Brompton has announced the T Line, the latest addition to its simplified range of folding bikes. The T Line is said to be the lightest bike it has ever produced, with a claimed weight of 7.45kg.
For the eagle-eyed, this might come as a surprise. The recently released Brompton P Line was said to replace the brand’s Superlight bike and – for a brief spell at least – was Brompton’s lightest machine. However, the T Line shaves 2kg off the claimed 9.65kg of the P Line.
Brompton says it managed to achieve the T Line’s low weight by using a new fully titanium frame manufactured in the UK, a new drivetrain and a host of carbon fibre parts.
According to Will Carleysmith, chief design and engineering officer at Brompton, every part of the bike has been pared back and the only thing carried over from Brompton’s classic model is the brake system.
This new bike will be available in two specifications with different drivetrains. The Line One is a single-speed bike and will cost £3,750 / $4,795. The T Line Urban has a 4-speed gearing system and will cost £3,950 / $4,995.
Brompton says the T Line will be available exclusively via a ballot system on its website and through selected Brompton stores in London, New York, Shanghai, Singapore and Paris.
Sheffield titanium
Sheffield may have once been known as ‘Steel City’, but Brompton has been using its new facility in the city to develop the T Line’s titanium frame.
Despite titanium being the ninth most abundant element on the planet, working with it takes a high level of skill and knowledge, which is part of the reason the best titanium road bikes are big investments.
Brompton says finding the right partner was key to it developing a titanium frame and its relationship with Sheffield-based manufacturer C W Fletcher, which began more than seven years ago, provided the platform to do so.
“With them,” Paul Williams, chief operation officer at Brompton, says, “we built Brompton Fletcher, a dedicated company with a purpose-built production facility and skilled team able to work with this demanding material and fabricate these fantastic titanium frames.”
The T Line frames are orbital welded and then tig welded and, Brompton says, despite having 37 per cent less mass than Brompton’s all-steel equivalent frames, they are just as strong.
Weight-saving carbon components
Brompton hasn’t just looked to the frame for weight savings. It has used a number of carbon components across the T Line to reduce weight.
The brand has chosen to equip the T Line with a carbon seatpost. However, it says an ordinary carbon seatpost wouldn’t be able to withstand the daily use of a folding bike – presumably because the seatpost is frequently lowered and raised as the bike is folded.
To reinforce the seatpost, Brompton has created a “steel-armoured” design. The post has 0.3mm of steel wrapped around the carbon core.
The T Line has a carbon fibre fork and steerer tube, as well as a carbon handlebar, which Brompton says makes the ride of the bike stiffer and more responsive.
Elsewhere, Brompton has opted for a carbon fibre crankset, which is paired with a cast titanium bottom bracket.
The saddle also has carbon fibre seat rails and a carbon-reinforced base.
Compact drivetrain
The T Line Urban model has a 4-speed drivetrain that uses a cassette and 60g derailleur, rather than Brompton’s internal gear hub system.
This drivetrain is said to keep things “as light as possible”. It first appeared on the Brompton P Line, where it was similarly praised for its low weight.
The drivetrain is also said to offer a 60 per cent larger gear ratio than Brompton’s 2-speed hubs and a similar ratio to its 3-speed hubs.
Unlike the P Line, which is available with either a 50- or 54-tooth front chainring, the T Line Urban appears to only be available with a 50-tooth chainring.
The T Line One forgoes the 4-speed drivetrain and is set up as a single-speed with a 50 × 12 gear ratio and chain tensioner. This single-speed design, as well as the fact the T Line Urban has mudguards and the T Line One does not, makes the One the lightest bike Brompton has ever produced, according to the brand.
Brompton’s folding bike range
In 2021, Brompton announced it was changing its bike naming conventions. Its range is now made up of ‘lines’, with models centred on different riders’ needs. These are the current lines:
A Line
A Line is Brompton’s ‘essential’, or most affordable line. The bike comes with a 3-speed hub and is available in one colour, gloss white.
C Line
C Line is Brompton’s ‘classic’ range, with models including Urban, Utility and Explore. Urban has a 2-speed hub, whereas Utility has a 3-speed hub. Explore has six gears and can be loaded with luggage.
Electric C Line
The Electric C Line currently consists of motorised versions of either the C Line Urban or the C Line Explore.
P Line
Released in November 2021, P Line took the place of Brompton’s Superlight, offering a lightweight build and featuring a frame that consisted of a steel front and titanium rear.
T Line
The latest addition to Brompton’s range, the T Line uses a titanium frame and has carbon finishing kit. It is available in either a single-speed or 4-speed specification.
Brompton T Line availability, pricing and specifications
The Brompton T Line is available exclusively via a ballot system on the Brompton website and through selected Brompton stores in London, New York, Shanghai, Singapore and Paris.
The T Line One and T Line Urban models are available with either a low- or mid-rise handlebar.
Brompton T Line One
- Frame: Grade 9 titanium
- Fork: One-piece carbon fibre
- Stem: Grade 9 titanium with integrated headset
- Chainset: Superlight carbon crankset with hollow BB30 axle
- Gears: 12-tooth sprocket, 50t front chainring
- Bottom bracket: FSA Mega Exo
- Brakes: Brompton dual-pivot rim brakes
- Handlebar: 31.8mm Superlight carbon handlebar in 560mm width
- Saddle: Superlight saddle with carbon rails, lightweight padding, carry handle and light mount
- Seatpost: Superlight seatpost with carbon core and 0.3mm steel armour
- Wheels: Lightweight rim with aluminium hub
- Tyres: Schwalbe One with Addix race compound and v-guard puncture protection
- Tubes: Tubolito Tubo 34g tube
- Pedals: Superlight CNC aluminium
- Price: £3,750 / $4,795 / €4,360 / S$7,465 / ¥34,550
Brompton T Line Urban
- Frame: Grade 9 titanium
- Fork: One-piece carbon fibre
- Stem: Grade 9 titanium with integrated headset
- Chainset: Superlight carbon crankset with hollow BB30 axle
- Gears: 12-18 tooth cassette, 50t front chainring
- Bottom bracket: FSA Mega Exo
- Brakes: Brompton dual-pivot rim brakes
- Handlebar: 31.8mm Superlight carbon handlebar in 560mm width
- Saddle: Superlight saddle with carbon rails, lightweight padding, carry handle and light mount
- Seatpost: Superlight seatpost with carbon core and 0.3mm steel armour
- Wheels: Lightweight rim with aluminium hub
- Tyres: Schwalbe One with Addix race compound and v-guard puncture protection
- Tubes: Tubolito Tubo 34g tube
- Mudguards: Curved profile with titanium stays
- Pedals: Superlight CNC aluminium
- Price: £3,950 / $4,995 / €4,590 / S$7,865 / ¥37,000
