{"id":15687,"date":"2026-02-25T10:57:00","date_gmt":"2026-02-25T01:57:00","guid":{"rendered":"https:\/\/webstylix.xsrv.jp\/tsr\/?post_type=tips&p=15687"},"modified":"2026-05-24T13:34:46","modified_gmt":"2026-05-24T04:34:46","slug":"blog06","status":"publish","type":"tips","link":"https:\/\/tsrjp.com\/en\/tips\/blog06\/","title":{"rendered":"Titanium is a strong and \u201cflexible\u201d metal."},"content":{"rendered":"\n

The Truth About Titanium, Part 6: \u201cTitanium is strong, but in reality\u2026 its stiffness is not great.\u201d<\/strong><\/p>\n\n\n\n

In Japan, many people tend to treat strength and stiffness as the same thing.
How about overseas?<\/p>\n\n\n\n

In general, the higher the strength of a material, the higher its stiffness tends to be as well, which makes the distinction easy to misunderstand.

This tendency is especially strong in metals.
In that context, titanium is a special metal that is strong, yet still \u201cflexible.\u201d<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

Difference between strength and stiffness<\/h3>\n\n\n\n

Before explaining titanium, let\u2019s briefly go over strength and stiffness.
First, strength\u2026<\/p>\n\n\n\n

\n
\n
\"\"<\/figure>\n<\/div>\n\n\n\n
\n

\u3000<\/p>\n\n\n\n

Strength is the resistance to pulling forces \u2014 in other words, how difficult it is to break a material.
In Japan, this is often referred to as \u201ctensile strength\u201d or \u201cultimate tensile strength.\u201d<\/p>\n<\/div>\n<\/div><\/div>\n\n\n\n

Next, stiffness\u2026<\/p>\n\n\n\n

\n
\n
\"\"<\/figure>\n<\/div>\n\n\n\n
\n

\u3000<\/p>\n\n\n\n

Stiffness refers to how resistant a material is to deformation under bending or twisting.
In other words, the harder it is to bend, the higher the stiffness.<\/p>\n<\/div>\n<\/div><\/div>\n\n\n\n

Strength and stiffness in metals<\/h3>\n\n\n
\n
\"\"<\/figure>\n<\/div>\n\n\n

The table above shows the mechanical properties of metals.<\/p>\n\n\n\n

Tensile strength represents strength \u2014 the higher the value, the stronger the material.
Young\u2019s modulus represents stiffness \u2014 the higher the value, the harder it is to bend.<\/p>\n\n\n\n

As mentioned at the beginning, it is generally observed that materials with higher strength also tend to have higher stiffness.
However, titanium is a bit different.<\/p>\n\n\n\n

If you compare Ti-6Al-4V (second from the bottom in the table) with chromoly steel SCM435 (fourth from the top), you\u2019ll see that although their strengths are almost the same, titanium\u2019s stiffness is only about half that of chromoly steel.<\/p>\n\n\n\n

Stiffness \u00d7 Yield Strength (Yield Point)<\/h3>\n\n\n\n

Titanium has about half the Young\u2019s modulus of chromoly steel, but that doesn\u2019t mean it easily bends.<\/p>\n\n\n\n

In fact, aluminum \u2014 which has an even lower Young\u2019s modulus \u2014 is far more flexible.
In this sense, aluminum is low-stiffness, while titanium is medium-stiffness.<\/p>\n\n\n\n

Here, \u201cflexing\u201d refers to elastic deformation, where the material returns to its original shape.
When the load increases further, it transitions into plastic deformation, where the material does not fully recover.<\/p>\n\n\n\n

The boundary between these states is called the yield point (yield strength).<\/p>\n\n\n\n

Therefore, materials with low stiffness but high yield strength behave in a more \u201cspring-like\u201d manner.<\/p>\n\n\n\n

Titanium falls into this category as well.
Its lower stiffness is not a weakness, but one of its inherent characteristics.<\/p>\n\n\n\n

Summary<\/h3>\n\n\n\n

I have summarized the properties of each material.<\/p>\n\n\n\n

\n
\n

\u25a0Aluminum\uff08A2017\uff09
Strength\uff1a425 MPa
Stiffness\uff1a69 GPa
Yield strength\uff1a275 N\/\u339f<\/p>\n\n\n\n

\u3000\u3000\u21e9<\/p>\n\n\n\n

Medium-strength, low-stiffnes<\/p>\n<\/div>\n\n\n\n

\n

\u25a0Titanium\uff08Ti-6Al-4V\uff09
Strength\uff1a900 MPa
Stiffness\uff1a106 GPa
Yield strength\uff1a845 N\/\u339f<\/p>\n\n\n\n

\u3000\u3000\u21e9<\/p>\n\n\n\n

High-strength, medium-stiffness<\/p>\n<\/div>\n\n\n\n

\n

\u25a0Chromoly\uff08SCM435\uff09
Strength\uff1a930 MPa
Stiffness\uff1a212 GPa
Yield strength\uff1a785 N\/\u339f<\/p>\n\n\n\n

\u3000\u3000\u21e9<\/p>\n\n\n\n

High-strength, high-stiffness<\/p>\n<\/div>\n<\/div><\/div>\n\n\n\n

Chromoly bolts have slightly higher strength than titanium bolts.
However, in terms of yield strength, chromoly tends to undergo permanent deformation first.<\/p>\n\n\n\n

So which is better as a bolt?
The answer depends on the application \u2014 specifically, how the clamping force needs to be maintained.<\/p>\n\n\n\n

Titanium Bolts vs Chromoly Bolts<\/h3>\n\n\n\n

\u25a0Chromoly Bolt\uff08SCM435\uff09
– Low elongation
– Small elastic stretch during tightening
– More prone to loosening under external loads
\u2003<\/span> Suitable for applications requiring a firm, rigid fixation.<\/p>\n\n\n\n

\u25a0Titanium Bolt\uff08Ti-6Al-4V\uff09
– High elongation
– Works like a spring
– Clamping force tends to remain stable
\u2003<\/span>Resistant to vibration and fatigue.<\/p>\n\n\n\n

Because of these characteristics, titanium bolts are well suited for reducing micro-vibrations in motorcycles. In that sense, they are truly ideal components for bikes.
However, there are cases where they are not suitable depending on the application.<\/p>\n\n\n\n

For example, bridge bolts on a two-piece brake caliper.
If the bolt flexes, the caliper can slightly spread, potentially leading to a loss of braking force.<\/p>\n\n\n\n

Engine mounts also help define the frame\u2019s characteristics through stiffness, so flexing can change the vehicle\u2019s behavior.
This may disrupt the intended design balance, although it cannot be said that this will necessarily lead to a deterioration in performance.<\/p>\n\n\n\n

For axles and suspension components, stiffness is currently prioritized.
However, in terms of tire compliance and grip, a \u201cflexing\u201d axle cannot be completely ruled out.<\/p>\n\n\n\n

In fact, there are reports of lap times improving with titanium axles.
If titanium axles were allowed under the regulations, it\u2019s likely that a number of teams would choose to use them.<\/p>\n\n\n\n

What is currently considered a drawback may, in a few years, come to be seen as an advantage.<\/p>\n","protected":false},"author":1,"featured_media":15691,"template":"","class_list":["post-15687","tips","type-tips","status-publish","has-post-thumbnail","hentry"],"acf":[],"_links":{"self":[{"href":"https:\/\/tsrjp.com\/en\/wp-json\/wp\/v2\/tips\/15687","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/tsrjp.com\/en\/wp-json\/wp\/v2\/tips"}],"about":[{"href":"https:\/\/tsrjp.com\/en\/wp-json\/wp\/v2\/types\/tips"}],"author":[{"embeddable":true,"href":"https:\/\/tsrjp.com\/en\/wp-json\/wp\/v2\/users\/1"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/tsrjp.com\/en\/wp-json\/wp\/v2\/media\/15691"}],"wp:attachment":[{"href":"https:\/\/tsrjp.com\/en\/wp-json\/wp\/v2\/media?parent=15687"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}