What is The Best Material for Bike Front Forks?

The type of material is one of the most important things you should consider when choosing a front fork for your bicycle, and when it comes to choosing the best material, there are three qualifications you should keep in mind: stiffness, strength and weight.

 

These three properties are often confused with one another, especially stiffness and strength. It’s better to understand the difference, so you would know exactly the real quality level of each material.

 

Stiffness – This property affects the riding qualities. The level of stiffness of a material depends on a property known as the “elastic modulus”, or the measurement of an object’s resistance to being non-permanently deformed when a force is applied to it.

 

Strength – This property relates to the level of durability and crash-tolerance of a matter, but it has nothing to do with the riding qualities. The level of strength relies on a property known as the “yield strength”. The yield strength itself very much relies on the quality, alloying elements, and heat treatment applied in the manufacturing process of the tubing.

 

Weight – This property tells the volume of a material, or also known as “density”. Unlike what most people believe, the density of a material is actually not heavily affected by the addition of various alloying elements.

 

The most common materials used for bike forks are steel, aluminum and titanium. Actually there is also another material that has gained a lot of popularity recently, which is carbon fiber, but for now let’s just focus on the first three materials.

 

Below is the breakdown of the important properties of the 3 materials:

 

Material Modulus (psi) Yield Point Density (lb/ft3)
Aluminum 10 to 11 x 106 11 to 59 x 103psi (4-22 annealed.) 168.5
Steel 30 x 106 46 to 162 x 103 psi 490
Titanium 15 to 16.5 x 106 40 to 120 x 103 psi 280

 

 

These qualities apply to all the above materials no matter where or how they are made. So for example, all steels whether those used in gas pipes, skyscraper’s construction or bike forks have a modulus of 30 psi and density of lb/ft3.

 

So, basically steel/aluminum/titanium made by different manufacturers have the exact same properties. So no one can claim that a particular brand of steel/aluminum/titanium is stiffer or lighter than others. What really makes real differences is the yield strength of different qualities of tubing.

 

Based on the values shown above, it’s obvious that steel bicycle fork is the toughest type of fork. If you build a bike fork using all 3 materials with identical wall thickness and tubing diameters, the titanium fork only half as stiff as the steel one, while the aluminum fork is even only â…“ as stiff.

 

Based on the yield values, steel is the strongest one that will not easily damaged as compared to the other two materials. It’s also heavier, which compare to the others, which means it provides better balance.

 

Carbon fiber on the other hand, is very different from metal tubing, it has completely different qualities of properties we have discussed earlier. A well-designed carbon fork actually can provide a considerable amount of strength to cope with maximum strength, but the problem is, it’s not really a mature technology in bicycle applications.

 

This material might be tough enough to handle maximum stresses from one direction, but a good bicycle should be able to handle various amounts of stresses from different directions. So when it comes to bicycle forks, this material hasn’t shown a promising level of durability and reliability.

 

So to conclude, steel is still the best option for a bike front fork, not only because it’s a tough material, but also because it offers better balance and relatively cheap.

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