Big Wheels, Big Battery: Brompton’s G Line Transforms The Folding Bike

Brompton’s electrified G Line transforms the legendary folding bike for the modern commute, offering larger wheels and a powerful battery boost without sacrificing portability. Jeremy Taylor and Jessica Talbot-Ponsonby saddle up to discover whether the company’s latest adventure-ready folder truly delivers.

Review: Brompton Electric G Line

Jeremy: In case you missed it, the Brompton World Championships took place earlier this month in London. The fastest commute into the City on two wheels? Not quite – but 650 riders did turn up to compete.

In a classic, Le Mans-style start, participants ran to their folded bikes, unfolded them and then raced around a circuit. And this being an event on classic Bromptons, Lycra is famously banned. Riders instead wore creative fancy dress, with business suits and ties de rigeur.

The lightweight Brompton started in a South Kensington bedroom in 1975, when inventor Andrew Ritchie looked at existing folding bikes and decided he could build a better one. Named after the famous Brompton Oratory, visible from his window, the small-wheeled machine took a decade of persistence, financial hurdles and hand-built prototypes to finally reach mass production.

One of the latest models is the electric G Line – sold as an adventure-ready folding bike, and a next-generation move on from its staple Brompton Electric P Line, launched in 2018. It features larger, 20-inch wheels, with puncture-resistant tyres offering extra grip for canal towpaths and gravel tracks. Best of all – or not so if you are a Brompton purist – the G Line packs a chunky 2.6kg battery pack above the front wheel that can power you to work with minimal effort. It’s good for 30-60 miles, depending on the assist level and rider weight. Charging time for the removable battery is about five hours on a standard three-pin plug. The G Line also features Bluetooth connectivity to Brompton’s app.

With bigger wheels and tyres, plus rugged Forest Green paintwork, the Brompton no longer looks like a delicate city folder – it’s almost ready for a proper off-road expedition. To put that to the test, we took a brace of G Lines into the Scottish countryside to see just what £3,699 buys.

Pressing the power button on the newly integrated handlebar controller, the LED display ripples to life. I can choose from three levels of battery assistance. Low is great for riding on the flat, while High is best for uphill and headwinds. As the G Line is considerably heavier than a standard Brompton, while turning the battery off and riding is possible, I wouldn’t recommend it. The traditional, sharp twitchiness of a folding bike disappears on the G Line. Thanks to the completely redesigned geometry and larger wheels, the ride felt planted and stable – remarkably like a full-sized gravel bike – with the back-up of hydraulic disc brakes.

This is not a bike for tearing up and down the side of mountains, although I’m sure somebody will try it. Instead, it’s best used for pootling along a forest track, or taking a short-cut across rough ground to reach the office on time. And while the G Line folds like a traditional Brompton, the extra weight and size of the motor and battery system make it harder to handle. If you plan to carry one on and off a train every day, try before you buy – this G weighs almost 14 kg, getting even heavier with the addition of a rack and mudguards.

Jessica: The electrified G-Line is the simplest way to beat city traffic – and cut a dash on the best-looking electric bike on the market. It has all the classic elements of a traditional Brompton, beefed up with larger wheels and tyres.

I’m not sure I’d want to make a long distance, off-road ride on a Brompton; my body prefers a suspension bike these days. But as a tried-and-trusted commuter bike, it’s still the one to beat.

Some might prefer the lower price and weight of a standard, non-electric G Line but our four-speed test bikes made my commute simple. The folding mechanism took some practise, but I got there in the end.

Discover more about the Brompton G Line at brompton.com.

Jessica Talbot-Ponsonby is Director of Programmes at London College of Fashion, studying for a PhD in sustainable e-textile design.