Single Wheel Conversion Facts

Ben Campbell - Thursday, October 02, 2014

ATW 19.5” Wheels & Tyres

The following information contains the facts and history behind the ATW Single Wheel Conversions (SWC) on Isuzu NPS’s and Fuso Canters using Toyo M608Z 285/70R/19.5” tyres. We trust that we have covered the legal and technical details and dispelled the myths that are out there concerning this conversion.

Toyo M608Z 285/70R/19.5” tyres.

These tyres are extremely heavy duty. We have had our customers travel across some of the most harsh terrain on the planet. Many have done the entire life of their tyres, 70,000kms, 80,000 kms or more mostly offroad without a puncture or incident. Across Australian deserts, Russian tundra, the plains of Mongolia and the stoney trails through Africa. 

These tyres are not a dedicated steer tyre, anyone with truck experience would know that steer tyres have a straight grooved pattern and provide minimal drive or traction. However, the M608Z is a “drive” patterned tyre perfectly suited for use on a 4x4 truck with a Gross Vehicle Mass of 6 or 6.5 ton. If by chance you use your 4x4 Isuzu or Canter for “logging” then this tyre would be ideal, just as it would be ideal for a private expedition style motorhome, tour bus, mining truck or most other typical offroad application. According to Toyo, they have been designed as a high traction “drive” tyre for use in all types of road conditions, the correct design application for a 4x4 vehicle.           

Many professional departments (Rural Fire Brigades, Parks & Wildlife Services, Police Departments, Shire Councils, etc) that operate in soft sandy conditions are now successfully converting their trucks to 19.5” tyres and airing down to very low pressures as required. The benefit of a strong side-walled tyre when aired down is that the footprint elongates rather than bags outwards. An elongated footprint still provides excellent floatation but has much less chance of sidewall damage and requires less power to drive through soft conditions.    

Of all the Single Wheel Conversions that we have undertaken since making the change to the 19.5” tyres back in 2007, we have never had a customer report that they have broken a bead when aired down and many will air down well below our recommended minimum pressure in order to cope with a tricky situation. Actually in a recent training session we hosted for a local rural fire service, we purposely attempted to roll a tyre off a rim on a heavily loaded Isuzu NPS fire tender running very low pressures through tight corners... no luck. The tyres remained intact and functioned perfectly in the dry, loose and steep sand dunes throughout the session.  

The maximum pressure of the M608Z is 120psi and this could be used if the load was the maximum allowable 2900kg per tyre. That’s 11,600kg in total! Does your Isuzu NPS or Fuso Canter weigh that much? Typical highway pressures for these tyres on NPS’s or Canters are between 65psi and 95psi depending on the axle loads. Pressures off highway, corrugated roads, sand, etc are reduced accordingly. For vehicles with an overall mass less than 6500kg, pressures may also be lowered but for a vehicle with a maximum weight of 6500kg, we recommend:

•  Highway @ 6500 Kgs.  Front 70-75 PSI  / Rear – 75-80 PSI
•  Dirt Roads @ 6500 Kgs.  Front 60-65 PSI / Rear – 65-70 PSI
•  Off Road / Mud @ 6500 Kgs.  Front 55-60 PSI / Rear – 60-65 PSI
•  Beach Sand @ 6500 Kgs.  Front 50-40 PSI / Rear – 55-45 PSI*

*  Lower pressures may be needed in very soft sand. 20-25 PSI but speed must be kept very low and tyres re-inflated when conditions clear.

A 285/70R19.5” tyre is 899mm high. When fitted to rims that track in the same line, this is the maximum size that can comfortably fit under the wheel arch of an Isuzu NPS without the scrub radius substantially interfering with bodywork and also allows the modified lower cab steps to remain in place when tilting the cab.

As a result of the increased rolling diameter of the 285/70R/19.5” tyres, overall gearing will be increased by 8% over standard. This is in our opinion the optimum for these trucks. Larger rolling diameters will only decrease bottom end power and braking efficiency.   

As mentioned, the tyre preferred by ATW for general offroad use is the Toyo M608Z. This is due to excellent aftersales and technical support, high quality products, availability and general performance in off-road applications. Other tyre options available in Australia in a 285/70R/19.5” size for 4x4 use are: Kuhmo KRD-02, Michelin XDE-2+, Aeolus HN-309 and the Goodride CM-986.

The main factors that led ATW into developing SWC’s using 19.5” tyres were based on real world experiences and feedback from commercial operators and numerous privateers. Prior to 2007 all our SWC’s were based mainly on 37” x 16” tyre packages. We had limited success with these on 4x4 vehicles that were downrated to under 4.5 ton but all of our other customers with slightly heavier trucks were plaqued with constant wheel failures, costly tyre damage and excessive wear.

Typically 16” and 17” rims available from wheel builders are originally designed for lighter vehicles such as LandCruisers, Patrols, etc. The gauge of the steel is so light that most will only give an 1850kg load rating. It is very easy to use thicker centre plates to build a stronger wheel but the outer rim will always be too light in our opinion. While theoretically this load rating is still adequate to be compliant for Australian road use it does not provide any safety margin for off road use. Once offroad a vehicle can placed be in many situations where the weight of a vehicle is transferred unevenly and loads on each wheel greatly increase. Corrugations and washouts add to the strain and fatique placed on wheels especially when asked to support up to 6 or 6.5 ton. New model Isuzu NPS’s and Fuso Canter’s have a rear axle load rating of up to 5800kg. Toyo M608Z tyres have a 2900kg load rating and ATW 19.5” wheels carry a 3000kg load rating. This means that the rear axle does not need to be downrated when using an ATW Single Wheel Conversion and you have a great safety factor for peace of mind.

As a result of this 2900kg load rating, the 19.5” tyres have a suitably strong sidewall. They do not undergo sidewall flex and deformation under typical high speed cornering on fast country roads that can be experienced with high and soft side walled tyres such as 37” x 16” and 37” x 17” tyres where body roll, mid-corner stability, braking, etc are noticeably affected.    

Regarding wheels, it should be noted that if a wheel has been built to an Australian or International standard it does not mean that a Single Wheel Conversion will be “legal”.  All vehicles in Australia will have a tyre placard stating the correct tyre size. For trucks you are only allowed a small tolerance within what is stated on the placard. If an individual with a truck over 4.5 ton fits  tyres bigger than stated on the placard without proper engineering compliance and the vehicle is involved in an accident, then the owner (not the seller of the wheels) could be liable for all damages or even face prosecution. So regardless of whether the wheels are built to an Australian standard, and regardless of whether the tyres and rims are load rated, if the size of tyre that the manufacturer of a “heavy” vehicle has stated on the placard has changed and proper engineering approval has not been obtained, then the truck no longer complies with ADRs. Vehicles at 4.5 ton and over are classified as “Commercial” and require Federal Approvals for changes to OEM components – the compliance plates/certificates are issued at State or Territory level but must comply to the Federal Rules. Many people who come out of light vehicle 4x4 are not used to these rules as they do not apply to light vehicles.

Before a truck manufacturer can introduce a new model, they have to undergo very strict tests on braking performance, speedo accuracy, noise levels, emissions, etcetera to prove that the truck meets all ADRs. Taller tyres effect many things especially braking. A truck with a “legal” single wheel conversion (and bigger wheels) still needs to meet the relevant ADRs. 

All ATW Single Wheel Conversions include modifications to the vehicles to meet all relevant ADR’s and carry either Federal or State Department of Transport engineering approvals. ATW has brake tested each model for which we hold compliance for at the vehicles full GVM – Approvals are on file with Federal Transport.

It should also be considered with a new truck fitted with a SWC, that if an issue arises in any part of the driveline, it will almost be certain that the truck manufacturer will not be held responsible. If a driveline issue occurs and is proven to be caused by the fitting a ATW SWC, then ATW’s Warranty policy will come into play. 

Recently, we have had several vehicles brought into our workshop with “illegal” single wheel conversions, officially put off the road until rectified. Expensive and could have been avoided with the correct information as contained here, of course it could have been worse if the vehicle was in an accident.

Our ATW sales team are always happy to discuss this information with you further, but don’t take our word for it, please contact your local Transport Department for clarity.

The ATW Team.

ATW 4x4 Truck Accessories

Ben Campbell - Tuesday, July 08, 2014

ATW 4x4 Truck Accessories

Have you ever wished your truck was a more comfortable vehicle to spend your day in? Ever wished for a bit more capability in the sand, more travel and ability off-road and on-road? Well the specialist 4x4 truck accessories from ATW are just what you need!  The accessory range from ATW is designed and developed to enhance both the on and off-road capabilities of 4x4 trucks from Fuso (FG637, FG649, FG84 and FGB71), Isuzu NPS (1990-2014), along with Single Wheel Conversions for MAN Isuzu FTS and others.

ATW’s developments in heavy duty off-road Parabolic Suspension Systems, Super Singles, Single Wheel Conversions and Helical Gear LSD, are a quantum leap forward in the conversion of the Fuso FG’s and Isuzu NPS into formidable off-road tourers and commercial trucks with a level of comfort normally reserved for high end 4x4 and SUV’s.

A few of the benefits of an ATW Single Wheel Conversion:

  • Wider and taller front tyres provide a larger footprint and added flotation to enhance off-road capability.
  • Same front and rear track means the rear tyres follow in the compacted wheel tracks of the front resulting in greatly improved off-road performance especially in soft sand and mud.   
  • Same front and rear track also promotes improved stability, handling and cornering at cruising speeds. 
  • Larger overall rolling diameter, which results in a smoother ride & better handling over corrugations and rough ground.
  • Same ATW rims used on the front and rear axles allowing scheduled rotation and also creates the same track.  
  • Inflation valves on both sides of ATW rims make inflating & deflating tyres easier, also easier access when tyres rotated. 
  • Eliminates the scenario of rocks caught between the dual wheels causing severe tyre failure and potential third party damage.   
  • ATW Speedo Re-Calibration Unit provides more accurate instrumentation.  
  • ATW rims are ISO tested and DOT approved at 3000kg for the 6.0 & 6.5 Tonne GVM vehicles.

A few of the benefits of an ATW Parabolic Spring Upgrade:

  • Improved flexibility
  • Parabolic springs will allow more axle movement due to their typical characteristics and lack of interleaf friction.
  • Improved stability & ride

Parabolic springs have a slightly higher spring rate. This, with the right shock absorbers, will give more stability and a better ride to the vehicle at all speeds, on or off-road.

ATW ATB Differential 

The ATW Auto Torque Biasing (ATB) Helical Gear Limited Slip Differential (LSD) is a direct replacement for the front axle OEM factory ‘open’ differential centres on all Fuso FG and Isuzu NPS. 

The new ATB differential is fully automatic and progressive in operation. Unlike conventional diff-locks and LSD’s, it will never lock but will seamlessly and progressively transfer power and torque away from a spinning wheel to the one with the most traction. This is the opposite action of an OEM ‘open’ differential, which in soft or loose conditions will promote wheel spin and loss of drive. In off-road situations, the ATB differential significantly reduces torque steer, under steer and steering ‘snatch’ associated with common clutched type LSD’s and air or electric diff locks. When off-road, this translates into reduced wheel spin (improved tyre life), virtually no torque steer and less under steer during cornering (improved safety and control), most importantly, it will greatly enhance performance and drive in soft mud and sand and therefore reduce the chance of getting stuck and the need for recovery. If one wheel is lifted from the ground so that there is no torque bias, the differential will revert to the same operation as an open differential, but simply tapping the brakes will be enough to regain maximum torque to the opposite wheel still in contact with the ground.

For the full rundown on these items and a list of national dealers and fitters, please visit the Accessories page.

ATW Tour Buses

Ben Campbell - Tuesday, January 21, 2014


The ATW 4x4 range of Tour Buses are purposely built so as to offer maximum viewing opportunity for all passengers. With large, heavily tinted windows and the rear of the 4x4 truck cab cutaway, forward and lateral vision is absolutely maximised. We have uniquely designed bodies that are shaped and designed for a purpose... ENJOYABLE off-road travel. 

It’s not until you experience the toughest four wheel driving conditions, that you will appreciate the innovations of an ATW Tour Bus.

As we construct so many beach vehicles that operate in extremely corrosive conditions, we saw the need to develop new fibreglass and composite construction methods. These composite modules are dent and corrosion proof, extremely tough and perfect for off-road commercial operations. The system consists of cross sections, or modules, that are joined together using high tensile bolts (only in certain areas) and MMA Structural bonding adhesive to finally assemble into a completed bus body. All modules are engineered and constructed from composite fibreglass, exceeding the strength of a conventional steel frame (no steel or metals are used). The seating numbers are determined by how many modules are needed to finish up with the required number. Each module is totally finished with seats, glass, flooring, wiring etc, so after the final assembly process there is very little work left before the bus can be put into service. These modules or sections can be easily shipped in a container to even the most remote of countries for easy assembly on their designated local truck chassis by supervised unskilled labour. 

The ATW Tour Bus body is an extremely low maintenance, long term asset that will save a business thousands of dollars over a 10 year period or longer when other 4x4 vehicles would need to be completely replaced many times over.

ATW have tour buses that have operated for many years in the extreme climate of Central Australia, others continuously running on the horrendous road conditions of Cape York and lasting over 12 years on the beach at Fraser Island, all with glowing reports of the superiority of our construction methods over previous vehicles with conventional metal clad bodies. 

Available in 4 different models from 12 to 37 seats and all are available in a variety of trim levels from budget commercial packages to VIP eco-tour operations and purpose built for any specific environment or terrain; day tour, overnight or extended tour, etc.

Up to 22 persons with a 2400 mm wide body
Available for MWB Fuso FG 84 DE and Isuzu NPS300.

Up to 38 persons with a 2400 mm wide body. 
Available for most LWB 4x4 and 6x6 cab chassis above 10 ton GVM.

ATW Customers

Ben Campbell - Wednesday, December 04, 2013

would you know if you were looking at an atw bus?

Over the past 25 years ATW have manufactured buses and supplied specialized accessories for a wide range of companies and their individual requirements. You have probably seen them all over the country and internationally without knowing it. Below is a list of the companies who we have had the pleasure of supplying vehicles to. As you see there are quite a few of them and the industries they cover are as individual as our buses…

Mining Transportation:
FK Gardiner
Europe Car
Transpec – Raptor Buses
BHP Iron Ore
BHP Billiton
Mine Vehicles Australia
Mitsubishi Buses
Isuzu Buses
MAN Buses
Downer EDI
Pangaea Resources Pty Ltd
Atlas Drilling
Murphy Pipe and Civil
Balunu Foundation
Down Under Tours
Fraser Island Adventure Tours
Outback Spirit Tours
Adventure Tours
Discovery Tours

Specialist 4x4 Accessories:
Total Drilling
New Hope Coal
Qld Parks and Wildlife
Fortesque Metal
Mt Gibson Iron 

With such a wide range of uses and capabilities the ATW Bus and Accessories range is bound to have the right fit for you and your business. Weather you would like an “off the shelf” standard shell fitted to a chassis, or a fully specced up go anywhere beast we can make it happen.


Testing Times

Ben Campbell - Wednesday, November 27, 2013

Testing times at AtW...

After 3 years of development work, we have spent the last 12 months manufacturing and testing a completely new lightweight composite modular system for our bus bodies. As with any new vehicle introduced for road use in Australia, it has to undergo and pass stringent Federal Transport testing and evaluation, in order to be allowed on our roads.

R.O.P.S testing (Roll Over Protection System) ADR 59

The lightweight composite modular system has been tested for Full Volume Approval (not restricted to 100 vehicle / year as is Low Volume Approval). To meet these regulations you are required to physically roll over an entire loaded bus to prove it can withstand such an impact without coming in contact with on board seated / seat belted passengers.

The test requires that the vehicle is complete. The body chassis with seats, glass etc. loaded to whatever seating kgs are required, minimum 65kg / person, luggage weight 15kgs / person, fuel weight, air conditioner weight etc. The bus is then placed onto a platform that is a minimum of 800mm high and hinged on one side. The whole unit is then tipped off, sideways. The impact simulates a bus during a roll over, 800mm from the ground, as it would be if airborne during a real roll over.

The bus seats are fitted with foam styrene templates at various locations across from the roof supports simulating the body and head position. The templates have long pins inserted through the styrene at set measurements from the side roof supports. The amount of deflection of the body is shown by how far the pins are pushed into the styrene foam templates during impact. High speed cameras capture the roll over from three different angles, front, rear and internal.

The ATW Composite Fibreglass body passed this test with ease and even allowed us to re-use the body for further testing as it was perfectly straight and unaffected from the roll over test.

Seat anchorage test ADR 68

Federal Transport requires a section of a bus body where the seats bolt to the floor and walls to be tested for strength. This test is for the floor mounts and wall mounts of the bus body, the seats have already passed their individual test for strength previously. As our lightweight composite modular system is an Australian first for this industry, we had to approach it very differently from the norm. The test required us to test a complete bus module section with 16 seating positions, with 14 seat belted and 2 without seat belts which is for gathering multiple test data. The bus section is placed on a sled and brought up to speed of 50 klm/hr. and stopped in milliseconds, simulating a head on crash at 20+ G’s of force subjected to the entire bus body section. The results from the APV test Centre in Melbourne were nothing but astounding.

The comment that the ATW lightweight composite modular system had the best results ever witnessed for sheer strength of the body was very pleasing indeed.

The ATW lightweight composite modular system is set to revolutionise the Mining Bus market, but will also be an ideal option for other industries and areas such as Tour Buses, Armed Services Vehicles, Mobile Lunch Rooms, Mobile Show Rooms, Mobile Healthcare Units, School buses, Government Vehicles, Indigenous Community Buses, Adventure Tours, Remote Vehicle Based Offices, the possibilities are endless.

For more information on the new lightweight composite modular system please contact our sales team on 1800 468 590.

All Terrain Warriors – ATW

Ben Campbell - Tuesday, August 20, 2013

Mine Buses, Luxury 4x4 Motorhomes, Tour Buses and 4x4 Accessories

Welcome to All Terrain Warriors – ATW online. Please take some time to have a look around the new site and view the image galleries of our products. If you are on Facebook and visit YouTube, please Like Us and Follow us on both platforms. This will ensure you are kept up to date with all the latest news from ATW.

In the coming months there will be some exciting changes in the ATW range of products and services. We have been conducting ROPS testing on the new Lightweight Modular Bus System. The initial testing has passed with flying colours and the next series of certification has started. We are very excited to bring the future of bus building to the Australian market.

ATW offer a full range of heavy duty 4x4 options covering the Mining, Expedition and Touring market.

The ATW 4x4 buses are renowned worldwide for their safe operation, sturdy and long lasting construction, operating in extreme terrains and highly corrosive environments. All vehicles are based on Japanese or European 4x4 truck chassis that are commonly available through existing dealer networks and incorporate specially developed passenger modules by ATW. The all new Lightweight Modular Bus System is about to take this market to an exciting new level of strength, safety and comfort.

If it’s the Expedition market you are interested in – we have the mighty Global Warrior Motorhome Conversion in full production at the moment. The new Global Warrior is a product we first began to develop nearly 2 years ago. We have settled on the base specification for the Global Warrior as being the most practical configuration to be taken comfortably into a remote location for extended stays. Our options list includes specialised equipment to tailor your vehicle to suit more specific travel requirements. As an example,  a fisherman in the Kimberlies would hardly need the high-tech heating system of a vehicle crossing Siberia! Our options and improvements will be added to in time as constant improvement is what ATW is all about

Our current ATW Accessories range to suit the Isuzu NPS 300 or Fuso FG Canter is available for the new Global Warrior. As an added benefit we are offering a 10% discount on selected ATW Accessories that are ordered in a package along with the new Global Warrior.

For further details please contact:

Our 12 to 37 seat 4x4 buses and coaches have been doing us extremely proud for over 20 years. ATW 4x4 range of eco-tour buses are purposely built so as to offer maximum viewing opportunity for all passengers. With large, heavily tinted windows and the rear of the 4x4 truck cab cutaway, forward and lateral vision is absolutely maximised. We don’t just build a square box with seats and mount it to a chassis as if it were a pantec and call it a bus - we have uniquely designed bodies that are shaped that way for a purpose… off-road travel where YOU are able to enjoy the experience. Constant upgrades and improvements to the ATW range of Buses ensure the ATW range remain the best value 4x4 buses available in Australia.

ATW Wheels, Suspension & Accessories have been specifically developed for common 4x4 cab chassis to enhance both on and off road capabilities and general operational performance. All of these products are well proven and are put to the test daily over some of the most horrendous roads and bush tracks in the country... some for over 20 years.

Thanks for checking in with us at ATW and please contact us for further information. Happy travels!

The ATW Team.