Steel: the Frame Material

"This Penny Farthing bicycle was made at ...Steel is mistaken as the original material used to build the first bicycle. The first bikes were actually made of wood. Why not? It was plentiful and easy to work with. Steel came along with the high wheel bicycle.

What do you need to know about steel as a frame material? First off, it is a “soft” metal. Soft as in it is flexible. That’s why you see steel commonly used in things like springs, coil or leaf. It can flex quite a bit before failing. Don’t worry, you won’t be able to flex a steel frame to the point of failure. As such, this makes for an ideal bicycle frame because bicycles started out without suspension. The ability of steel to flex allows the frame to soak up road vibration and shock, making for a comfortable ride.

This might explain why some riders are so passionate about steel. For long distances, rough roads, in addition to a long fatigue life, a bicycle owner has a bike that could stay with him/her for quite some time. Let’s get to the nitty-gritty of this material after the break.

There are different kinds of steel that are used to manufacture bicycle frames. The most plentiful being high tensile steel.This version is use in mostly entry level bicycles or mass produced bikes that are generally inexpensive. The next level of steel tubing is commonly referred to as “cro-moly,” which is short for Chromium-Molybdenum. These two elements are combined with the iron to make steel stronger, therefore less material is needed. This in turn lightens the material. You may have heard the term “4130” thrown around when talking about steel. That is the most common form of cro-moly tubing. There is a lesser form known as “1020” as well. Knowing these number allows you to know how good the steel is. Better cro-moly tubing uses the 520, 631, and 835 designations. They go higher than that, which also makes the price rise as well. The numbers actually refer to the makeup of the steel alloy. Some steel tubing manufacturers replace the number with a product name. If you want a quick lesson on steel as a frame material, go on over to Ibis Bicycles for a very good article on the subject.

As a side note, don’t get *alloy* confused with aluminum. All metals used in manufacturing are alloys, which means different metals are combined to make the resulting material stronger, or more resistant to corrosion.

Let’s list the pros and cons of steel.

  • Tough. Steel, even though it is “soft”, is hard in relation to other frame materials. It resists denting fairly well so there’s not much to fear when it tumbles. It can even be bent back in certain circumstances if need be, without breaking (However, there is a limit to that).

  • Soft. As I explained earlier, this characteristic allows the frame to flex with road shock and absorb vibration as you ride. This in turn lessens the fatigue on your body. This makes for a comfortable ride.

  • Less expensive. Now this is relative. As a material it is less expensive in the entry level bicycles, but not by much now that aluminum is easier to process. Steel, depending on its specific tubing, can get quite expensive. Especially in the hands of a skilled custom builder.

  • Repairable. Okay, this is a subject of great argument. In reality, any frame material is repairable, to a point. Some frames are easier to repair than others. If you were stuck in the middle of a bicycle tour out in the middle of nowhere and your steel frame breaks or cracks, as long as you can find a competent welder, it can be repaired. The same can’t be said for aluminum and titanium, which require specific skills and equipment to weld properly; or carbon fiber, which requires a remarkable amount of skill, and even more specialized equipment to repair. At its most basic, all you need is a MIG welder to put two steel tubes together.

  • Heavy. Like cost, this is relative to the type of steel used. Frames made from high end steel tubing can rival the weights of aluminum and some carbon fiber frames.

  • Corrosion. Rust as it’s commonly known. Steel can rust. There are things you can do to prevent 99% of it, but realize that if you quit fighting this battle, rust eventually wins through attrition.

  • Stiffness. Because it is soft, frames tend to not be as stiff as aluminum or carbon fiber. Through tube shape manipulation, this flex can be minimized, but again, you will have to pay for it.

  • Availability. Bicycle companies don’t make a lot of steel bikes. They generally have a few models in niche bicycle models. Many custom frame builders use steel.

There’s more than enough information here to give you a dangerous grasp of steel as a frame material. To see some beautiful examples of steel in the form of a bicycle, check out Stanridge Speed, a frame builder in Columbus, Ohio; and Waterford Precision Cycles, a builder who has had hands in bicycle history.


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