Last time, we talked about bike types or styles and price points. Today, we will take a survey of the various frame materials from which bike frames are made.
If you have decided on a hybrid bike or any of the variations from there, you probably are limited to the frame material that your particular bike is available. That will probably be either steel, in the less expensive variations, and then aluminum or nicer grades of steel as price points go up. If, however, you are looking at a mountain bike or road bike, you will have your choice of steel, aluminum, titanium or carbon fiber in a wide variety of price points. Here are a few thoughts on each.
Steel - Bikes have been made from steel for a long time. They have a particular "lively" feel which causes proponents of steel to say, "Steel is Real." Yes, steel is real, real Victorian. Butted steel bikes were made literally in the Victorian era. Admittedly, steel technology did advance a lot after that; all the way up until WW II. Really. Reynolds 531 tubing was introduced in 1935.
Oh, the steel aficionados will want to argue about it, but the reality is that steel is a great and practical material for bike frames. It is not surpassed for practical bikes, but even though steel lovers will talk about the spring, the liveliness or the character of their bikes, if you are considering characteristics beyond practical, pragmatic or cost, you will probably wander into other materials.
Aluminum - Aluminum has a higher strength to weight ratio than steel, so a well-made aluminum bike typically weighs less than a steel bike. A cheap aluminum bike may be heavier, however, also due to the characteristics of aluminum. In order to achieve the same strength and durability, the aluminum tubes have to be larger than steel and the result of the larger size and underlying properties means that an aluminum frame will generally be stiffer than steel - nice for acceleration, but can be fatiguing. Aluminum is more difficult to weld and early models had some welding/joint issues, but like steel, and aluminum bike can take some abuse and minor dents won't destroy the integrity of the frame as a whole. Compared to a steel bike, expect to spend more, have it weigh less, be stiffer and expect your friends to comment on your bike being made out of recycled beer cans.
Titanium - Titanium is a nice combination of steel and aluminum characteristics - it is lighter material than steel in the same strengths and it is less rigid than aluminum. It is also very corrosion resistant and like steel and aluminum, is not subject to failure (or collapse) with minor dents or crashes. On the other hand, it is a much more expensive material and much harder to weld and work. As a result, it is an expensive frame material and takes more skill to combine the positive attributes with the negatives. It is possible to end up with a noodly titanium frame, so care needs to be taken in selecting a maker and expect to pay for the privilege.
Carbon Fiber - Carbon fiber is an excellent material for the most demanding bike frames. It is possible to create a frame that weighs much less than any other material and, with enough expense and engineering, it is possible to build in almost any combination of stiffness, flexibility or characteristics sought in a frame. Not surprisingly, this material and engineering comes at a steep price. As with the other frames, inexpensive carbon frames exist, but often you get what you paid for, with a stiff but clunky and not necessarily light frame. On the other extreme, with enough money (literally $10,000 plus for the frame alone), you can achieve an extremely light, extremely stiff for pedaling forces and turning but compliant for ride comfort frame. But, this wonder material comes with a big downside, which is less resistance to crashes or the potential for failure of the frame from the same impact that any of the other materials would handle. The good news - no dents. The bad news - it goes straight from fine to broken.
So with those comments, what is the right material for your bike frame? That is strictly dictated by what you want to do with your bike and how much you want to spend. If you are a professional that will be handed a new bike after a crash and your only objective is to win a race, then carbon fiber is the way to go. If you are a non-professional that has to buy your bikes and have goals beyond getting to a finish line first, then despite its sex appeal (which has gone a bit amuck as you can find damn near everything made from carbon fiber - literally including plates and coffee mugs), the other materials warrant a good hard look.
The reality is that very nice bikes can be made from any of these materials. Any of them can also produce bikes that aren't fun to ride. What I would suggest is consulting with a local bike shop and getting some help finding the right bike for you.