Boardman Air 9.4 review

Boardman’s Air 9.4 aero road bike has a bold profile, with deep, slim tubes that recall the early days of aero road bikes, before we’d heard of Kamm Tails or truncated aerofoils.

A modern aero bike without dropped seatstays is a novelty, but the flattened stays join in a wishbone, and the chainstays are, in typical Boardman fashion, perfectly straight and symmetrical.

The fork legs look svelte alongside the down tube and extensive head-tube area, but from in front, the Air offers minimal frame structure to the onrushing wind. But the round alloy handlebar and conventional stem let the aero side down a little on this model, unlike the wing-profile seatpost.

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At the time of writing, Boardman was offering this Air 9.4 at £2,399, discounted from £3,000, which explains why, compared to other bikes in the under £2,500 bracket, it wears Ultegra rather than Shimano 105. But not the mechanical groupset, because the Air 9.4 comes with Ultegra Di2. On the face of it, that’s pretty impressive value for money, but is it enough?

If you want one bike for road and time-trial or triathlon use, the Boardman Air 9.4 has great potential

It does prompt the question of where best to spend your cash if funds are limited. In this instance, I'm looking for an out-of-the-box race weapon, and as slick and lovely as Ultegra Di2 is, does including it compromise the bike’s overall speed potential? Wheels hold the key to a bike’s performance. So, do the Trimax 35 clinchers cut it?

That seatpost offers four possible saddle clamp mounting positions, determined by separate bolt holes, and the saddle can slide on its rails too. It produces an effective seat angle between 73 and 75 degrees, with a ‘standard’ angle of 73.5 degrees, and however it’s set up, the 150mm head tube on my medium model allows for the most aggressive position.

If you want one bike for road and time-trial or triathlon use, the Boardman Air 9.4 has great potential and the round bar makes more sense for mounting clip-on TT extensions.

Those deep tubes make the frame look smaller, and it’s definitely stiff, feeling direct when stepping on the gas to launch out of corners or over short climbs. That stiffness isn’t really damped though and the road surface can be felt as a constant chatter with bumps and holes providing shouty clouts that can’t be ignored.

Descending on rough tarmac can get choppy and feel like you’re skipping across, rather than conforming to, the surface. Even with its short 984mm wheelbase, the bike is never anything less than stable, but it’s not the most comfortable place to be compared to the competition.

There’s a ruthlessly efficient feel to the Air; that uncompromising frame and the rapidfire Ultegra Di2 shifting giving a sense of focussed purpose, and the aluminium Trimax wheelset keeps its end of the bargain too. They’re not the lightest, fastest or most aero, but they go well and along with Vittoria’s excellent 25mm Corsa tyres, gave no cause for complaint.

The main argument for mounting a rear caliper brake below the chainstays is aerodynamic benefit. Most attempts have suffered from rubbing or a lack of power. Although the Tektro brake fitted here doesn’t rub, it’s not an effective stopper, and a great argument for discs.

The Boardman Air 9.4 is quick, superbly specced for the money, with great race potential, but seems behind the current aero road bike crop in design.

Boardman Air 9.4 geometry (MD)

Seat angle: 73.5 degrees
Head angle: 73 degrees
Chainstay: 41cm
Seat tube: 50cm
Top tube: 55.5cm
Head tube: 15cm
Fork offset: 3.75cm
Trail: 6.5cm
Bottom bracket drop: 6.8cm
Bottom bracket height: 26.6cm
Wheelbase: 990mm
Stack: 55.3cm
Reach: 39.1cm