Brompton’s popular electric bike range now comes with a 12-speed option, courtesy of an innovative new gear system. This utilises a three-speed Sturmey-Archer hub and a four-speed derailleur, and will give riders a wider range of gears – apparently enough to ride up some rather steep inclines, going off the pictures the brand has released.

The bikes available with the new 12-speed option are the brand's lightest e-bike, the Electric P Line, and also the Electric C Line.

> Review: Brompton Electric P Line

The way the system works is unusual, but the brand says the approach helps retain the compact size the folding bikes are famed for.

Bikes are fitted with a 3-speed Sturmey-Archer hub which when combined with a four-speed derailleur offers riders 12 gears to choose from. The derailleur is only 60g in weight and is constructed from titanium – the same as used on the lightweight Brompton T Line bikes.

To use the gears, riders use the right shifter to control the hub gear, and the left shifter to control the rear derailleur. Even with these extra components, the Electric C Line Explore still weighs under 17.5kg with the battery in and it doesn’t look to interfere with the folding system.

The Electric C Line Explore currently comes with a 6-speed gear system, while the Electric P Line comes with a 4-speed option. So there is a significant increase in the range of gearing available.

The price isn’t even that much more, with the Electric C Line Explore 12-speed costing £3,150 compared to £2,995 for the 6-speed edition, while the increase for the Electric P Line Explore is slightly more, at £3,895, compared to £3,695 for the Electric P Line Urban.

The bikes will be available globally from the Brompton website, as well as from Brompton retailers and their stores.