Brompton G Line with Big 20″ Wheels is their 1st-Ever Folding Gravel Adventure Bike

This all-new Brompton G Line gravel folder might just make a lot of cyclists reconsider a folding bike. The core Brompton folder concept is still there – this thing still does origami magic to pack down barely bigger than its wheels. But scaled up to a more standard 20″ wheelsize and up to 2.1″ wide tires, the Brompton G Line is a much bigger bike than every 16″-wheeled Brommie before it. And it promises to ride much more like a full-sized bike than any past folding bike…

Brompton G Line: folding adventure gravel bike on 20″ wheels

Brompton is calling their G Line folding gravel bike the “most versatile bike in the world”. That obviously sounds a bit extreme, but there’s something to be said for the G Line. Brommie folders are already quite versatile in that they are simple to take with you places a normal bike just can’t easily reach – like in trains, buses, the trunk of a taxi or friend’s car, under your desk at work, or any other tight spaces. And gravel bikes are also so hot these days because of their versatility. Ride them on smooth tarmac, underdeveloped dirt & gravel roads, or often even on stretches of trail that we’d only have thought to ride on a mountain bike just a few years ago.

So, combine a compact Brommie folder and a gravel bike, and this is unquestionably the most versatile Brompton ever.

“Now, as more and more people look to escape the city, exploring roads and trails less traveled, it was the right time to take everything that makes the Brompton so special, and make it capable of going beyond the urban environment and into tougher terrain.”

– Will Butler-Adams, Brompton CEO

What’s new?

To make the G Line suitable for gravel riding, Brompton had to bump up the wheel diameter from their traditional (but obscure) 16” to a bigger and more common 20”. With that you also get much wider tubeless-ready 2.1” Schwalbe G-One gravel tires to take on rough terrain.

Not only do you get improved rollover (think going from 26” to 29” wheels) and larger tire volume (54mm vs. the 35mm of the standard C or T Lines), you also get a longer wheelbase too. The signature Brompton folding mechanism – 1st in the middle of the toptube and 2nd just behind the bottom bracket – means the wheel size pretty much determines wheelbase length.

And combining the longer wheelbase and larger wheels, that means that the Brompton G Line folding gravel bike is said to simply ride much more like a full-sized bike.

This also happens to be the first Brompton folding bike to get disc brakes. Bigger wheels, bigger adventures, and better hydraulic stopping power to keep you in control over any riding surface.

Tech details

The Brompton G Line gravel bike still executes that signature Brompton fold in just 20 seconds. It packs down to just 69(h) x 73(l) x 40cm (w) when folded to fit into tight spaces (size Small). The lightest regular G Line build has a claimed weight of just 13.9kg/30.6lb (Small) or 14.8kg/32.6lb with rack & fenders.

The ebike version Brompton Electric G Line with complete rack and fenders weighs a claimed 19.5kg/43.0lb, including the 3.4kg/7.5lb battery with its quick-release bag.

A Brommie in 3 sizes, too!

In addition to big wheels, this G Line Brompton gravel bike also comes in 3 different sizes. Essentially due to the fact that this is more of a performance-oriented bike where fit is more crucial than a classic commuter, the new G Line introduces 3 folding bike sizes – S, M & L. We are still talking just contact points, though – they all share the same folding frame. So the three sizes dictate the rise and offset of the extended stem and seatpost length range, effectively varying handlebar Stack and saddle-to-bar Reach.

Brompton G Line gravel folder – Pricing, options & availability

This all-new 20″ gravel Brompton G Line folding gravel bike is officially available two weeks from now in October 2024, in Europe and the UK. American folding bike fans will have to wait until spring 2025, though. But of course, like many gravel travelers, and Brompton themselves, we simply can’t wait. Essentially there are two main options for the new Brompton gravel folder – pedal or electric-assist power. Both are available in Forest green, Adventure orange, or Traildust white.

The standard pedal-powered G Line starts at 2850€ with an 8-speed Shimano Alfine internally geared hub. On top of that base build, you can get one pre-built with rack & fenders or lights-only for 2970€, or with lights & the rack for 3080€.

Or you can get the pedal-assist ebike variant Electric G Line for 3500€ complete with lights & fenders. That gravel ebike folder pairs a tiny 4-speed cassette on the outside of an all-new 250W motor in the rear hub, powered by a 345Wh front bag battery for 30-60km range.

Then, in classic Brommie style, there are also a whole suite of add-on accessories available separately, including various custom-fit luggage, racks, fenders, toolkits, tubeless setup kits, phone & bottle mounts, lights, and much more. As always, Brompton makes it easy to customize your folding bike to how you want to ride.

Brompton.com