Aluminium mountain bikes
The number 1 material in mountain bike frame construction, especially for fullys. The light metal is processed in various alloys. The high-quality, tried-and-tested types include 6061 or 7000 aluminium, with a T behind it standing for heat treated: to make aluminium durable, it has to undergo heat treatment after welding. The largest aluminium suppliers are Easton (USA) and Alcoa (Aluminium Company of America). For around three years now, traditional steel manufacturers such as Tange (Japan) and Columbus (Italy) have also been producing aluminium tube sets, while Oria (Italy) also stands for mature quality. Experienced manufacturers such as Cannondale, Scott, Rocky Mountain, Rotwild or Canyon and other brands, which have aluminium manufactured to their own specifications and weld it themselves for top frames, vouch for high-quality workmanship.
Carbon mountain bikes
Previously used for exotic prototypes and small series, carbon is now used in mass production. Manufacturers such as Scott, Trek, Giant, GT, Simplon and Merida have paved the way. The processing forms and components are varied and often a secret recipe of the manufacturer. In principle, carbon fibre frames should be processed flat, as tubular shapes do not fully exploit the weight-load advantages of the fibre material. In addition to the weight advantages, carbon fibre scores points for elasticity and damping; the disadvantage is often greater torsion, especially in the headset and bottom bracket area. The only difference between carbon fibre frames and so-called thermoplastic frames is the resin material in which the carbon fibres are embedded and which stabilises the carbon fibres.
Steel mountain bikes
The heyday of steel bikes is definitely over in the new millennium, although chrome-molybdenum steel (Cromoly) can be easily and safely processed for a frame in its various alloys and thanks to the great experience in varying the wall thicknesses. Design as a socket frame (connecting "sleeves" between the tubes) or as filled brazed: the tubes are butt-soldered together by hand. Aluminium manufacturers' competitive prices and increasing experience in the design of aluminium tubes have replaced steel. However, a steel frame can still be a good choice for hard trails for riders up to 75 kilos and bikers who don't like the oversized look and hardness of aluminium or appreciate the elasticity and handling of a steel frame.
Titanium mountain bikes
Precious material for classic hardtails. Significantly lighter than steel, titanium alloys used in bicycle construction sometimes have a higher tensile strength and significantly better corrosion properties. For bike frames, however, the precious material is on the decline due to fully technology and high prices. Titanium frames are difficult to process. Clever designers such as Scott Nicol (Ibis) utilise the elasticity of titanium to construct "sprung" rear triangles without bearings. For purists and lovers of precious materials, titanium is still interesting because of its durability (forms scratch-resistant oxide layers, does not "rust") and its flair, but for the average biker, a titanium bike is too expensive, as the advantages are disproportionate to the price.
