Bike test: Brompton T-Line One

The Brompton T-Line is much lighter than the part-titanium Superlight, now called the P-Line. That has a steel main frame; the T-Line's is titanium. With a carbon fork and lightweight bits, it weighs as little as 7.5kg.

This makes a palpable difference when you pick it up – which you do a lot with a folded Brompton, as you carry it onehanded onto trains, into buildings, and so on. While it also feels a bit peppier to ride, the main benefit is portability.

There are two versions of the T-line: the Urban (£4,415, 7.95kg), which has a four-speed derailleur, mudguards, and a front luggage block; and the spartan, singlespeed One. I'd have preferred to test the Urban as a Brompton is impractical without mudguards; its raison d’être is short-distance utility trips. It wasn't to be.

The T-Line’s main frame has a larger diameter tube (51mm) than a steel Brompton (45mm) to compensate for the fact that titanium isn't as stiff as steel. Its hinge has a tongue-andgroove joint rather than flat faces. The end result is that the T-Line feels stiffer when riding out of saddle, something the One's single gear makes inevitable.

The T-Line’s reach – by which I mean: saddle clamp to handlebar clamp distance – is slightly longer than the last Brompton I tested, so the riding position is a bit more athletic. Otherwise it’s standard Brompton geometry, right down to the overly low trail figure that gives the bike its characteristic nippy/nervous (delete to taste) handling.

It folds in the familiar Brompton way. The hinge catches have stops on the ends of their bolts (finally!) so can’t unscrew and fall out. The left-hand pedal doesn’t fold but quick-releases, presumably to save weight. The Advance chain tensioner is simpler than the double-jockey-wheel model, so rear wheel removal and fitting is easier.

Riding performance is like any Brompton, just sportier. Much of that is down to the Schwalbe One tyres, whose rolling performance eclipses Marathons and even Kojaks. Small wheels benefit more obviously than big ones from good rubber as their rolling resistance is higher to begin with.

Verdict

Four grand is a huge sum but, unlike a Sunday-best bike, a T-Line might be used daily and (judging by other Bromptons) last longer. If you have deep pockets and want the improved portability a titanium Brompton offers, why not?

Other options

Hummingbird Single-Speed £3,495

Much longer when folded (117×60×20cm) as there’s no hinge in the carbon frame, but even lighter at 6.9kg. Will need mudguards etc.

Bike Friday Pakit $1,895 (£1,562)

Buying direct from the USA means adding shipping (~£330) and import duty (~£530). It weighs about 10kg but with custom options (singlespeed etc) can be 7.3kg.