Steel as a Frame Material

• Steel bicycle tubing comes in various wall thicknesses and relatively small tube diameters. Steel is an incredibly hard compound and appropriate bicycle steel tube size has largely remained unchanged. Steel welds are exceptionally strong. Steel compounds vary from manufacturer to manufacturer. A common steel tubeset used in bicycle frame manufacture is double-butted 4130 cromoly alloy steel.
  
  

Aluminum as a Frame Material

• Aluminum is frequently alloyed in various combinations for use as a bicycle frame. Aluminum tubes use larger diameters and multiple shapes--ovoid, triangular, box, etc.--to increase strength ratios. Aluminum is more corrosion-resistant than steel. A common aluminum alloy used in bicycle production is 6001 series aluminum.
  
  

Ride Quality

• Bicycle ride quality is more dependent on tire size, seat and post selection and proper rider fit than frame material, according to Brown. Larger tires are more comfortable than thin tires. Saddles that fit an individual rider's physique are best. Carbon fiber seat posts are more comfortable than metal posts. Proper frame fit is one of the most important aspects of enjoyable cycling. A trusted local bicycle shop is the best place to ask about fit issues.
  
  

Durability

• Aluminum and steel are both durable bicycle frame materials that may provide lifelong bicycle frames when manufactured properly, reports IBF. These materials are both damaged when exposed to the elements, but aluminum decays at a slower speed than steel. Both frames retain stiffness with age when welded properly, but steel is easier to weld than aluminum.
  
  

Exotic Exceptions

• There are many exotic or super-lightweight steel and aluminum alloys that have come and gone in the last century of the cycling industry. Some of these are too new to report on aging properties and some have aged well. Vanadium steel alloys and Scandium aluminum alloy tube sets have seen use for more than a decade in cycling and both have done well. The expense of some exotic alloys renders them unfeasible for mass production and instead these alloys are the preferred choice of many boutique frame manufacturers.