The Push The push refers to the start of the race. There is 50m distance between the starting block and where the first timing eye catches the sled. The goal of the push is to accelerate the sled as much as humanly possible, jump in, and get the best aerodynamic profile set before entering the first corner. Every track has a different start. Some are very long and flat, and athletes can continue to accelerate the sled slightly longer. Other starts have a very rapid decline, and it is difficult for the athletes to contribute to the velocity of the sled as it pulls away quickly, and you have to load into the sled sooner. In general, the total time an athlete will push the sled is about 5 seconds, depending on how the start ramp is played out. Its amazing how 5 seconds of the most explosive power you can draw out of every muscle fiber to get that sled moving can feel like an eternity. Ideally, the pilot and the brakeman initiate force on the sled at the exact same moment to maximize the initial inertia.
Ideally without skidding sideways anywhere or hitting any walls along the way. Tracks usually have between 14 and 20 corners over the 1.5 km descent, with top speeds between 120-150 km/hr. A typical trip down a track takes about a minute.
This is why most teams have a set of commands they use at the line, which creates a cadence so that timing is a rhythm and more likely to be simultaneous. After the initial “hit” on the sled, the pilot and brakeman push the sled as hard and as fast as possible, until they feel they are no longer contributing to accelerating the sled as it starts to pull away. The pilot jumps in over the side of the sled to the front, and the brakeman usually continues to push for a few more cycles before loading through the back of the sled. The pilot has a release mechanism to lower the bar they have used to push the sled so that it returns to its bullet shaped profile. The brakeman sits with his/her feet forward and folded over so the helmet is below the cowling, and holds on! It is described that a tenth of a second push advantage at the top of the track relates to 3 tenths at the bottom!
The Drive Once the pilot jumps in he/she takes control of the D-rings....Two rings attached to ropes are the pulleys of the steering mechanism. Despite common misbelief, the sled is only in grooves for the first 50 m, the rest of the way down it is open ice that is steered at the pilot's discretion. The goal of a pilot is really not to steer at all. Every time the D-rings are manipulated, it represents the cutting of ice, or friction, which actually is slowing the sled down. Obviously, there are situations which require lots of steering, otherwise you may end up on your head. Races are measured to the hundredth of a second. The best pilots are ones that can feel the pressures and execute the fast lines in the corners.
A second important piece of equipment are the runners. These blades of steel are interchangeable. Every day for sliding we put them on the sled, and when we are finished we remove them to protect their stature. Runners can cost anywhere from $2,000 to $20,000. The steel used to create the runners is standardized for density and must be approved by the IBSF (the bobsleigh governing body) for any race. The runners are designed to be thin or thick, and have some variations such as a parabolic or straight cut. Because they are supporting hundreds of pounds of weight, the edges of the runners are actually rounded, not flat like a skate blade. Most bobsleigh athletes will tell you, the most tedious part of the sport is caring for the runners. Any scratches on the steel can represent lost hundredths of a second on the downtime, so we are constantly polishing the steel using high grit sand paper. Getting a set of runners “race-ready” takes hours of preparation. Runner selection for a race is also vital.
The Equipment Just like race cars, bobsleighs have different classes. At the World Cup level, you will see different brands of sleds, each engineered to be as fast as possible by different use of materials and overall design. A top of the line 4-man sled can cost up to $150 000.00 CAN!!! At the development level you can find sleds of all different designs, and are usually sleds that are a little older, or a little bit more “reinforced” for the pilots learning how to drive. There are also different types of steering mechanisms. Some drivers prefer one type over another due to the amount of feedback they can feel in their hands.
Bobsledders wear special shoes that are formulated for running on ice. The “spikes” resemble what a track athlete would wear for a sprint, but instead of just 10-15 large spikes on the toe, there is a plate that has over 100 small teeth that help propel the athlete forward without slipping. Helmets used must be DOT approved and are generally motorcycle helmets. Pilots can choose whether they use a visor or would prefer to wear googles.
Other Important Notes:
2-man vs 4-man
At the 2018 Olympic Winter Games there will be three disciplines. Women compete in 2-woman, men will compete in both 2-man and 4-man events. Traditionally, only men compete in the 4-man event, but at the start of the 2014 season the IBSF allowed women to compete in the event. Some women began competing against the men in mixed-gender or all female crews. In the 2015/16 World Championships there was a 4-women test event. Because the 4-women event did not get accepted as an Olympic event for 2018 many athletes chose to just focus on 2-woman, but hopefully interest will pick back up again in the 2018/19 season.
Sled weight: There is a minimum the sled can weigh, but you can add weight in the sled if needed.
4 person- 210 kg (468 lbs)
2 man- 170 kg (379 lbs)
2 woman- 165 kg (367 lbs) *** new this year. previously was 170kg Weight class/restrictions
There is a Maximum weight that the Sled + the Crew + all equipment can weigh when competing. (Physics lesson: the velocity is directly related to the force applied to the sled and the mass of the object in motion)
4-person 630 kg (1404 lbs!)
2-man 390kg (870 lbs)
2-woman 325 kg (725 lbs)*** new this year. Previously was 340kg
Disqualified At the top of the track there is a timer that starts once the announcement is made that the track is clear. The athletes have 60 seconds to get the push bars out, get set at the line, do their cadence, and advance the sled to the start line that is 10 m from the block. If they do not reach the start line in time, it results in a DSQ. All crew members and everything that started in the sled must cross the finish line in the sled. If you crash and the sled crosses the finish line, and no one looses a visor or any equipment before crossing the line, the time will still count.
SO....IN BOBSLEIGH TERMS: To create the fastest velocity, you want to have the maximium total weight possible when going down the track. BUT having heavier people pushing a minimum weight sled would most likely accelerate the sled faster than lighter people pushing heavier sled. This is why bobsledders are generally heavy athletes.
Pending ice conditions, humidity, and whether or not it is snowing is a big factor of what benefit you can get from a runner, what kind of response and control the pilot will feel, and how much it will cut into the ice. It is up to each team to decide what runners to use for each race. As an example, a set of “skinny” or thin-radius runners will give a pilot more control when it is cold out and the ice is hard. The same set of runners on a sunny day on a track with a humid climate where the ice is soft will tend to dig in to the track more, creating more friction and actually slowing the sled down. A top ranked pilot may travel with up to 6 sets of runners on tour.