Things that make up a bicycle drivetrain. All parts are not present on all bike
How you apply force to the drivetrain. In general, there are three categories: flat pedals, pedals with clips or straps, or clipless pedals
Connects the pedals to the front gears. There are 4 main ways that Crankset functionality varies:
Typically cranksets come in lengths from 165mm to 175mm.
There are varied opinions on proper sizing
The crankset needs to spin in the frame. The options are:
The primary options for connecting the crankset to the front gears are:
The right pedal has a normal thread, but the left pedal has a left (reverse) thread.
The majority of pedals are 9/16" x 20 tpi (14.28 x 1.27 mm).
One piece cranksets have pedal threading at 1/2" x 20 tpi (12.7 x 1.27 mm).
For additional knowledge about pedal threading (including an explanation for the reverse thread left pedal and 2 standards that didn't catch on), read Pedal threading on Sheldon Brown.
The bearings that the crankset rotates around.
They have an interface for connecting with the crankset.
Bottom brackets come in a variety of sizes and may thread in or be press fit.
Front gears. May be a single chainring, double chainring, triple chainring or internal
Moves the chain between the front gears. It has to match the number of speeds - e.g. a double front derailleur is triple must be a
Not present in single speed, fixed gear or one by drivetrains.
Drives the wheel. May be a fixed cog, single speed, multiple cogs or internal.
Most common method of connecting front gears to rear gears.
The pitch of the chain is the distance between the rollers. It is 1/2" on all modern bicycle chains.
The width of bicycle chains must be matched to the number of rear gears.
A less common way of connecting the front gears to the rear gears.
- Doesn't support external shifting (front derailleurs or rear derailleurs) or fixed gear. The only options are single speed or internal rear gears.
- Can't be open and re-closed, always a single loop. The rear triangle of the bicycle must be split, which makes retrofitting hard/impossible.
- Doesn't require oiling - making the drivetrain less dirty
- Doesn't wear out over time (unlike chains, which experience chain wear)
- Longer lasting citation needed
An uncommon drivetrain on bicycles. Heavier and less efficient, all the benefits of a shaft drive system can be obtained by using a chain case ^citation
Electric Bikes have a few additional considerations when choosing drivetrains:
- Where does the power come from? The two most common types of e-bike motor locations are mid-drive and hub-drive. The motor might drive a specific choice in the drivetrain - e.g. a mid-drive motor might include a crankset
- With increased torque, components wear faster (some components are made specifically for use with e-bikes to address this)
- If you expect to always have the motor, you may want a different gear range - one that has
Choosing an e-bike has many considerations beyond drivetrain (which may impact the drivetrain choice) - see Choosing an e-bike for more information.
Riding on dirt is less efficient and can have steeper uphill sections than road. This requires very easy gears.
Want easier gears
Connected with offroad travel
Provides the best power transfer. Very simple and durable.
Are you riding on the track?
Simple and durable and inexpensive
Sram's 12 speed mountain drivetrain.
- More speeds in the rear - 12 becoming standard
- Electronic shifting
- flat pedals popularity in mountain biking
Things that could be checked via CI:
- All
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