“After initially looking at expensive ceramic bearings we approached R.A. Rodriguez who recommended Kaydon Reali-Slim® angular contact, thin section ball bearings, which are ideal for space and weight saving applications, and the team never looked back” says Mr Kyte.
Kaydon angular contact ball bearings supplied by R.A. Rodriguez (U.K.) Limited helped Plymouth University beat the women’s arm-powered land speed record in Nevada, USA.
During the week of 12-19 September 2016, cyclists from around the world gathered on State Route 305 outside of Battle Mountain, Nevada for the 17th World Human Powered Speed Challenge. The location is home to one of the straightest, flattest and smoothest roads in the world. Here, staff and students from the Faculty of Science and Engineering at Plymouth University launched an ambitious attempt to break the women's world arm-powered land speed record, currently standing at 24.76 mph, using its innovative ‘handcycle’ design.
For 2016, the university teamed up with Sarah Piercy, who won the Women’s Wheelchair Marathon in London in 2000, in an attempt to take their handcycle – nicknamed Reynolds – to new heights. The shell of the bike remained the same as when Plymouth University made its only previous attempt in 2015, although experience and ongoing analysis (including student dissertations) were used to change various elements for 2016.
“To help the athlete generate more speed this year we wanted greater elbow space within the bike shell,” explains project leader Adam Kyte, Lecturer in Mechanical and Marine Engineering Design, who led the design and build process alongside various students. “We couldn’t change the shell as it took hundreds of hours to create, so to achieve more elbow room we had to narrow the width of the steering system, which in turn involved changing the bearing configuration.”
With this in mind, the team set out to source four large (100mm diameter) angular contact ball bearings for the steering system hub assemblies – two each per front wheel. In essence, Plymouth University was looking to achieve more power for the same aerodynamic drag, hence the need for large bearings. Although the use of 100mm diameter bearings would increase rolling resistance, this would be far outweighed by the ability of the athlete to generate more power.
“After initially looking at expensive ceramic bearings we approached R.A. Rodriguez who recommended Kaydon, an SKF group company, Reali-Slim® angular contact, thin section ball bearings, which are ideal for space and weight saving applications, and the team never looked back” says Mr Kyte.
“As well as their slim profile, the angular contact functionality was also important as it meant we could design a system whereby the pre-load could be adjusted,” explains Mr Kyte. “This adjustment would allow us to limit any play without increasing rolling resistance.”
With the bearings duly installed, the team set out for Nevada with the goal of bringing home the world record, succeeding by reaching 24.85mph and beating the previous record by 0.1mph. Sarah described the achievement as “the greatest sporting achievement of my life”. The event included a run-up of up to five miles before a timed section of 200 metres. The week-long event had seen Sarah exceed 22mph on numerous occasions, but strong winds and technical difficulties had hampered any progress until the final successful run.
“The bearings ran beautifully, both in test runs and on the big day itself,” says Mr Kyte. “Kaydon bearings would normally feature seals to protect against the ingress of dirt but we requested these were left off to avoid any extra drag. Who knows, with such a small margin of success, this might have made the all-important difference.”
The world record is a deserved reward for thousands of hours of hard work, as Mr Kyte outlines: “The whole team has worked so hard on the bike to maximise its performance. This record attempt was made possible by a range of sponsors and key suppliers. We would like to say a very big thank you to all at R.A. Rodriguez for their assistance. They were very helpful, not only with regard to bearing selection, but with the design of the pre-load adjustment system.”