Kind of sport
The four-man bob has been on the Olympic programme since 1924. In 1924 and 1928 a team could consist of four or five men. The two-man bob joined them in 1932 and except for 1960, both events have been on the Winter Olympic programme ever since. In 1960 competitions were not held because the organization in Squaw Valley found it irresponsible to build an expensive bobsleigh-run for just a handful of participants. The bobsleigh-runs nowadays are almost totally artificially built runs. They must have a minimum length of 1500 metres and decline between eight and fifteen procent. The run has curves with a large radius and the walls of the curves can be anywhere from 2 to 7 metres high. The straight stretches may not be wider than 1.4 metres. Nowadays, when ideal conditions prevail on the run, the two-man bob can reach speeds of up to 110 Km/h and the four-man bob can reach speeds in excess of 130 km/h. In 1952, rules and regulations regarding the total weight of the sleigh and its crew were set up. There is a maximum weight and teams which weigh less may compensate the differential between their weight and the maximum. The finish-time is determined by adding up the times of four races. Helmets which protect the whole face are obligatory.
The length of the two-man bob is 2.70 metres with a maximum weight of 375 kg. Both team-mates push the sleigh for the first part of the run-up. The steersman is the first to jump into the bob and the brakesman pushes a little bit longer before he too jumps in. On account of the modern materials and the technique which are being used nowadays, he only breaks when the bob crosses the finish.
This bobsleigh has a length of 3.80 metres and a maximum weight of 630 kg. The two team-mates who sit in between the steersman and the brakesman do not only act as a ballast in order to gain more speed. Through the shifting of their weight, they are expected to support the rhythm of the bob. In this way, the steersman is able to follow the ideal line with the maximum efficiency. Through the length and the heavier weight of the four-man bob, the bob otherwise reacts slower during corrective movements than does the lighter and more sensitive two-man bob.