly what I want, but is available in Oz.