Aero-Horsepower & Drag Loss Calculator

Early Aero

Joe Petrali

Joe Petrali set a speed record of 136.183 mph on the sands of Daytona in 1937. He did not use the tail fairing as it caused handling issues.


You can dream all you want but this is ancient history. The salt is gone, period...Nothing but a thin crust, only barely raceable to 4 miles with the crust breaking up .

The 12 mile race to the floating mountain is only in the dreams of the old competitors who are already dead or are dying off.

No more 24 hour records driving in a circle guided by burning smudge pots. No more safe spins in a highboy at 270 are going to dig in and roll.

They keep moving the course over trying to keep the meet going...and you may, in desperation, switch back to the short course hoping it's better. It isn't.

More dangerous now...but still a good photo op.

It all depends when you were born whether you deem the salt "good" or not...If you were old enough to have raced there 40 years ago then that was your perspective...and it was already going away then with cars stuck in the mud down past the 9 mile marker.

Gun for the "Two" and make sure you have some suspension to deal with the ruts, low spots, and bouncing.

August 2022 Save The Salt report

1978 – 318.59mph – Don Vesco Kawasaki Lightning Bolt

Vesco claimed the record for the last time in 1978 hitting 318.598mph in Lightning Bolt, powered by turbocharged twin Kawasaki Z1000 motors. His record stood for the next 12 years. Vesco, incidentally, was inducted into the AMA ‘Motorcycle Hall of Fame’ in 1999 and succumbed to cancer in December 2002.

He designed it and rode it...both the Lightning Bolt and many before it. Pretty much always a record. We worked with Don a bit when he was to ride Bob George's last liner and asked him why he did not go out and beat the Easyriders time...he said..."If I  wanted to I'd just dust off my old liner and put two Yamaha YXZ motors in it...But I want 500 in the Turbinator first". He also said "If it's slippery enough you don't need that much power".

One of a kind.

Burt Munro

About as low as you can go on a situp bike/liner. Burt Munro with head at steering neck height. Met his son but not Burt. Very narrrow, large sail area, long w/ tail for stability.

Bill Warner (Deceased)

Bill Warner died at 285 MPH trying to get 300 MPH in a mile on asphalt...He had previously run 311.945 MPH in a longer distance. Flat bottom, tires not rated for 300 mph, carbon fiber wheels...who knows what went wrong. Mention was made that the rear tire was worn before the run. Speculation rear BST wheel failed. There is no need for carbon fiber wheels in this game or even road racing.

Gordon Murray, designer or the F1 McLaren and the new T.50, when asked why he did not use carbon wheels...His answer was "They can have sudden catastrophic failure..whereas forged aluminum will not".

Guy Caputo (severely Injured)

Multiple record holder with Nitrous, Guy Caputo went down in a serious crash trying for 300 mph like Bill Warner. Side winds and a flat bottom with little lean angle were suspected. Guy survived but with serious and lingering injuries.

The large majority of these short wheelbase stock frame and rake bikes have crashed, some multiple times.

Tom Mellor

Bike has been raced in both 750cc and 1000cc variations, holding speed records in both classes. Very efficient aero.

New Fairing Tom Mellor


Pretty much proved Bonneville has to have purpose built aero...not store bought aero. Long wheelbase with short overhang.

Bob Bennett Sportster

Early handling issues were traced to the frame itself. A trip to Dr John's got that straightened out. Bonneville is a cruel place...On a record pass his shifter button failed.


Bob has hit 203 MPH with 165 HP but is still chasing his backup run and salt conditions are terrible and are not going to get any better. Very efficient.

In 2020 he bumped the record to 197 after missing a few events and a move out of California. Bob Bennett is listed as KIA on the Viet Nam Memorial Wall. As you can see he is still alive although most of his unit were killed.


Concept. Zero competition.

Easyriders Harley 322.149 MPH (Fuel record stands)

The double-engined Harley-Davidson streamliner of Easyriders Magazine's Joe Teresi. Piloted by Dave Campos it still holds the S-PF (Streamliner Pushrod Fuel) record at 322.149 mph. The design is by Bob George and the liner was originally the Jammer liner. It has an estimated Cd of .2, a frontal area of 5 square feet, and a weight of 2400 lbs. Short overhang past rear wheel.

The two nitro burning engines were only putting out about a total of 380 hp. The engines were tired and the team was down to their last 5 gallons of nitro but Dave did the job and the record still stands. If it's slippery it doesn't take that much horsepower. 300 mph rated Goodyear rubber, no prominent tail fin, rear wheel positioned for the long wheelbase and no long tail overhang. Driver positioned center for best corrective response.

The last Denis Manning Bub7 liner has twice as much rear overhang behind the rear wheel as does Easyrider / Bob George design...Perhaps making it more sensitive to sidewinds.

Very slippery Cd. Briefling held record before ACK took it back. 500 HP. Crashed at Lake Gairdner, cause not disclosed. Rider positioned far forward.

Ack Attack Liner: Mike Akatiff and Rocky Robinson (Record holder)

Currently the world record holder at 376 mph with two Hayabusa motors. 1000 HP expected. Rocky actually had a Motec GPS exit data recording of slightly over 400 mph. The Bonneville Salt Flats are now too rough, too short, and too thin a salt crust for streamliners, so it's off to Bolivia and 15 miles of rock hard salt.

300 mph tires, a rounded bottom, no tail fin (ala Bob George), a long wheelbase with minimal tail overhang and, after a number of record runs, the practical aero instead of an expert's theoretical aero (rear chute doors) was worked out. Full tubular safety structure that has proven itself in crashes. Rocky has more seat time in these than anyone except perhaps the late Don Vesco. Mike is in the aero industry and rider safety is paramount.

Survived several crashes (sound design). Mike Akatiff says it's Bolivia or nothing...The salt at Bonneville is too thin, broken up and there is only maybe an iffy 5 miles v. 15 miles in Bolivia.

A return trip to Bolivia was a bust as un-diagnosed issues with the fuel system stopped the effort. Complex critters.

Returned in 2023, as Bonneville no longer offers a track for these, but gremlins with the engines, the electric stabilizer wheels, the rear tail door section, and a suitable push vehicle led to a last day 303 mph. Huge effort on a 400 mph quest. Still the record holder with an unrealized 450 mph potential. 12000 feet altitude and a long way from home.

2023 ACK After Action Report.

Lambky Vincent

Only four square feet of frontal area. Keeps breaking parts. Inspired by Bob George's successful design but on about a 7/8 scale. Teardrop tapered tail section. This effort folded with no results and the shell and the chassis etc, minus the Vincent engines was put up for sale. Resources, time, money, and age all converge at some point.

Don Vesco once got in it and said he could not see and got out of it. Man machine interface.

Was up for sale minus engines after multi-year effort. Fatal disease.

Streamliner Conundrum

When you up and decide to build a motorcycle streamliner you bascically have put yourself into a corner that takes years or decades to get out of...How is that? Well bippie, the conundrum is you can't test the damn thing until you get to the Salt Flats. We've been there with two streamliners and watched it up close building skids, shifter mechanisms, testing fuel systems and doing low speed tow testing at Bonneville and El Mirage...working with Bob George, Dave Campos and Leo Hess.

Factor in the weather and the usual fuckups and you best be in it for the long haul. Ask Denis Manning, Max Lambky, Vance Breeze, and Rocky Robinson (fastest). Don Vesco had it down.

Take a look at that smile on the NSU pilot above...try that in your streamliner. Having fun testing.

Sam Wheeler (deceased)

Sam Wheeler's ZX-11 powered streamliner next to a Kawasaki ZX-11. Bonneville is all about getting through the air. The shape for Sam's Liner was developed at The California Institute of Technology wind tunnel. In the 1997 wind tunnel document you can see Mike Geokan and his #226 Blue Bike in one of the pictures. The Cd is tested at .103. People ususally build something then test it. Here it was done correctly i.e. the shape was developed then the shell was made.

2017: Sam died in his liner when it went out or control and he had massive head injuries. Sam had spent years updating the liner. Perhaps too many new things at once...solid metal front "tire" (never worked for Bob George...he tried it) 2 speed secondary transmission also untested, new Hayabusa turbo motor, and a new belt final drive.

20 years later you put on weight and it gets more crowded in the cockpit...helmet too close to roll hoop. Hard to exit in fire suit.

You can put these streamliners on a dyno but you just can't drive them around so testing is done minutes at a time years or decades apart..Sam had more decades of experience than anyone except the late Don Vesco. It is a dangerous undertaking.

Not sure there is any post crash analysis...there seems to be a pass on this unless there are four wheels involved. Was not a full tubular structure post the rider.

Bonneville Bullett

The Bonneville Bullett with a 139" ORCA Turbo motor. Here pictured at the 2009 SCTA-BNI World Finals where it qualified for long course at 191 mph in 3rd gear. 1000 lbs and about 425 hp if the boost is turned up. It ran 191 with about 9 psi in 3rd gear getting the new rider his seat time and licenses. Cd is estimated at .476 and a frontal area of 5.5 feet. Rider and bike weigh 1250 lbs. 300 mph LSR tires.

 Bryan Stock got a 200 mph record at low boost. Now the salt is mostly gone. Like streamliners, not a bike you can test i.e. ride until you get there.

Notice the floorboards with the rider's feet exposed to the air where they can get blown off. We made some left and right heel restraints for the bike but the owner declined saying they were not necessary..."As all you have to do is have piece of carpet and wipe your feet off at the start line". Beyond stupid.

We finally put the right one on, drilled, bolted and loctited, not asking anyone before so doing. We did not get the left one on as we would have had to cut off the heel shifter which would have been a political statement. Well, maybe Bryan can hang on at 200+ with one leg anchored. Politics of insanity. It was only briefly run up to 345hp @ 19PSI. Bike geared for 312 mph @ 6500 RPM.

Turbo was sized for 560HP but with low RPM (6500 rev cut 6750) and small valve area relative to displacement 425 HP @ 6500 if taken out to 30psi.

We left this project when the owner got a bit ornery and defintely unappreciative. Has not gone faster after we got Bryan a 200mph record in 2011.,,long long ago.

Ralph Hudson (Deceased) ...262 MPH Mojave Mile..and 297 MPH Record in Bolivia...Crash SpeedWeek 2020 @ 252mph

Currently fastest situp bike in the world...shooting for 300 mph back to back runs in Bolivia.  Ralph designed the fairing. Dunlop Road Race tires not certified for 300 mph. Change tires each run if they chunk...700lbs. Ralph tried LSR car tires but could not get his bike to handle. Ralph tried tire warmers but the tires chunked easier. They were never shaved.

One way 307 MPH. Ralph designed his own bodywork...Rounded bottom closed tail. Ice-cooled water to air intercooler. Minimal rear overhang. Over 500HP with 1000cc!

141mph in 1st gear. Well sorted Motec electronics by Shane Tecklenburg. Years and years of development. New chilled air to water intercooler and bigger Xona Rotor Turbo for the 12000 feet altitude in Bolivia.

Bolivia is the best bet for 300+. COVID-19 cancelled the 2020 year trip. Bigger turbo (Xona Rotor) for 12000 ft altitude in Bolivia. He's was still faster than a Bugatti Veyron.

SpeedWeek 2020: After setting a record with his 600cc bike Ralph crashed on a return record run with his 1000cc bike, going down at 252 mph. Possible cause...sidewind. Ralph passed away...he was 69 years old. Last interview of Ralph before his final run.

Not sure of current regs relative to sidewinds. Long ago...Back in 1985 it seemed that 5 MPH was the cut off point. The winds can vary down the course, so having a readout of the side winds at the two, four, and six mile points is critical. Not sure that is a go anymore as we have seen 14 MPH side winds at the start line and people were still going. Maybe no one to stop Ralph on his return run that last day when gusts were reported up to 9 mph and can be worse down the course where a gap in the mountains funnels the sidewinds.

With the longer tails gusts will turn the bike into the wind.

Al Lamb


 Charlie Toy based fairing from Airtech. Road race tires not certified for 300 mph. Two trips to Bolivia...the second trip the bike arrived too late due to shipping issues. Damn.

The bike was subsequently modified with a longer tail to inprove the Cd. which will make it more susceptible to side winds. You best have your own three spotters down wind with aneometers to give you a go or no go with the trigger being 5mph.  Gusts from a gap in the hills from the left will push the tail around and veer you left.

For 2023 bike was completely redone but engine and turbo gremlins resuletd in one last day pass at 260. Cruel place.

Tom Bookhamer

120 CID Harley motor...transmission breakage got Tom at Bonneville but he's back with a Baker 6 speed Grudge Box that hopefully won't break. Tom worked to lower the Cd a bit after a trip to a wind tunnel where he made improvements in laminar flow by preparing removable fairing sections.

 In his first trip he managed to get inspected and licensed for long course before his transmission broke. He's a senior engineer and had it all worked out then the salt bears got him. So it goes.

At his next SpeedWeek, where he did not run due to salt conditions, on the way home he and a big rig were cut off by a woman driver making a sudden lane change for an exit ...his race trailer rolled. The driver that cut Tom and the big rig off went on her merry way and did not stop. His aluminum fairing was destroyed so Tom started over with fiberglass shooting for 2024, as 2023 was a wash-out.

Long expensive trip from Florida. Tom is rebuilding and upping the a new trailer.

You are at the mercy of the elements so to call it a crap shoot is correct. Get lucky once and then years afterwards zero success...has happened to lots of people. Best get the money photo shots.

In 1992 we put Henry Louie and Fred Wiley into the 200 mph club (Red Hat) on their first try on our Turbo GSXRs...They thought it was easy. It isn't....It's all preparation, testing, and luck.


Tires: Donald Campbell's Dunlop tires only had .050" of rubber and were tested in a special bunker constructed by Dunlop to 450 mph. 52" tall they were inflated to 130 psi. No thick rubber to build up heat and chunk. With the advent of the turbo Jap bikes that we pioneered in 1989 with the GSXR Suzuki's going 200 was easy...We limited them to 255Hp which was enough to push them to 215+ pretty much instantly on asphalt...and 203 on the salt with 34 mph wheelspin. Aero wall.

Later on the more aero Hayabusas made 250+ attainable with up to 500Hp...and the motorcycle tech station was full of chunked tires. Tire failures put people down like Jason McVicar at 242MPH.

Streamlined teardrop bodywork followed Jon Amo (272 MPH) and side winds became the enemy along with a deteriorating course with ruts and thin crust.

Got dangerous fast.

Nate Jones and Son...Nate Jones Cowboy Tire

Nate Jones and his son with the Bullett's 2017 Goodyear LSR tires...Mounted, shaved and balanced. Nate wants everyone to know that shaving new tires whether it's for Bonneville, your new pickup truck or your $200,000.00 Porsche Turbo Carrera will make the vehicle safer and smoother as even new molded tires are not perfectly round and, if not shaved, require more balance weights than needed to try to correct the out of roundness. All Bonneville motorcycle tires whether Z-Rated or Road Race slicks should have additional shaving to remove excess rubber to cut down on heat build-up on the long course at Bonneville to prevent chunking. Even the Bullett's $650.00 tires get shaved and balanced. Nate Jones Cowboy Tire 1-562-597-3369.

When we first went to Bonneville in 1985 the late Jack Dolan, of two and four wheeled Bonneville fame, advised us to get Goodyear Road Race Slicks and have Nate Jones shave and balance them. It's something we have done ever since. Zero problems with the Bullett's LSR rubber prepped by Nates. People have died using tires not rated for these 200+ mph speeds and it's damn stupid to have the excess rubber that a street tire has. Z-Rated does not cut it on the great white dyno. Tire shaving has been around a long time.

If you have ever looked at the tires, or pictures of the same, of Sir Malcolm Campbell, Craig Breedlove, Al Teague, Mickey Thompson, and others you will find an extremely stiff carcass (bitch to mount) with very thin rubber and no treads. Nate Jones does pretty much all the SCTA-BNI Bonneville tires as well as Duallies, Rolls Royces, Bentleys and Porsches.

Why LSR turbo bikes do not get heir tires shaved at Nates is a mystery. Guess the old guard like Jack Dolan took that advice with them.

Circa 2006 Jack Dolan Quote re LSR:

"LSR stuff is different and is forever. If you make a rule change, it should be the minimum to follow technology and safety and never obsolete anything that has gone before . Burt (Munro) is an example of how it should be done. His package should never be allowed to run today because the safety requirements that have proven themselves time and again would not allow it. He did know about the value of shaved and prepared tires and that is a lesson that is still tough for some to swallow. Now that does not include shoe polish in the cracks but you should know how to care for the tires."

Fluid-Dynamic Drag

 RSR Bonneville Aero-Horsepower & Drag Loss Calculator:

Calculate your horsepower requirements based on the physical limits of drag and frontal area. To get correct gearing for your top speed runs use our Gearspeed Calculator  . Simply enter the four figures for your vehicle and see what you face horsepower-wise to meet your objectives. Keep in mind that you can never have enough horsepower. However, all the horsepower in the world won't help you if you are limited by a high Cd or traction on surfaces like Bonneville.

Coefficient of Drag: Street, faired motorcycles are notoriously inefficient aero-devices with Coefficient of Drag (Cd) figures in the .6 range. For example a Suzuki Hayabusa has a Cd of .561 whereas a Kawasaki ZX-12 has a Cd of .603. Modern cars often have paid close attention to aerodynamics and may have Cd figures of .3 . Streamliners may have Cd figures of under .2, perhaps as low as .15 or in some cases figures of .10 have been achieved.

Frontal Area: Reducing frontal area is key to going fast as the horsepower requirements go up exponentially as you push that "barn door" through the air. You'll need a close approximation of your vehicle's frontal area in square feet to make this calculator entry. A Suzuki Hayabusa has a frontal area of 6.01 suare feet. A Kawasaki ZX-12 has a frontal area of 6.09 square feet. Some streamliners like the Lambky Vincent have only 4 square feet frontal area.

Vehicle Weight: On shorter courses with asphalt surfaces and good traction weight is more of an issue than it is at Bonneville where weight can aid traction on the slippery salt surface. Short courses are more of a drag race and accelerating extra mass is not a good idea. At Bonneville the big dogs will be on the long course with over six miles of salt with the clocks at the 2 , 4, and 6 mile markers, so weight is not nearly as much of an issue.

Speed: Miles per hour that is your objective. Remember when you set your gearing for Bonneville that you have to plan for wheelspin due to the slippery conditions. This can be factored into our Gearspeed Calculator. The biggest mistake you can make at Bonneville is to gear too close to your intended speed...

Coefficient of Drag (Cd):

Frontal area (sq. ft.):

Vehicle and Rider Weight (lbs):

Speed (mph):


Horsepower Needed:

Horsepower Lost to Drag: