The specific gravity of Ti-6AL-4V is about 4.4. This is about 56 % with respect to the specific gravity of 7.8 of stock axle shaft using iron( SS400 ) and carbon steel ( S45C ), or chromium molybdenum steel shaft ( SCM440 ). This means that if you manufacture the axle shaft in the same mass, 64 titanium will be able to produce about 44 % reduction. The reduced weight of the axle shaft also reduces the unsprung weight and corner approaches will improve the handling and stability. In addition, the reduction of unsprung weight will not only improve the movement of the suspension, but also improve brake performance.


Strength of Ti - 6A L- 4V is c omparable to chromium molybdenum steel ( SCM435 ) 900 - 930 Mpa. With the higher strength axle shaf t, you will be able to feel more road sur face informat ion more direct ly. You wi l l be able to sense the bumpy road that could not be felt until now.


The Young’s modulus ofTi-6AL-4V is about half of iron and chromium molybdenum steel at 106 Gpa. The Young's modulus represents the rigidity and elasticity, the higher the number, the higher the high rigidity. Generally, one thinks "high-strength = high rigidity,” also 64 titanium has been taken for granted as high rigidity, but actually it is only half the rigidity of iron. Therefore it easily deformed, but there is elastic deformation where a material tries to return to it’s original state and plastic deformation where deformation is permanent. 64 titanium has a wide range of elastic deformation. In other words this is "BENDING". It is this bending that produces the suspension effect, and high strength that softly transmits road surface information.



Not only Light. Not only strong. Not only flexible. If it is made of aluminum or magnesium it will be lighter than 64 titanium but it will lack strength. If it is made of chromium-molybdenum steel and nickel-chromium steel it will be stronger than 64 titanium, but it will be heavy. There is also materials having Young's modulus lower than 64 titanium, but it will not mean that there is "BENDING.” 64 titanium is superior to a balance of these materials. Therefore it may be said that it is the best material for the axle shaft.

Also we must not forget the appearance of titanium. It more difficult to rust than stock shaft and chromium-molybdenum steel shaft that has a protective surface treatment. However, it does not escape corrosion where the surface is compromised for some reason. Ti-6AL-4V forms a passive film surface to prevent semipermanent rust to form.
Materual Material symbol and heat treatment Tensile strength
Young's modulus
Specific gravity
Rolled steel for general structure SS400(Annealing) 450 206 7.87
Carbon steel for mechanicalstructure S45C(Normalizing) 570 or more 205 7.83
Chromium-molybdenum steel SCM440
(Tempering quenching)
980 or more 206 7.86
Austenitic stainless steel SUS304(Solution treatment) 520 or more 197 7.93
Pure aluminum A1085 P(Annealing) 55 69 2.7
(aluminum alloy)
A2017 P(Natural aging) 355 69 2.79
Ultra duralumin
(aluminum alloy)
A2024 P(Natural aging) 430 74 2.78
Extra Ultra duralumin(aluminum alloy) A7075 P
573 72 2.81
Pure titanium (JIS grade1) TF270 275-412 106 4.51
Pure titanium (JIS grade 2) TF340 343-510 106 4.51
Pure titanium (JIS grade 3) TF480 481-618 106 4.51
Titanium (αalloy) Ti-5AL-2.5Sn 850 118 4.48
Titanium (α-βalloy) Ti-6AL-4V 900-930 106 4.43
Titanium (βalloy) Ti-15Mo-5Zr-3AL 1470 75-95 4.8