Who wants to spend more on fuel than they need to? Certainly not us. Anything you can do to reduce your fuel bill without negatively affecting your car’s performance has to be a good thing. 

And that got us wondering: are alloy wheels any more fuel efficient than their steel counterparts? After all, they’re lighter - and they tend to be fitted to most modern cars. Manufacturers are keen to maximise the fuel efficiency and range of all their new models, so surely they wouldn’t fit alloys if they were worse for fuel efficiency.

We decided to do some research - and here’s what we found.

Do alloy wheels increase fuel efficiency?

Factor #1: Weight

This is actually a far less straightforward question than it might seem.

Yes, alloys are far lighter than steelies. Typically, a lighter vehicle with lower unsprung weight will have better handling and, logically, it should use less fuel too. There’s less work for the engine to do when it’s moving less weight, which means less throttle input is required and less fuel is consumed. 

However, this theory only holds water if you are replacing like-for-like. If you were to replace your steel originals with larger alloy rims, any weight saving you thought you might be achieving will actually be negated by the increased wheel dimensions.

Factor #2: Aerodynamics

Aside from weight, the main contributing factor to fuel efficiency is aerodynamics. The difference in weight between alloy and steel wheels really is a small contributor in comparison to the way they cut through the air: the less air resistance they create, the more fuel efficient the car will be.

This is where steel wheels begin to claw back an advantage. In general, they have a smooth, flat surface for the air to pass across. Spoked alloy designs tend to break up the airflow, noticeably increasing drag and therefore fuel consumption, although they do help dissipate the heat generated under braking more efficiently than their steel counterparts.

When you remember that the wheels are positioned on all four corners of the car - right where the air is travelling at high speed - the increased turbulence of spoked wheel designs can have quite an effect on your car’s aerodynamics.

It’s for this reason that you’ll see modern F1 cars running with smooth carbon fibre wheel covers, which clean up the airflow along the side of the car, reducing drag and allowing the various aerodynamic devices around the car to work more efficiently.

The bottom line: what’s the relationship between alloy wheels and fuel economy?

So, to answer the question, if you replace like-for-like then you may well see a slight reduction in fuel consumption by switching from steel to alloy wheels. However, for any kind of noticeable improvement, something a little more radical is needed - like those carbon wheel covers we just mentioned!

Although the benefits of alloys from a fuel economy standpoint are negligible, they do offer a wide range of performance benefits. In motorsport, the weight saving and heat dissipation offered by alloys makes them a no brainer - and the same applies to high-performance road cars.

Now we have an answer to the question posed in the title, let’s delve a little deeper and work out how you can identify fuel efficient alloy wheels.

What makes a wheel design more fuel efficient?

For drag to be at a minimum, a car needs to pass through the air with the least amount of disruption possible - kind of like how an olympic diver enters the pool with the smallest of splashes. Something like an old-school Land Rover Defender or a Hummer H1 would be the equivalent of a belly flop, while a Honda Insight or a Volkswagen XL1 would score a perfect 10 in a diving contest. 

If you picture any vehicles renowned for their speed, you’ll often notice flat (or even covered) wheels to help reduce drag. The air needs to ‘stick’ to the car and not be broken up as it flows across the surface. A good example of this is the Koenigsegg Jesko Absolut - just look at the aero covers on those rear wheels.

Some newer vehicles designed with fuel efficiency in mind have certainly embraced this approach, sacrificing appearance for the sake of great fuel mileage figures. Ideally, you need to cover not only the rear wheels but the front ones too, though this can provide its own set of additional problems with steering, brake cooling and such. For the front wheels, aero covers are really the only option.

The greatest issue here though is simply appearance - no one seems to like this look much at all, or it would have hit general manufacturing procedure much more widely than it has.

The narrower the wheel, the better. Thinner wheels can slice through the atmosphere more easily, preventing air resistance from building up too much in front of the tyre.

Another area for serious consideration is low rolling resistance ‘eco’ tyres. Running your tyres at high pressures can also help reduce their rolling resistance, albeit at the expense of grip and handling.

Ideally, from a fuel efficiency perspective, you need a lightweight, smooth-sided, narrow wheel with no holes in it.

Explore our range of alloy wheels online today

Searching for a new set of alloys for your car? We have a massive range to choose from here at LK Performance, with a vast array of different styles, brands and colours on offer. To find your dream wheels, explore our complete range of alloys online today.