Wheel Spacers are just one part of the cowboy approach to 4wd modification. We have covered a lot of these type of back yard hodge bodge modifications in the article below.
Below are ten reasons why wheel spacers should never make it onto your vehicle.
1. 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 wiggle room for safety, but with heavy vehicles, unexpected shock loadings (such as hitting potholes) all conspire to give your wheel bearings hell. The load on any given wheel bearing is mostly caused by centrifugal force. See image.
By placing wheel spacers on the hub the load is moved too far outward adding much greater loads to the outer bearing race. This will cause the wheel bearings to fail very quickly.
2. Spacers put extra load on wheel studs
For the same reasons as mentioned above, the use of spacers also results in additional stress to wheel studs. 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.
3. Spacers usually aren’t hub-centric
Following on from point 2. As majority of these products are knocked out with no real engineering involved and made for the cheapest possible price in inferior factories, the quality of these parts are less than desirable. Being located near-enough to the centre but on just the wheel studs leads to the situation where wheels are now more likely to spin out of round, causing what feels like a wheel balance fault.
4. Spacers affect suspension
The out of round issues caused by the spacer now cause subtle or even severe vibrations through the suspension and drive line. This can cause problems as slight as an annoying noise or can be as serious as wheel nuts regularly coming loose and suspension bushes wearing out prematurely.
5. 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, chases or suspension components. That limits tyre size. Similarly, under the rear, there’s more chance of the tyre fouling on the wheel arch edge. You’ve just built yourself a less capable tourer, not a better one.
6. 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.
7. Spacers mess with stability control
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.
8. Spacers nearly always 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.
9. 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?
10. Unroadworthy means no insurance
Your insurance is a 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 lied to them … so your insurance contract was null and void from the beginning. And now you’re paying for someone else’s Mercedes Benz at $43.50 per week for the rest of your life.