All About Seven's Original Titanium Tubesets
Integrity™, Argen™, and Cirrus™. These are the three titanium tubesets that Seven Cycles prides itself on. What are their unique characteristics, and how do they enhance bike performance for different riding styles and custom-geometry frames? In this article, we will take a detailed look at the structure and properties of each tubeset and their relationship to iconic Seven frames like the Axiom S / SL / SLX.
From Tubes to Tubesets
Seven sources its 3-2.5 titanium straight-gauge tubes—which come in over 35 different diameters, wall thicknesses, and specifications, with an average length of 15 feet (approx. 4.6m)—directly from partner factories based on its own unique specifications.
These tubes must meet rigorous standards, including:
- Resistance to fatigue
- Precision in diameter and wall thickness
- Quality of surface finish
- Straightness
- Concentricity (stability of the tube's central axis)
Only materials that pass these criteria are subjected to Seven’s ultra-butting and custom processing to be crafted into their unique tubesets.
XX Multi-Butted 3-2.5 Titanium
Seven’s proprietary multi-butted titanium, designed for ultimate weight reduction.
By continuously varying the wall thickness throughout the tube, unnecessary weight is eliminated to the absolute limit. It is our lightest tubeset to date.
SL Double-Butted 3-2.5 Titanium
The balanced tubeset that anchors Seven’s material lineup.
This is an all-rounder with an ideal balance of weight, responsiveness, and durability, and it serves as the base configuration for most of our frames.
S-Type (Straight-Gauge) 3-2.5 Titanium
A highly durable, straight-gauge (uniform wall thickness) tubeset.
A practical, performance-oriented tube that combines the strength to withstand long-term use with a relatively reasonable price.
Tube Processing and Butting Technology
What is Butting?
A butted tube is shaped so that the walls are thicker at the ends and thinner in the middle. This process is used to provide extra strength at the points where the frame is welded or joined—areas where stress is most concentrated.
Butting is the technology that makes it possible to maintain strength where it is needed while keeping the frame lightweight.
What is XX Multi-Butted 3-2.5 Titanium?
Based on a more highly refined stress analysis than conventional double-butting, XX Multi-Butted 3-2.5 titanium has its wall thickness optimized at specific points.
This method allows us to create a tubeset that provides high durability and low weight, even in general riding environments.
Butting Methods: Internal vs. External
What is Internal Butting?
Internal butting is a method of thinning the walls from the inside using a mandrel.
- Can only be designed with a wall thickness variance of 40% or less
- Limited freedom in tube size and shape
- Molecular-level stress is applied to the material during processing, making the crystalline structure prone to change
Furthermore, if the material is cooled too quickly after heat treatment, the CSR (Coefficient of Shrinkage Ratio) can rise excessively, creating a risk that fatigue strength will drop significantly.
What is External Butting?
External butting creates a butted shape by thinning the material from the outside of the tube. This offers the following advantages:
- Does not damage the internal crystal structure or grain orientation
- Flexibly adaptable to a wide range of tube sizes and wall thicknesses
- Lower risk of stress concentration from machining marks
From an engineering perspective, external butting is considered an efficient method for maximizing material strength while achieving weight reduction.
Why Seven Uses This Method
Seven has established a unique process that maintains the **grain structure (the orientation of the crystals)** of the tube without causing internal damage. As a result, we are able to provide externally butted tubes that combine high fatigue strength with a supple ride quality.
This process offers benefits such as:
- An optimal balance of strength and weight
- A wide variety of diameter and wall thickness combinations
- A finish free of surface scratches or defects
We take pride in the fact that our original titanium tubesets are at the pinnacle of frame-building, where both performance and quality are pursued.