Robert Q. Riley Enterprises: Product Design & Development

Build it yourself from plans

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A Recumbent Bicycle You Can Build From Plans

Popular Mechanics, April 1969

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Plans Include...

Printed Plans

4 - 24 x 36 inch

12-page booklet

CAD Plans

2D CAD drawings
   in dxf format
    on CD-ROM

  3D Models in

12 page booklet

Printed... $39
CAD...     $35
Both...     $50

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These are original 2D CAD drawings & 3D models done in Rhinoceros

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Robert Q Riley Enterprises

Ground Hugger
A Recumbent Bicycle You Build From Plans

Featured First in Popular Mechanics Magazine, April 1969
Own the bicycle that sparked the recumbent's return

          Printed Plans - $39         2D CAD (dxf) & 3D Model (Rhino) on CD-ROM - $35  
          Both Printed and CAD - $50  
(See NOTICE below in left margin)

Order Ground Hugger Plans
(order a second item to get a discount & free shipping)

Order Ground HuggerGo to Ground Hugger XR2This unique human powered vehicle was developed and patented in the mid 1960s, and first introduced as "Ground Hugger" in a special plans offering by Popular Mechanics magazine. Ground Hugger's sleek lines and elegant mechanical design captured the interest of bicycle manufacturers, worldwide. But the benefits of the recumbent were not widely understood, and it would be another 10 years before recumbents reached even low-volume production. Due to today's popularity of recumbents, the original Ground Hugger plans have been updated and republished.  And we've also developed the Ground Hugger XR2 - a computer-engineered carbon fiber machine utilizing the latest in cycling design and componentry (click image above).

         Ground Hugger VideoA major benefit of a recumbent is the awesome power that a rider can deliver to the pedals. Nearly everyone has enough strength in their legs to lift up to twice their own weight, and some of us can lift as much as three times. A recumbent provides the rider with something to push against (the back of the seat), so total leg power can be delivered to the pedals. In contrast, a conventional bicycle limits the maximum push against pedals to roughly that of the rider's weight. This, in combination with its inherently lower frontal area and reduced air resistance, is responsible for the recumbent's greater speed. The speed record for a recumbent is over 65 mph. In addition, a recumbent naturally positions the body for improved blood flow because the heart does not have to work against gravity.

         Safety in the event of a spill, and virtually zero stress on arms, hands, and low backs are other advantages. The attribute that receives the most accolades from new riders, however, is also the most difficult to justify in practical terms. The sheer thrill of gliding along at 30 mph just inches above the ground puts Ground Hugger in a class of its own. It's a sensation that has to be experienced in order to be fully appreciated.

         Riding a recumbent is an entirely different experience. One's sense of balance has to be reoriented to the new seating position and close proximity to the bicycle's reaction point. Because the ground is a bicycle's reaction point, the conventional riding position high above the ground translates into greater lateral distances between opposing lean angles, which means slower reaction times. A recumbent reacts more quickly because of the rider's low center of gravity and close proximity to the ground. New riders initially sense this quick reaction time as instability.  But it's a matter of retraining one's sense of balance - about 15 minutes, depending on the person.

         Early versions of Ground Hugger were equipped with the Sturmey-Archer 3-speed hub; the type with a built-in coaster brake.  Plans also show how to install calipers brakes, lightweight crank and head sets, and a multi-speed derailleur system.   The original frames were built of inexpensive mild steel tubing.  But the frame can also be built of thin-wall 4130-N or aluminum tubing to keep the weight down.  The cost to build Ground Hugger will depend on the type of components and materials you select, and on whether you purchase new parts individually or buy a used bike and take the components from it.  So the rock-bottom cost-to-build will be on the order of $200 (mild steel frame with parts from an old bike).  But a high-performance multi-speed road bike with a 4130 frame and new high-end components will cost much more - depending on the materials and components you select.

Order Ground HuggerPlans may be purchased as 2D CAD drawings and 3D electronic models (Rhinoceros) in electronic format on CD-ROM, as large 24 x 36-inch prints on bond paper, or in a set containing both CAD and printed drawings.   (See NOTICE in left margin.)



Length: 88 inches
Weight: 30 - 45 lbs (depending on materials and accessories)
Height: 29-3/4 inches (to the top of the handlebars)
Wheel Base: 66-3/8 inches
Front Wheel: 18 X 1.125 inches (optional 16 - 20 inch wheel)
Rear Wheel: 26 - 27 inches (optional cross-section)
: Optional (multi-speed derailleur or hub)
Brakes: Optional (caliper or hub brakes)
4-inch longitudinal seat and handlebar adjustment (Fits a 64 - 72 inch rider height. Frame may be shortened or lengthened for shorter or taller riders.)

Essential Resources for the Do-It-Yourselfer



To Order Plans

  • Mail: Use the online Order Form to automatically calculate shipping charges and provide a total amount. Click on the "Order Ground Hugger Plans" link above, then press "Add Item to Cart." Fill in your shipping information. You cannot proceed to the Confirmation Page (for freight calculations) without making entries in the credit card fields. If you prefer to enter your credit card information later, simply enter a series of spaces in the Credit card fields then press "Proceed to Confirmation." Print the Confirmation Page and enter any missing information.  Mail your confirmation page to us, along with your check, money order, or credit card information. (Outside the U.S., please make payment in U.S. funds using a credit card or International Money Order.)

  • Order by Phone: Weekdays 8:00 am to 6:00 pm MST: -   480-685-3225.

                  -   Shipments to U.S. destinations go by First Class or Priority Mail (depending on weight).
                   -   Shipments to destinations outside the U.S. go by mail: "Airmail, Letter-Post."
                   -   Arizona residents, add 10.2% sales tax.

Robert Q. Riley Enterprises, LLC.
P.O. Box 14465
Phoenix, AZ 85063-4465
Phone;   480-685-3225


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Robert Q. Riley Enterprises: Product Design & Development
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P.O. Box 14465, Phoenix, AZ 85063-4465
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