Learn How to Build a Bike From Scratch

Understanding Bike Frame Types and Materials

Building a bike from scratch begins with understanding the frame—the foundation of your entire bicycle. The frame serves as the structural backbone, connecting all components and determining how your bike handles, feels, and performs. Different materials offer distinct advantages and disadvantages, and your choice will affect cost, weight, durability, and maintenance requirements.

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Steel frames remain popular among builders and riders worldwide. Steel offers excellent strength-to-weight ratios and can be shaped through welding and bending. A typical steel frame weighs between 2 to 3 pounds, depending on tube diameter and wall thickness. Steel absorbs vibrations well, creating a smoother ride on rough terrain. The material requires regular maintenance to prevent rust, though quality paint and proper storage can extend a steel frame's lifespan to 20 years or more. Steel frames cost between $150 to $400 for quality options.

Aluminum frames have become increasingly common due to their lightweight properties and resistance to rust. Aluminum frames typically weigh 30 to 40 percent less than comparable steel frames. A standard aluminum frame weighs around 1.5 to 2.5 pounds. However, aluminum is stiffer than steel, which means it transfers more road vibration to the rider. Aluminum frames are durable when properly manufactured but cannot be easily repaired if cracked or bent. Aluminum frame costs range from $200 to $600.

Carbon fiber represents the premium material option. Carbon frames offer the best strength-to-weight ratio of any common bike material. High-quality carbon frames weigh as little as 1 pound or less. Carbon provides excellent vibration dampening and can be shaped into aerodynamic designs. The material is fragile compared to metal frames and requires careful handling. Carbon frame repairs are difficult and often uneconomical. Expect to pay $400 to $1,500 or more for quality carbon frames.

Titanium frames combine many advantages of steel and aluminum. Titanium offers superior strength, weighs less than steel, and resists corrosion without paint. Titanium frames have a lifespan exceeding 30 years. The material is expensive—frames cost $800 to $2,000—and requires specialized welding equipment and expertise.

Practical takeaway: Select your frame material based on intended use, budget, and maintenance commitment. Steel suits builders prioritizing durability and traditional aesthetics. Aluminum works well for riders wanting lightweight performance at moderate cost. Carbon fiber and titanium suit riders with specific performance goals and higher budgets.

Selecting and Installing the Bottom Bracket and Crankset

The bottom bracket and crankset form the pedaling system of your bike. The bottom bracket is a bearing assembly that allows the crankset to rotate smoothly. Understanding bottom bracket standards and compatibility is essential, as incorrect sizing will prevent proper installation.

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Bottom brackets are sized by shell diameter and width. The standard bottom bracket shell diameter for modern bikes is 1.37 inches (34.8 millimeters). Bottom bracket width varies—most modern bikes use either 68 millimeters or 73 millimeters. The type of bottom bracket you choose depends on your crankset's spindle diameter. Common spindle sizes include 1.37 inches for older bikes and 1.1 inches for newer designs. Always verify your frame's bottom bracket specifications before purchasing components.

Sealed cartridge bottom brackets represent the most common option for new builders. These units arrive pre-assembled and sealed against water and dirt. Installation involves inserting the cartridge into the frame's bottom bracket shell and tightening the cups. A bottom bracket tool—typically costing $15 to $40—is necessary for proper installation. Sealed cartridge bottom brackets cost $30 to $150 depending on quality and bearing type.

The crankset connects to the bottom bracket spindle and converts your leg power into forward motion. Cranksets consist of crank arms, chainrings, and pedals. Crank arm length ranges from 160 to 180 millimeters, with 170 millimeters being most common. Longer arms provide more mechanical advantage but limit ground clearance on mountain bikes. Chainrings are the large circular gears attached to one crank arm—most bikes have one to three chainrings.

When selecting a crankset, match the spindle diameter to your bottom bracket. Verify that your frame's clearance accommodates your chosen chainring sizes. Measure the distance from the bottom bracket center to the frame's chainstay to ensure chainrings won't strike the frame. Road bikes typically use larger chainrings (50 and 34 teeth), while mountain bikes use smaller ones (30 and 40 teeth) for climbing control.

Installation begins with inserting the crankset into the bottom bracket. One crank arm has a crank bolt; the other uses a pinch bolt system. Tighten the crank bolt to 350 to 450 inch-pounds—over-tightening can strip the spindle. After one month of riding, check and re-tighten all crankset connections, as components settle with use.

Practical takeaway: Document your frame's bottom bracket specifications and spindle requirements before purchasing any crankset. Use proper tools and torque specifications during installation to prevent component damage. Check all connections after your first month of riding.

Building the Wheel Systems

Bicycle wheels represent complex assemblies involving hubs, spokes, and rims. Building wheels requires precision and understanding of spoke tension, wheel truing, and component compatibility. For most builders, purchasing pre-built wheels represents a practical option, though understanding wheel construction enhances your ability to maintain and repair bikes.

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Wheel size is designated by rim diameter measured in inches or millimeters. Common road bike rim sizes are 700c (622 millimeters), which accommodates tires ranging from 20 to 32 millimeters wide. Mountain bike wheels use 26, 27.5, or 29-inch rims, each paired with appropriate tire widths. Match your frame design to wheel size—most frames accommodate a single wheel size only.

Hubs are the rotating assemblies at wheel centers. Road bike hubs typically contain sealed cartridge bearings requiring minimal maintenance. Mountain bike hubs often feature cartridge bearings as well, though some use cone-and-race bearings allowing for adjustment and maintenance. Hub flanges—the wide sections where spokes attach—vary in diameter. Larger flanges create stiffer wheels suitable for heavy riders and rough terrain. Standard hub spacing for road bikes is 100 millimeters (front) and 130 millimeters (rear). Mountain bikes typically use 100 millimeters (front) and 135 millimeters (rear).

Rims are the circular aluminum or carbon structures that hold tires and brake pads. Rim width affects tire fit and handling characteristics. Wider rims (internal width of 23 to 35 millimeters) pair with wider tires for better traction and comfort. Narrower rims (16 to 19 millimeters) work with road tires and reduce rolling resistance. Select rims compatible with your brake system—rim brakes require specific rim profiles with smooth, flat braking surfaces, while disc brake systems allow more rim design flexibility.

Spokes connect the rim to the hub and transfer pedaling forces. Standard spoke count is 32 spokes per wheel, suitable for riders up to 200 pounds. Lighter riders and wheel sets designed for speed may use 24 or 28 spokes. Heavier riders and cargo bikes may use 36 spokes for increased durability. Spoke length varies based on rim and hub dimensions—incorrect spoke length prevents proper wheel assembly.

Pre-built wheels from reputable manufacturers provide superior quality and reliability compared to hand-built wheels for new builders. A quality road wheel pair costs $200 to $400; mountain bike wheels range from $300 to $600 per pair. If you decide to build wheels yourself, expect to invest in a spoke wrench ($10 to $30), wheel truing stand ($80 to $300), and detailed instructional resources. Hand-building wheels requires several hours of practice to achieve proper spoke tension and wheel trueness—wheels must be perfectly circular and laterally aligned for safe operation.

Practical takeaway: Determine your frame's wheel size and brake type before purchasing wheels. For most builders, purchasing quality pre-built wheels saves time and reduces the risk of safety issues. If building wheels yourself, invest in