Choosing a Bike Frame Material - Should You Buy Used?

Alex Godbout Simard
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Bike Frame Materials: Understanding the Benefits and Drawbacks of Each

Bikes have evolved rapidly over the last few decades, moving from the original steel frame to lighter alternatives. Today, there are multiple options of frame materials to choose from, making the decisional process a bit harder, especially for pre-owned bikes.

Aside from the bike types, you need to understand the materials used in the frame. A steel road bike might not be ideal for professional riders looking for the pinnacle of racing performance. However, it would be perfect for adventurers who are not necessarily in a hurry. The following article will give a clear insight into the four most common frame materials and what makes them unique.

Steel Frames: Are they still relevant in 2021?

Steel has been around for a long while in the cycling world, but it doesn't mean it’s past its prime. Albeit heavier than carbon or aluminum alternatives, steel is praised for its ability to absorb vibrations and bumps in the road. Its durability is also second to none: a skillful mechanic might be able to bend some sections of the frame back to their original shape after an incident. It’s also easy for a specialist to weld the tubes back together if needed.

These are the main reason why steel is making a strong comeback in the adventure and bike-packing world, where comfort and reliability are of the essence.

But because of its weight, it would be almost impossible for a steel bike to incorporate modern aerodynamic shapes and design. It also doesn't have the same lateral stiffness that other materials can provide, making it a poor choice for a cyclist looking to gain every ounce of speed from his bike when pushing hard on the pedals or during a sprint.

But since not everybody is racing for time, steel has made quite a resurgence in the last few years, especially in the gravel bike world where all day comfort is more important than shaving a few seconds.

In the used market, buyers need to be aware of rust marks when browsing for an older steel bike. Rust usually appears where the pain has been scratched. Newer steel bikes are made of better-quality steel that is less prone to corrosion. They also have the latest bottom bracket and headset standards, so swapping parts is much easier.

If you are not in a rush, a steel bike will be the perfect adventure companion. They have been the trusty steeds of many adventures around the world and their reliability has been proven again and again. Just don't expect to see one win the Tour the France in the 21st century.

Pros of Steel Frames:

  • Comfortable: naturally dampens small vibrations
  • Reliable: Can be bent back in shape after a crash

Cons of Steel Frames:

  • Heavier than most available options
  • Not very aerodynamic

What is the difference between Chromoly and Alloy?

Chromoly and Alloy are two words we hear often in the world of cycling. Even if they are more scientifically accurate than to plainly say Steel or Aluminium, they don’t help a lot when it’s time to differentiate frame materials.

By definition, alloy is a metal made of two or more metallic elements. Simply put: all the different bikes that are made of metal, from steel to titanium, are alloy bikes, since the metal they use is always a composite of many elements, and never pure metal. A pure aluminum frame, without other metallic elements, would be shockingly soft!

Chromoly is another type of steel alloy which is combined of mostly chrome and molybdenum, thus the acronym: Chromoly. All steel frames are, in a way, Chromoly frames. Different grades of Chromoly steel are used depending of the kind of bike: A BMX will use a stronger but heavier alloy compared to a lighter road bike that does not need to survive big impacts.

Aluminum Frames: Best budget king?

Aluminum, or aluminum alloy, was one of the first alternative materials to come to market. The first generation of aluminum bikes was oversized with rough designs and large tubes. Their reduced weight and the ability to form the tubes into different shapes made them very appealing.

Nowadays, aluminum is used for most bikes you’ll find in the shops. The material is not as expensive to produce as it was in previous years. Aluminum 6061 is commonly used for bike frames. After years of development, these bikes are now much lighter and durable. The downside of this would usually translate into a harsher ride. Unlike steel and some carbon frames, aluminum bikes are not known to be very forgiving if the roads are bad, thus reducing the overall comfort of the rides.

While it still might be slightly heavier than carbon for a road bike, cutting-edge fabrication techniques now allow manufacturers to form this material in aerodynamic shapes whilst keeping the bike reasonably light. Aluminum is also now widely used for mountain bikes since it can take a beating and still be relatively light. Aluminum is still the jack of trade in the cycling world: It's lighter than steel, affordable, easy to shape, and offers great reliability.

Being less expensive than its carbon fiber counterpart, an aluminum bike will have better components all-around at a slightly lower price. The bike will be a bit heavier, but for some cyclists, components quality trumps the weight penalty. The major drawback of aluminum is the fact that it is quite hard to repair- even impossible- if the frame is cracked or bent. Aluminum is notoriously harder to weld than steel and very few people have the knowledge and tool required to repair an aluminum weld.

The aluminum bike is a lightweight, yet durable bike for weekend riders, but can also be used for competition or cyclists looking to gain some speed without breaking the bank.

Pros of Aluminum Frames:

  • Cost effective option
  • Can be slightly aerodynamically optimized

Cons of Aluminum Frames:

  • Almost impossible to repair
  • Harsher ride quality

Carbon Fiber – Still the best performer

Carbon fiber, which used to be reserved for only the best road bikes, is now being utilized in many different types of bikes at very interesting price points. The process of making carbon fiber frames is very different from the traditional tube welding fabrication: Paper-like sheets of carbon fibers, called layups, are stacked on top of one another in a mold and bonded together with a special epoxy ‘’glue’’. The multilayer ‘’sandwich’’ is then put into a vacuum bag and cured in an oven at high temperatures.

Carbon fiber is a light material, but once cured, it becomes very strong and resilient. Unlike the frames made of metals or alloy, carbon does not fatigue. This means that, unless the bike gets damaged during a crash, the frame could last more than a lifetime.

The ability to fine-tune the layups gives carbon fiber frames gives engineers the capability to target specific zones where the bike should be stiff for power transfer and where to be more compliant for comfort. The bottom bracket area, where most of the power transfer is happening, is usually super stiff, to make sure that every watt is going to the rear wheel. The seat stays, which are only there to support the rider, can be designed to flex and absorb vibrations from the road.

Carbon fiber has very few weaknesses, but it can be a bit fragile if not handled correctly. Clamping the frame just a bit too strongly on a bike rack is a common way people crack their frame. It also has more chance to be seriously damaged during a crash. But, contrary to popular belief, carbon fiber repair specialists can make wonders and repair almost any damage or crack. Carbon fiber might be the easiest material to repair of all the materials we covered today. The cost of the repair is often worth it since a carbon frame could be worth a few thousand dollars.

From the Tour the France to the gnarliest Downhill World Cup, carbon fiber bikes are used at the biggest competitions around the world. Many weekend riders also prefer these bikes for their lighter weight and unparalleled performance. Carbon fiber is the perfect combination of strength and weight. The popularity of the material brought the price point down by a lot in recent years and more people can now enjoy the pinnacle in frame material technology.

The carbon fiber bike is the ultimate bike on the market, it stands tall in every comparison and offers the perfect durability to weight ratio.

Pros of Carbon Fiber Frames:

  • Best stiffness to weight ratio
  • Comfortable and aerodynamic

Cons of Cabon Fiber Frames:

  • More expensive for the same specs
  • Very durable but must be handled with a bit more care

Titanium – What’s the hype all about?

PrTitanium is a versatile material that is widely used in a lot of high-end components in cycling and other industries where performance is key. Some of the most beautiful bikes, according to some, are made of Titanium. But you must be willing to pay the price since it requires a very skilled manufacturer to make them. It has features similar to steel but is even lighter, stronger and stiffer. The only drawback would be the slight loss of comfort because of the added stiffness. The reduction in weight is greatly appreciated by adventure seekers who are doing long endurance races where reliability and weight are as important.

Prices are often higher than carbon fiber bikes: the raw material is more expensive, and the product is more niche. That being said, you can still find some incredible deals that will give you value for your money because of its durability. They are used in all weather conditions and won't rust like a steel frame might do overtime if the paint has been chipped. They are often easy to spot because of their bare metal finish and blue hues in the welds. Many manufacturers are offering to custom build the frame and tailor the geometry to the client’s needs. Just like in F1, titanium parts can also 3D printed to create some astonishing bike parts.

In the used market, Titanium bikes can be handover like a family heirloom. If well taken care of, Titanium bikes can last for decades. Although, compared to its carbon counterpart, it will suffer from fatigue over time if ridden tens of thousands of kilometers every year.

Pros of Titanium Frames:

  • Extremely Durable, yet lighter than steel
  • Unbeatable look and finish

Cons of Titanium Frames:

  • Harsher ride quality than steel
  • Few options widely available

Conclusion – Which frame material is right for you?

As you might have seen, each of these materials has a different purpose. The purpose they serve makes each one of them great for specific riders. These are by no means all the materials used in the bike industry. A simple search will show you that materials like bamboo, plastic, and graphene have also been used.

Cost is always a determining factor when browsing for a new bike and Aluminium and Steel will- most of the time- represent the best value for money. For outright speed, aerodynamics, weight, and rigidity, Carbon fiber bikes are still king. New and improved layups are coming out every year for the road. Steel would be one of the best adventure companions if the goal is to enjoy the journey more than the destination. If you are dreaming of a light and durable forever bike, go for a Titanium frame and never look back.