BACK in July we dissected off-road tyres, and this month one we’re taking a closer look at what lives inside that rubber: wheels. A set of off-road wheels are an integral make-up of any serious touring machine; a good set from a respected manufacturer wrapped with good quality rubber – ensures peace of mind when pointing your bullbar toward a crumbly climb. But what kinds of wheels are better for off-roading? What sizes should you be looking at what? What are they made of? And what are the benefits of different compositions? We chatted to a few experts to get to the bottom of all these questions.
CRITICAL things prowling the various catalogues for a new set of rims is size, construction and whether they’re load-rated to suit the GVM of your current 4x4.
Buy a trusted brand of wheel that is compliant with manufacturing and test standards.
Compliance to AS1638 or equivalent JWL, VIA, SAE standard is also vital, according to Glynn Helgeson, product designer for ROH Wheels. This is to ensure the wheel has survived adequate testing and is constructed correctly
“Buy a reputable brand,” Helgeson added. “You don’t want to be stuck out in the middle of nowhere with an unusable wheel due to a slight off-road incident.”
Corey Longstreth, art director at MHT Wheels, added it’s also important to keep an eye out for exposed lug bolts, because if they get damaged, removing them could prove difficult.
THE DIFFERENCES between alloy and steel wheels are obvious from a visual perspective, but the reason alloy wheels are popular goes much deeper than simply optical appeal.
Alloy wheels are lighter, tend to be stronger and have greater heat conduction, which can be beneficial in tricky terrain.
In contrast, steel wheels are heavier and don’t pack as much of a visual punch, but can be easier to repair – something of extreme importance for remotearea travellers.
Helgeson told us: “Steel wheels are inexpensive and strong, yet heavy compared to alloy wheels. Alloy wheels are lightweight, corrosion resistant and look great, but they’re more expensive than steel wheels.”
Steel wheels are heavy but repairable, while alloys are lighter and stronger but dearer to buy and harder to mend.
Martin Tonkin, GM of Allied Wheel Group added: “Steel wheels are cheap and can be banged back into something that can get you home, but that’s about where it stops. However, they’re heavy and often not hub-centric, so vibrations are a common issue on late-model cars. They’re usually not as tough-looking as a well-styled alloy, and only as strong as the welds that hold it together.”
Tonkin was more positive when it came to alloys: “There’s an excellent range of designs and offsets. If a reputable high-load brand is bought, the wheels will be substantially stronger. They can often be custom-drilled to more uncommon offsets or fitments, and can usually be made hub-centric.”
However, he said if an alloy gets a crack they often can’t be repaired; and they can easily be damaged on rocks. “They’re usually at two to three times the price of steel wheels,” he added.
PICKING up a set of wheels from an unknown website might save you time and money, but there are reasons why you should avoid purchasing from companies that lack a reputation in the industry.
The most important reason is that buying from a reputable brand means you’ll get a factory-backed warranty – as opposed to a lack of product liability from some online eBay sellers – and adequate customer support and service.
“Be aware of ‘no-name’ brands online,” Tonkin said. “These are usually imported by smaller companies looking for a quick buck. You can still buy trusted-name wheels on eBay, but make sure you check that the seller understands your vehicle’s offset and specific needs, particularly if you are unsure yourself.”
“The wheels might be cheaper, however there is a greater possibility of fake wheels, copies and wheels which aren’t tested adequately,” Helgeson added. “Again, you don’t want to be stuck out in the middle of nowhere with a cracked or bent wheel.”
MHT’s Longstreth reiterated that point: “When buying any wheel it’s important to know it’s been manufactured and approved to the standards of the country it’s being driven in.”
“Not having proper certification can cause legal issues and in extreme cases could potentially expose to potential for failure.”
WHEEL SIZES in the off-road world typically range from 15 to 20 inches, but the larger the diameter the more impractical they become when tarmac turns to dust and eventually mud.
The bigger the tyre, the more the sidewall can sustain impacts and provide more protection to the rim.
“Multiple sizes are available,” Helgeson said. “However, 16- and 17-inch are the most common off-road sizes due to being able to maximise the sidewall of the tyre to absorb impact and shock.”
A bigger sidewall tyre affords more protection for the rim, which, as mentioned previously, is possible due to the size of the rim itself, as Tonkin explained.
“Smaller diameter wheels allow a bigger sidewall tyre, and hence can protect the rim more from a hit from the tyre’s sidewall profile. Lower profile tyres have less of a sidewall and can mean the wheel is less protected and more prone to copping the full force of a hit directly to the wheel.”
Longstreth says that there are other things to keep in mind when opting for smaller diameter wheels: “Smaller diameter wheels can allow you to run a larger tyre, which, in-turn, can have the ability to create a larger contact patch; but, at the same time, it might have a rotational weight penalty from the additional rubber. Smaller wheels severely limit brake sizes.”
But how do you decide what’s best? Well, the choice is dictated by tyre size and OEM wheel size limitations.
“Wheel size is now dictated by tyre choice and OEM wheel size limitations,” Helgeson says.
“17-inch now has the greatest variety of tyre choices; what to pick depends on what terrain you will cover, i.e. sand, rocks, mud, etc.
“Off-roading on 18-inch or 20-inch wheels is probably not the best idea as you’ll feel every bump, however good 18-inch off-road tyres are now readily available for vehicles which cannot downsize due to a large OEM wheel size,” he added.
However, it’s important to remember that consumers will run into clearance issues when they increase a tyre’s diameter and lower the offset. “This is why it’s recommended as you increase size to also lift the vehicle,” Longstreth explained.
“As you increase the diameter of a wheel you can, at the same time, limit the tyre sidewall size you can run. If your vehicle is lifted and can fit a 33-inch tyre, going from a 15, to 16, to 17 (and up) limits sidewall selection. This can have an adverse effect on ride quality as well as the ability for the tyre to flex over objects.”
Another thing to look out for is wheel poke, as in, how much the wheel sticks out. “The more ‘poke’ on your wheels potentially can mean you will graze them against things if outside the line of your cars body,” Tonkin says. “Then again, wider fitments can give stability and allow for a larger footprint on the dirt.”