This article originally appeared on BikeRadar
It's no secret that the rider, not the bike, contributes the greatest amount of aerodynamic drag to enterprise of cycling. And while it's easy to feel a change in speed by moving your body – say, tucking on a downhill versus sitting bolt upright like Mary Poppins – it's more difficult to feel aero improvements on the bike itself. So, when you climb aboard a machine like the Look 795 Aerolight and the increased speed is tangible, that is worth something.
- Highs: Sails through the wind, integrated design looks clean, light
- Lows: Grossly expensive for an ultegra di2 bike, flexy stem, raised top tube, brake pad rub under heavier riders unless pads are backed way out
- Buy if: You want a unique aero machine and money is no object
While the biggest gains over a standard bike may arguably come from 60mm-deep Mavic CXR 60s, the airfoil tubing and integrated brakes, stem and seatpost figure into the aero mix too.
Yet, as such integration comes at a cost of compatibility, the question arises: is it worth it? With this machine, at this price, I'm not so sure. (It's worth noting that we've tested the outgoing 2015 model here. For 2016, Look's bikes have seen their price points reduced significantly – we're looking forward to getting some in to see how they stack up in comparison.)
Made in France
In addition to the French-made frame, fork, integrated stem and hidden-in-the-fork front brake, Look also manufactures its own unique crankset. Triangular inserts on the Zed2 crankset allow for three effective cranks lengths (170, 172.5 and 175mm), achievable by rotating the insert before installing the pedal. Whether this design is more beneficial to the rider or the manufacturer is debatable.
While Look argues that in-house manufacturing allows for greater freedom and control in design, it also drives the price up.
At the heart of the Zed2 is a single piece of carbon that forms both crank arms, the spindle and the spider. This unit weighs 320g (not including the chainrings) and spins inside a massive 65mm BB shell.
On the road, the Zed2 feels like any other stiff crank. This particular 795 Aerolight build came with compact 50/34 rings, a surprising choice for a bike built for speed.
The Aerostem comes in six lengths (80-130mm), with angle adjustment from -13 to 17 degrees. In place of external clamp bolts, the Aerostem clamps onto the steerer with a clamp hidden inside the stem. The idea is to offer sufficient height adjustment of the handlebar with minimal aerodynamic cost. In my experience, putting the stem all the way down caused the rubber gasket underneath it to act as a steering damper — causing a surprise when I went to take my vest off while riding!
The high front end is a weird one. Ostensibly having the stem flow straight into the raised top tube smooths airflow and thus lessens aerodynamic drag. But you still have a tall front section of a bike. This is a different direction than other brands have taken with the stems and top tubes of aero bikes like the Specialized Venge ViAS, the Trek Madone or the Scott Foil.
Aerodynamics aside, what the elevated top tube meant to me was that the frame bumped the inside of my quads sometimes when climbing, and I had to consciously limit the side-to-side sway of the bike when out of the saddle.
While the cables are routed internally through the frame, they dangle under the stem with clunky quick-release cylinders attached. Wind tunnel operators will tell you that more cable length up front means more drag, and surely these quick-release cylinders don’t help. Furthermore, the things don’t work very well, and require some decent finger strength to push open.
The top tube sits inline with the aerostem, making for a massive head tube: the top tube sits inline with the aerostem, making for a massive head tube
A magnet covers the stem bolts atop the stem, which clamps onto the steerer with two side panels. The Di2 junction box hides in the top tube just behind the stem
Fast frame and wheels
Having sat through a number of wind-tunnel presentations by various companies, I don't find anything objectionable about Look's claims that the NACA aerofoil tube shaping makes the Aerolight fast. Tucking both the battery and the junction box of the Shimano Ultegra Di2 drivetrain is a nice touch, too, for both aesthetics and wind-tunnel measurements. (To charge the Di2 battery, you pull the junction box out of its hiding place in the frame and plug it in to the Di2 charger.)
Thin elastomers in between the seat tube and the in-line seatpost offer a little cushioning.
On the road, the bike excelled during fast, steady efforts, with the frame and wheels sailing through the wind, especially on somewhat windy days. For me, at 185lb / 84kg, hard out-of-the-saddle efforts weren't as satisfying, as flex in the system had me backing off the brake pads to prevent rubbing. Similarly, yanking hard on the 3T stem resulted in noticeable bending up front.
The stock CXR 60 wheels have rubber 'Blade' inserts that ease the transition between clincher and rim, smoothing airflow and further speeding up forward progress. The micro-ribbed Exalith treatment on the rims does improve the brake's bite, effectively acting as a cheese grater on the brake pads.
I did have one incident with the front Blade, however. On a long, steep hill, I felt something fluttering against my leg after exiting a tight switchback where I braked hard at the entry. I looked down, and saw the front Blade, completely dislodged from the rim, now dancing around the hub like a hula hoop. (And yes, the Blade was installed properly, with no contact from the brake pad.) It seems some combination of frictional heat from the braking and torque from the cornering popped the Blade out.
A rubber 'Blade' snaps into the channel between the rubber and the rim, smoothing airflow
The Shimano Ultegra Di2 drivetrain, paired with the Zed2 crank with Praxis 50/34 chainrings, is excellent. Shifting couldn't be much easier, and the derailleur response is crisp and reliable. The carbon levers provide plenty of brake leverage, although friction from the internal cable routing compromises the smooth feel and perhaps the power a touch.
A direct-mount Ultegra brake is tucked underneath the bottom bracket and is paired with Look's Aerobrake 2 up front, which hides inside the fork legs. Personally, I'm not a huge fan of BB-mounted brakes because of all the road grime that gets kicked up down there.
For an aero bike presumably targeted at riders who want to go fast, the gearing choice is a little odd. On downhills I would spin out at 40mph / 64kph doing 115rpm. (And yes, you can buy the bike with other chainring configurations.) On the flip side, your uphill route options expand considerably with a 30-25 as your low gear, especially on such a light machine. This size L tester weighed in at 7.47kg / 16.47lb.
You can't go wrong with Ultegra componentry
Bottom line: who is this bike for?
All bikes make some sort of compromise. Cheap bikes are heavy, and nowhere near as smooth as high-end bikes. Endurance bikes are comfortable but not as lively as criterium machines. And aero bikes are fast but sometimes not easy to live with on a daily basis.
The Look 695 Aerolight delivers on its name, but the price just isn't justifiable for the performance and component package. I salute innovation and the courage or loyalty to manufacture in house, but for my money, I'd go with a Foil, a Madone or a Venge for an all-out aero bike.
Name: 795 Aerolight
Built by: Look
Price: £7,999.00 / US$13,499.00 /AU$N/A
Available Sizes: XS S M L XL
Brakes: Shimano Ultegra direct-mount rear, Look integrated Aerobrake 2 front
Cassette: Shimano Ultegra, 11-25
Chain: Shimano Ultegra
Cranks: Look Zed 2 Compact
Fork: Look HSC 8
Fork Weight: 320
Front Derailleur: Shimano Ultegra Di2
Front Tyre: Mavic CXR Ultimate GripLink C
Front Tyre Size: 700x23C
Handlebar: 3T Ergonova Team
Rear Derailleur: Shimano Ultegra Di2
Rear Tyre: Mavic CXR Ultimate PowerLink C
Rear Tyre Size: 700x23C
Saddle: Selle Italia SLR
Seatpost: E-Post 2 with Di2 internal battery mount
Shifters: Shimano Ultegra Di2
Stem: Carbon Aerostem
Weight (kg): 7.47
Wheelset: Mavic CXR 60
Weight (lb): 16.47
Brake Levers: Shimano Ultegra Di2
Chainstays (cm): 40.5
Standover Height (cm): 79.9
Top Tube (cm): 57.3
Frame size tested: L