City and hybrid bike chainsets, e-bike cranks

Which chainset for a city bike or a hybrid?

The chainset transmits the force of your legs to the chain: it brings together the two cranks, the chainring or chainrings and, depending on the system, the axle that runs through the bottom bracket. On a city bike, above all it has to last, stay clean and not damage your clothes. Single-speed bikes and bikes with an internal gear hub make do with one chainring, often surrounded by a protective guard. Hybrids and touring bikes, which climb loaded with panniers, keep two or three chainrings and a front derailleur for lower gears.

On entry-level models, the chainrings are riveted to the cranks: the chainset is replaced as a whole when the teeth are worn. More advanced models bolt their chainrings on, so that only the worn part needs replacing.

Square taper, ISIS or integrated axle: how are the cranks held?

The square taper axle is still fitted to many city bikes. The axle is then part of the bottom bracket, and each crank fits onto a tapered end where a bolt holds it in place. Two standards coexist, JIS and ISO, whose tapers differ slightly: a crank fitted to an axle of the other standard sits too far on or not far enough, and the chainline shifts. The ISIS splined axle spreads the load better; it is found on reinforced bottom brackets and on several e-bike motors.

With an integrated axle chainset, such as Shimano's Hollowtech II, the hollow axle is attached to the right-hand crank and turns in bearings housed outside the frame, on either side of the shell. The whole assembly is stiffer, but each system needs its own bottom bracket: identify yours before ordering.

E-bike chainsets: cranks mounted on the motor

An e-bike with a mid-motor has no conventional bottom bracket: the cranks attach directly to the motor's axle. The interface varies with the brand and generation of the motor. FSA's CK-320 cranks, with the ISIS standard, for example, are designed for fourth-generation Bosch motors, the Yamaha PW-X and Brose motors. When replacing them, also compare the distance between the pedals and the clearance from the frame's chainstays, which vary from one model to another. The chainring is fitted separately, directly on the motor or on a spider.

No drivetrain part should be used to remove the motor's assistance limit. In the UK, an e-bike whose motor still assists above 15.5 mph no longer counts as an electrically assisted pedal cycle: it is classed as a motorcycle or moped, which must be registered, taxed and insured, and ridden with a driving licence.

Single, double or triple chainring, and chain protection

In town, a single chainring is enough with a single speed or an internal gear hub; combined with a rear derailleur only, it also simplifies the controls. Double and triple chainsets widen the gear range for hilly terrain and long distances, and the triple chainset for 7 or 8 speeds remains common on touring bikes. The number of speeds stated for the chainset must match that of the chain and the cassette.

The chainguard, or chainring guard, stops the bottom of your trousers from getting caught in the teeth or stained with grease. Some chainsets also take a chain case that encloses the chain: check the number of teeth specified by the manufacturer before combining them.

Crank length and bottom bracket: the measurements to note

The crank length is engraved on its inner face, near the pedal hole. City bikes are often fitted with 170 mm cranks; shorter cranks suit smaller riders and keep the pedal further from the ground when cornering. Also note the width of the frame's bottom bracket shell, most often 68 or 73 mm, and its thread, English or Italian. For a square taper axle, the length of the axle sets the chainline: match that of the original bottom bracket, marked on its body.

The other parts of a city bike drivetrain

A new chainset often goes with a new chain: city bike cassettes and chains cover internal gear hubs as well as e-bikes. Chainrings let you change the number of teeth without touching the cranks, and derailleurs go with a switch to a double or triple chainset. For performance-oriented chainsets, see road bike chainsets and MTB cranksets.

Which chainset brands for the city?

FSA, short for Full Speed Ahead, equips road bikes and e-bikes alike: its CK-320 and CK-220 cranks with the ISIS standard fit mid-motors, and its Vero Pro chainset comes in a square taper version.

Shimano has built its Cues range around the Linkglide drivetrain, in three levels of 9, 10 and 11 speeds. The FC-U4010 chainset has riveted chainrings and a square taper axle, the FC-U6000 bolted, replaceable chainrings; the single-ring Alfine FC-S501 goes with internal gear hubs.

Prowheel, a Taiwanese manufacturer specialising in chainsets and chainrings, offers simple, sturdy models: a triple chainset for 7 or 8 speeds, the PRA-115 and a single-ring chainset with 48 teeth for fixed gear.

Stronglight, founded in the Saint-Étienne area where its site still stands, offers chainsets designed for the city: the SL55 in 170 mm, with a chainring of 38 to 48 teeth, the single-ring City and the triple Impact.

Chainsets on sale and new arrivals

End-of-line chainsets join our city bike drivetrain clearance, and newly added references appear in new arrivals. To get an everyday bike back in shape before the fine weather, look out for Black Friday or the winter sales.

Frequently asked questions

How do you know which type of axle your chainset has?

Remove the cap from the left-hand crank. A central bolt on a four-sided axle indicates a square taper, a bolt on a splined axle an ISIS axle. If the left-hand crank is clamped by two side bolts onto a large-diameter hollow axle, it is an integrated axle chainset. On an e-bike, go by the brand and generation of the motor.

Where does play in the chainset come from?

It comes either from the bottom bracket bearings, worn or loose, or from a crank that is not tight enough. On a square taper axle, riding with a loose crank quickly deforms its aluminium socket, which will then no longer hold. At the first knock, tighten the bolt to the specified torque, then have the bottom bracket checked if the play persists.

Do you need a special tool to remove a chainset?

Yes, in most cases. Square taper or ISIS cranks come off with a crank puller screwed into the crank, once the bolt has been removed. Integrated axle chainsets need a small tool for the preload cap, and the bottom bracket unscrews with a tool that fits its cups.

Can you change the cranks on an e-bike?

Yes, provided you respect the motor's interface and its measurements: distance between the pedals, chainstay clearance and length. Cranks designed for e-bikes take the width of the motor housing into account. Tighten them to the torque specified by the manufacturer and check that they are still tight after the first few rides.

Does a chainguard fit every chainset?

No. The size of a chainring guard depends on the number of teeth on the large chainring and on the fixing method planned by the manufacturer, and a full chain case also depends on the shape of the frame. On many city chainsets, the chainguard comes already fitted.