A number of riders from the German team helped demonstrate the fastest way to take on corners on a descent in a scientific experiment

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Giant-Alpecin has used hi-tech experiments to prove the fastest way to descend a twisty mountain road is to brake early, hard and for a short time at corners.

Six unnamed team riders have had their bikes loaded with sensors to record their trajectory, speed, steering, gradient and braking forces. They were instructed to take the swiftest line downhill from their high altitude training camp at La Plagne, France.

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Now, data captured by the sensors has confirmed that to corner quickly, you should brake hard and for a short time on the approach. While many pros know this from experience, it’s the first time it has been proven scientifically.

To verify the theory, each rider has had to freewheel down a one-kilometre road, on their own, four times, so that enough data was generated for scientific analysis.

The route they took is not for the fainthearted – it includes three hairpins, three other sweeping corners and a total fall of 64 metres in altitude.

La Plagne 23-07-2015 TRAININGCAMP TEAM GIANT ALPECIN Photo: Wouter Roosenboom

La Plagne 23-07-2015 TRAININGCAMP TEAM GIANT ALPECIN Photo: Wouter Roosenboom

By the final hairpin three of them hit 70 km/h (43.5 mph) before braking to little more than 20 km/h (12.5 mph).

The results have revealed a significant difference between the Giant-Alpecin pros. The most cautious put on the anchors some 50 meters sooner than the most confident and some riders lost an entire second at corners compared to their team mates.

The fastest completed the kilometre course 4.3 seconds swifter than the slowest – a variation due not just to better braking technique but also to lower drag and being heavier.

“Braking hard, over a short distance and early before the corner seemed to be correlated with a fast trial time,” says Niels Lommers, the scientist from the Technical University of Delft, Netherlands, who led the research.


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Four sprinters from the team rode their aerodynamic Giant Propel bikes and two climbers used the lighter Giant TCR Advanced SL, fitted with Dura Ace Di2 and Pioneer power meters.

More research is planned and new sensors will measure how much the riders lean when the attack a corner.

“This is just the beginning’, says Teun van Erp, the scientific expert at Team Giant-Alpecin.

‘We’re going to be collaborating with the TU Delft Sports Engineering Institute to see what the next step should be. We are certainly keen to further develop this method of measurement and to make more widespread use of it.”

Descending: Measuring and comparing descending technique and performance in professional road cycling. by C.R. (Niels) Lommers can be downloaded from here.

Max Glaskin is an award-winning freelance journalist who tweets about cycling and science as @CyclingScience1 and is the author of Cycling Science (published by Frances Lincoln UK, Chicago University Press USA, and seven other languages).

  • Cycling Science

    Sorry about the apparent contradiction in my article. It’s not always easy to go into details in a 400 word story.

    It’s not 100% clear from the research paper but the implication is that those who started to brake 50m sooner, entered the hairpin at the wrong speed. Either they scrubbed off more speed than optimum, by braking harder and/or for longer, or they didn’t slow down enough, perhaps by releasing the brakes too soon and accelerating again before the hairpin, and had to brake again during the corner.

    Some great points in the discussion comments and I hope this one is also helpful.

    Max

  • Stevo

    I’m not sure about that. The article still seems to contradict itself, since in one place itself it says you should brake early and in another it says riders who started braking earlier lost time on their team mates.

    Incidentally it’s not true that a driven wheel has more grip. The torque you apply to the rear wheel will tend to put more weight on the rear wheel, which which will increase the grip available to that wheel. However, part of that grip is being “used” to overcome wheelspin and so is not available to prevent the tyre sliding sideways. The result can be seen if you accelerate hard in a rwd car on a wet roundabout.

  • Ian Hayward

    Because you are going downhill and a driven wheel has more grip so you have your power assisted by gradient rather than in the corner itself which is flatter, if you only accelerate when you are part of the way through the corner there is a ‘loss’ compared to braking prior to the corner, in a straight line. The later the braking is left means you may end up braking in the corner and at risk of locking a wheel thats changing direction. What they mean is a window of opportunity where you do brake late, but not so late that a substantial deceleration has to take place, and early enough that your acceleration through the corner has had some assistance from the gradient itself, not just you. Phew, I think that explains it.

  • Stevo

    It also says this though: “The most cautious put on the anchors some 50 meters sooner than the most confident and some riders lost an entire second at corners compared to their team mates”. That implies you should brake late rather than early before the corner, which is what you would expect. The article seems to contradict itself.

  • James G

    Yes Stevo, on a motorbike, but not a pushbike. On a pushbike, you want to ‘carry’ as much speed as possible through and at the exit of a corner. Once you ‘drive’ it deep into a corner and brake later, you have scrubbed off all of your speed and now you have very little speed for the exit (which is the most critical part of the corner)

    So a little slower in usually means faster out. On a motorbike, you can brake wildly late and gas it as soon as you pass the apex and then begin to accelerate towards the exit. But it does depend on the specific type of corner. Whether it is a constant radii, decreasing, or increasing radii corner. Single apex, double apex, esses, hairpins, etc.

  • Stevo

    Why would you want to brake early before the corner? Surely you would want to brake as late as possible.

  • Gary Jogela

    Zzzzzzzz

  • Jay

    But at the end you still need guts to trust your judgement. So yes you need balls.

  • Giant Bikes Break

    So at the end of one of these road race camps will the participants say “I really feel my spatial judgement and reflex times have improved” or will they say “I feel a lot more confident”?

    And when they’re not “fully covered head to toe and in a controlled environment” will they go as fast or will the presence of other road users and no protection other than a helmet and a layer of sun screen mean they are not as confident so they go slower?

    Confidence (balls) is a huge part of fast descending.

  • James G

    Actually not true at all. Fast descending comes down to Visual Perception, Reflex Reaction time and Spatial Judgment skills. Same skill set that MotoGp, SBK and Roadracers in general utilize. Has nothing to do with balls. It’s all about being able to judge objects in the field of vision (the road or trail) over any given time/distance (Speed) variations.

    If these lads want to improve their descending, they should take roadrace camps/schools. Closed circuits, fully covered head to toe and in a controlled environment with top notch instructors.

  • Giant Bikes Break

    As Sean Yates once said, “Fast descending comes down to who has the biggest balls”

  • Tony Cooper

    Whats new?