B’Twin is sports giant Decathlon’s in-house bike brand, and the Ultra AF is its aluminium racer, big brother to the super-affordable Triban series.
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The Ultra’s headline selling point is its spec, which is remarkably good, especially compared to some of the competition whose offerings have taken a hammering from unfavourable exchange rates. You get a full Ultegra groupset with no substitutions apart from the chain, and the brakes are the outstanding direct-mount version rather than conventional single-bolt variety.
The wheels are Mavic Cosmic Elites, which retail for £370 a set — these are not the bargain basement rims that bikes at this level typically come with. It doesn’t end there, the saddle is a proper Fizik Arione that’s stylishly colour-coded to the frame and bar tape, and the alloy cockpit and seatpost are basic, but very nicely finished.
All this good stuff is bolted to an aluminium frame that’s distinctly B’Twin in flavour. It has sharply defined lines with a seductively arched top-tube, a design that mirrors that of the carbon version.
There is one fly in the ointment: I wish B’Twin hadn’t chosen to hide the rear brake underneath the chainstays. Although it looks tidy and removes the need for a rear brake bridge (potentially allowing more comfort-giving seatstay flex), this isn’t a bike with any real aero pretensions and doing so makes minor adjustments less convenient.
It also necessitates an awkward inline quick-release at the handlebar end as the brake caliper lacks one of its own, and it places the brake in an area that sees bigger deflections under pedalling loads; with pads set to run fairly close I found that the slightest hint of muck on the rims caused irritating scraping noises as I hauled myself up steep climbs.
The simplest solution is simply to run the pads a bit wider of course, but I shouldn’t really have to. And while I'm on the subject of funny noises, I also suffered a bit of cable rattle over rough surfaces.
These minor annoyances aside, the Ultra is an impressive bike. It’s heavier than its more expensive carbon counterpoint, the Ultra CF, but it gives up little in ride quality, striking a very acceptable balance between comfort and verve. The seatpost isn’t carbon and you’ll feel the bigger hits through the back end, but this isn’t a bike that wears you down with excessive road buzz by any means.
The Ultra’s geometry is racy without being ultra-aggressive, with a medium model sporting a 148mm head-tube and a 548mm top-tube. The latter is near-horizontal, meaning some riders won’t have a lot of seatpost on show, but get the sizing right and you’re rewarded with a very capable and well-rounded ride, and an exciting one too — the Ultra rewards whether you’re heading uphill or down.
The Ultegra groupset is as competent as ever too and those brakes really are excellent, despite the issues with the rear noted above.
The Ultra is a precise and confidence-inspiring racer that doesn’t come with the usual caveats about cut-corners on the spec. It isn’t absolutely perfect but however you slice things, it’s an awful lot of bike for the money.
