BMX Glossary

Name Description
1020 Hi-Ten Steel Simple and cost-effective, non-alloyed steel with significantly lower tensile strength than Chromoly Steel (CrMo Steel).
4130 CrMo Steel Steel alloy composed of carbon, chromium, and molybdenum. Chromium and molybdenum provide higher strength and stiffness compared to conventional steel like 1020 Hi-Ten.
4140 CrMo Steel Steel alloy composed of carbon, chromium, and molybdenum. Unlike 4130 CrMo Steel, 4140 CrMo has a higher carbon content, making it harder and more wear-resistant but also more challenging to weld.
6061 Aluminium Aluminum alloy used in the manufacturing of BMX Race frames and parts like stems, rims, or chainrings.
6066 Aluminium Alloy of aluminum, magnesium, and silicon. Known for its high strength, stiffness, and corrosion resistance, used in BMX parts such as brakes.
7005 Aluminium Strong, stiff, and lightweight alloy. A good choice for BMX parts requiring a balance of strength, stiffness, and weight, occasionally used in BMX rim production.
7075 Aluminium Aluminum alloy used in the production of BMX parts like chainrings, axles, or hub guards. An age-hardened alloy with zinc, magnesium, and copper as its main alloying elements, providing high strength, stiffness, and toughness.
8-spline / 48-spline (Crank) Splines are grooves or indentations on the crank axle. More splines mean more contact points, resulting in a tighter fit of the crank arm on the axle. The number of splines determines the type of cranks compatible with the axle.
Aero Rims Aero rim profiles have a higher and consistently semi-circular shape without brake surfaces. They are usually lighter but can only be used without brakes.
China-BB China-BB stands for "Chinese Bottom Bracket" and was developed by BMX brand Fareast Cycles specifically for BMX Flatland. China-BB bottom brackets are threadless and have a diameter of 31mm, using the same bearing size as EuroBB BMX bottom brackets.
CNC CNC stands for Computer Numerical Control. CNC milling is a manufacturing process where a computer-controlled tool removes material from a workpiece. The tool can move in three dimensions to create complex shapes.
Double Wall Rims Double Wall rims have multiple chambers or walls in their cross-section, making them stiffer and more stable but also slightly heavier than Single Wall rims.
Wire Bead Tires Wire bead tires are a type of bicycle tire with a steel wire bead in the tire's edge. This wire ensures the tire maintains its shape and does not come off the rim. Wire bead tires are the most common type of tires for bicycles and offer a good balance of price and performance.
Euro-BB (Bottom Bracket) Euro-BB stands for "European Bottom Bracket" and was introduced as a new standard in Europe to solve compatibility issues in the bicycle industry, especially between Italy, France, and the UK. Euro-BB bottom brackets have threads where the bearing cups are screwed in and a diameter of 35mm, commonly used in BMX Race frames.
Folding Tires Folding tires are a type of bicycle tire without a steel wire bead. Instead, the tire is held together by a bundle of Kevlar threads. These threads are very durable and keep the tire in shape despite being lightweight.
Cast, Casting, Investment Cast Casting is a manufacturing process where liquid metal is poured into a mold and solidifies. This method is used, for example, in the production of stems or details on BMX frames (including chainstays, dropouts, seat clamps) to achieve complex shapes and details.
Weight The heaviness of a BMX part, measured by weighing. It's worth noting that weight specifications for BMX parts can vary and may not always be precise. Several factors contribute to this:
  • Manufacturer's weight specifications may be inaccurate or incomplete.
  • The weight of two identical parts can also differ.
  • We cannot weigh every individual part.
For example, if there are handlebars in different heights, the manufacturer usually provides a weight specification for all heights. When weighing two identical tires, you might get two different results.
LHD / RHD (Crank, Hub) RHD stands for "Right Hand Drive" (right side), LHD for "Left Hand Drive" (left side), indicating the side where the drive, including chainring, chain, and driver of the rear hub, is located. When buying cranks and rear hubs, it's essential to ensure compatibility with the corresponding drive side.
Linear-Slic Cables

Linear-Slic cables are an evolution of Slic cables. They are made from a special material with even lower surface friction than traditional Slic cables. This ensures the cables run even smoother through the cable housings and cause even less friction. The linear arrangement of the steel wires makes the cable flex even less, resulting in a much more precise brake feel.

Advantages of Linear-Slic cables:
  • Smooth braking
  • Consistent tension
  • Precise brake feel
  • Low maintenance
  • More durable than traditional Slic cables
Disadvantages of Linear-Slic cables:
  • More expensive
Loose Ball (Bearings) Loose Ball is a term used for bearings without seals. These bearings are more susceptible to dirt and water, leading to a shorter lifespan and poorer performance. Loose Ball bearings are commonly used in the following components of budget BMX bikes:
  • Bottom bracket
  • Front hub
  • Rear hub
  • Headset
Advantages of Loose Ball bearings:
  • Cost-effective
Disadvantages of Loose Ball bearings:
  • Shorter lifespan
  • Poorer performance
  • More maintenance required
Low Pressure / High Pressure Tires The term "Pressure" describes the maximum tire pressure of a BMX tire. In BMX, there are two types of tires depending on tire pressure, typically with the following maximum values:
  • Low Pressure Tires: maximum 60 PSI
  • High Pressure Tires: maximum 100-120 PSI
Mid-BB (Bottom Bracket) Mid-BB stands for "Mid Bottom Bracket." It is currently probably the most widespread standard for BMX bottom brackets. Mid-BB bottom brackets are threadless and have a diameter of 41mm; they cannot accommodate one-piece cranks.
Press Fit (Bottom Bracket, Hub) Press Fit, also Pressure Fit, describes the stable connection of two parts through pressure. This principle is mainly used in industrial bearings or sealed-bearing (SB) bearings, which are pressed into the hub or bottom bracket.
Sealed-Bearing (SB Bearings) Sealed-Bearing (SB), also known as encapsulated bearings, are bearings where the bearing rings are enclosed in a plastic housing. This housing protects the bearings from dirt, water, and other contaminants. SB bearings are frequently used in BMX bikes for the following components:
  • Bottom bracket
  • Front hub
  • Rear hub
  • Headset
Advantages of SB bearings:
  • Long lifespan
  • Better rolling properties
  • More resistant to dirt and moisture
  • Require less maintenance
Disadvantages of SB bearings:
  • More expensive than open bearings
Single Wall Rims Single Wall rims consist of only one layer in their cross-section. This makes them light and cost-effective to manufacture but also less stable.
Slic Cables

Slic cables are a type of brake cables known for their smooth operation and low friction. They consist of a brake cable inner core made of steel or stainless steel, surrounded by an outer sheath made of Teflon or another low-friction material.

Advantages of Slic cables:
  • Relatively long cable lifespan
  • Low maintenance
  • Affordable
Disadvantages of Slic cables:
  • Softer brake feel
Spanish-BB (Bottom Bracket) Spanish-BB stands for "Spanish Bottom Bracket" and was invented in 2005 by the Spanish BMX brand Flybikes. Spanish-BB bottom brackets are threadless and have a diameter of 37mm; they cannot accommodate one-piece cranks. They are commonly used in BMX bikes for kids and BMX Flatland.
Straight Wall Rim Straight Wall rim profiles have a straight wall construction on the sides, also called brake surfaces. They are suitable for rim brakes. Straight Wall rims are the most common rims in BMX.
US-BB (Bottom Bracket) US-BB stands for "United States Bottom Bracket" and is also called American Bottom Bracket. It is a bottom bracket standard originating in the United States. US-BB bottom brackets are threadless and have a diameter of 51mm, allowing for the installation of one-piece cranks. Older or entry-level BMX bikes often have this type of bottom bracket.