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And now for something really different.....

Roehr Supercharged Harley V-Rod Superbike
by Calendar Kitten Apple Price • photos by Jim Gianatsis, Alan Cathcart / Roehr

Walter Roehrich is a roadracing enthusiast from Gurnee, Illinois, who dreamed to build his ultimate street bike. It needed to be light weight, powerful and above all handle like a current GP bike. The desire to take on this challenging project grew from Walter Roehrich's love and passion for sportbikes and a desire to express his ideas and build a unique bike that was not available from current manufacturers. That uniqueness including using an American Harley-Davidson supplied power plant.

The final finished result shown here, the Roehr 1250SC Supercharged, is now in limited production for customer ordering. The bike is certainly beautiful, a well thought out and tested design, individually hand built and equipped with the best components like a high end Ecossem Confederate, MV Agusta or Ducati 1098R Superbike. It's priced accordingly at $49,999 which is actually very reasonable.

The initial Roehr prototype shows its small compact blower which resembles a turbo, mounted above the engine in the space normally reserved for the airbox. CLICK TO ENLARGE

The finished production bike we got to test has carbon fibre rear subframe covers hiding the aluminum structure, a full Akrapovic racing exhaust system, and two big radiators, one on each side, and a big oil cooler, all neded to cool the big twin which was designed to produce less power and heat and be exposed to the open air for additional cooling from its cylinder fins, now hidden behind a full fairing. Photo curtesy Alan Cathcart / Roehr.
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The Engine
The Roehr 1250sc is powered by a 180hp, specially developed version of the Harley-Davidson* V-Rod* engine. The engine was designed by Harley Davidson back in the 1990's with assistance with Porsche AG. It is loosely based on the Harley-Davidson VR1000 superbike engine. The design goal 15 years ago was to create a new engine that was modern, powerful and reliable providing HD with an engine for the future. The result was an 1130cc (since increased to 1250cc) liquid cooled, DOHC, eight valve, 60 degree, V-Twin engine with a performance like large bore short stroke architecture. This engine was named the "revolution" engine.

Roehr Motorcycles has applied its Roehr Supercharging System (RSS) technology to enhance this engine's power output without changing the character of it's power delivery, resulting in a truly thrilling riding experience. The result is the most powerful American production motorcycle engine available. But, just as important as outright power is the way the power is delivered. RSS provides smooth controllable power responding to the riders commands.

At the heart of RSS lies the patented Rotrex (C15-60) centrifugal supercharger unit. This supercharger provides the highest levels of efficiency and performance in a compact, light weight unit. This unit weights only 6.4 lbs. and is no larger than a typical small car alternator. Combined are a high efficiency, highly developed "Turbo" centrifugal compressor section, mated to a patented planetary roller drive mechanism. This drive mechanism provides an extremely high step-up ratio of 12.7/1 as well as very low noise output, low wear and excellent reliability.

RSS is designed to provide boost upon rider demand. A special bypass valve is employed to re circulate unneeded air back into the compressor during certain operating ranges such as idle, cruise and deceleration, this effectively disconnects and unloads the supercharger, thus reducing parasitic drag and increasing engine efficiency. In this mode, the engine operates as it's stock normally aspirated self.

Under acceleration the bypass valve closes allowing compressor air to pressurize the intake plenum. The Rotrex supercharger delivers air in proportion to it's driven speed. As engine speed increases the supercharger air output increases proportionally. This strategy is responsible for the extraordinarily smooth and linear power delivery. Power increases in proportion to engine RPM all the way to redline.

RSS enables efficient engine operation with stock emission output levels. Due to the relatively low boost levels of the RSS and low intake charge temperature increase relative to other supercharger types, an intake charge intercooler is eliminated, contributing to a lighter and more compact system.

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The Chassis
The Roehr 1250sc features a unique Bi-Metal beam frame. The frame is constructed of 4130 Chrome-Moly steel and 6061 T6 Aluminum. This method allows each material to be used in areas of the frame that their material characteristics are best suited.

A motorcycle frame needs to be strong, stiff and light weight, but also needs to flex just enough under certain conditions. This controlled flex provides essential information, providing the rider with added confidence near the limits of tire grip. Additionally, this flex also adds a level of dampening which is especially beneficial when the motorcycle is leaned over on the edges of the tires. Under these conditions the motorcycle's suspension effectiveness is dramatically reduced due to road forces no longer acting on the suspension at parallel angles.

The Roehr 1250sc boasts high-spec running gear – Ohlins suspension, Marchesini alloy wheels, Brembo brakes with radial-mount calipers at the front, composite bodywork The single sided rear swingarm and rear wheel hub / brake / sprocket assembly was obviously soured from a Ducati Superbike.

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Is the Roehr 1250SC a serious sport or racebike? Not really. It doesn't fit in any race class with its oversized engine and supercharging charging. And it's some 20-40 pounds heavier than the competition thanks to it's cruiser based Harley V-Rod engine. And a disconcerting thing for race track use is the shallow wet sump oil pan on the street touring bike engine that isn't designed to pick up splashed about oil under high G-loads from braking, acceleration, cornering, and least of all wheelies. And the bike's $60,000 price tag will have you think twice about riding it hard enough to risk pitching it down the track.

Where the Roehr will find a niche though, is among wealthy motorcycle collector enthusiasts (Jay Leno and Tom Cruise, to name a few) who own a stable of unique high end bikes, machines like the exotic American V-Twin powered Ecosse and Confederate naked custom sportbikes, or the Italian Bimota with their unique chassis and high-end suspension components. In this respect the Roehr sits right in as a cruise night, Rock Store or Alice's Restaurant attention getter.

It's only big marketing drawback is unique supercharged V-Rod engine unit that is hidden from view behind the full fairing and under gas tank. And the MotoGP clip-on handlebar riding position that's no longer practical for middle age millionaires. Marketing wise, it might be a good idea to also offer a high handlebar naked bike version of the Roehr, similar to the Aprilia Tuono and Ducati Streetfighter, which puts the supercharged V-Rod engine on display for all the world to see what makes your bike so unique, and expensive!

Return to New Bike Index • Pit Lane News

Roehr Motorcycles LLC
Gurney, Illinois, USA

Tel: 708-212-7324 RoehrMotorcycles.com

Calendar Kitten Apple
takes a bite out of the
Roehr Superbike.
Look for Apple and the Roehr featured in the 2011 FastDates.com Calendars!

Riding the Roehr
The Roehr's 1250cc Harley-Davidson V-Rod motor was originally developed by Porsche and Harley engineers around their 1990'a VR-1000 Superbike race effort. The liquid cooled, double overhead cam, internally counterbalanced 60-degree V-twin (not the H-D traditional 45-degree) engine has a displacement of 1250cc (up from the original 1130cc when introduced in 2001). But what is so very special about the Roehr modified engine is that it is supercharged!

The stock V-Rod engine only puts out about 110 hp, not the power this category of high-end sportbike requires.
So Roehr installs his own supercharger on the engine, running directly off the water pump drive shaft. to boot it from a normally adequate 110 hp cruiser bike engine to a serious 180 hp sportbike powerplant. The water pump in turn, is replaced by a simple external electrical pimp. The result is the healthy production of broad, linear power. On paper, this engine is at the heart of what promises to be the most powerful American sport bike.

With extensive development and testing, the Roehr puts out a claimed 180 hp @ 9500 rpm and 115 ft/lbs of torque at 7500 rpm. To put this in perspective, the standard V-Rod claims only 84 ft/lbs, the Ducati 1098 claims 85 ft/lbs, and the Destroyer (Harley's 6.7 second drag-bike) 97 ft/lbs.

"I have been building bikes for over 15 years and now the culmination of my dreams is about one month away from final street legal approval," Roehr says. We can't help but be distracted by the 2009 Roehr 1250sc as Walter tosses us the keys for a first ride. Produced in limited numbers, this is a true American exotic with top-shelf European appointments including Brembo, Ohlins, Marchesini, and Akrapovic.

The 1250cc motor fires instantaneously and idles with a refined and tamed rumble. After familiarizing ourselves with controls and gauges, the feel is familiar to other exotics we have ridden. The reach to the bars places you in forward and ready-to-sport-ride position. The seat is a bit wide but once on the pegs your legs tuck-in nicely for the anticipated speed rush.

The Roehr's throttle response is flawless. It runs from just off-idle straight to redline, and bounces off the rev-limiter before you know it. It is in its powerband most of the time as it is so very wide. Deceptive as it may be, looking down at the speedometer tells the true story; this is one fast machine.

With its high end Ohlins suspension and Ducati aftermarket sourced sturdy single sided sided rear swingarm, the bike steers with monorail like precision around corners. At 425 pounds dry, it is not a light bike, but it is well balanced. The broad power makes it easy to run it hard out of the corners, almost regardless of gear selection. The bike handles the tight stuff just fine, but gives some indication that she wants to stretch her legs and might prefer some faster sweepers and longer acceleration runs. The Brembo brakes perform as well as you'd expect. The back-torque limiting clutch is most "slippery" while downshifting from higher speeds with higher forces. - xoxox Apple

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