MOTORSPORTS APPLICATIONS

SMW wheels are impeccably forged to safely sustain high speeds. Carefully crafted to serve the most demanding professionals.

WHY CHOOSE MAGNESIUM?

LOW WEIGHT

Magnesium is the lightest of all structural metals. It is 1.5 times lighter than aluminium, 2.5 times lighter than titanium, and 4.3 times lighter than steel. Its specific strength is the highest of them all; so by adding crossection, the strength is increased and structural stiffness becomes superior to that of aluminium.

REDUCED FUEL CONSUMPTION

Magnesium wheels are more efficient by being lighter, and this weight reduction is more impactful because wheels are unsprung and are rotating – so the effect (together with tyres) is exponentially more significant than other components’. The resulting fuel consumption economy is up to 8% for city driving. And reduction in harmful carbon dioxide emissions is proportional.

UNIQUE DAMPING PROPERTIES

Magnesium alloy wheels are superior in absorbing and dissipating shocks and vibrations. Magnesium’s unique damping properties are up to 50 times higher than in the case of aluminium. So vibration loads on a vehicle, especially on the engine, suspension and transmission are reduced, thus improving its performance and increasing its lifecycle.

SUPERIOR MATERIAL RESISTANCE

The stiffness and reliability of structures, especially under bending and torsion load conditions, depend both on the properties of the material and on its geometry/shape. As such, the rigidity of a plate is proportional to the third degree of its thickness, its weight proportional to the first degree. Stiffness leads to higher level of control, which is very important at cornering.

HIGH THERMAL CONDUCTIVITY

Magnesium alloys dissipate eat better, and can thus reduce the temperature of brake systems and hubs – increasing the service life of brake pads and adjacent components.

IMPROVED VEHICLE DYNAMICS

A lighter wheel is faster to rotate and also to decelerate – thus slowing down the vehicle as braking dynamics improve under some circumstances, providing higher safety. Lighter wheels provide for improved handling and better maneuverability, especially at turns – resulting in safer cornering even at higher speeds.

QUALITY CONTROL AT POINT OF MANUFACTURE

Thorought X-ray and ultrasonic testing ensures sustainable long-term reliability of SMW magnesium wheels.

HIGHER MECHANICAL PROPERTIES

SMW develops proprietary higher-strength magnesium and aluminium alloys – thus enabling design optimization aimed at weight reduction. SMW Engineering has accumulated vast expertise during 22 years of experience designing and producing components in aviation-grade aluminium and magnesium alloys, including the most reliable high-performance magnesium alloys ZK60А and AZ80А. SMW employs 2024, 7050 and Almascan, among alloys possessing highest characteristics. This provides for stronger forged wheels. SMW puts its know-how to work – for obtainment of truly superior products. The competence of SMW engineers compounded with the state-of-the-art forging process enables to achieve optimized lightweight designs of automotive and motorcycle components – both for professionals aiming to improve their lap-time and for discerning enthusiasts who want only the best for their esteemed vehicle.

AZ80

Chemical Composition

Composition limits: 7.8 to 9.2 Al, 0.20 to 0.80 Zn, 0.12 Mn min, 0.10 Si max, 0.05 Cu max, 0.005 Ni max, 0.005 Fe max, 0.30 max other (total), bal Mg

Mechanical Properties

Tensile properties: See Tables 1, 3

Table 1. Typical mechanical properties of AZ80 alloy

Temper	Tensile strength		Yield Strength		Elongation	Shear Strength		Compressive Yield Strength
Temper	MPa	ksi	MPa	ksi	%	MPa	ksi	MPa	ksi
T5	345	50	250	36	Min. 6	160	23	195	28

Hardness: T5 tempers: 72 HB. Data obtained using 500 kg load, 10 mm diam ball, and 30 sec duration of loading.
Elastic modulus: Tension, 45 GPa (6.5 × 106 psi); shear, 17 GPa (2.4 × 106 psi)
Poisson’s ratio: 0.35
Density: 1.8 g/cm3 at 20 °C
Fatigue strength: T5 temper: 95 MPa (13.7 ksi). Data correspond to 5 × 108 cycles of completely reversed stress in R.R. Moore type tests

Table 2. Design Stresses and Fatigue limits for Passenger vehicle wheel design (non-motorsport)

Test type	Load type	No. of cycles	Max. design stress	FoS YS	FoS TS
Test type	Load type	1	MPa	1	1
High Cycle	½ Mbmax	1,800,000	90	2.8	3.8
Low Cycle	¾ Mbmax	200,000	135	1.85	2.5

* Within 5% error band.

Table 3. Typical tensile properties of AZ80-T5 alloy at various temperatures

Temperature		Tensile Strength		Yield Strength		Elongation
°C	°F	MPa	ksi	MPa	ksi	%
-18	0	355	51.5	252	36.5	10.5
21	70	338	49	248	36	11
93	200	307	44.5	221	32	18
150	300	241	35	176	25.5	25.5

* Temperature dependent values shall be considered individually, case-based

2024 Alloy (4.4Cu-1.5Mg-0.6Mn)

Chemical Composition

Composition limits: 0.5% Si max, 0.50% Fe max, 3.8% to 4.9% Cu, 0.30% to 0.9% Mn, 1.2% to 1.8% Mg, 0.10% Cr max, 0.25% Zn max, 0.15% Ti max, 0.05% max other (each), 0.15% max others (total), bal Al

Density: 2.77 g/cm3 at 20 °C

Mechanical Properties

Tensile properties: See Tables 4, 6

Table 4. Typical mechanical properties of alloy 6061

Temper	Tensile strength		Yield Strength		Elongation	Shear Strength
Temper	MPa	ksi	MPa	ksi	%	MPa	ksi
T3	485	70	345	50	18	285	41
T4, T351	470	68	325	47	20	285	41

Hardness: T4, T3, T351 tempers: 120 HB. Data obtained using 500 kg load, 10 mm diam ball, and 30 sec duration of loading.
Poisson’s ratio: 0.33 at 20 °C
Design Stresses: See Table 2
Elastic modulus: Tension, 72.4 GPa (10.5 × 106 psi); shear , 28.0 GPa (4.0 × 106 psi); compression, 73.8 GPa (10.7 × 106 psi)
Fatigue strength: T4, T3, T351 tempers: 140 MPa (20 ksi). Data corresponds to 5 × 108 cycles of completely reversed stress in R.R. Moore type tests

Table 5. Design Stresses and Fatigue limits for Passenger vehicle wheel design (non-motorsport)*

Test type	Load type	No. of cycles	Max. design stress***	FoS YS**	FoS TS**
Test type	Load type	1	MPa	1	1
High Cycle	½ Mbmax	1,800,000	180	1.8	2.6
Low Cycle	¾ Mbmax	200,000	225	1.45	2

* Within 5% error band.
** For minimum values of YS and TS
*** Design stress values for each use case shall be assigned individually and shall not exceed herein specified values (not applicable for motorsport)

Table 6. Typical tensile properties of alloy 2024-T3 at various temperatures*

Temperature		Tensile Strength		Yield Strength		Elongation
°C	°F	MPa	ksi	MPa	ksi	%
-28	-18	496	72	352	51	17
24	75	483	70	345	50	17
100	212	455	66	331	48	16
149	300	379	55	310	45	11

* Temperature dependent values shall be considered individually, case -based.