Felt AR Advanced Ultegra Di2 review

Back in 2008, the likes of David Millar raced aboard Felt’s AR for Slipstream/Chipotle. The original’s wheel-hugging down and seat tubes broke new ground.

It’s been revised since, the last time in 2014 with ‘variable geometry’ via a seatpost that could be run in both directions.

• Best road bike wheels
• Best road bike pedals

According to Felt, that delivered optimum positions for both road (72.5 degrees) and time trial (78.5 degrees). The new bike’s versatile, too, though via a seat clamp that you flip from zero to 20mm offset.

The post sits within a polymer sleeve that dampens road vibrations. It also has a split design where the two halves of the post can flex independently of each other. Felt claims it offers 112 per cent more deflection than the previous bike.

This AR isn’t truly top spec, though Ultegra Di2 and Reynolds carbon wheels are nothing to be sniffed at. But you’re given Felt’s top-tier frame and forks, built using UHC (that’s Ultra Hybrid Carbon) where construction uses three types of fibre, orientated to maximise elasticity, rigidity and impact resistance.

Nano-tech resin bolstered by Textreme carbon boosts strength-to-weight ratio further.

As for shape, Felt’s chosen a truncated aerofoil tube profile. This kammtail design ‘cheats’ the air into believing it’s a long airfoil for drag-reducing benefits without sacrificing weight.

Upfront, the AR carbon stem flows smoothly into the head tube while custom-shaped head set spacers allow height adjustment. It’s neat and clean, just like the internal routing.

The Devox carbon bar offers plenty of hand holds, and the top wing section is broad enough to hunker down on your elbows.

Integration often comes at the expense of practicality. Not here. Neatly, you can remove the stem with bars in situ and unclip the cable routing from the underside ‘pocket’ making it easy to pack. Simple and very effective.

The AR’s disc-only, which steered the aerodynamic design, because recessing the thru-axles into the frame makes it cleaner.

The freedom afforded around the fork crown and rear stays from discs means increased tyre clearance, too, to a generous 30mm.

Felt claims that the AR is 10 watts more efficient at 48kph. In the wind, that’s a 5.1 per cent saving over the previous model.

Felt AR Advanced Ultegra Di2 ride impressions

The original was quick in a straight line, but a degree of flex minimised cornering speed. It flexed beneath sprints, too.

This new version, however, is taut, responsive under pedalling and surefooted in the corners. The parallel 73.5-degree angles are aggressive, and the stack of 567mm, reach of 392mm (large/56cm) and short 988mm wheelbase are unashamedly racy.

The Shimano Ultegra Di2 groupset with a 52/36 chainset and wide 11-30 cassette is ideal for a bike of this type.

The 52 chainring gives you the top-end gears you need for maximum speed on rolling terrain, while the 36/30 bottom-end means it ascends superbly.

Reynolds AR58s are, as the name suggests, 58mm-deep aero wheels. They impress with their superb stability in blustery conditions and 1,730g a pair isn’t excessive for this depth. They share the same tubeless-ready carbon rims as Reynolds’ range-topping ARx range.

They’re shod with Continental’s brilliant Grand Prix 5000 clinchers in 25mm width, which swell closer to 28mm on the wide Reynolds carbon.

The AR’s on-road feel is race-bike firm but not harsh. The vibration-damping seating keeps the back end’s compliance just right. And while the AR doesn’t possess the unadulteratedly nimble feel of a SuperSix EVO, it still inspires confidence through corners and on descents.

Overall, the new AR builds on its illustrious legacy.

Felt AR Advanced Ultegra Di2 geometry

• Sizes (* tested): 48, 51, 54, 56*, 58, 61cm
• Seat angle: 73.5 degrees
• Head angle: 73.5 degrees
• Chainstay: 41cm
• Seat tube: 52.6cm
• Top tube: 56cm
• Head tube: 14.7cm
• Fork offset: 4.3cm
• Bottom bracket drop: 7cm
• Stack: 56.7cm
• Reach: 39.2cm