The Birdy World Sport is a more versatile folding bike than similarly priced compacts like the Brompton. That's not to say it's better: the Brompton beats it hands down as a bike-rail commuter. It's not the best folder for touring or training rides either; that would be an Airnimal of some description. But it's a jack-of-all-trades folding bike that does all jobs well.
Good quality folding bikes aren't cheap. Folders already have to compromise between portability and rideability. Throw 'cheap' into the mix and it's too easy to end up with a hinged heavyweight that's awkward to carry and horrible to ride. That's why even an entry-level Brompton, that benchmark British folder, will set you back well over £800. The German Birdy is more expensive still, with the all the range comfortably into four figures. Except this one.
A price of under £1,000 for the Birdy World Sport means losing out on the refinements and options of the other models. There's no hydroformed tubing, hub gear, disc brakes, lights, or a la carte choices. What you see is what you get. And it comes in black.
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It's still a Birdy, however, not a look-alike. It folds the same; the suspension is the same; and Birdy accessories like racks and bike bags will fit it. It reminded me very much of the old Birdy Red. Black, then, is the new Red.
Frame and fork
Like other Birdies, the TIG-welded aluminium frame and fork of the World Sport are unusual in a couple of respects. For one thing, there's no hinge in the main frame. That saves weight and, more importantly, eliminates flex. For another thing, there's suspension at both ends.
At the rear, there's a single pivot just behind the bottom bracket like there is on the Brompton. It's there so that the swing-arm (the 'rear triangle') and rear wheel can tuck underneath the main frame when the bike is folded. And like the Brompton, there's an elastomer bumper in between the top part of the swingarm and the seat tube. This is the rear shock.
It looks and is simple but works surprisingly well. Claimed travel is up to 60mm. At 65kg, the medium-density elastomer provided worked fine for me. Significantly heavier or lighter riders could retro-fit a firm or soft elastomer respectively; they cost about £15 each.
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The front suspension also uses an elastomer – and again, firmer or softer versions can be fitted. It looks weird because of the leading link design. This kind of suspension fell out of favour off-road, where telescopic forks rule, but you still see some iterations of it on road; for example, the Moulton. A leading link fork has an advantage over a telescopic fork in that it doesn't 'dive' during braking. It also tracks well, so the steering feels firm. Pivot wear, a problem off-road, is a negligible issue on road. Fork travel is up to 30mm, so it'll cope with most potholes without bottoming out.
There's another advantage of this suspension setup for the Birdy that isn't immediately obvious. To fold the front end, you unclip the elastomer at the fork crown and tuck the front wheel under, rotating the fork on its pivots. Clever!
While the World Sport is a 'stripped down' Birdy, it nevertheless comes with frame-fitting SKS mudguards. You can fit Birdy racks front and rear too, although I would use a large Carradice saddlebag on an SQR block on the seatpost instead. It's neater, and 16-23 litres of luggage capacity on a folder is enough for me. Like most folding bikes, there are no bottle mounts.
Components
Like other Birdies, the World Sport uses 18-inch wheels. Nominally 18-inch, at any rate. The bead seat diameter is only 6mm more than the 16-inch wheel Brompton, at 355mm versus 349mm. That's close enough that you can use Brompton-sized innertubes in Birdy tyres, if you can't get hold of Birdy ones. (Bear in mind the Birdy rims are drilled for presta valves.)
I can't think of another bike that uses ISO 355 wheels, so it's not surprising that tyre choice isn't great. It's not as bad as it was; Schwalbe offer several decent options, including the Kojak (which I'd pick), Marathon Racer, and Marathon Plus. In fact, tyres are the one component that it's worth upgrading immediately on the World Sport. The Impac Streetpac tyres supplied are stodgy and don't excel in any area.
Gearing is 8-speed, like the Birdy Red of old, using a twist-grip shifter and a Shimano 2300 road rear derailleur. The range of 33-90 inches is fine for most situations, although bottom gear could usefully be lower if you live anywhere hilly or plan to use the bike for touring. You can't just stick an 11-34 cassette in place of the existing 11-30 as a 2300 rear derailleur won't cope with that. If you don't mind losing a bit at the top end, you could fit a smaller chainring.
The V-brakes offer more power and modulation than the brakes of most folding bikes, despite unavoidably convoluted cable runs.
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