Brompton makes arguably the world’s best folding bike. Based around a robust steel frame and rolling on diminutive 16-inch wheels, it can be folded into a package measuring 585mm x 565mm x 270mm in under 10 seconds. It is, as its inventor intended, like having a magic carpet you can unfurl anywhere.
Despite recent tweaks and upgrades, including an electric model, all Bromptons follow a similar pattern to the bike as created by founder Andrew Ritchie back in 1975.
To help prospective owners navigate the range of options available, we’ve compiled a guide explaining all of the Brompton folding bike’s main features.
The first thing to understand is the Brompton coding system. All models are described by a three-part naming convention. The first part of this relates to the bike’s handlebars, the second describes the number of gears and the last tells you whether the bike has mudguards or a rack fitted.
Own a Brompton yourself by buying one at Evans Cycles here.
So a Brompton M3L is a bike with M-type handlebars, three gears and mudguards.
Below is an explanation of each of these three variables, along with everything else you might need to know to build your dream bike…
Brompton folding bikes: All you need to know when choosing
Three handlebar options are offered, each of them performing two different tasks. First, they can adjust the classic upright Brompton fit for riders of different heights.
Secondly, they can tailor the position of the rider, allowing them to attain a more aggressive or relaxed position.
This flat handlebar is the lowest of the three. It’s suited to smaller riders or average size users after a more aggressive position. If you like a racier position on the bike and aren’t massively tall this is the one to go for.
The classic option. Not too upright, not too aggressive. Generally good for leisure riding or sedate commuting, it offers a more upright position for short riders or a more aggressive one for taller people.
The high and mighty H bar provides the straight-back riding style found on traditional Dutch bikes. The go-to option for most very tall riders, anyone of medium height will find it easy on the neck and shoulders.
As simple as you can get. Choosing a single-speed bike cuts weight and maintenance to a minimum. It’s also the cheapest of the available options. However, you’ll be stuck making a big effort if you find yourself facing hilly terrain.
Our personal favourite. Brompton’s two-speed derailleur is incredibly robust and adds just 188g to the weight of the bike. Giving you one gear for accelerating or hills, the other can be engaged once cruising speed has been reached.
Sturmey Archer’s ever-reliable enclosed hub gear is the classic choice. Providing a trio of widely spaced gears, these can be shifted even when the bike is stationary. However, it’s a weighty system, adding 738g to the bike.
Two times three is six. Brompton’s maximal gearing option combines the two previous gearing systems to provide six closely spaced gears. Slightly more complex to choose between and maintain, this system is 920g heavier than a single speed.
Mudguards and rack
Doing without mudguards saves both money and weight. However, while it might look good, you’ll be at risk of a soggy bum. Bromptons also sit more nicely when fitted with mudguards, while they’ll also help preserve your brakes and rims from wear.
Our recommendation? Get mudguards! Not only will they keep you dry but they’ll help preserve other parts of the bike too. Weighing a couple of hundred grams, this mudguard set also includes a little wheel on the back that helps manoeuvre the bike when folded.
Mudguards and a rack. A rear rack adds a small amount of weight but lets you carry up to 10kg. However, given that our preference is for one of Brompton’s excellent front-mounted carriers, it’s only an option we’d pursue once we’d filled that first.
Given the bike’s tiny wheels, you won’t be able to use conventional panniers anyway.
X-Type Superlight Titanium
While all Bromptons are made equal, some are more equal than others. The superlight X-type option sees the standard fork and rear triangle swapped for alternatives made of titanium.
Beyond this, the wheelset is also upgraded to a lighter and more responsive design, while the headset and mudguard stays are also uprated.
The result is a machine up to 0.74kg lighter than an all-steel Brompton. Noticeable when you ride, even more noticeable when you carry, it’s a great option, although at £600 you’ll be paying around 80 pence for every gram saved.
Discover more about the full Brompton range here.
The biggest change in Brompton’s long history, the process of electrifying its bikes took 13 years to bring to market. The result is a practical if not particularly revolutionary makeover.
Created in conjunction with F1 maker Williams, Brompton’s narrow front hub drive is powered by a 250W battery that sits on the mount normally occupied by a front pannier.
Readily detachable, the great benefit of this system is it doesn’t compromise the foldability of the bike. With the battery popped over your shoulder, this leaves the bike on your arm just about manageable to carry.
Fancy buying a Brompton Electric? Find them on sale at PureElectric here.
Combined, both items tip the scales at around 18kg – a not inconsiderable weight that means the electric Brompton is a lot more fun to ride than carry.
Still, when unfolded the quality of the motor – and in particular its bottom bracket based motor control, which holds the torque sensor – combine to ensure it always delivers just the right amount of assistance. Electric Bromptons start from around £2,600, about £1,660 more than a standard model.
You can read our full review of the Electric Brompton here.
While the electric Brompton looks much like its conventionally powered siblings, it also features a few tweaks to strengthen the frame and accommodate the electrical parts.
Due to the increased loads placed on the bike, Brompton does not offer an electrical upgrade kit for existing bikes. However, several firms do make kits to convert existing Bromptons, although their use will void any warranty on the bike.
Brompton offers a range of conventional lights. These are either made by Japanese firm Cateye or created by Brompton to fit directly onto the bike’s rear rack.
This system uses a high-quality Shutter Products SV-8 hub dynamo to offer a reliable fixed lighting solution. This means you’re never at risk of a flat battery, cost, weight and the efficiency of modern battery lights count against it.
By default Bromptons now come with an extended seatpost which should suit riders with an inside leg of 84-89cm / 33”-35”.
For riders with an inside leg of 84cm / 33” and under, this seatpost is 60mm shorter. Marginally lighter, it allows you to get the saddle down as low as possible when folded.
Taller riders with an inside leg of 84-89cm / 33”-35” will appreciate the 60mm extra this post offers above the extended model. It’s also the heaviest option.
The Brompton uses a 16 x 1⅜ inch tyre, this has an etrto/iso number 35-349 mm.
Brompton now only provides its bikes with Schwalbe Marathon Racer tyres – a good thing too as we feel these offer the ideal balance of protection and ride feel.
Some riders like fitting lighter and narrower Schwalbe Kojaks. However, given the work such a diminutive tyre has to do, we prefer something more durable.
Another alternative is to go the opposite way and fit puncture-resistant Schwalbe Marathon Plus tyres. In our experience, these are a pig to get on, which combined with their increased weight means we aren’t fans.
The best place to carry weight on the Brompton is via its front carrying block. Attaching directly to the head tube, once here it won’t adversely affect the steering, and if anything actually makes the bike more stable to ride.
Brompton now makes a huge range of different panniers, while brands like Carradice, Ortlieb and even the Cambridge Satchel Company also produce options.
Find a variety of Brompton luggage available at Condor Cycles here.
Brompton recently discontinued its rear rack mounted trunk bag, which was probably for the best as it was a bit rubbish.
Bromptons come in a huge array of colours. If you’re having your bike custom-built you can choose two: one for the extremities, and one for the main frame.
Currently, Brompton offers around 20 different colours. Of these a handful are referred to as standard colours and don’t incur an additional charge. All the rest will add £30 per section painted.
Each year Brompton rotates in a few new shades which can be had for free. For 2021 these will be the fetching Turkish Green and Cloud Blue.
Then there’s the option to go for a raw lacquer finish. This clear coat shows off the skill of the brazer who’s made the frame. Something of a premium option, it costs £240.
However, besides looking pretty, opting for this finish guarantees you’ll be getting the very best work as only the most experienced torch holders at Brompton are let loose on these machines.
Brompton produces regular special editions with limited runs and custom paint jobs. Recent examples include the adventure-focused Brompton Explore and the CHPT3 edition created in collaboration with former pro cyclist David Millar.
Ordering a custom Brompton
Bromptons can normally be built to your exact specification at no extra cost. Lead times for this service have varied over the years between a couple of weeks to three months.
However, current Covid-related demand has seen Brompton cancel this service for the time being. This means you’ll have to hold off on ordering or buy a stock model from a retailer.
Brompton controls more of the manufacture of its bicycles than any other bike maker we know of. Keeping a complete range of spares, Bromptons are therefore Land Rover-like in their ability to roll through the decades.
While most workshops or home mechanics will be able to fix the majority of problems, some occasional jobs like replacing hinge bushing or seatpost shims are best tackled by a trained service centre.
We love dreaming up fantasy Brompton builds. Here are a few of our favourite configurations…
H6RL: The ‘I want it all’
Upright handlebars, six gears, a rack and mudguards, plus dynamo lights. Like a touring bike in miniature, this build ensures you’ll want for nothing.
On the downside, you’ll pay for your additions, both with your wallet, and when it comes to carrying the bicycle.
S1E-X: The ultra-minimalist
An aggressive flat handlebar, a single gear, no mudguards and a dollop of extra titanium goodness. At a touch under 10kg, this is as light as you can make a stock Brompton. Great for going fast, some might miss the practicality offered by mudguards or additional gearing.
S2L: The racer’s commute bike
A flat handlebar will suit most roadies who want a Brompton to commute on. Two closely spaced gears are also very efficient. The included mudguards are a must for year-round riding and like the twin gears, don’t add much weight.
Read our full review here.
M3L: The classic Brompton
Medium height handlebars, three gears courtesy of a gently-ticking Sturmey Archer hub, and sensible silver mudguards. For true retro value, this should probably be ordered in classic black and red, although green is also an acceptable colour choice.