By: Selina Krijt, Rad employee and RadWomen ambassador
Hello friends! Im Selina, one of your friendly female ebike ambassadors, and I’m here to help guide you through the world of biking (and ebiking) with our brand new RadWomen Program. Whether you’re new to biking or you’ve been cycling for years, knowing the words is a key part of feeling comfortable with your bike. Not only will these terms help you know your way around your ebike, but they’ll also come in handy when taking your bike for maintenance.
To help you learn the basics, and maybe a few extras, here are our RadWomen Top 10 Must-Know Bike Terms:
The shifter is the little dial on the right side of the handlebar that lets you switch between gears depending on the terrain you are riding. Shifting gears allows you to pedal more effectively, extend your ebike's range, and travel over hilly terrain. To learn more about how to shift gears, check out this Help Centre resource.
2. Brake Pads + Calipers
Brake pads are the pads connected to the brake caliper. The caliper squeezes the brake pads against the brake rotor to slow or stop the wheel when you pull the brake levers on your handlebar. Or in other words: they are the part that comes directly in contact with the brake rotor to stop the bike.
The brakes on your bike function much like those on your car. On your bike’s wheels, there is a shiny metal ring, usually with a fancy outline and holes drilled into it. This is the brake rotor, and it is what the brakes squeeze to stop the bike. The pads are attached to the brake caliper, which is the device that applies force to the pads to push them against the rotor. When you squeeze the brake lever on the handlebars, the caliper pushes the pads against the metal ring and “grabs” it, causing the bike to stop. The pads will wear out over time, and are meant to be replaced.
Ensuring the brake pads continue to have adequate thickness to stop the ebike is very important. Check out our Brake Pad Replacement Guide for tips on removing and replacing brake pads.
PAS is shorthand for Pedal Assist System. All ebikes by Rad Power Bikes are equipped with a pedal assist system. The Pedal Assist System adds extra power from the electric motor every time you pedal so you can go faster and up hills with less effort.
Need lots of assistance? Use the PAS selector button on the handlebar display to choose a higher level. Just want a little help so you can still get a good workout? Put it on a lower setting. You can dial up between 1-5 on an LCD display and between 1-4 on an LED display using the buttons on your display, located on your handlebars (see image below).
With PAS assistance on, the PAS sensor sends a signal with every pedal stroke to the controller to draw up power from the motor, helping you zip around without even breaking a sweat. The higher the PAS level, the more power is delivered with each pedal stroke, and the easier it is to ride. The PAS is only active while the rider is pedaling.
When you feel like you’ve got all the power you need for a ride and don’t want help from the motor, you can select no pedal assistance (PAS level 0).
Check out this article from our Help Centre to find out more about how pedal assist feels.
4. Cadence Sensor
For most ebikes, pedal assist uses a cadence sensor that is built into the drivetrain of the bike. (Don’t know what a drivetrain is? Keep reading…) The sensor detects when the rider is moving the pedals and signals the electric motor to provide the level of pedal assistance that has been selected (PAS 0-5 on most models and 0-4 on the RadRunner and RadMission).
How does the bike “know” to provide motor power to help you ride? It uses a cadence sensor to measure the rotation of the pedals. This cadence sensor is built into the bike where the pedals are attached, and tells the motor that you are pedaling. This signals the electric motor to provide the level of pedal assistance (PAS 0-5 on most models and 0-4 on the RadRunner and RadMission) that has been selected.
5. Torque Sensor
The RadCity is the only bike in our line up with a torque sensor today. This sensor serves the same function as the cadence sensor: it engages the pedal assist. The main difference is, that on top of detecting pedal rotations, it also detects when the rider is exerting pressure on the pedals (hence the term torque, describing pressure). Using this combination of sensors, it detects how hard the rider is pedaling and prompts the motor to kick in.
6. Geared Hub Motor
There are two basic types of electric hub motors - direct drive, and geared hub. The details of how and why the motor is designed a certain way are an interesting application of lots of physics, but the most important thing to understand is that a geared hub motor provides much more push than a direct drive (nearly double). This means that if you are just starting to pedal, or riding up a hill, the geared hub will provide more force and thus more assistance. The standard motor for Europe is 250W and can handle both off road and city riding easily.
The geared hub motor is technically maintenance free – you never have to open it up to work on it.
Told you to keep reading! The drivetrain of the bike consists of a group of parts that you use to push (or pull) the bike along. (Crank + chainring + pedals + bottom bracket + chain + gears + derailleur).
At its simplest, these are the parts that move the bike when you pedal. The device on the rear wheel with the two small, toothed gears is called a derailleur, and it is what moves the chain when you shift gears. The gears themselves are the metal teeth on the back wheel that the chain attaches to the rear wheel.
The drivetrain wears down as you ride and change gears, so periodically check in to see if it’s time to replace parts of your drivetrain.
8. Freewheel (how it works and why it’s not a cassette)
All Rad Power Bikes that have gears have a freewheel system*. In contrast to a cassette hub, Rad bikes have a large external thread machined into the hub. The cogs and ratcheting body assembly, called a “freewheel,” threads onto the hub. The ratcheting mechanism comes off with the cogs when the freewheel unthreads for removal.
*the whole Rad lineup except for RadRunner & RadMission (we call it a single-speed freewheel)
Some of our bikes (excluding the RadMission, the RadRunner and the RadWagon) come with a suspension fork. The suspension fork alleviates some of the shock that comes from riding over rough terrain, curbs, or any other bumps in the road. This makes riding a bike more comfortable by reducing the vibration going through the fork to the frame and handlebars and ultimately into your arms.
Not to say that there are no advantages to the rigid fork (i.e., no suspension). The rigid forks are better for bikes that are more city-oriented and they require less maintenance. In the end, the choice comes down to use-case and personal preference.
10. PSI (pounds per square inch) or BAR
Tire pressure is measured in PSI (Pounds per Square Inch) or BAR (which comes from the Greek word for ‘weight’). The recommended tire pressure is written on the sidewall of each of our tires. Some pumps measure the pressure in PSI, while some measure in BAR. Both are written on the tire sidewall, usually as an interval recommendation, not a fixed measurement. That way you can adjust the pressure (within those interval limits) according to your preference for the type of riding that you do.
Lower tire pressure will result in more comfort and better handling on loose terrain like gravel, but it will also result in more road resistance, which makes it harder to pedal and uses up slightly more battery. The opposite is true for higher tire pressure, which is good for smoother surfaces.
11. Derailleur and Chain Tensioner
See this really good explanation of what a derailleur is and how it works.
Derailleurs are only on Rad bikes that have gears. It is the mechanism that moves the chain along the different gears when you use the shifter (explained above). It makes sure that the chain is in the right position and in tension so that the power from pedaling is perfectly transferred to the wheel to get the bike moving.
Chain tensioners are only present on our single-speed bikes (RadRunner & RadMission). They are there to keep the chain in tension, so that the power transfer from the pedals to the rear wheel propels you forward. Since there are no gears to move the chain, the mechanism differs slightly from the derailleur.
You already knew your Rad Power Bike was pretty awesome. Now with these terms under your belt, you’re well down the path to knowing exactly what makes it that way! If you want to learn even more, you can find a full glossary of terms here on our site.
What did you think of our Top 10 Must-Know Bike Terms list? Did you learn anything new? Did we miss any terms? If you have any questions or topics you want to learn more about, please send them to us here.