Felt was one of the first companies to explore designing a road bike that incorporated aerodynamic elements originally found on time trial bikes. While the original AR was a thoroughly decent bike, it suffered a little with flexibility issues owing to the narrow aerofoil tube shapes not being able to handle torsional loads as well as a standard road machine.
The new AR launched at the tail end of 2013 to great acclaim – it was one of our favourite debuts at Eurobike. Felt's engineers have spent considerable development time ensuring the AR is as stiff under load as their current pro-level race machine, the F-Series – a fact that's apparent the minute you saddle up.
HIGHS: Exciting to ride, rapid turn of speed and snappy handling
LOWS: Too much wheel flex
Ride and handling: sprightly yet solid
It feels taut and solid at the back under pedalling, yet the front is consistently light and lively. In fact, if this bike wasn't so blatantly all about aero we’d swear we were on the equally impressive F bike.
The AR has plenty of parallels with another highly impressive aero bike, the Giant Propel: it doesn’t feel compromised by its wind-cheating abilities, it’s exciting to ride, its hugely responsive acceleration through the gears is rapid and it feels genuinely eager everywhere.
As mentioned above, the AR's responsive front end feels a lot like its F-Series stable mate: nimble and easy to slot though tight apexes and lean into corners just that bit further and faster. Aside from that its impressively comfortable too – an aero bike that’s nimble enough for crit racing, fast enough for a TT (with a set of clip-ons) and smooth enough for the toughest sportive.
Frame and equipment: classy innovation with minor niggles
Indeed, the AR's new seatpost design, the VariMount, is quite brilliant at killing vibration and buzz through the seat of your pants – and that’s not even its cleverest trick. It fits to the frame not via a traditional clamp around (some aero shapes can suffer from slipping, because it’s a tricky thing to clamp an aerofoil shape with the same force as a traditional round post), but with an expanding wedge on the inside of the fully slotted post, which pushes the thin-walled post onto the frame for a truly slip-free fit.
All in all it's a neat solution – and the amount of flex the post generates is impressive, thanks to the thin walls not having the risk of being crushed that a traditional clamp would give. The VariMount moniker, incidentally, comes from the seatpost's ability to be flipped – effectively altering the standard angle of 72.5 degrees to a steeper, time trial friendly 78.5. Add a set of clip-on bars and the AR will make a truly fine time trial companion, and one that – if Felt’s aero figures are to be believed – will outperform a fair few dedicated TT bikes.
The AR5 is a light bike too, with our 58cm test machine tipping the scales at an impressively slight 8.1kg. That means it climbs superbly too, aided by the inclusion of a compact 50/34 chainset even with its racy 11-25 block out back.
The main drivetrain is made up of an as-you’d-expect 105 group; the chainset, however, is FSA’s budget Omega unit, which is hugely improved on the previous version as it now follows the same design as FSA’s new top-level designs. It’s amply stiff with decent ramps on the chainrings, so shifting is as smooth as we’d expect from Shimano. The coarse matt black finish does, however, look a little low rent compared with the classy looks of the rest of the bike.
Braking is via a combination of a standard 105 unit on the fork and an under-BB direct mount at the rear. In some truly foul conditions the front performed admirably, but the rear brake lacked a little in feel. This could be adjusted out but it’s not the easiest operation to perform, and on the bike nigh on impossible.
It’s something we could live with easily but it did give the bike one minor niggle. It’s not the brake position or the brake itself, more a symptom of the Aero R3 wheelset. The Felt own-brand R3 wheels have a decent 35mm broad aero shaped alloy rim and well-sealed hubs (which did get submerged in flood water on more than one occasion), but the rear wheel wasn’t as stiff as we’d have liked – and is mismatched to the rock-solid rear chainstays.
That meant on out-of-saddle efforts the rim would scrape each brake pad in turn under every pedal stroke, which with the brakes and pads covered in road spray and filth (which let’s face it will happen a lot in the UK) made for an irritating sandpaper soundtrack to out of the saddle efforts. If this happens on a bike with a standard rear brake you can reach back and adjust the brake while riding, but when it’s under the BB you can’t. This means that in a worst case scenario, such as buckling the wheel and needing to ride home carefully, you can’t knock the brake release out to silence it.
We adjusted the rear wheel spoke tension and cured some, but not all of the flex. On a new bike we’d rather not have to do this.
The AR’s cockpit is all alloy and we really liked the shape of the bars – ovalised and oversized means a comfortable on-the-tops hold and the semi-compact drop encourages down-in-the-hooks aero efforts. They're fitted with plush thick tape, which this bike does need because you get a bit of buzz coming up through the bars – surprising, as the more expensively equipped AR we’d tried previously with carbon bars had no discernible noise making it through to our palms.
We’ve no doubt that the new AR frameset is truly, truly exceptional and at the price it’s a fantastic buy – as well as being a contender for the Cycling Plus Bike of the Year Awards.
It’s let down a little by slightly flexi wheels, though they're competitive and light compared with similar value rivals. To get the maximum out of the AR it deserves better, and you’ll also need to be prepared to tinker and stay on top of maintenance with the rear brake setup too. Sort out these minor quibbles and the AR will make a fabulous companion, a brilliant all-rounder. It certainly seems Felt (like Giant) has cracked the aero bike code.