4wd Rims and Tyres explained – Rims

Cooper Tyres Prado - Fraser Island

4wd Rims and Tyres

How often have you talked to a 4wd enthusiast about their 4wd rims and tyres? Have you managed to make head or tail of what they say?

Have you ever seen a post on a forum asking for advice about what 4wd rims and tyres to run? The strings of numbers that people come out with are sometimes harder to follow than the ideas of Sheldon Cooper from the Big Bang Theory!

If I said to you that “My 4wd rims and tyres are a set of 285/75/R16s on a 16 x 7.5 steel rim with a +10 offset” (which I don’t by the way) would that send you stark screaming crazy?

If that sounds like you then read on and maybe I can clear some of it up for you. Firstly, lets start with 4wd Rims.

4wd Rims Explained

So firstly lets start with the basics. There are essentially two types of 4wd rims; Alloy and Steel.

The difference between Alloy and Steel Rims

Alloy and Steel rims are pretty easy to tell apart. Most modern 4wd rims now days are alloy. With the movement towards soccer mums and urban four wheel drives that never leave the bitumen, alloy rims have more visual appeal. They’re usually silver and shiny and look nice. According to Drive.com.au and Jax Quickfit Tyres, the main differences between alloy’s and steelies are:

  • Alloy rims are made of lightweight metal alloys (hence the name)
  • Because they’re lighter, they have less rotational resistance and therefore allow the vehicle to accelerate faster
  • Alloy wheels shed heat better than steel wheels
  • Alloy rims tend to be stronger
  • Alloy rims have a lower melting temperature.
  • Alloys are usually much more expensive

Another thing to keep in mind when 4 wheeling, is that if you damage an alloy rim, then it may be more difficult to repair out in the bush. Or in fact at all. On the other hand, if your steel rim is dented or deformed, then you can generally tap (bash) it back into shape.

So what’s best for us 4wd enthusiasts? Well that’s up to you really. 4wd Action have compared alloy vs steel rims. The article  goes into a bit more detail to help you make up your mind.

What does Stud Pattern mean

Very basically, the stud pattern of a rim is how many nuts you have to undo to change your tyre. Most 4wd rims have either 5 or 6 studs, or nuts, that hold them on. Understand? Pretty simple really, right?

Well there is actually more to it than just that. A stud patter is expressed as two numbers.

So for example, on a rim that has an even number of bolt holes, a stud pattern of something like 6 x 125 would mean that there are 6 bolt holes and the distance between the centres of opposite bolts is 125mm.

On a rim with an odd number of bolt holes, for example 5 x 125, there are obviously 5 bold holes. But the measurement of 125 is taken from the back side of one bolt hole, to the centre of the most opposite bolt hole. Confused? Take a look at the pictures. They’re worth a thousand words. Thanks to Wheel-Size.com.

6 bolt stud pattern – Measure from centre to centre

5 bold stud pattern – Measure from the back of one to the centre of the most opposite one

 

Wheel Bold Patters

4wd Rim size

The size of your Rim is measured usually in inches and is made up of two parts. The diameter and the width. So in the example at the very top of this page, I mentioned a Rim size of 16 x 7.5. This means that the diameter is 16 inches, and the width is 7.5 inches. That’s not to difficult either right?

Rim Offset

Rim offset is a measure, in millimetres, of the distance between the hub of your rim (where it actually mounts to your car) and the centre line of your rim. Why are diameter and width measured in inches, where offset is measured in millimetres? No idea. If you find out then please comment below!

So imagine you’re looking straight at your tyre as it’s rolling towards you. You’re looking at the tyre tread. Imagine a line drawn from top to bottom, splitting the tyre in two, length-ways. The offset is how far away your hub is from that centre line.

Rim Offset Diagram
Rim offset – http://kgm.tiwing.com/calcs/offsetcalc.htm

There are three kinds of offset.

  • Positive offset – A positive offset means that your hub sits outside the centre line if your rim. Effectively this pulls your tyres back in towards your vehicle. It also makes the rim appear ‘flatter’ from the outside.
  • Zero offset – A zero offset means that your hub sits exactly on that centre line of your rim.
  • Negative offset – A negative offset means that your hub sits inside the centre line of your rim. So closer to your car. This effectively pushes your tyre out away from your vehicle giving your car a wider stance. Your rim will appear more ‘bucket-like’. Or hollow.

The image to the right shows this perfectly. Note that the right hand side of each rim in the picture is the outer side. The one that you’d be able to see if it were on a car.

4wd Rims

That basically explains 4wd Rims for you. Hopefully you’re a little less confused about the whole thing now. If I say to you that “I run a set of 285/75/R16s on a 16 x 7.5 steel rim with a +10 offset”, at least you’ll be able to decipher half of it now.

Take a look at my article about Tyres. Then you’ll be a full bottle!

 

*Featured image – Cooper Tyres Prado – Fraser Island

MaxTrax Paper 4wd Models

MaxTrax Paper 4wd

While cruising around the internet the other day, I stumbled across the coolest thing. The awesome people at MaxTrax have provided us with a way to pass an hour or so of time when we’re not out in our exploring.

And I’m talking about their paper 4wd models! What a great idea!

MaxTrax have created two downloadable PDFs that you can print on your home printer. You then get out your scissors and glue and a bit of patience and start creating.

There is an FJ Cruiser with optional bulbar and spare tyre on the back, and a twin set of MaxTrax. There is also a 100 series Land Cruiser with a bunch of accessories such as dual spare tyres, a snorkel, and awning, a bull bar, a rear bar, spotties and shovels.

Both models used to be available from the MaxTrax website below. But they don’t seem to be around anymore which is very sad.
http://www.maxtrax.com.au/maxtrax-fj-cruiser-paper-model

I decided initially to put the FJ Cruiser together because it looked simpler. I’ll do the 100 series cruiser next. If you’re going to have a go at it then here are a couple of tips.

  1. Print the PDFs in colour. I really can’t see the point in making black and white ones, right?
  2. Print onto good quality paper. Or even something a little thicker. Not quite cardboard, but whatever goes through your printer.
  3. Cut accurately. I accidentally cut part of the rear bumper off my FJ Cruiser. Not really a big deal but if you’re going to go to all that effort, then you want it to come out OK.
  4. Take your time and do it right. Once again, if you’re going to do it, you may as well get a good result.
  5. Have fun!

Here are some photos of my end result. I’m pretty happy with it!

MaxTrax Paper 4wd

MaxTrax Paper 4wd

MaxTrax Paper 4wd

Mitsubishi Super Select 4wd and Super Select II

Mitsubishi PB Challenger water crossing

Super Select 4wd and Super Select II

Mitsubishi’s answer to off-road driving comes in 3 flavours; the Pajero, the Triton and the Challenger. They are all very capable vehicles with some obvious differences. However somewhere between the engine and the wheels, there is a key element that Mitsubishi has included on all of the 4wd options of these 3 vehicle models. And they call it the  Mitsubishi Super Select 4wd system. The super select 4wd System is differnt from the Mitsubishi All Terrain Technolgy (MATT). MATT incorporates systems such as Active Stability Control, Traction Control and ABS, whereas the Super Select 4wd system allows you to select your driving mode based on the terrain you’re driving on.

The Super Select 4wd system provides you with 4 driving options to suit terrain and road conditions. Note that some of the models listed above are also available in a 2wd configuration. Super Select 4wd is obviouly not available on 2wd models. However MATT is.

Super Select 4wd driving options

Mitsubishi Super Select 4wd offeres 4 driving options. SuperSelect II is basically the same. These are:

  • Super Select 4wd 2H2H – Two wheel drive, high range. In this mode, the front wheels are completely disengaged from the drive train. All engine power is directed towards the rear wheels. This mode is said to be the most fuel efficiant and causes the least wear and tear on the vehicle’s drive-train. It is recommended for use on dry, good quality, sealed roads
  • Super Select 4wd 4H4H – 4 wheel drive, high range. 4H connects the front wheels to the drive train through a viscous coupling unit. This means that there is no physical connection between the engine and the front wheels, but power is delivered to the front wheels to assist with traction on wet or slippery roads. This mode is recommended for use in slippery conditions on sealed roads, or on good quality tracks. It can be used on dry, sealed roads with no adverse impact to the drive train. It is possible to change from 2H to 4H and back again while the vehicle is in motion. When changing from 2H to 4H, the engine must not be powering the wheels. I.e. the vehicle must be coasting.
  • Super Select 4wd 4HLc4HLc – 4 wheel drive, high range, locked centre. Locking the centre differential forces even power to be delivered to both the front and rear wheels. The advantage of this is that it provides significantly greater traction in more serious off-road situations. However it’s very important not to dirve on sealed roads in this mode. Locking the centre also will prevent the front and rear wheel from spinning at different speeds. When a vehicle is turning, the rear wheels will travel less distance than the front and will therefore need to spin more slowly. If the centre is locked and forcing the front and back to turn at the same speed, then the drive train can ‘wind up’. Rotational tension is placed on components and over time will rapidly cause damage. So it is critical to never use 4HLc on terrain where the tyres are unable to slip (such as roads). It is possible to change from 4H to 4HLc while the vehicle is in motion.
  • Super Select 4wd 4LLc4LLc – 4 wheel drive, low range, locked centre. This mode is the same as 4HLc except will provide greater torque for situations that require it. This mode can be used for steep climbing and decending or for slow driving where precision and power are required. As with 4HLc, it is important not to use this mode on good quality road surfaces. The vehicle must be stopped to move between 4HLc and 4LLc.

In addition to these 4 modes, some models are fitted with a rear differential lock, that is available in 4HLc and 4LLc modes only. 4wd Impassable When WetIt is recommended that the vehicle be stopped when engaging the rear differential lock. Having said this, the vehicle can be in motion when activating the rear diff lock, however locking will not actually occur until the vehicle is travelling slower than 6km/h.

The rear differential lock forces both rear wheels to spin at the same speed regardless of traction. With an unlocked differential, if one wheel loses traction then power will be directed to that wheel. This results in a loss of forward momentum. Locking the differential will ensure that the wheel that maintains traction will continue to recieve engine power and will drive the vehicle forward.

However it is critical not to drive the vehicle on quality sealed roads. When turning, the inside wheels will spin slower than the outside wheels. Locking the differential will prefent this and will cause windup and eventual damage to the vehicle.

When changing between 4wd modes, indicator lights on the dash board will flash to indicate that the mode has been selected, and will stop flashing when the mode has been activated. On occasion it can take some time to move between the different modes.

Super Select II 4wd System

Providing the same functionality, the Super Select II system is controlled via a twist dial on the dashboard rather than a gear lever. Additional features are the downhill assist button, the 4wd mode button and the electronic park brake.

Super Select II 4wd System