This posting is a shortened version of a technical paper I wrote for work. I hope you enjoy, and learn in the process! At one time, all bikes were made of steel. Steel has been popular thanks to its strength to weight ratio and ease of use. These factors as well as it’s low cost and availability make it ideal for use in bicycles. The most common type of steel used for bikes is chromoly , and 4130 chromoly is the most widely recognized. So what does chromoly mean and what do the numbers 4130 refer to? Steel is an alloy of iron and other metals. The term ‘alloy’ is commonly used to refer to aluminum but it actually refers to any metal that’s mixed with other elements in order to achieve the desired mechanical properties such as strength, weight, durability, hardness, weldablitly, etc. ' Chromoly ' refers to a specific type of steel alloy that combines Iron with Chro mium and Moly bdenum (chro-moly, get it?) along with small amounts of oth...
The Bike Hive - Indy Professional Bicycle Mechanic