What is Derny racing?

What's Derny Pacing and Racing all about?

Why pace a cyclist?

Cycling, as a competitive sport, is about either how fast or how far a cyclist can go in a given time and in the early 19th nineteenth century, it was recognised that one way of increasing a cyclist's speed and endurance, was to pace them with another vehicle as this encourages them to work harder on the bike than they might otherwise do.

Originally, pedal-powered tandems, triplets, quads and even quints were used for this purpose, as well as both electric and pedal powered motor bicycles. These gave way to specialised pacing motor cycles, called Dernys, which were capable of running at a constant cycling speed and at the same time giving some slipstreaming or drafting effect to the cyclist behind.

The history of the Derny

The first Derny went into production in 1938, it was designed built by an ex racing cyclist, Roger Derny and Sons and it was a motorised bicycle, with a 90 cc engine, that was also pedalled through a fixed gear. The combination of both engine power and pedalling allows for very smooth acceleration and deceleration, which is critical when the front wheel of the cyclist riding behind the Derny is (when it is done right) just centimetres off the pacer's back wheel.

Another feature that shows how the safety of the cyclist was paramount when the idea was first conceived is that the Derny will not stop dead even if the motor stops or seizes. Roger Derny and Sons are no longer in business, but the term 'Derny' is now the generic term used to describe the specialist motor pacer bikes that developed from the pacing bikes first used in the famous Bordeaux -Paris road race which dates back to 1891. Bizarrely, even today the bikes still have to be pushed and bump-started, but once they are going they can cruise at speeds of up to 90 km/h.

What is the technique for riding a Derny?

The driver of a Derny will sit close to the back of the bike, in an upright position, with their heels on the pedals and knees turned out, to provide as large a wind break as possible to benefit the cyclist riding behind.

There are rules about the number of layers of clothing that can be worn, this is to stop drivers padding themselves out 'Michelin Man' style to further add to their bulk and therefore the efficiency of the wind break they can provide for the cyclist behind.

Which cycling events use Derny pacers?

For road races, like Bordeaux-Paris, the cyclist will sit in the slipstream of the derny and be paced, one derny for each cyclist, for the duration of the event. On the track there are two types of Derny paced race; the first is an endurance race typically over distances of c30km for women in the British National Championships, where each cyclist rides behind a Derny, racing at speeds that would not be possible un-paced.

The other type of race is a Keirin, very common in Japan where betting on these races outstrips betting on horseracing. In this race, the derny is used to bring a group of riders (say 7 or 8) up to speed over a number of laps, the derny then pulls off the track and the cyclist sprint for the line without the pacer. This type of race features in national and world track cycling championships.

How difficult is it?

To the casual observer the pacer seems to have the easy job, but it takes a considerable amount of skill to keep the pace as smooth as possible, taking into account the inevitable head and tail winds that are experienced on an outdoor track and the interference from other teams. The noise of the engines makes it very difficult to communicate, so the pacer must take responsibility for delivering the race plan whilst driving to his follower's strengths.

It is easy to underestimate just how long it takes to pass a derny and a rider in a race situation. For safety reasons, there is no overtaking on the inside, a rule that is strictly enforced and added to this, the pacer being overtaken can hold a position on the track that means the overtaking team must ride a long way up the banking to get past.

Feedback from a Derny newcomer after the British National Champs. We spoke to Mel Williams, bronze medallist from this year's National 10 TT about her first ever Derny race:

Why did you decide to ride this championships?

Having never ridden a derny race in my life, I decided that the National Derny Champs would be my first and entered just to have a go. Only then did I discover that they reach to speeds up to 40mph!

What sort of training have you done to prepare?

I didn't really think that drafting mopeds or London buses on my commute to work would really suffice and I managed to squeeze in three sessions behind a derny, which at least allowed me to choose a gear.

How was the race for you?

It has been a whole new experience on the bike! I really had no idea what to expect and was a little surprised when someone shoved a bag in my face and told me to pick a number. I discovered this gave me my start position on the line. I was shaking with nerves and then suddenly we were off. Within less than a lap, everyone had over taken me. I started to panic and realised I was fighting the bike, I felt crowded and the changes in pace made it difficult to hold the wheel of the derny. Thankfully Dave (my pacer) had recognised this and just sat calmly at the back of the race while I sorted myself out! Eventually I was able to focus and relax on the bike and we started to move up. Not wanting to give everything in qualifying, we had got ourselves in a comfortable 3rd position and headed towards the line when, out of nowhere, Joanna McRae sprinted past me in the home straight and took 3rd place on the line.

How will you remember it and will you be back for more?

It was great training - I don't think I have ever breathed so hard in my life. Having said all this, I loved it and am definitely up for giving it another go. Amazing how the memory forgets the pain!