Technology, ingenuity, and hard headed stick-to-it-ness is the backbone of land speed racing. Take Burt Munro and his Indian Scout. Production of this machine began in 1920. Stock displacement was 37 cubic inches, (600cc) producing a top speed of about 55 mph. Burt tossed many of the OEM parts in favor of parts he built himself: pistons, flywheels, cams, overhead valves, even the lubrication system.
New Zealander, Richard Assen poses with his LSR crew.
His connecting rods were essentially ‘hand-carved’ from an old truck axle. Burt also experimented with streamlining, knowing that aerodynamics were a key element in his search for greater speeds. In its final form, his Indian Scout was fully enclosed in a composite shell. After half a century of development Burt can lay claim to having the “World’s Fastest Indian”, having an official time slip just over 190 mph and a claimed best top speed of over 200!
Enter the modern-day gladiators:
Jon Minonno – first over 250 on a sit-on bike, in 1992!
Scott Guthrie – 60 personal LSR records, Scott Guthrie Racing as a team, 380 records!
Jason McVicar – over 30 LSR records, first SCTA open bike record over 250 mph!
Shane Stubbs – 265 mph at Loring riding for Scott Guthrie Racing.
Leslie Porterfield – fastest female on sit-on motorcycle, 240 mph at BUB 2009!
Bill Warner – 272 mph at Maxton on a paved airstrip!
Joe Amo – 272 mph at Bonneville on a 1000cc machine!
Shane Stubbs giving the thumbs up after completing a 264 mph pass.
They may not carve connecting rods out of discarded axles or cake shoe polish into cracks in the sidewalls of their racing tires, but make no mistake, the same passion and desire burns in the belly of every one of these top contenders. We discuss the direction land speed racing is headed for the two-wheeled contender, and get their reaction to the reality that one of them may reach 300 mph on a sit-on bike in the not so distant future.
What has been the limiting factor as to why a sit-on bike has yet to reach 300 mph?
Richard Assen: Over 250 mph it is all about aerodynamics. We have more horsepower than we can get to the ground and are limited primarily by drag.
Tires become a key concern at 300 mph. What is being discussed and what—if any, tire is deemed ‘safe’ or the ‘right tire’ for this type of attempt?
Jason McVicar, Richard Assen, and Scott Guthrie all agree at this point LSR tires will have to be adapted to the bikes. It is a requirement at all SCTA sanctioned events.
What other safety concerns would you think need to be addressed as these top speeds become more prevalent?
This is a close-up of Jason McVicar’s tire which failed at a speed of around 240 mph. Imagine what it would look like if it failed at 300?
Fire systems, back protection, and possibly neck protection.
Richard Assen: The effort required to hang onto the bike becomes quite intense. Some form of restraining device may help this.
Aerodynamics have played a key role in the latest speed gains. Bikes are beginning to look more like Burt Munro’s Indian with the sleek, longer bodywork. Are there new rules allowing additional streamlining that wasn’t allowed in the past?
Scott Guthrie: The change in SCTA “special construction” rules are promoting the biggest aero gains.
Leslie Porterfield: I’m headed to the wind tunnel to optimize what I have! I’m putting more focus on aerodynamics this year, and it seems to be paying off in my issues with traction, handling, and speed.
Richard Assen: SCTA and FIM have moved to allow extension of tail piece behind rear wheel as well as a few other adjustments.
Asphalt versus salt: Is there any advantage to running on the retired air force bases with their paved or concrete surfaces?
Jason McVicar: Traction is the limiting factor at Bonneville. Length is the limiting factor at the airstrips. Take your pick!
Tucked and on the gas, Richard Assen has proven he’s one of the best on a sit-on bike on the salt.
As it stands the asphalt surfaces hold more 260 mph passes than the salt on a sit-on motorcycle.
Leslie Porterfield: Traction is a huge benefit of the paved courses. Unfortunately, with the speeds that have been seen recently it’s obvious that distance for braking is a big issue.
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Note: Bill Warner and Joe Amo both have posted top speeds of 272 mph, Warner on pavement, Amo on the salt. All seem to agree there is more wheel spin on the salt which increases tire temperature and increases the possibility of a tire failure…
What other innovations are bringing speeds to an all-time high?
Jason McVicar: Traction control and boost control is the key to going fast in the future.
Shane Stubbs: Aero improvements and traction control.
Scott Guthrie: Suzuki Hayabusa – easy power for not a lot of money.
Leslie Porterfield accelerates away. Her hat is in the ring with some very stiff competition looking to be the first to 300 mph.
There will always be people pushing the limits of speed which may be out of some people’s comfort zone. If we can figure out how to run fast and minimize the risks, the sky’s the limit.
Leslie Porterfield: I don’t know what too fast is yet. I think it’s when the bike isn’t safe to ride at a certain speed. I think 300 mph can be achieved safely. Too fast is only when it is not safe. That can be 60 mph on a bike that handles bad!
Scott Guthrie: It is (too fast) to me. The chance of failure is much higher, the penalty much greater. That’s a lot of kinetic energy to dissipate before the body comes to a stop.
Richard Assen: Personally I would love to do 300 mph on my bike, and to be honest, it is achievable.
Should a catastrophic accident occur as a result of excessive speeds obtained on a sit-on bike, would that be cause enough to restrict aerodynamics or restrict power output in the name of safety?
Jason McVicar: I think we should look at increasing the safety of the bike and rider versus slowing the bikes down.
Richard Assen: God forbid an accident like that occurs, but it would push the button of restrictions and/or controls.
Leslie Porterfield: That depends on the cause of the accident. Racing is inherently dangerous, but safety at high speeds can’t be ignored. I think sharing information is important as speeds climb.
In summary, the key issues are tires, safety and improved aerodynamics. Each rider knows the risks, and yet no one is taking their hat out of the ring. It's an exciting time in LSR competition and we wish each contender success and many happy returns…
