In short. Alloy is not automatically lighter. In one car maker's own catalogue, for the same car and the same size (6.5J x 16, offset 46), the steel wheel weighs 7.6 kg and the two alloy wheels 9.5 and 10.2 kg; other sources say alloys are lighter, so the answer depends on the wheel. Strength depends on what you ask. Per unit of weight, aluminium wins on yield strength and not on fatigue strength in typical data; steel stretches two to four times as far before it breaks, which is why a kerb tends to dent a steel wheel and crack an alloy one. UN Regulation 124 asks alloy replacement wheels to pass a salt-spray test and a kerb-impact test that it does not list for steel disc wheels. In winter, the sources favour steel for toughness and a closed shape; alloy needs a good coating and washing. Steel is cheaper: in that catalogue the alloy wheels were listed at about 1.4 times the price of the steel one. Alloy wins on design and, per two of the sources, on brake cooling.
What the two are
A steel wheel, in Wikipedia's wording, is usually pressed from sheet metal and then welded together; most alloy wheels are cast, and some are forged. "Alloy" here means an aluminium alloy. The two used for wheels differ: a cast wheel is usually A356, and a forged one 6061-T6, the alloy of the wheels we make. For what that difference means, see forged, cast and flow-formed wheels. Wikipedia also notes that not all alloy wheels are lighter than their steel equivalents, and says so without a source (Wikipedia); the catalogue figures below back that sentence.
A quick way to tell which you have: a magnet sticks to a steel wheel and not to an aluminium one.
Weight: one catalogue, three wheels
The pages we read do not agree, and most give no figures. A catalogue does. Škoda's online shop for Genuine Accessories lists a steel and two alloy wheels in the same size for the same car, with a weight for each:
| Wheel (Octavia III and IV, 6.5J x 16, ET 46, 5 bolts) | Material | Weight | In pounds | Against the steel |
|---|---|---|---|---|
| Steel wheel 16 inch | Steel | 7.6 kg | 16.8 lb | 0 |
| Alloy wheel Velorum | Light alloy | 9.5 kg | 20.9 lb | 1.9 kg heavier (25 per cent) |
| Alloy wheel Alcatras | Light alloy | 10.2 kg | 22.5 lb | 2.6 kg heavier (34 per cent) |
Sources: the steel wheel, the Velorum and the Alcatras pages, read on 15 October 2026. The pages do not say whether the weight includes the tyre; at these values it plainly does not. Pounds use 1 lb = 0.45359237 kg (NIST SP 811).
Read it for what it is. One maker, one size, two styled designs. It does not say that every alloy wheel is heavier than every steel one. The same maker's catalogue lists a 15-inch steel wheel (6.0J, ET 43) at 6.93 kg (page) and a 17-inch alloy wheel (7.0J, ET 49) at 11 kg (page), which are different sizes and not a like-for-like pair. It does say that the rule "alloy is lighter" is not a law, and that wheel size and design matter more than the material.
Other sources split. Auto motor und sport says alloy wheels are lighter, which helps electric cars' range and matters little on heavy vehicles (article, August 2025). Auto Zeitung says that thanks to technical progress the difference is now hardly worth mentioning (article, February 2024). Neither gives a figure. If weight matters to you, look for the figure on the wheel's data sheet or weigh it.
What a few kilograms are worth is in lightweight wheels and unsprung weight. By its table, 2 kg off each wheel of a 1,600 kg car is worth about 0.05 s over a 6 s run: the Škoda difference runs the other way, and is of that size.
Strength: the metal, then the tests
The metal. These are typical values from a materials database for the base metals, not for a wheel. The steel is a common high-strength structural steel, not the grade of any particular wheel; wheel steel sheet differs.
| Property | A356.0-T6 (cast alloy) | 6061-T6 (forged alloy) | Structural steel (ASTM A572) |
|---|---|---|---|
| Density, g/cm3 | 2.6 | 2.7 | 7.8 |
| Yield strength, MPa | 200 | 270 | 330 to 510 |
| Tensile strength, MPa | 270 | 310 | 470 to 620 |
| Elongation at break | 6 per cent | 10 per cent | 18 to 25 per cent |
| Fatigue strength, MPa | 90 | 96 | 240 to 340 |
| Yield strength per unit of density | 77 | 100 | 42 to 65 |
| Fatigue strength per unit of density | 35 | 36 | 31 to 44 |
Sources: MakeItFrom for A356.0-T6, 6061-T6 and ASTM A572. The last two rows are our division of strength by density.
Two things stand out. Per unit of density, aluminium leads on yield strength, which is the usual argument for it. It does not lead on fatigue strength, which matters for a part that turns millions of times: the figures per unit of density are about the same. And steel stretches two to four times as far before it breaks. That fits what two German motoring titles report: a hard kerb strike on a steel wheel usually leaves a dent, and aluminium reacts more sensitively, often with cracks or breaks (auto motor und sport); a kerbed steel wheel can usually be repaired, an alloy one less easily, sometimes not at all (Auto Zeitung). The limits on repairing an alloy wheel are in alloy wheel repair.
The tests. UN Regulation 124 covers new replacement wheels for passenger cars, not the wheels the car came with. For those, it lists the tests by material (UN R124, section 6.5):
| Test | Steel disc wheels | Aluminium alloy wheels (one piece) |
|---|---|---|
| Rotating bending (Annex 6) | Yes | Yes |
| Rolling (Annex 7) | Yes | Yes |
| Corrosion: salt spray, ISO 9227, 384 hours (Annex 5) | Not listed | Yes |
| Kerb impact (Annex 8) | Not listed | Yes |
The corrosion test is run on a surface-treated sample that has been damaged by cross-engraving and stone impact; there must be no significant corrosion after 192 hours, and after 384 hours the wheel's function, its mounting parts and the tyre bead seat must not be adversely affected. The impact test drops a striker of 0.6 × the wheel load (in kg) + 180 kg from 230 mm onto the rim flange of a wheel tilted at 13 degrees; the wheel fails if a visible fracture goes through the centre section, if the centre separates from the rim, or if the tyre loses all its air within a minute, and deformation of the struck part of the rim is not a failure. The text does not say why the tests differ by material. The lists are what they are: the regulation asks alloy wheels to show how they cope with salt and with a kerb, while for steel disc wheels it lists bending and rolling. It is a replacement-wheel regulation; original wheels follow their maker's own specification.
Cost
Steel wheels are cheaper to buy and to replace in all the sources that mention cost: Auto Zeitung calls them usually much cheaper, and auto motor und sport cheaper both to buy and to replace. In the Škoda shop's list prices on 15 October 2026, the alloy wheels cost about 1.4 times the steel wheel (the steel wheel was out of stock, and one alloy carried a 20 per cent discount, so the ratio is of list prices in one market).
The savings add up when the wheels are a second set. Auto Zeitung's conclusion is that some drivers fit alloys in summer and steel wheels in winter. Cost also includes repair: a dented steel wheel is more often repaired than an alloy one.
Winter and road salt
Road salt is at least 94 per cent sodium chloride, says RIAL, a wheel maker, and its sodium can oxidise aluminium, which shows as white patches of corrosion and undermines the coating. RIAL says its fully painted wheels have a triple-layer coating, a polished wheel has a single coat and is therefore more prone to stone chips, and it recommends cleaning alloy wheels once a week in winter (RIAL). Nissan's owner's manual says the same in other words: road salt residue could discolour the wheels if it is not washed off regularly, and wheel cleaner should not contain strong acid or alkali, nor be applied to hot wheels (Nissan Qashqai manual).
The ADAC technical expert quoted by Auto Zeitung is more specific. An alloy wheel not made for winter can oxidise at the rim edge, where the tyre sits, causing a slow loss of air that is often invisible while the tyre is on the wheel and may not show for five or six years. No standard sets what a winter alloy wheel is; the maker decides, so ask. For steel, he calls the wheels very robust and generally suitable for winter, with rust usually only cosmetic and without effect on the strength of the metal (Auto Zeitung, 5 September 2025). Auto motor und sport adds that a steel wheel's closed shape protects better against road salt and abrasion.
UN R124's salt-spray test, above, is the one regulatory yardstick we found for an alloy wheel and salt; it is not a winter label.
Brakes, trims and the MOT
Brake heat. UN R124 states that the heat transfer from the brakes into steel wheels is regarded as being more severe than into light alloy wheels, and asks a replacement wheel with smaller ventilation holes than the original to show it does not worsen brake temperature (Annex 10, 2.2). Auto Zeitung and auto motor und sport both say alloy conducts brake heat away better; Auto Zeitung adds that this matters most on powerful cars.
Wheel trims. A steel wheel is often fitted with a plastic cover. EUWA, the wheel makers' association, asks that it is mounted without excessive force, which could damage the surface protection, in the right angle to the valve so as not to bend it, and that you check it is seated, to prevent its loss or overheating of the brakes (EUWA ES 1.07, 4). Auto Zeitung lists covers that can fall off or be stolen among the drawbacks of steel.
The MOT. The manual's defects do not depend on the wheel's material: a fracture or welding defect is dangerous, a badly distorted wheel is major, a loose or missing nut is major. The manual also tells the tester not to remove wheel hub caps (MOT manual, 5.2.2), and the manual does not say how a tester checks nuts behind a cover. The guide to the MOT and new wheels has the list.
Changing from steel to alloy, or back
The wheel has to fit the car whatever it is made of: bolt pattern, centre bore, offset and tyre (see PCD and centre bore and what size wheels fit my car). Two things change with the material. The first is the fixings: EUWA says the mounting parts, including the special parts for steel and light alloy wheels, must fit the wheel exactly and may not be interchanged, because a mix-up can damage the stud holes and finally make the wheel fail (EUWA ES 1.02, 4.3.1). Check the seat, the thread and the length before you refit, and use the car maker's torque: see wheel nut torque. The second is the weight on the machine, and the kind of balance weight: Michelin says steel rims take clip-on weights and aluminium rims take adhesive ones, in wheel balancing.
Which to choose
| If you care most about | The sources point to | Why |
|---|---|---|
| A winter set in a salty region | Steel, or an alloy its maker says is made for winter | Steel's closed shape and robust, cosmetic rust; no standard for a winter alloy, so ask the maker |
| The lowest cost | Steel | Cheaper to buy and to replace in every source that gives a view |
| Kerbs and tight parking | Steel | A dent more often than a crack, and more often repairable |
| Looks and choice of design | Alloy | Cast and forged shapes allow almost any design |
| Brake cooling on a powerful car | Alloy | Two sources, and UN R124 treats steel as the harsher case |
| Low weight | Check the figure | One catalogue shows steel lighter; others say alloy |
Wheels from Onyx Forged
Our wheels are alloy: forged aluminium, made to order for the car as you described it, and designed to JWL/VIA standards. We do not make steel wheels. The Onyx Forged design office works out the wheel for the car and checks it with you before anything goes into production. We do not quote a percentage of weight saved: the weight of a wheel depends on its diameter, width, offset and design, and the figure that counts is the one for your wheel. The terms and conditions list corrosion linked to de-icing salt among the warranty exclusions, with a shorter finish warranty in that case (article 6.2): if the car will see salt, say so when you ask, and consider a second set for winter.
Frequently asked questions
Are alloy wheels lighter than steel wheels?
Not always. In one car maker's catalogue, for the same car and size, the steel wheel weighs 7.6 kg and the two alloys 9.5 and 10.2 kg. Other sources say alloy is lighter or that the gap is no longer worth mentioning. Compare the data sheet figures for the exact wheels.
Are alloy wheels stronger than steel?
Not in every sense. Per unit of density aluminium leads on yield strength and is level on fatigue strength in typical data, and steel stretches two to four times as far before breaking. In a kerb strike steel tends to dent and alloy to crack. UN R124 asks alloy replacement wheels for a corrosion test and an impact test that it does not list for steel disc wheels.
Which is better for winter, alloy or steel?
Steel, on the sources we read: very robust, with rust usually only cosmetic, and a closed shape that protects against road salt. An alloy wheel can be used if its maker says it is made for winter and it is washed often; there is no standard for the label.
Do steel wheels rust?
Yes, but the ADAC technical expert quoted by Auto Zeitung says the rust is usually only on the surface, a cosmetic flaw that does not affect the strength of the metal.
Are alloy wheels more expensive than steel?
Yes in all the sources that give a view. In one catalogue the list price of the alloy wheels was about 1.4 times the steel wheel's, in one market on one day.
Can I fit alloy wheels to a car that came with steel wheels?
Yes, if the new wheels fit the car: bolt pattern, centre bore, offset and tyre size. The nuts or bolts may have to change, because the seat, thread and length must suit the wheel. Use the car maker's torque and check again after 50 to 100 km.
Which is easier to repair, a steel or an alloy wheel?
Steel, according to Auto Zeitung and auto motor und sport: a dented steel wheel can usually be repaired, while an alloy wheel is more complex to repair and sometimes cannot be repaired at all.
Do alloy wheels cool the brakes better?
Two German motoring titles say alloy conducts brake heat away better, and UN R124 says heat transfer from the brakes into steel wheels is regarded as more severe than into light alloy wheels. The effect is greatest on powerful cars.
Where to go next
For the metal and the process behind a forged wheel, read forged, cast and flow-formed wheels; for what weight at the wheel is worth, lightweight wheels and unsprung weight; for what happens after a kerb, alloy wheel repair. Onyx Forged is a French brand of made-to-order forged wheels, designed to JWL/VIA standards: see Onyx Forged and the catalogue.
Sources
- Škoda Auto, Genuine Accessories: steel wheel 16 inch, alloy wheel Velorum, alloy wheel Alcatras, steel wheel 15 inch, alloy wheel Hawk 17 inch.
- UN Regulation No. 124, replacement wheels: section 6.5, Annexes 5 and 8, Annex 10 section 2.2.
- MakeItFrom: A356.0-T6, 6061-T6, ASTM A572.
- RIAL, alloy wheels in the winter (2 November 2021); Nissan Qashqai 2023 owner's manual, cleaning aluminium alloy wheels.
- Auto Zeitung: Alufelgen im Winter (5 September 2025) and Alufelgen oder Stahlfelgen (21 February 2024), in German; auto motor und sport, Autofelgen (7 August 2025), in German.
- EUWA, ES 1.07 (June 2020); EUWA, ES 1.02 (May 2011).
- GOV.UK, MOT inspection manual, section 5.2.
- Wikipedia, Alloy wheel; NIST Special Publication 811, Appendix B.9.
All pages were read on 15 October 2026. The three German-language articles are summarised in English from the German text.
The Onyx Forged design office.