Speed Bike Projects

In our ’spare’ time, the Tri-Sled team is desiging, building and racing world-class recumbent speed bikes. The streamlined recumbent format is the fastest known way to transport a person using human power alone.

The world human powered vehicle (HPV) record is held by Sam Whittingham, who has reached 81 miles per hour (just over 130 kms) on high-altitude flat terrain in the Nevada desert. That makes Sam the fastest man in the world!

In October 2005, Tri-Sled’s Director, Ben Goodall, visited the famed World Human Powered Speed Challenge at Battle Mountain in Nevada, where HPV speed records are set and broken, wetting his appetite for a speed bike project of his own.

The one-hour speed record is currently held by veteran HPV rider Freddy Markham, who set a new world record in 2006, riding 85.991 km in an hour. For more information on the one hour record click here.

A combination of aerodynamic advantage, light weight and cardiovascular efficiency are the main reasons why human powered vehicles are capable of achieving such high speeds. Like all recumbents, the reclined position of a speed bike allows the rider to open his or her chest while keeping the upper body almost completely relaxed. This position increases lung capacity and cardiovascular capability.

Sled-Edge one hour speed record attempt

In 2006, Tri-Sled’s HPV skills were enlisted by Tim Marquardt to design and construct a streamlined two-wheel recumbent to fit Matt Weaver’s Kyle Edge molds in time for an attempt at the Dempsey-MacCready Hour Record. The prize, which expired at the end of June 2006, was to be awarded to the first single-rider to equal or surpass 90 kilometers (55.924 miles) in just one hour. Tim also recruited local HPV enthusiast Ken Houghton, who has a lifetime of composites experience which proved invaluable to the project’s development. Tim secured limited access to the Holden Lang Lang proving ground - a perfect surface for speed bike testing and racing. This combination of factors was enough to tempt Ben into the world of speed bike design and construction and it wasn't long before the ’Sled- Edge’ was born.

The initial start-up project involved the construction of a low-tech speed bike to fit the molds. ’Whoops’, as Tim named it, was completed in May 2006 and proved to be a very solid and stable machine, with novice HPV riders able to ride it with ease. Tim’s account of the construction of Whoops can be found here.

Full of confidence and enthusiasm, the team was keen to get serious, and there was little time to waste. Ben contacted the Tri-Sled racing team and recruited Scott Hawke as an assistant technician and Jeff Neilson as ’the engine’. The team initially used Whoops and a Tri-Sled Sorcerer for training and testing to prepare Jeff to ride what would be a far more advanced and challenging machine.

As with Whoops, Ken and Tim were called on to assist with laying up the Sled-Edge shell, which this time was made of carbon/klegcell to ensure a more solid and crash resistant finish. However, unlike the true-form molds used for Whoops, Ben decided that a few ’nip-n-tucks’ were needed to reduce the frontal area for the Sled-Edge speed bike and gain a little more speed. In total he took 60mm out of the height and 20mm out of the width to get Jeff extra snug inside the fairing. Ben also designed and constructed a custom drive system and crank set into a Chromoly chassis to allow for the even tighter fit.

Further thinking and testing lead the team to decide that a combination of a smaller windscreen and camera in the nose would be the best way to get the most out of the bike with the limited time available. With only a few days to go before the attempt, Ben rebuilt the Sled-Edge and finished the bike with a shiny silver paint job.

Following four weeks of hard work and development, bad luck with the weather kept the Sled-Edge grounded on the designated day of the trial. Holden were only able to grant the team one day at the track within the time deadline and the conditions were not safe or suitable to run.

Ironically, the teams attempting the same record on the other side of the world in Arizona were having the opposite problem. Scorching temperatures meant that none of the teams in the US achieved the 90km needed to claim the full prize. As no team has been able to reach the target, the cash has been divided up to the top three teams.

For the Sled-Edge team, the fun didn't stop with the expiration of the prize. During the 2006 November Melbourne Cup Weekend, the Sled-Edge speed bike team had access to the Holden proving ground again. Several of the team members and other interested enthusiasts who are designing, building and learning to ride their own speed machines, also came along to test their bikes. In total, there were five speed bikes on the track that weekend.

With a full four days access to the test track, the Sled-Edge team was sure there would be at least one suitable day for setting some Australian records. But as the weekend came closer the forecast looked increasingly grim. The Saturday morning appeared to be the only option as strong winds were forecast for all of the remaining days.

The team arrived early to begin the final shake down of the vehicle and practice their launching and catching. During this time they fitted strips of plastic to the outside of the body to protect the highly polished laminar flow surface from any scratches due to mishaps.

Rider Jeff Neilson was on his final testing lap when disaster struck. While cruising along at around 65 km/h the Sled-Edge had its rear tyre blow out. The chase vehicle behind Jeff noticed that something was wrong and sped ahead of the bike to deploy the catch crew. With no rear tyre and the fairing dragging, it was only a matter of time before the vehicle lost control and fell over. Jeff did an amazing job of controlling the bike down to a mere 15 km/h (a mean feat in a wobbly speed bike with locked steering!) but unfortunately he slipped through the catchers by a matter of a few meters. The Sled-Edge sustained minor body damage and a mangled rear wheel.

The conditions were still calm at this stage, and knowing that this would be the only good day, the crew frantically rebuilt the side where the flat had occurred and carefully sanded back the scratches, costing them around an hour and a half of good riding conditions.

With the sea breeze on the brink of coming in, Jeff pushed off for another test run. It became obvious within about half a lap that the conditions were now not suitable to run. With this in mind, Jeff used the opportunity to gain experience in the bike for future trials.

In the test runs Jeff was able to sit well above 60 km/h with very low power input. In one sprint he reached 76 km/h within the space of 500 meters or so. He did this with the protection strips still fitted, which makes the team very optimistic about the vehicle’s potential.

Tri-Sled is continuing its speed bike research and has already had several more testing days at the Holden proving ground since these the previous trials took place. Ben is keen to move on to the next generation of the Sled-Edge with some new ideas and possibilities.

Tri-Sled and the Sled-Edge team thank General Motors Holden for use of the Holden Lang Lang proving ground for this project.

Thanks also to Chris Mosley (Moz) for travelling down from Sydney to take a series of awesome photos during the two main trials. For more of Moz’s speed bike photos click here.

What’s inside the Sled-Edge?

Underneath the sleak ’Kyle Edge’ fairing (outer shell) designed by Matt Weaver from the US (with a few nip ’n tucks from team members) is a reiteration of the Tri-Sled Nitro two-wheel recumbent.

Weighing in just over eight kilograms, Nitro is a fresh approach to low racing geometry. The 16-inch wheels on the front and rear give the bike a compact size and short wheelbase. Nitro’s unusal front- wheel drive also contributes to the bike’s light-weight, efficient and compact advantage.

Is it hard to ride?

Because the weight-shift is different to an upright bicycle, two-wheeled recumbents do require some practice for first time riders, especially when they are enclosed inside a fairing. Increasing aerodynamic advantage invariably means reducing the frontal area of the bike, and therefore the rider’s visibility. In some speed bikes, the rider is completely enclosed to maximise aerodynamic advantage, relying entirely on cameras for vision. For further aerodynamic benefit, the Sled-Edge has just four degrees of steering lock, making the bike especially difficult to launch and ride at slow speeds.