When we developed the rider focused philosophy at Avanti Design Technology we knew the selection of the best and most appropriate materials would be pivotal in achieving optimum performance for each bike. It started years ago with Avanti when we were one of the first companies in New Zealand to introduce alloy across our range and continues today with framesets developed from Carbon, Alloy and Cr-mo specifically designed for the intended rider purpose.

Stiffness, Strength and Weight.

Strength and stiffness are different properties that are often confused with one another. It is important to understand the difference if you want to understand differences in frame materials.


Stiffness is the resistance to deflection an object has when loaded. Stiffness affects the riding qualities of a bike frame, since a frame suffers no permanent deformation in normal riding. Stiffness is determined by a property of the material called “elastic modulus” (Elastic Deformation). Elastic modulus is essentially independent of the quality or alloying elements in a given metal.


Strength is the resistance an object has to permanently bend or fracture when loaded. Strength relates to the crash-worthiness or general durability of a frame, but has no effect on the riding properties. Strength is determined by a property of the material called “yield strength”. Yield strength is very much affected by the quality, heat treatment and alloying elements used in a particular type of material.


Fatigue also affects strength of many materials. When you repeatedly apply force to a piece of metal, in general, it will eventually fail. The higher the force, the fewer cycles to failure, and the lower the force, the more cycles until failure. However, when the force falls below a certain threshold, called the endurance limit, you can repeat the application of force forever, with no failure.


In addition to the strength and stiffness, there’s also the question of how heavy a given volume of the material is. This is called “specific gravity”. Like stiffness, the specific gravity of a given metal is not significantly affected by the addition of different alloying elements. For instance, all steels used, from entry level bikes to the exotic alloys used on the more expensive bikes have a modulus of 210 GPa, and a specific gravity of 7850 kg/m3.

Frame material properties


Modulus of elasticity (Stiffness)

Yield Point (Strength)

Specific Gravity (Weight)


70 GPa

250 MPa

2800 kg/m3


210 GPa

480-590 MPa

7850 kg/m3


110 GPa

920 MPa

4450 kg/m3


235-377 GPa


1700 kg/m3

As a frame manufacturer we need to make the necessary selections of different tube diameters/wall thicknesses and materials, allowing a frame to be made stiffer, or stronger, or lighter for its intended purpose.