Knowledge

Basics

• Convert a Bike to an E-Bike: Overview and Steps

  What a conversion costs, which motor fits, what the law says and when you should buy a used e-bike instead. An honest overview from the workshop.

• E-Bike Conversion Motor Types Compared

  Front, rear and mid-drive motors, friction rollers and seat-tube motors compared: feel, installation, cost and which bikes suit which.

• Mid-Drive or Hub Motor: What Suits You?

  Ride feel, hills, gears, installation and cost compared, with a clear guide to when a mid-drive and when a front or rear hub motor makes sense.

Measuring and fit

• Measure Your Bottom Bracket for a Mid-Drive

  How to measure shell width and bore of your bottom bracket and tell BSA 68/73, Pressfit and BB30 apart. Step by step for a mid-drive motor.

• Hub Spacing and Axles for an E-Bike Conversion

  How to measure hub spacing, quick release versus thru-axle, spreading 130 to 135 mm on steel frames and what to watch with dropouts.

• Wheel Sizes and ETRTO for E-Bike Conversions

  Inches are unreliable, ETRTO is not: how to read wheel size off the tyre and avoid the 635/622 and 406/451 traps.

• Frame and Weight: Which Bike Suits a Conversion

  Steel and aluminium are usually fine, carbon is not. Plus the magnet test, total weight, warranty and the wear parts to replace before converting.

Parts and accessories

• Coaster Brake and E-Bike Conversion: What Works

  A coaster brake is the most common deal-breaker. Which motors work, where coaster-brake variants exist and when to leave it.

• Brakes for an E-Bike Conversion: What You Need

  Rim or disc, cut-off levers and sensors: which brakes are enough for a 250 W pedelec and when an upgrade is needed.

• Torque Arm: When You Need One

  Why the axle of a hub motor turns in the dropout, when you need a torque arm and how to fit it.

• E-Bike Battery for a Conversion: Position, Space, Range

  Where the battery fits on a converted bike, how to measure the space, what branded cells bring, real-world range and how to dispose of it.

• Tools for an E-Bike Conversion: The List

  Which tools you need for front, rear and mid-drive conversions and what kits usually lack, above all the lockring tool.

Planning and law

• What Does an E-Bike Conversion Really Cost?

  Cost items at a glance: kit EUR 400 to 1,700, brakes, tools, small parts. Plus the comparison with used and new (about EUR 2,500) and the cost calculator.

• Pedelec Law: 250 W, 25 km/h and Walking Assist

  What a conversion may do legally: 250 W rated power, assist only while pedalling up to 25 km/h, walking assist up to 6 km/h and what lies beyond.

• Common Problems After an E-Bike Conversion

  Axle spinning, broken spokes, motor cutting out, jerky starts, fast chain wear: causes and fixes from everyday conversions.

• E-Bike Conversion Glossary: Terms Explained

  Rated power, volts, watt-hours, newton metres, PAS, torque sensor, Higo and Julet, controller and display: the glossary for e-bike conversions.

By bike type

What usually fits when converting a particular kind of bike, and what does not.

• Converting a Cargo Bike to an E-Bike

  Long john and other cargo bikes: mid-drive as the normal case, weight and brakes as the sticking points. What to measure and when to leave it.

• Converting a Dutch Bike to an E-Bike

  Dutch bike with coaster brake and hub gears: why a front motor is usually the only fit, what to measure first and when to leave it.

• Converting a Folding Bike to an E-Bike

  Folding bike with 20-inch wheels: small rims, little room at the bottom bracket and for a battery. What works, what does not, when to leave it.

• Converting a Mountain Bike to an E-Bike

  MTB with thru-axles, suspension fork and disc brakes: why usually only a mid-drive fits, what to measure and when to leave it.

• Converting a Trekking Bike to an E-Bike

  The trekking bike is the normal case for a conversion: almost any motor type fits. What to measure, where it snags and when to leave it.