By Glenn Torrens
Article from Unsealed 4X4 Magazine
Wheel spacers can increase your 4WDs track and stability; they’re also illegal to fit and more trouble than they’re worth. Here are 11 reasons why wheel spacers are a dumb idea.
Wheel spacers. There isn’t a day – no, maybe an hour – that goes by when someone doesn’t jump on the internet and mention, ask about – or try to justify – the use of wheel spacers under their 4X4.
The fact is, wheel spacers are illegal in Australia unless the manufacturer fitted them. The End.
And no – don’t shoot the messenger – but you can’t have spacers ‘engineered’ into a vehicle. This information is listed in the Federally produced regs that tells us what is, and isn’t, cool when we’re setting up our 4WDs to suit our touring ambitions.
The trouble is, the internet is only the internet so, much of the information/opinions you’ll read when someone asks the question: ‘Thnkin of spacers, wot r ppl’s opinons?” will be from people who don’t give a rat’s about legality because they’ve Never Had A Problem.
But no matter where you live, it’s difficult to skirt around the Feds’ VSB14: Section LS Tyres, Rims, Suspension and Steering: 4.2.2 Wheel Attachment: Wheel spacers (or adaptors for dual wheel conversions) between the wheel mounting face and the road wheel must not be used unless fitted as original equipment by the vehicle manufacturer…”
And right now we can’t think of any 4WDs that have spacers from the showroom floor.
But there’s always someone who will nod into their beer and claim that spacers are legal. But because a bad idea is usually for a good reason, here’s Unsealed 4X4’s list of good reasons why wheel spacers are a terrible idea.
1. Spacers widen your vehicle track
Yeah! No kidding! Of course! Derr! People fit spacers to pack out the track; the distance between the centre of each of the two tyres’ treads, across the vehicle’s width. The trouble is, these days vehicle track increases are limited to – usually – a maximum of 50mm. Yeah, we know your good mate on the internet who you’ve never met might have written that a rig with a wider track will have more stability – and hence be ‘safer’ – but if you think an inch or two extra stance will give your 2.4-tonne, A/T tyred 4X4 a better lap time then maybe it’s time for another beer. Or not.
2. Spacers put extra load on wheel bearings
Closely related to an increase in vehicle track is an increase in hub and wheel bearing load: Said simply, placing a wheel further outboard will increase these loads. Sure, vehicle manufacturers design-in plenty of extra ceiling for safety, but with heavy vehicles, unexpected shock loadings (such as hitting potholes) all conspire to give your wheel bearings hell. This is true, too, of a wider-offset wheel; and all a good part of the reasons why vehicle track increase is limited to a modest 50mm.
3. Spacers put extra load on wheel studs
For the same set of reasons as mentioned just above, the use of spacers also results in additional stress to wheel studs. But wait, there’s more: Many if not most spacers are not hub-centric; that means the flat face of the spacer does not engage the hub and wheel’s centre bore. This is a big problem as it means the wheel studs – and not the hubs’ forged and machined centres within the wheels – are now taking the full (and now extra) load of the vehicle’s weight.
4. Spacers usually aren’t hub-centric
See above. Being located near-enough to the centre but on just the wheel studs leads us to the situation where wheels are now more likely to spin slightly out of round, causing a balance issue. Which leads us to…
5. …Spacers can affect suspension harmonics
Did you ever make a school ruler go ‘twang’ by holding it over the edge of your school desk, pulling the unsupported end down and letting it go? You may not have realised it then, but that little kiddies’ kindy trick is a life lesson with relevance to our 4WDs: that unsupported length of the ruler is a bit like what can happen under a vehicle. See, the further ‘out’ the wheels are the more tendency they have to shimmy the vehicle’s suspension. That can cause problems as slight as an annoying noise in the cabin or as bastardly as wheel nuts regularly coming loose and damper bushes – especially the lower ones – being flogged out in double-quick time.
6. Spacers often cause body fouling issues
Placing your front wheels further outboard means they swing a wider arc toward full-lock, increasing the chance of the tyre touching the body. That limits tyre size. Similarly, under the rear, there’s more chance of the tyre snotting the wheel arch edge. It also means less running clearance for that horrible, sticky black-soil or High Country clay/mud that we all try to avoid, but sometimes can’t. No matter what, you’ve just built yourself a less capable tourer, not a better one. Once again this is a problem that affects different offset rims and larger tyres, too – not just spacers.
7. Spacers screw your vehicle’s stability under brakes
Most vehicle suspensions from the past 30, or so, years, have some smart stuff going on that most drivers don’t realise. There’s much more to the suspension geometry than the wheel merely going up and down and – at the front – turning left or right. An example of this smart geometry is steering that doesn’t ‘grab’ and spear the vehicle into the trees if one wheel drops onto the dirt adjacent to the bitumen while braking hard. That geometry usually relies on the centre of the tyre’s tread being in a particular place in relation to other arcs and swings in the suspension. Spacers can mess that up.
8. Spacers mess with stability control
Stability control has had a lot of bandwidth in the last couple of years, mainly due to the QLD coppers cracking down on illegal cartoon-spec vehicle lifts and wheels/tyres last year. But for similar reasons to the steering geometry issues mentioned above, modifying aspects of your vehicle – such as suspension and track – could trigger the vehicle stability control at the wrong time. That wrong time might not be when you need it, or it might be when you don’t.
9. Spacers might mean loose wheel nuts
Let’s say you fit a 25mm spacer. With the same wheels over the top, you’re effectively shortening your wheel studs by 25mm. Will the nuts engage properly? If the nuts are closed-ended, how will you know? Bolt-on spacers – or PCD adapters that are also sometimes used on road cars – are bolted to the hub using the vehicle’s original wheel studs, then the wheel installed using the second ring of studs poking from the spacer. So, now you have two surfaces that can fret, gradually loosening the studs and, with the wheel in place, there’s no way to give the inner set of studs a casual glance each morning, let alone a quick check with a wheel brace. Do you want that on your tourer … really?
10. Spacers are sometimes made from junk
Most spacers are made from alloy. But as anyone who has tried to weld a length of Bunnings’ steel will know, there’s metal, and there’s metal. Most OE-grade wheel hubs are forged steel with the studs interference fitted from the back-side after tight-tolerance finish machining. Alloy spacers are sometimes cast and often use the same studs – which means the studs are liable to come loose from the softer alloy. Sure, you might be able to buy a set of four comp-spec, machined billet, load-rated, ISO 9000 quality-assured you-beaut spacers for $69.99 with free shipping from eBay … but probably not. We even saw one set of eBay spacers described as ‘High Safety’. If that doesn’t sound like a Bali back-street bargain buy, then what is?
11. Unroadworthy means no insurance
Your comprehensive vehicle insurance is a tightly worded contract between you and your insurance company. While you’re on the phone organising your insurance, the nice girl on the other end of the line will more than likely talk to you about accessories, modifications, existing damage and being roadworthy. You can choose to lie or withhold info about your vehicle if you wish…but if you ever have that big crash your mum warned you about where you write-off someone’s Mercedes, your insurance company does NOT have to prove the spacers did – or did not – contribute to the crash, it simply has to show you bull-shitted to them … so your insurance contract was null and void from the beginning.