Brompton launches its lightest ever bike, the T Line

Brompton turns to titanium and a host of carbon components to create its lightest bike ever.

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Brompton’s new T Line of folding bikes takes a big technological leap forward, with an all-new titanium folding frame that’s 37% lighter than the original all-steel equivalent (presumably putting the “T” in T Line). This new frame is the result of three years of development and a partnership with Sheffield, UK-based titanium experts CW Fletcher. Fully built, the 7.45 kg T Line is more than 2 kg lighter than the lightweight P Line launched in November, which itself was 2 kg lighter than the C Line Brompton.

Titanium has its advantages, but it’s difficult to work with.

Brompton didn’t simply remove and replace individual components to achieve these phenomenal weight savings, either. Instead, the British brand says it, “reinvented every millimetre of the Brompton” with new materials and components with only the fold design remaining untouched. There’s a new carbon fork, a carbon crank, a saddle with a carbon base and rails, and a steel-reinforced carbon seatpost. Despite the steel armour being just 0.3 mm-thick (and the huge amount of exposed seatpost relative to the relatively shallow insertion depth), Brompton says it has 100 kg rider weight capacity and is also durable enough to withstand the unusual rigours of a folding bike used for daily commuting. 

While most of us associate weight savings with increased performance, the real benefit of a lighter bike here is in easier day-to-day use. The T Line is said to be easier to fold and easier to carry. Think hoping off a subway and carrying a bike up a set of stairs gains rather than Strava KOMs. 

Updates galore: titanium frame, carbon cranks, new derailleur system, and Tubolito tubes.

Beyond the weight savings, Brompton has refined the folding design with self-aligning hinges and a spring-loaded handlebar catch. It would have been nice to see the new larger diameter wheels and the wider handlebar get the carbon treatment, too, but presumably, this would further spike the already lofty price. However, Brompton did find some weight saving in the wheels in the form of Tubolito’s polyurethane inner tubes. Perhaps one of the largest weight savings is the shift from the internal hub gearing to the new lightweight, compact derailleur system designed for the P Line launched back in November. 

The basic geometry of the T Line is in keeping with the rest of the Brompton range and is available with a range of low (flat) and mid-rise bar options. Brompton does claim the new carbon crank and cast Ti bottom bracket “shift your power for a faster ride”, which, at least for the cranks, seems like it might be an incredibly marginal gain. The titanium frame might also provide a smoother ride.

The T Line is available in four specifications. The One is the most stripped back and lightest T Line with a 50x12T singlespeed drivetrain. The Urban is a more versatile four-speed setup fully equipped with mudguards and a 50-tooth chainring paired to a 12-18T cassette. Both bikes feature Schwalbe One tyres with the brand’s Addix race compound and V-guard puncture protection. 

Brompton will make the first round of the new T Lines available to purchase through a ballot on the Brompton website. The lucky ballot winners will have the chance to buy a T Line One priced at US$4,795 / £3,750 / €4,360 or an Urban at US$4,995 / £3,950 / €4,590 (Australian pricing is to be confirmed). In the meantime, Brompton is offering T Line test rides at its New York, London, Paris, Singapore, and Shanghai stores.

More information can be found at 

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