general design considerations

General Design Considerations:

Some of the factors that were important to me might not be of concern to you.  Some however, are basic and probably universal.

Permanent vs. On & Off:  If you converted to a normal tike, you would be permanently committed to that configuration.  On the other hand, a “quad” design gives you the option to switch between your multi-wheeled configuration and your basic motorcycle at your convenience.  How important is this to you?

Being permanently committed to a “quad’ simplifies the design in that the outrigger frame can be solidly and permanently welded to the bike’s frame eliminating multiple bolt connections and brackets.  One can also permanently wire the fender light electrical circuit without a quick disconnect connector.

On the other hand, if you want to enjoy that unique feeling of a motorcycle every now and then, the quick On & Off feature is essential.  I live at the foot of the winding Ortega Highway mountain road in California and swooping through its twisting grades is an absolute delight on a sunny weekend ride.  I would really hate to part with that pleasure.

Multiple Bike Compatibility: You are probably most interested in converting a single motorcycle to the quad configuration. I, on the other hand, had two different motorcycles to consider.  I wished the outrigger frame to be compatible with both and was pleasantly surprised to find that this required no compromise!  The outrigger frame was sufficiently universal that only different bike brackets were required to connect it to the same locations on the outrigger frame.

Modifications to Your Bike:  Are you willing to make modifications to your bike for brackets at appropriate hard points?  This will require changing some brackets and bolts and possibly some welding depending on the design.  I was fortunate in that the Road Star had bolt on passenger foot rests that were perfectly suited to the simple brackets I needed.  On the other hand, my girl friend’s Honda Shadow had peg brackets that were an integral part of the frame.  To achieve suitable attach points; I had to weld on a bracket to replace the original configuration, thereby making a permanent modification to her bike.  These minor modifications had no effect on the operation as a motorcycle alone.

In one case (the Yamaha Road Star) I could return to the original virgin configuration if I chose to by simply unbolting and discarding two brackets.  This could be important should I wish to sell the bike alone at some future date.  The Honda, on the other hand, is permanently modified.  The modifications do not in any way interfere with the operation of the bike or diminish its appearance.  Nevertheless, it is not in its original virgin configuration which might concern a future buyer.

Safety:

I used 1-1/4 inch square steel tubing with a 1/8 inch wall thickness in fabricating the outrigger frame.  I have no idea just how overdesigned the configuration might be but anything less would have given me sleepless nights.  The frame of the Road Star itself is fabricated from 1-¼ inch diameter steel tubing.

The loads on the outrigger wheels are minimal but one’s life depends on the performance of the finished product.  The added weight is largely born by the outrigger wheels without loading down the bikes own suspension.  The total added weight of the entire assembly (about 164 lbs.) does demand extra power to accelerate and does result in some reduction in gas mileage.

I used an experienced talented heliarc welder to join the frame elements that I fabricated.  Again, your life can depend on the quality of those welds.  I used corner gussets to add rigidity and help counter joint fatigue in the future.  Only #8 quality nuts and bolts were employed where needed.

I took special care to design a suspension adjustment system that would allow alignment of the outrigger wheels in three dimensions to insure perfect tracking.

High or Low Platform Frame:

The outrigger frame and platform can be constructed in either of two ways ...  suspension above the frame or below the frame.  I chose to suspend the wheels from below the level of the frame.  This results in a flat unobstructed platform with all of the wheel suspension elements out of sight.  The top of my frame platform is approximately 17 inches above the ground.  The lowest element of the suspension is 10 inches above the ground, well in excess of the bike’s  4-½ inch clearance.  There is no need for a complex fairing to obscure the unattractive suspension components and keep passenger feet and fingers safely out of harm’s way.  The entire flat platform is therefore clear for use.  Furthermore, the high frame is in close proximity to the useful passenger footrest brackets and requires only short bracket straps from the rear fender hard points.

Alternatively, one could choose to place the wheel suspension elements above the level of the frame.   Some commercial kits do this.  This lowers the frame substantially but some type of fairing is necessary to safely cover the protruding suspension components.  The platform is no longer unobstructed.  It also somewhat complicates both the forward and rear brackets as the frame will be further from the most accessible attach points.  Your choice will most likely be influenced by the dimensions of your hard saddlebags and exhaust pipes.

Outrigger Width:

In general, one would do well to minimize the width of the outrigger assembly.   You will have options in this regard ranging from 50“ to 64” wide.  The best frame width will depend on how you are planning to use your Trike+Plus.  Street bikes generally go for a narrow configuration even if it means using “squashed” saddlebags of the long narrow variety.  On the other hand, I use my bike for interstate camping and I appreciate the added carrying capacity of a wider platform allowing generous saddlebags and tent storage space hence I favored a relative wide outrigger design.  Either way, you will be riding a vehicle which is considerably wider that what you are accustomed to and this takes some getting-used-to!

Saddlebags:  Before committing to a design, consider the luggage you are using and its compatibility once you have converted to a quad.  On the Road Star, I use soft sided saddlebags that are well suited for camping.  They are easily removed and carried to the campsite and they more readily hold irregular shaped items.  To work with the outrigger frame, I had to raise the bags several inches as the top of the frame platform was 17 inches above grade.  I also discarded the original chrome saddlebag support brackets that allowed the bags to stand off from the rear suspension and wheel.  The new brackets used to attach the rear portion of the outrigger frame to the bike now served this purpose.  These brackets are obscured from sight by the saddlebags themselves.

I similarly had to raise the hard sided saddlebags on the Honda several inches for the same reason.

It is tempting to consider monster luggage now that one has the option for an ample flat platform to load things on (if one uses the high frame with suspension components below).  When picking up firewood recently, we used a large 15” x 21” plastic storage bin on each side to carry all that we needed.  I must say, a quad is really versatile in this respect.  Remember, however, added volume capacity is great but added weight can be problematic.

Exhaust Pipes:

Both my Road Star and the Honda have exhaust pipes on the right side of the bike.  The height and width of these pipes had a major influence on the outrigger frame design.  I chose to make my frame symmetrical, standing off from the bike’s centerline the same amount on each side even though the pipes were only on the right side.  This assured equal weight on each outrigger wheel.  Your bike may be different resulting in a symmetric frame of lesser dimensions.

If you chose to use the high platform (suspension below the frame), the height of the outrigger frame will be approximately 15 to 17 inches from the ground depending on the size outrigger wheels you choose to use.   Here again, the exhaust pipes are the most likely element to interfere with the frame’s platform and will determine the needed frame clearance.

The original rubber torsion independent suspension unit I used had to clear the exhaust pipes and ended up determining the ultimate width of the finished conversion … approximately 64 inches wide.  By using a smaller standoff distance from the exhaust pipes, I could have reduced this to 60 inches and after truncating the suspension torsion tube to achieve a softer ride, I could have produced an outrigger no more than 50 inches wide.

Finish Coating:

I chose to have the final outrigger frame powder coated for a most durable finish.  I could have simply primed and spray painted the frame at a quarter of the cost and the final appearance would have been the same.  As it happened, I was able to “piggy-back” on a larger powder coating job so my costs were modest ($100). 

Although power coating is a more durable finish, it is difficult to adequately coat small crevices such as the U-channel edging the perforated platform.  To be certain this was sealed to moisture, I ran a bead of black silicone based sealant alone each open edge.