Buyer's Guide Topics

Materials Guide

If you really want to enjoy cycling, you'll want a bike that's durable, efficient, comfortable and easy to use.  To a large extent this is determined by the materials used for the frame and components.

This guide is split into 2 sections:

1. Frame materials
2. Component materials

Frame materials

The materials that make up the frame influence its weight, strength, rigidity, comfort, efficiency and price.

Steel

Steel is cheap but it is heavy and also rusts.  Cheaper and older bikes might still have steel frames and components, but it is becoming increasingly rare as the prices of the alternatives come down.  Steel-framed bikes are slow and heavy and will tend to rust.

Be Aware!  "High Tensile Steel," "Hi Performance Steel," "Lightweight Steel" - they generally mean the same thing: Steel.

Steel alloy

Steel alloy is much stronger than steel.  Chrome-molybdenum steel, often abbreviated to chrome-moly or chromoly, is a commonly used material for bicycle frames.  Due to its increased strength, tube walls made of steel alloy can be thinner and lighter without any loss of strength or reliability.  It is more expensive than steel but it will still rust!

Aluminium

Aluminium (or Aluminium alloy) is the most commonly used material for good quality modern bikes - it doesn't rust, it's much lighter than steel, and it has an excellent capacity to absorb road shock.  An aluminium frame can be about 20% lighter than an equivalent steel alloy frame.  As you might have guessed, aluminium is more expensive than steel alloy.

Be Aware!  "Alloy" on its own could mean "Steel Alloy" or "Aluminium Alloy" - there's a big difference!

Carbon Fibre

Carbon fibre is even lighter still and is often used on top-of-the-range road or mountain bikes.  Carbon fibre is rigid, light, very strong and doesn't rust.  Of course, it is also very expensive.

Titanium, Kevlar and other high-performance materials

These specialised materials can make for extremely lightweight and stiff frames, but are very expensive and usually only available from a few specialised manufacturers.

Note:  Changing the cross-sectional shape of the tubes used to make a bicycle frame can have many advantages.  Oval tubing can help to streamline a bike (important for road racing machines or time trial bikes), and the oval shape can offer significant strength advantages over round tubes.  However, building oval tubes is far more expensive than building round tubes.

Components

The materials used in components determine how long they will last, how easy they are to maintain and how smoothly they work (the more smoothly they work the more efficiently the rider's effort is used to drive the bike forward).  Lightening the moving parts of a bike will greatly improve its efficiency.  The suitability and compatibility of components can be as important as quality: there's no point having an elite racer's wheels (designed to be light, not strong) on a touring bike that needs to carry heavy loads.

Be Aware!  The components used on cheaper bikes are often disguised to look like they're made from more expensive materials.  The most common examples are chrome-plated steel (which looks like stainless steel), or plastic painted an aluminium colour.  Don't be fooled!

New chrome-plated steel forks might look good, but they're very heavy and will rust as shown below.  These rust spots will damage the rubber seals, allowing dirt into the forks that will grind away or seize them up.

Some components and their materials:

• Wheels (Rims, Hubs and Spokes):  Poor quality, cheap wheels (as sold with many cheap bikes) will be far more prone to buckling, particularly if ridden over rough ground.  All good quality bikes are fitted with aluminium alloy rims because they are lighter and stronger than the cheaper steel variety.  Brakes also work far better on aluminium than on steel, particularly in wet weather.  More expensive hubs will be made of aluminium alloy which will be more durable and will not rust.  Spokes can be made from chrome-plated steel (weak and prone to rust), galvanised steel (which is strong, rustless and reasonably priced), or stainless steel, which makes the best, though most expensive spokes.  Note: The inertia of a wheel is magnified several times by rotation.  Reducing the weight of your wheels is an extremely effective and relatively inexpensive way of making a bike feel light and fast.
• Brakes:  Smooth and effective brakes require little pulling effort and will stop you immediately in an emergency.  Good quality brake levers will be made of aluminium as opposed to plastic or resin coated steel, which are much more heavy and likely to rust and seize up.  Brakes work far better on aluminium rims than on steel rims, particularly in wet weather.
• Drivetrain (Pedals, Bottom Bracket, Cranks, Chain and Sprockets):  Lightweight moving parts can greatly improve the efficiency of your bike.  A good quality bike will use aluminium as opposed to steel for many of the drivetrain components.
• Shifters and Derailleurs:  Cheap shifters and derailleurs made of steel and plastic will quickly become rusty, sticky and ineffective.  Due to the harsh conditions these components need to endure, good quality materials have to be properly treated (anodised or case-hardened) to ensure they are durable and remain effective.

Too many technical terms?  Read more about components in our Jargon Buster