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The Ultimate Ute Chassis Extension Guide for Dual Cabs

The popularity of getting a Chassis Extension for 4WD utes like the Toyota Landcruiser, Toyota Hilux, Ford Ranger, Isuzu D-Max and Mazda BT-50 has exploded over the last year here at Trayon Campers.

Toyota Landcruiser 70 Series Dual Cab - Chassis Extension
Landcruiser Chassis Extention – Dual Cab Ute with Fullsize Trayon Camper

Perhaps it is fuelled by more and more people deciding to travel nationally instead of internationally, we aren’t 100% sure.

One thing is for sure though, a chassis extension can significantly improve vehicle handling under heavy loads, while also increasing towing stability.

Pair that with a GVM upgrade, you can also carry more with a higher payload and larger load area. So it does make sense if you are towing or carrying more than your typical 1-tonne ute on a consistent basis.

There’s also another huge advantage specifically for Dual Cab 4WD utes that not many people are talking about.

In this article, we aim to provide a full guide to 4WD ute chassis extensions for dual-cab utes in Australia. The why, the how, the pros, the cons and the price.

We’ll talk to expert Hugh Ager from Limitless Chassis for his trusted insights on the process. He lives and breathes chassis extensions every day.

What is a Chassis Extension?

A chassis extension is where a licensed engineer cuts the chassis of a vehicle and welds in an additional steel segment to extend the wheelbase. Usually, this also involves extending wiring harnesses for sensors and lights, while also extending drive shafts.

Ford Ranger XLT Dual Cab - Chassis Extended
Ford Ranger XLT Dual Cab – Chassis Extended

Sometimes it might also require making modifications to the body of the vehicle. However, when extending cab-chassis utes this is not commonly done.

Who is a Chassis Extension for?

Hugh said, there are basically two types of people who want one (and it’s about 50/50% split):

The first one is, “I want to extend my chassis because I want a bigger camper”,

And the second one are people who think: “I want to keep the same size camper/load, but I want to make it safer to drive by getting the weight balance correct and getting the braking correct.”

Typically at Limitless Chassis, we do a smaller extension for those guys and a bigger extension for the guys who want the big trays.

So, from this we have determined that a chassis extension is for two primary kinds of applications:

  1. People who want to increase towing stability under heavy loads without spending big on American pickup trucks like the F250. This includes
    • Horse floats towing
    • Tradies or needing to tow for work
    • Caravaners to increase stability, especially large caravans 2.5 Tonne+
  2. People who want the room of a 2100mm long tray (add a full-size canopy or slide on camper) as well as the benefits of a Dual Cab vehicle. This group are looking for:
    • Still have a 5 seater vehicle
    • Maximising load area for a full-size single cab slide on camper or canopy
    • Have a more stable, comfortable ride while travelling long distances on sealed and unsealed roads while still having good off-road performance

We like chassis extensions at Trayon because it more evenly distributes the load area to be closer to the centre of the wheelbases by moving the rear axle toward the rear.

Hugh mentions that for these two types of people you want to give them a short extension, just to get the wheels under the middle of the tray (or as close as possible).

That pushes the weight closer toward the center between the two axels, which is ideal.

The exact length to do that varies from vehicle to vehicle. We discuss lengths below.

Here is a graphic demonstrating how the weight distribution of the load has a big part in affecting your handling (braking, steering and traction).

slide on camper weight distribution

It should be noted that the entire Trayon Camper range is specifically designed to even out the weight distribution on the wheelbase. We do this by placing all the heavy items (Battery, Fridge, Water Tank etc) as close to the center of the wheelbase as possible.

This graphic demonstrates the weight distribution of our campers on the three ute configurations.

Trayon Camper - Weight Distribution


The Pros and Cons of a Chassis Extension

Every modification to your ute will inevitably have Pro’s and Con’s that you’ll have to weigh before you rip into the manufacturer’s engineering. Particularly those which impact the vehicle structurally.

It’s no small feat to lengthen the chassis and maintain all the proper geometry and functionality of the vehicle. So it’s important you do it with an accredited specialist engineer.

It’s becoming more popular to get a chassis extension for 4WD dual cab variants of vehicles like the Ford Ranger, Toyota Hilux, Landcruiser 79, Isuzu D-Max, Mazda BT-50, and the Landcruiser 200-300 series models.

The main reason why people are getting dual cab conversions:

A chassis extension allows you to keep the benefits of having rear seats and more cabin storage of a dual cab ute, while also having a full-size aluminium tray of a single cab.

It removes the trade-off between the two.

Here are some Pro’s and Con’s to consider for chassis extensions.

Pro’s

  • More space in the tray
  • A longer wheelbase provides a more comfortable and stable ride while fully loaded or empty
  • A more even weight distribution over the wheels provides better handling
  • 4-door vehicles will make better use of the cabin space without sacrificing tray space and pushing the tray load past the rear axle
  • Climbing hills without too many changes to vertical angle will feel more planted to the terrain
  • Driveshaft angles are better thus improving the life of the drivetrain
  • A longer wheelbase provides more stability while towing, minimising the chances of trailer sway
  • Departure angle improved in most cases
  • More space under the tray to install water tanks or long-range fuel tanks

The Towing Advantage

Just to illustrate the improvements to towing; Picture this if you are towing a 3.5 Tonne caravan, a short wheelbase is easily manipulated if the caravan starts to fishtail or sway.

Whereas a longer wheelbase reduces sway. This is why it is stable towing in a 4 Meter long Ford F250 compared to a Suzuki Jimmny.

Con’s

  • Small increase in turning radius
  • Small reduction in the break over angle
  • Sharp turns on a narrow track will need to be taken with a bit more care to ensure body panels aren’t damaged by branches, tree trunks or rocks.
  • If you go too long, and your wife takes your ute to the shops, she may not like it.

How long is too long?

Generally speaking over 500mm and the vehicle does become quite cumbersome. Anything longer than this is usually for a very specific reason. Like carrying something specifically long.

We asked Hugh, at what point would someone consider a 6×6 conversion? And he said, the only reason you would consider a 6×6 is that you are going to carry some serious weight.

Keeping in mind that the maximum GVM you can have on a Car license is 4495 kg. So with a 6×6 may end up exceeding that, so you would need to register it as a light truck.

We also think, that an extra set of wheels, suspension, brakes, axle and driveshaft with a 6×6 is more to potentially go wrong when you are in the middle of nowhere.

What about going to the shops?

Hugh puts it this way – the only real issue is if you go to long and your wife has to take your big ute and park it down at Woolies, she may not like it because you’re making that big ute even longer.

The length of the vehicle can become problematic and cumbersome when parking in shopping centres which are usually smaller than normal car spaces. When you are driving down a tight lane and you have to turn into a space it may take a couple of back and forwards to get in.

Hugh’s wife drives a ute with a 450mm extension and just parks in a space at the end of a row where you can just drive straight in and straight out.

Where there is a will there’s a way.

Is the Turning Radius Increase a Deal Breaker?

Although there is a turning radius increase, most of our customers who get a chassis extension don’t really notice it. For example; if a customer gets a chassis extension for their dual-cab GXL Toyota Landcruiser 79 series,as stock before modification it already has a sub-optimal turning radius that many say is similar to that of a barge. So you barely notice it.

For the other vehicles with independent front suspension, you don’t really notice it unless you go above the 500mm length. That’s when they start to become more cumbersome.

Check out the section below about how a chassis extensions impacts off-road performance.

How Will It Affect Off-road Performance?

There’s no definitive number for wheelbase length that equates to a reduction in off-road performance. It really depends on your intended application.

Think of your shoes, it’s best not to run a marathon in steel toe work boots right? Therefore you must keep this in mind when off-roading and determining what wheelbase is best for you if you intend to do serious off-roading tracks.

We do think though that the reduction in 4WD capability is generally less dramatic than most people think. And that most people will be driving on beaten track more often than not given the size of Australia.

Even so, we wanted to ask Hugh directly how a chassis extension can impact the 4WD performance.

More specifically we wanted to ask how it affects the break-over angle.

He said, “So the theory behind that is correct, obviously. You’re physically making the vehicle longer so that it can get breached in the middle more easily. The reality is no one actually does that type of four-wheel driving. We use two of our demo cars for extreme, like seriously extreme, some of the toughest tracks in the country, and we’ve never once had the middle belly out.”

He goes on to say, “You’ll more likely get hung up on the back of the vehicle. So the longer the tray hangs out the back, the worse it is off road because that’s always the bit that gets stuck.”

This is the dilemma with many Dual Cabs off the factory floor. He says: “So an extension improves your departure angle, it does reduce your break over angle/ramp over. But like I said, the only time you find them to belly is at the top of a sand dune, if you’re actually climbing sand dunes. But again, all cars struggle there because it’s super soft and aggressive terrian.”

Sand Dune Illustration

I went on to ask which tracks they have done, and he was specifically talking about Litte Red in the Glass House Mountains in QLD and basically any track on the Cape York track.

Although break-over angle, in theory, is an issue, it’s not that big of an issue for 95% of people who don’t do hardcore offroading. And for those that do, they would most likely be upgrading to lifted offroad suspension, have larger tires, a locker or two, recovery gear and be travelling with another vehicle to help get them out if they do get stuck. So the break-over angle issue is negligent.

The line you choose may differ from someone in SWB vehicle on rocky and narrow tracks. But a chassis extension less than 450mm shouldn’t make your vehicle too big for most of the track. However, if you extend your vehicle longer than that you will find on really narrow tracks that you’ll have to swing wider to maneuver around trees. Hugh mentions that in this situation it is very similar to driving a camper trailer off road.

Typically, our customers have campers on the back and set their vehicle up as a touring vehicle for long-distance travel with a chassis extension no more than 450mm. So the benefits of better weight distribution, the ability to add long-range fuel tanks and having a more comfortable ride outweigh the break-over angle reduction.

We believe that if your goal is to set up a touring vehicle for long-distance travel + off-road tracks the advantages outweigh the con’s if you have the budget to do it (more on that below).

Should I get a GVM Upgrade as well?

Okay, so you don’t NEED to get a GVM upgrade to get a chassis extension. However, if you plan on buying a vehicle new, then we absolutely recommend getting a second stage manufacturing GVM upgrade before you register it.

Because once you have an extended wheelbase, it does become much easier to overload your vehicle if your payload remains the same and the load area increases.

If you order a vehicle and camper through our turn-key vehicle service, we can organize that for you.

There are aftermarket GVM upgrades available, however, usually, the GVM increase is less than if you were to get one prior to the first registration.

Hugh put this well: “If you’ve got a bigger tray, you’re going to put more stuff on it.”

So although not required in any way, it is a good idea to do a GVM upgrade as well.

Landcruiser 79 Series dual cab wheelbase extension

Wheelbase extensions are nothing new in Australia. Particularly for the dual-cab Landcruiser 79 series.

With many of the Dual Cab utes factory wheelbase carries heavy loads in a less than ideal way. However, with the dual-cab Landcruiser 79 series, the factory wheelbase is far too short. This causes it to put too much weight past the rear axle, which not only puts undue strain on the chassis when carrying heavy loads, it also lifts the weight at front of the vehicle up, which affects handling.

79 Series Landcruiser Dual Cab - Chassis Extension
79 Series Landcruiser Dual Cab – 450mm Chassis Extension (Chassis Correction)

So a Chassis extension is seen as a “correction” of the design to enable a more comfortable ride while carrying heavy loads to restore handling and correct load distribution.

Why Get a Chassis Extension for a Touring Vehicle?

Touring vehicles are not built with one thing in mind unless that one thing is everything. The goal is to get you, your loved ones, your gear, sleeping arrangements, family, and or course food and water, to the next destination regardless of the terrain. But mostly sealed & unsealed roads with some off-roading in-between if you live in Australia.

When you think about it, it’s a pretty tall order for ute manufacturers.

The question is can you carry what you need (or want) within your payload and storage volume. A 4 door vehicle is much more flexible in terms of storage, and you can still use it to take someone to the airport or drop the grandkids off to footy.

Let’s go over two popular ute’s that our customers choose often to receive the extension process quite regularly. The Dual Cab Ford Ranger and Toyota Hilux

Ford Ranger Chassis Extension Example

Many of our customers use the Ford Ranger Extra cab because it still has a little space in the back for small passengers and luggage while allowing them to have a full-size Trayon Camper on the back with a 2100mm aluminium tray.

This vehicle is ideal if you don’t carry passengers often. Yet still have room for in-cabin storage and seats to drive someone to the airport now and then.

However, if you want the extra space of a 4 door ute, while having a full-size camper on a 2100mm tray, you’ll need a chassis extension. The following example shows the difference between a Ford Ranger extra cab vs a Dual Cab with a chassis extension (exact same model and year).

The Ranger Dual Cab will give you all the comfort of a four-door cabin and the ability to take the family along as well. If you decide to apply the 450mm chassis extension and a 2100mm aluminium tray, you’ll be able to utilize a full-size camper while having the durability and stability of a longer wheelbase. It’s the best of both worlds.

Before (top), After 450mm Chassis Extension.

Details:

  • 2021 Ford Ranger Dual Cab XLT
  • 450 mm stretch in the wheelbase
  • 2100mm tray
  • With a Trayon 1980 (Trayon Model)
  • Key difference is the Ford had a longer wheelbase to begin with

Toyota Hilux Chassis Extension Example

A Toyota Hilux Dual Cab receiving the same treatment goes from a 4275mm chassis to 4725mm and allows a full size 2100mm aluminium tray to be installed. Carrying a full-size camper will give you a lot more room so you can go further into the outback and keep all the necessities tucked away nicely.

Toyota Hilux Dual Cab Chassis Extension

Full Turn-Key Build, including custom tray, 4×4 accessories and full-size Trayon Camper:


Details:

  • White Dual Cab Toyota Hilux SR
  • 450 mm stretch in the wheelbase
  • 2100 Tray
  • With a Trayon 1980 (Trayon Model)

When you compare the Hilux and Ranger from a side profile that the rear axle sits further to the rear of the tray then it does in the Hilux. Which is a good thing, because it allows more weight to be in the centre of the wheel, with the tray on having its 75% weight profile to the front.

Will a Chassis Extension Void my Warranty?

We wanted to directly address the elephant in the room when doing such a major modification to your ute. “Will it affect my warranty?”.

So we asked the expert Hugh on this: “So, the answer to that is no, it doesn’t. We’re in the same boat as any other modifications. So whether it’s a bull bar from ARB, or a suspension from Ironman. Whatever part we physically touch, we carry the warranty on.”

Since they don’t touch the gearbox, the engine, the differential all of that get’s covered under the manufacturer’s warranty.

Keep in mind, that Hugh and his team are completely accredited with ADR approval. ADR approval is national for being incredibly stringent, even more so than the manufacturers.

Have you had any Customers with Warranty Claims?

Hugh said, “Yeah, we’ve had a few customers that we know who have had warranty claims, and they’ve all had no issue with the manufacturer allowing the warranty claim, paying out, fixing the problem.”

What about Electronics?

So, when you extend the chassis, there is usually one or two small wiring harnesses that go toward the rear of the vehicle which includes tail lights, sensors etc.

And of course, if something happened to the electronics it could potentially damage the computer or cause a fire.

Hugh says: “We know all cars have such temperamental electronics these days, we don’t actually cut wiring harnesses. A few guys out there cut harnesses. We don’t cut them, we just reroute them in a different route so they can still reach, but they don’t have to be modified. so there’s no question over any electronic issues, because we haven’t touched a wire. We pride ourselves on keeping everything as standard as possible so we don’t have any issues with warranties”

Is it Certified?

Hugh answers: “All our work fits within ADR and state laws. Because each state has different laws and in QLD we provide a blue modplate, whereas in NSW it’s an engineering certification”

What Warranty do you Carry?

We asked Hugh, since you are modifying the Chassis, do you carry the warranty on the Chassis? And he brought up a good point.

Although chassis damage is rare, he said: “The backs of them have snapped in standard form, but obviously we’re fixing that problem. So basically we’re trying to fix the issue that the manufacturer won’t warrant the rears of the chassis. So the whole point of the chassis extension is to create a warranty. We are the warranty for that, basically.

But besides the workmanship, it carries a five year warranty on the chassis. And then stuff like your other bits and pieces have got different warranties like tail shafts, and bearings, and brakes, and this, that, and the other.”

However, keep in mind that it is a case by case basis.

How Will It Affect Overall Vehicle Length?

Interestingly, getting an extension doesn’t proportionately increase your overall vehicle length.

For example, if you get a 450mm chassis extension, it doesn’t necessarily mean your vehicle will be monstrously bigger than equivalent sized vehicles from the front badge to the end of the tray.

Consider the picture below.

Super Cab vs Dual Cab Extended

On the right is a Ford Ranger XLT Super Cab, and on the left is a Ford Ranger XLT Dual Cab with a 450mm extension. Identical year and colour. Both have a 2100mm long aluminium tray fitted.

Yes, the dual-cab is longer than the end of the Tray, however, it is only 300mm longer than the Super Cab.

So from a Dual cab with a chassis extension, with the same size tray as a super cab, you are looking at only a 30cm difference in overall length. That is not because the chassis has been extended or the wheelbase is longer, as all those things are done under the tray.

As long as these things don’t protrude past the tray, it won’t be the longest point. The longest point other than the cab itself is the Tray.

So that’s 300 millimetres difference in cab size between a Ford ranger super cab and a Ford Ranger dual cab.

What is the Cost of a Chassis Extension?

As with any heavy modification to your ute, the cost will be factored into choice. A chassis extension is not as costly as some might think.

The cost is determined by what vehicle you want to extend. Many of the alterations require vehicle-specific parts etc.

Mid-range utes such as the Ford Ranger and Toyota Hilux have a history of being extended so the process is a bit more refined and range from 7500AUD – to 8500 AUD (estimated) for a 450mm extension depending on the options you choose.

Each vehicle will be different as well, Hugh says that, for example, a Isuzu D-Max will be a bit more expensive than a Ranger because it comes standard with one-piece tail shaft, whereas the Ranger has a two-piece tail shaft. So depending on how long you go, you might have to convert to a two-piece tail shaft.

Remember that it’s not as simple as cutting and welding the frame. Everything to the rear of the chassis extension point will need to be lengthened.

So as you can see, it is much cheaper than say upgrading your vehicle.

Hugh says, “The way we look at it is: a two-inch lift kit, and a set of mud ties won’t get you as far as an extension, but it will cost you more than an extension will”

Meaning, “You won’t benefit as much if you went out and bought mud tires and a suspension lift, you still cannot carry more weight or drive more safely. Yes, you could get further off-road in the dirt, but if you did a wheel based extension, obviously you could carry more load, drive more safely, you would notice a bigger difference from a wheel based extension for the same cost.”

What is the Process of a Chassis Extension?

Hugh mentioned that is actually a pretty straightforward process. He said, “Normally takes five days. Basically, a day to strip it down, two to three days to do the extension, a day painting, and a day to put it all back together again.”

He goes on to say that “we’re all qualified welders, and we do way higher quality welds than the factory does.” and we chalk that up to Robots in a production line.

“But also the whole point of the ADRs is that it’s complete overkill, that you’ve got to totally over-engineer this”

“We just basically go above and beyond. Because at the end of the day, I don’t want to see you again.”

“So we make sure that it’s far stronger. For instance, a 300 mil chassis extension, which is obviously only 300 mil long, around about 1500 millimetres worth of metal will be made to cover that 300 mil piece.”

What type of Metal do you use?

“We use high tensile steels according to the chassis. There’s a lot of guys that just use normal steel on them, but we’ve done material analysis on them and we know exactly which chassis is made from which material and which place, and we match that material to that chassis.”

In Summary

A Chassis extension is one of the best mods you can do to your ute to increase handling, load area, towing performance and overall safety. This is especially the case with Dual Cab utes where typically the rear wheels are not in the centre of the tray and there is a large overhang to the rear.

By extending a Dual Cab 4WD you get the best of having a 2100 mm tray on an extra cab AND a 4 door cabin. Pair that with a GVM upgrade and you can carry more as well with little impact on off-road performance.

We have found that the ideal size is around 450mm for the Ford Ranger, Toyota Hilux, Landcruiser 79 Series and Isuzu D-Max. Anything longer than that can become cumbersome.

Want Your Own Capable Touring Vehicle?

Trayon Campers Turn-Key services bring all our knowledge and experience to creating a very capable touring vehicle for you. So you don’t have to spend hours of research, getting quotes and vehicle transfers. We handle everything from:

  • Sourcing The Vehicle (fleet purchase)
  • Second Stage Manufacturing GVM Upgrade (pre-rego)
  • Chassis Extension
  • Aftermarket accessories (Bullbars, Snorkels, Winches, Roofracks etc) – based on your preference
  • Adding your Camper or Canopy

We Bring it all together to give you a Turn Key touring vehicle without the overwhelm of choosing between thousands of options.

We know what works with over 25 years of touring experience in the harshest, most remote terrain Australia has to offer.

lack Dual Cab Landcruiser 79 Series - Chassis Extension
Trayon 79series Dual-cab 450 stretch Turn-key

To learn more about our turn key options click here.

This article was lovingly written by the Trayon Team with the help of two well-known industry experts for chassis extensions. Hugh from Limitless Chassis in Coolum.

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