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The Ultimate Guide to BMW Performance Wheels: Give Your Ride a Unique Look and Feel

Few car parts have both the tantalising visual appeal and performance credentials as do a good set of wheels. They provide the handling characteristics to match the grunt coming out of engines and exhausts and can turn a few heads in the process. Swapping the stock wheels is one of the most common modifications anyone can do. But getting what’s right is easier said than done.

Performance almost always is about bigger numbers, but bigger wheels are not always the way there. There are so many other things to think about, like materials, designs and weight, and how new wheels fit the whole scope of other modifications. You can spend just a few hundred quid, and end up transforming your mundane hatchback or sedan into an unsuspecting sleeper. Adversely, you can spend thousands and get the opposite result, even in performance cars.

Why Upgrade Your Wheels?

When configuring a new car, performance alloys are just some of the options dealers throw at you. They may be pleasing to the eye, but OEM wheels rarely can play on the same field as bespoke wheels from aftermarket specialists. Here, you get more choice and better quality. And the expected performance results in a modified vehicle.

Specifically for the UK market, BMWs in all guises and ages are the first cars to get a do-over. And many owners start with wheels. Finding the right set of BMW performance wheels largely depends if you’re going with stock settings, or set on modifying your bimmer for more power and torque. The better looks just add to the satisfaction.

This is only part of the picture though. Aluminium or magnesium alloys ensure you get better handling, cornering, and road feel. Steering is more direct, and brakes are more responsive. This is down to the reduced ‘unsprung’ weight of precision-machined alloys. Lighter is always better in performance car mods, and wheels are no different.

Innovative designs provide for optimal brake cooling and increase component longevity. High tensile strength ensures alloys are less susceptible to road shocks and cornering forces. In short, you get a faster, more responsive car. Provided you have the right rubber. Tyre selection is another bonus of going for performance wheels. Taller and wider profiles generally mean more rubber on the road, and increased levels of grip.

What You Miss Out On

What you gain in overall performance, handling, braking, and better grip, you sacrifice in ride quality. But, let’s be honest- getting out of your comfort zone is what fun is all about, and the reason you went with an M3 or M5, or any modified and belting BMW, in the first place.

Wheel Types

Although ‘alloys’ are in the strict sense a mixture of varying metals in different concentrations, alloy wheels always refer to either magnesium or aluminium, with trace metals added in the mix. Choosing one over the other is a matter of where you’ll be driving your bimmer most. Generally, aluminium alloys are the preferred choice for the street, whereas superlight MAGs (magnesium alloys) are what you’d want on a smooth track.

Aluminium Alloys

Aluminium alloys are relatively easy to shape (displaying high malleability and ductility), have high tensile strength while coming in at a third of the weight of steel, are durable and impact resistant, and are available in a variety of finishes. 6061 T6 is the most popular choice of aluminium alloy. It is often anodised to a shiny and corrosion-resistant finish and hardened for additional strength.

Magnesium Alloys -MAGs

MAGs came to prominence in 1960s muscle cars, and continual refinement has made them the sought-after performance wheels. They’re much lighter than aluminium alloys and have comparable strength and corrosion resistance. In addition, magnesium alloys better dissipate heat, so provide for better brake cooling. Where they fall behind is brittleness and are not intended for pot-hole-ridden roads.

How They’re Made

Cast Wheels

Cast aluminium alloys are the cheapest and most accessible. Casting involves pouring molten aluminium into a mould to form the desired wheel shape. Once the metal cools, the wheel needs to be machined, and excess metal removed. This isn’t ideal for uniform strength, and cast wheels are more prone to fissures and cracks on impact. To relieve these issues, wheel makers must use more molten metal. The disadvantage is that to achieve appropriate strength, cast wheels carry a weight disadvantage over other types of wheels.

Flow Form Wheels

Flow forming is a step up on casting. It involves applying pressure and heat to a pre-cast wheel while it spins on a mandrel. The process stretches and compresses the metal, thus increasing its tensile strength. Less molten metal is used in the process, and wheels are therefore lighter (around 20 per cent) than comparable cast wheels. Flow-formed wheels are good for light racing uses and an affordable option compared to forged or 2- and 3-piece wheels.

Forged Wheels

The lightest and strongest BMW performance wheels are forged from a single block of aluminium 6061 TG or magnesium Az91 alloy (hence, the name monoblocs). Forging involves applying immense pressure and heat to the alloy billet, and then rolling the resulting disc in a process similar to flow forming. The pre-formed wheel is then heat treated and subsequently CNC machined (turning, front and back milling, sharp edge removal). Blasting removes any remaining imperfections, and powder coating allows for a weather-resistant layer to ensure that they look good at all times.

Forged wheels are substantially lighter than cast wheels (5 to 10 kilos depending on size) and this allows for superior performance on the track or the road. Conditioned for ultimate tensile strength (with changes to the metal grain), they won’t buckle or crack under heavier loads. This rigidity is also coupled with the freedom for more varied designs and finishes. So, if you want unique, strong and virtually unbreakable wheels, go the forged route in the right size and width for your car.

2 and 3 Piece Wheels

These are essentially forged aluminium or magnesium barrels with bolted outer and/or inner hoops. The design allows for more variety in tyre choices and widths as well as wheel offset, or how the wheel sits in relation to the suspension and the road. They are essentially pure race spec wheels, with parts that can be changed to suit track surfaces and layouts. The unique designs aren’t just for show, as any sustained damage is cheaper on the wallet than forged monoblocs. The convenience (and the complexity of the design) means 2- and 3-piece wheels are the most expensive alloys currently sold.

Which Wheels for Your BMW?

BMW UK offers advice on summer and winter wheel and tyre combos, including wheel sizing and tyre profiles, widths, and tread patterns. Taller and wider wheels often means donning on tyres in lower profiles. Specifically, for aftermarket wheels, you have more options, depending on how you intend to use your car. Anyone with performance in mind should go for lower weight and materials and designs that give better brake cooling. Drivers who put aesthetics first should consider designs that will gracefully hold up to general wear and tear.

Forged wheels are a reasonable choice and in line with the torque and bhp figures in M models, suitable for more spirited everyday driving. 2- or 3-piece wheels, on the other hand, are usually reserved for track use. Most performance car owners will have both, and swap them out when needed.

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