Know How - Beating the Wind

Cycling fast is made hard by the drag that riders and their bikes produce - but there are easy wins out there

Cycling fast is made hard by the drag that riders and their bikes produce. It feels easy to do 15mph on the flat, but raise it to 20mph and up goes the effort slightly.

Make the leap up to 25 and it's just about tolerable; aim for 30mph and you only have a few very talented people who can hold that in no wind on the flat.

Until the 1970s the only ways to go faster were to crouch down low, ride behind other riders or use downhills. Aerodynamics was for jets, motor racing cars and fancy demonstrations with smoke trails on Tomorrow's World .

It's hard to work out who exactly brought aerodynamics to cycling, but between Swiss engineer Toni Maier-Moussa, Team Renault Gitane and a certain Francesco Moser, bike aerodynamics were born. It allowed Moser to break Eddy Merckx's hour record and prompted the 'funny bike' explosion of the 1984 Olympics in Los Angeles.

Moser used two disc wheels, a lycra cover over his helmet, skintight full arms and legs lycra suit, plus cut-off 'cow horn bars' and aero overshoes to boot. Photographs taken at the time show Moser in the wind tunnel honing his position - something that Maier-Moussa and Renault were also doing. However, unless you have a lot of dosh to pay for wind tunnel time and the experts to help you, it's best to simply learn how to go faster from the data that's out there.


Get serious


The right aerodynamic tweaks can make you seriously faster. The difficult part is knowing how much to spend and what's the best area for you to focus on first. Sexy-looking equipment can distract you from something that may be cheaper and more effective. For example, a new rear disc may give you 15-30 seconds over 40km compared to a conventional 32-spoke box-rimmed wheel, but body position changes can save you minutes for nothing.

Check out the annotated picture - each item is given a priority and an approximate gain. The rider is the biggest object producing around 70 to 85 per cent of the total drag. What you do with your torso, arms and legs can produce massive differences. It's not worth having a super-aero bike if you sit up regularly because your core is weak, you fail to practise in a low tuck or it's not comfortable enough.

An evolving science


There's a constant stream of new developments when it comes to aerodynamics. Zipp are testing some new wheel configurations and new independent data on fork and wheel combinations suggest that some aero combinations don't mix and match (see www.biketechreview.com). Dimpled tyres, hubs and special lycra suits are also emerging onto the marketplace.

My own recent track testing data from Newport Velodrome using SRM cranks suggests that moving from a box section 18/20 pair of wheels to a disc plus a deep-rimmed front combination reduces power requirement at 25mph by 20 watts. This equates to approx 1:40 faster. Using aerodynamics wisely, you'll be able to optimise the time you can sustain your top speed to compete harder in the race of truth. Get aero, get faster and get a new PB.


1 BODY POSITION: 1 to 6 minutes.
Cost from £20
Moving the torso into a flat position, producing a lower head and flatter arms, significantly reduces frontal area without buying much more than a new stem.

 

2 AEROBARS: 30sec to 2 minutes.
Cost from £50
Assuming the arms are narrowed, torso position is easier to maintain and drag from the bars is reduced.

3 AERO HELMET: 30 to 120 seconds
Cost from £70
Reducing vents and smoothing airflow behind the rider's head is a significant drag reducer that can give you more than a second per pound spent.

 

4 SKINSUIT: 30 to 60 seconds
Cost from £30
Flapping pockets, rough material and bad seam placement make run of the mill clothing un-aero. Skin-tight suits work, though the exact figures are kept secret by the likes of Nike, Pearl Izumi and Descente.

 

5 FRONT WHEEL: 30sec to 60 seconds.

Cost from £200
Keeping air close to the rim as opposed to air swirling around a box-shaped rim reduces drag. As does a reduced spoke count to ideally 12 to 18.

 

6 AERO FRAME: 30sec to 2 minutes

Cost from £500
Taking round tubes and giving them an aero profile reduces drag. Reducing the seat tube or wrapping it around the rear wheel, or just behind the front wheel, also works.

7 FRONTMOUNTED AERO BOTTLE: 30sec to 60 seconds

Cost from £15
Keeping the rider's arms on the bars and not reaching for a bottle keeps drag low and allows power to be applied constantly. Bottles behind the saddle will slow you down by 30-40 seconds.

 

8 REAR DISC WHEEL: 15 to 30 seconds

Cost from £500
The effect is roughly half that of a front wheel due to the frame shielding the wheel (Martin & Cobb). It may make you more aerodynamic, but high winds can make handling tricky.

9 OVERSHOES:10 to 20 seconds
Cost from £15
You can get some cheap speed with tight rubberised Lycra shoe covers that take straps, vents and buckles out of the wind.

 

10 CONCEALED CABLES: 10-20 seconds approx
Cost from none
Merely routing cables through bars and into the appropriate frame hold can reduce drag.

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