Over the weekend, Denise Mueller-Korenek pedaled her bike faster than anyone else in the world, pushing her custom rig to nearly 184 miles per hour on the famed Bonneville Salt Flats in Utah.

Feats like that take extraordinary effort and training. And in Mueller-Korenek’s case, it also required an extraordinary bike—one stable enough to stay upright at those speeds, with a tire strong enough to roll that fast, and a gear large enough to accelerate faster than any human has ever pedaled a bike.

It Started With a Tire

Mueller’s KHS bike was built by two San Diego engineers: Len Lochmiller and Chris Garcia. But the bike didn’t start with the frame, as it would with most traditional builds. Given the stresses and challenges that come with rolling at 183.93 mph, the engineers started their project with another critical component: the tire.

They started from scratch designing a bike around a tire that they thought could handle her incredible speed. Garcia told us that the tire, which is an IRC model designed for dragster scooters in Thailand, was shaved down to make sure it was perfectly round to prevent speed wobble. Garcia picked this model as it was simply the strongest and most trustworthy tire they could use. Mueller used an inner tube rather than tubeless technology as that was what the tires were designed around.



Surprisingly Small Wheels

Chris Garcia told us the wheels were designed around the tires and the bike around the wheels. In order to accommodate the tires, he used 17-inch 1970s Akront motorcycle rims laced with 12-gauge Phil Wood spokes to Profile Design hubs modified by Garcia to take the larger spokes. The bike ran a 15mm front thru-axle and a 135mm rear fixed hub, and the rims were perfectly balanced to avoid any extra instability at speed.

The bike was designed around a tire that could withstand such incredible speed. Courtesy of Len Lochmiller

A Special (and Highly Unusual) Frame

Lochmiller put a lot of thought into the frame, which he built from scratch using his experience in both bicycle and automotive design. He needed to build a bike that was stable at high speeds and able to handle the special 17-inch wheels and accommodate the gearing required to go 184 mph. Lochmiller made the rear triangle from two Cannondale road forks joined together at the dropouts to yield a longer and stiffer rear end to accommodate the gearing and high speeds.

Lochmiller used two road forks and tubes made by wrapping carbon around light bulbs to make this one-of-a-kind frame. Courtesy of Len Lochmiller

The top and down tubes were made using a process Lochmiller cleverly designed himself. Carbon was wrapped around a fluorescent light bulb and then a special durable plastic bag was placed around the tube and the air sucked out by an industrial vacuum to form the carbon into the tube shape. Once this was set, the bulb was then smashed and removed, yielding a cylindrical tube much thicker than any road frame. Lochmiller says that he then wrapped the tube with extra carbon, which he thinks “probably wasn’t necessary.” But given the extreme speeds, he said the extra layers help him sleep at night.

Geometry for Speed

The geometry of the bike was based on one used by Fred Rompelberg to set a record of 167 mph in 1995. The bike was more than 35 pounds and 7 feet long, but weight isn’t an issue on the pan-flat surface used for the record, and the length adds stability at such high speeds. The chainstays and seatstays were so long that they required a brace halfway down to stop any flex.

A HUGE Gear

Lochmiller then used a custom-engineered mount for a reduction gear that allowed a reasonable cadence at such high speeds. Mueller used a 60-tooth front chainring going to a 13-tooth cog on a Jackshaft that was supplied by da Vinci. The Jackshaft transferred to another 60-tooth chainring going to a 12-tooth cog on the rear wheel. This combination yielded the equivalent of a 204x11 road gear without the need for a chainring that would have scraped the ground, which would have been the case with a traditional chainring-cog drivetrain! This top gear was more than four times larger than the 52x11, which is the biggest gear on a standard road bike.

A custom gearing system was used to accommodate Mueller’s unique needs. Courtesy of Len Lochmiller

Other Gear

Mueller used an X-Fusion downhill fork, reduced to 1 ½ inches of travel in order to smooth out the rough terrain of the salt flats where she made her record attempt. In previous attempts she had a brake on the chainring as well as on the rear rim, but she felt that she didn’t really need brakes and this year went with only a rear rim brake as a safety measure. Mueller also used a suspension seatpost to soak up some of the vibrations of riding at more than double the speed limit.

Mueller’s Secret Weapon

Mueller drafted a top-fuel dragster with a custom fairing and used a tow in to get up to 90 mph as there would be no way to turn her bike’s huge gear from a standstill. Once up to speed, she pedaled at more than 700w for a minute in the draft of the specially designed vehicle to set the record. Mueller used a camera to communicate with her driver, which is vital because coming out of that tiny pocket of draft, just under four feet wide, would be fatal at these increasing speeds. She also used motorcycle safety gear, appropriate given that she was moving at speeds far beyond those most of us would ever achieve in a car!



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