Project Narrative
The Inspiration:
This
project began in November of 2009 in Death Valley when I saw a bike similar to
mine with added rear wheels converting it to a “Trike+Plus” or more correctly,
a “Quad”. The Nevada rider was
handicapped which was his motivation for making the modification. I took pictures and ruminated on the
prospect of converting my own bike to a quad as well. At that time, I had never ridden a trike but had
talked to several riders about the pros and cons. Most of my riding is long distance interstate
while tent camping off of the bike. I
routinely encounter campground access roads that are quite demanding when
riding two-up with a full camp gear load.
The added stability would allow me to explore less improved roads that today
I find intimidating and dangerous. As I
age, I have become more cautious.
I
had briefly considered a conventional trike conversion but felt the cost was
excessive, especially for an older bike like mine. I currently ride a very comfortable seasoned
(dented and scratched) highly reliable 1999 Yamaha Road Star having numerous
“experience dings” with 43,000 miles on it.
The Prelude:
I
“Googled” trike conversion kits and found one made by Tow-Pac and another make
by Voyager that resembled what I’d seen in Death Valley a year ago. Although they are under the “tike” heading,
they actually were “quad” conversion kits employing a removable “outrigger
frame” having two extra unpowered roll-along wheels. These commercial kits are designed to be more
or less universal and adaptable to most any bike.
The kits were well designed and appeared to be
of quality construction; however, they were complicated and costly compared to
what I had in mind. Both kits are
designed to be very easily removable so that the rider is not permanently committed to the quad configuration. These designs require a permanent bolt on
frame with a hitch into which the second frame with wheels attached can be
joined to the bike. I, on the other
hand, was concerned with only a specific bike and I felt a much simpler less
complex and less costly design could therefore be achieved. I was perfectly willing to spend 15 minutes
easily undoing six to eight readily accessible bolts to get back to the basic motorcycle
configuration when I chose to so do.
After
examining my bike and reviewing the pictures I had taken in Death Valley, I
concluded that bolting one single outrigger frame to the bike’s hard-points
should not be much of a problem. I was
certain that a local welder could fabricate what I needed rather
inexpensively. The suspension, however,
presented somewhat more of a challenge.
Since
I am not a car buff or much of a metal working craftsman, I consulted my friend
Ray Miller at Special Interest Motorcar
Restorations in Santa Ana by phone. He makes living restoring classic cars. Ray gave me some key words to Google which
would bring me up to speed on simple independent suspensions and the associated
components. He suggested that I look at
motorcycle trailers and their components for a start.
Research:
After
an afternoon on the computer, I had undergone a crash course on hubs, torsion
suspensions, wheels and tires. I had
earlier spent time thinking about the general nature of the frame I wanted to
build but I realized that my design had to be based on available standard components to avoid costly custom items.
Once
I had a general idea of what I was looking for, I began searching Google
websites and eBay for components.
I
found that rubber torsion axle suspensions appeared to be commonly used on many
of the small motorcycle trailer designs.
There are other suspension
systems but these are simple and easy to work with. I recommend the Dexter Axle website http://www.dexteraxle.com/torflex_axles which will give you quite
a bit of information on this type suspension.
The suspension comes in various load capacities. Since the rear wheel of the motorcycle only
carries 300 to 400 lbs normally and the weight would now be shared with the two
outrigger wheels, I really needed a relatively soft unit.
The
lightest unit I could find was on the Northern
Tool website http://www.northerntool.com/. After an exchange of faxes, I was able to pin
down most of the unit’s dimensions. All
of these smaller units were compatible with a 1” spindle wheel bearing/hub,
which is one of several standard sizes. The
suspension was rated at 500 lbs (for two wheels, 250 lbs. each) which was the softest
I could find. (Now that I have riding experience with the finished product, I realize
that an even softer lower load range unit would have been acceptable had it
been available). The independent torsion suspension was one of the more
expensive components costing $176 including shipping. (The photo shows both of the torsion
suspension units with protective covers on the axle spindles).
------------------------------------------------------------------------------------------------------------------------------Edition
7 Insert:
Once I
finished my Trike+Plus, I felt the ride was “stiff” and I mention this in
several places in the narrative. I was
never able to find a reliable supplier that made a torsion suspension with a
load limit of less than 250 lbs per wheel.
I spoke to an engineer at Dexter Axle
about the interior of their torsion tube and its length in proportion to its
load range. There are no lubricants or
fluids in the tube. I wanted to significantly
reduce the load range so I decided to cut the torsion tube roughly in half. I chose a cut location about 5 inches from
the outer end that would still leave about 6 inches of tube plus the two weld
joints to the base plate as shown in the adjacent picture. I used my Makita hand held grinder with an
abrasive disc and cut deep enough to sever the central square torque rod but
not completely through the entire tube. When I was finished, I used a good grade of
black latex caulk to fill the gap.
I considered this to be a daring experiment
but it worked out beautifully. This
effectively reduced the load range by about half and made a dramatic
improvement in the quality of the ride.
The harsh stiffness was completely eliminated leaving a really comfortably feel to the Trike+Plus ride.
I
now realize that I could have also designed the outrigger frame to be much
narrower if I had wished to so do, by cutting off the torsion suspension tube and the associated excess portion of the
supporting base plate as well and using this reduced dimension in the
subsequent design process. This would
also have reduced the weight of the suspension unit by several pounds. (Weigh your components as you go along as the
information will come in handy later).
If you make this cut early in your design process, you should tap a bolt
hole in the exposed end of the central torque shaft and a corresponding hole in
the end cover you will be replacing. By
using a bolt slightly longer than the depth of the tap, you can provide
positive retention to resist axial pull-out forces without restricting the
movement of the shaft itself.
Keep this in
mind as you proceed through the subsequent sections.
I
am pleased that I softened the ride and I would urge any builder who is using
the 250 lb suspension units to consider doing the same. However, I personally would still retain the
wide unobstructed platform as it perfectly suits my camping needs. I have seen trikes and quads that have been
forced to use “squashed” saddlebags because of the over emphasis on minimizing
the width of the unit. You, as designer,
can have whatever you want in choosing the width best suited to your needs. The quality soft ride will be pretty much the
same.
See section 9.0 “Truncated Torsion Suspension Unit” for more
details on this option.
-------------------------------------------------------------------------------------------------------------------------------
The next
task was to locate a wheel hub with a 1” bearing to be compatible with the
suspension. In searching other sites, I
homed in on a compatible hub with a 5 hole, 4-1/2” circle wheel bolt pattern rated
at 2000 lb. load capacity, quite comfortably exceeding my requirements. Two hubs cost $54 plus shipping. These hubs were specified as being compatible
with either 8 to 10 inch wheels or 12 to 15 inch wheels … another decision to
be made … wheel size? I ended up
specifying a 13” wheel (24” outside diameter) which just looked right to me. Smaller wheels would have reduced the weight
at the extremities of the outrigger frame which in turn, would reduce the
possibility of unfavorable dynamics (dumbbell effect). This is something to ponder! ( I discuss the effect of wheel size on shimmy dynamics
in Section 7). Note for future
reference, that these hubs weighed about 6 lbs. each.
Polyethylene Plastic Fenders
|
While I
was at it, I also found a nice looking inexpensive pair of sturdy black high-density
polyethylene plastic trailer fenders that were about the right size for my
intended design. My next step was to
move to eBay to see if the same components were available at a better
price. Sure enough, I was able to
purchase the hub and fenders through eBay at etrailer.com at half the cost advertized
on the other websites I’d been viewing.
Only the rubber torsion suspension was not available except through Northern Tools.
Commitment:
The
evening of February 25th, 2010, I sat back and took a deep breath
after turning off my computer. I had
just purchased $316 worth of parts on-line (two suspension units, two fenders
and two hubs) … I was pregnant … the project was launched!
Think It Through
Before
going any further, I decided to think the project through and be sure of the
logical steps needed and the order of doing the various tasks. With the help of a glass or two of wine, I
began laying out a diagram of the tasks ahead.
I call this my “flow chart” and it is
included in a separate section. You can
get a quick overview of everything ahead by viewing it now.
Detail Design Phase:
The
next task was to work out a design that would, of course, be safe and sturdy
but would also allow for adjustments once things came together. For example, I noticed that the commercial
designs were able to adjust the height of the outrigger wheels to manage the
weight distribution between the bike’s rear tire and the outrigger tires. This weight distribution significantly
affects steering and traction factors. However,
no features were apparent to adjust wheel track alignment and cant in these
commercial kits.
There
was also the question as to putting the suspension above or below the
frame. Since I did not have bulky hard
sided saddlebags to contend with, I had quite a bit of latitude in my
choice. I quickly realized that by
putting the suspension below the frame, I could easily use brackets at the
passenger footrest position as the major connection point. I may have chosen the other option (above the
frame) if I had to deal with large hard sided luggage.
Wheel Shopping:
Some of
the commercial designs used relatively small diameter outrigger wheels which
gave the final product the “training
wheel look”. I’m sure the wheels
were adequate for the job, yet they simply did not look right. I considered wheel sizes from 12” to
15”. I wanted to use a wheel size that
looked “trike-like” and finally decided upon 13 inch rims in a standard trailer
wheel. A 13 inch wheel is actually 24
inches in outside diameter which means the axle will be 12 inches above grade. As a general rule of thumb for trailer tires,
the outside diameter will be about 1.8 times the rim size. Also remember that the weight of the tire plus rim increases linearly with the wheel size
and added weight is undesirable!
The
choice of wheel size is important for my type of design as it is one of the
determinants as to the height
of the outrigger frame which must clear exhaust pipes, suspension elements and
reasonably match the intended attach points on the bike.
I
stopped by the local America’s Tire
store and found that they had a quality 13” trailer tire 20% cheaper than what
I’d been looking at online. They also
had a 13” chrome wheel at half the price of what I found online. Two tires and chrome rims cost $307 including
mounting and balance. This was the most
expensive components that I was to purchase.
(Other builders have subsequently
told me that they located even better deals, so shop around). I decided to order the tires and wheels up
front as it would make the task of design easier if I had the items in
hand. It would also help visualize the
final product. I was getting excited and
wanted to simply lean the new wheels against the bike just to savor the changes
ahead!
Let the Measurements Begin!
Knowing
the dimensions of the key parts, I could now mold them into a compatible
design. The basic starting condition for
my design was that the outrigger wheel axle would align with the motorcycle’s
rear wheel axis. In retrospect, I have
now seen several designs on Youtube that place the outrigger wheel axle either
forward or aft of the motorcycle’s rear axle.
They appear to perform adequately but I nevertheless chose to keep all
three wheels aligned for my design. Both
the Voyager and Two Pack kits appear to align the rear wheel axle as well.
Carpenters’ Square Measurement Technique
|
I spent a considerable
amount of time examining the bike for hard points to which I might attach the
frame. The task of establishing
dimensions began in earnest. I first
used a level to secure the bike in an upright position. I then carefully marked out the motorcycle’s
rear axle position which became my forward and aft point of reference for all
subsequent measurements. I used two carpenters’
squares to establish height and lateral dimensions of points of interest. The adjacent sketch illustrates the procedure
which is quite simple and accurate.
Bolt-on Passenger Footrest
|
The most
attractive “hard points” to brace the outrigger frame appeared to be at the
passenger’s foot peg area and at the end of the rear fender frame at the
saddlebag support points. On the Road
Star, both locations are strong points and have existing bolts which could be
easily extended to support an additional strap or plate.
However, the
foot pegs on my second bike, a Honda Shadow, are solidly welded to the frame so
custom brackets needed to be fabricated and
welded in their place for that application.
This changes the bike from its “stock” condition but without
compromising any basic feature.
Passenger Footrest Hard Point
|
Height of the Outrigger Frame:
The
dimensions of the torsion suspension unit are very important in that it ultimately dictates both the height
and width of the final outrigger frame.
I am using the dimensions of the original 500 lb. (250 lb. per wheel) load
unit I purchased from www.Northern Tool.com. A smaller, more compact unit, if
available, would result in even more design flexibility. (See the earlier edition
7 insert and section 9 pertaining to truncating the torsion tube).
This
rubber torsion suspension unit consists of a 10‑½ inch rubber packed square tube
from which extends a 6 inch swing
arm ending in a 1 inch diameter axle shank.
Don’t be mislead by the online
specifications showing an 8” dimension for the swing arm … that is the overall
length, not the axis to axis length.
Protective
black vinyl caps cover the wheel axle shank in the adjacent photo. The torque
tube comes welded in three spots to a sturdy steel base plate with bolt holes. The plate is at a 45 degree angle to the
swing arm. The swing arm is meant to be
in a horizontal position when under no load (the bike sitting at rest). As load is placed on the wheels, the swing
arm rotates twisting against the rubber in the torque tube creating a
spring-like resistance. At maximum load
(250 lbs per wheel) the swing arm axle moves approximately 2‑½ inches so fender
clearance must be provided to accommodate this motion and a “stop” must be part
of the frame to preclude overextension.
When
the torsion suspension arrived, I noted small differences in the actual
dimensions compared with the specifications and I modified my plans
accordingly.
I have
chosen to use a 13 inch (24 inch outside diameter) trailer wheel. The axle of the outrigger wheels will thus be
12” above grade. Furthermore, the outrigger
wheel axle will be in line with the motorcycle’s rear axle. A portion of the torsion suspension unit will
be several more inches above the wheel axle.
I employed a design that supported the torsion suspension on an
adjustable swing arm suspended below
the outrigger frames as shown in the adjacent illustration and in the accompanying
drawings.
When
I added all of the height consuming elements together, I had a frame whose
underside height was approximately 15+ inches above the ground. Note that the height dimension on your
drawings will be reduced by about 1/2 inch when you account for the fact that
the suspension will compress by about that amount when you place the wheels on
the ground and the wheels are supporting the weight of the frame, fenders and
suspension components. These elements
weigh about 86 lbs in total which calculates to be 43 lbs. per wheel which is 17%
of the rated 250 lb load range per wheel so naturally, the torque unit will
respond by lowering about 1/2 inch. (Incidentally, it
is desirable to record the weight of all of the individual components if you
wish to conduct the shimmy analysis in section 7.2)
(Note that if you elect to truncate
the suspension by as much as 5 inches to achieve a softer ride or narrower
frame, you reduce the load range from 250 lbs per wheel to approximately 135
lbs. As a result, the 43 lbs per wheel at rest outrigger
weight will compress the softer suspension by approximately 3/4 inches when the
outrigger is at rest, supporting only its own weight. The system will therefore more easily bottom
out on large bumps. This factor is also
discussed in section 9 dealing with the truncated suspension option).
Unfortunately,
anything less than 17 inches in height above grade would interfere with my
rather large right side exhaust pipes.
This conflict dictated that the outrigger frame be outside the envelope
of my exhaust system placing the inner most frame element (A) no closer than 11‑¼
inches from the bikes centerline.
(See Frame Layout
Drawing in folder 2 for the frame element labeling or right click on hyperlink
to go to the drawing). (Hyperlink)
Since
I wanted the unit to be symmetrical for weight and balance considerations, I
employed the same standoff distance on the left side as well resulting in a 22‑½
center opening for the final configuration.
I’m sure
your bike’s dimensions will be somewhat different but the considerations are
basically the same.
Width of the Outrigger Frame
As
mentioned above, the original length of the torsion suspension unit’s rubber
tube section is approximately 10‑½ inches.
The overall length from the inner end of this tube to the outer end of
the 1” diameter wheel axle shank is 18-¼ inches. The inner end of this suspension unit must
clear the right side exhaust pipes with a small margin. I
chose an overly generous standoff
distance of 2 inches. This locates the suspension unit laterally. Adding the hub, wheel and tire dimensions at
the end of the suspension’s axle shank establishes the width of this portion of
the outrigger assembly. A smaller exhaust system standoff could have
reduced the overall outrigger frame width by as much as 4 inches.
Since
I had all of the components at hand (suspension, hub, chrome wheel and tire), I
simply laid the assembled group on the floor and measured the overall length
(L). I then added the standoff distance
from the exhaust to determine the overall half width of the unit. (The length (L)
could be shortened by up to 5 more inches by cutting off the end of the torque
tube and associated base plate to make the ultimate ride softer and more
comfortable. I now highly recommend than
one consider doing this).
Once the width
of the assembly had been established, it remained to locate the outermost elements
of the frame. The outside frame member
(B) serves two functions. First, it
borders the fender and second, it supports the torsion suspension swing arm. Placing this frame member at the inside edge
of the fender resulted in a reasonable position to support the suspension
system as well. If the frame (B) were much
further out, it would interfere with the wheel. If it were closer in, it would increase the
twisting cantilever load from the wheel to the suspension support point.
Note that
the fender support frames (F) are cut a little short so as to not interfere
with the curved outer edge of the fender itself. The otherwise open ends of these fender
support frame members are plugged with black plastic caps designed for this
purpose. It was necessary to “notch” the
inside corner edges of the fenders where they rest on the frame as the fenders
extend below frame level. Be careful to leave some minimal clearance
between the fender and the frame in the final assembly. The plastic is prone to fatigue and fracture
at the corners of the cut if it rests on the frame.
The outer edge protrusion of the fenders added
another 1-½ inches on each side. For the
Road Star application where I used the full 10 ½ inch torsion tube and a 2 inch
exhaust system standoff, this worked out to be approximately 64-½ inches overall
maximum width which is typical of the commercially available conversion kits. It
takes a little time to become accustomed to riding such a wide vehicle! I could have reduced this overall width by 4
inches if I had used less exhaust system standoff and another 10 inches if I
had truncated the suspension torsion tubes in the beginning for a softer ride.
Passenger Footrest Connection
|
Length of the Outrigger Frame
The
forward extent of the outrigger frame was determined by the location of the
passenger foot peg connecting point on the bike so this was rather straight
forward. Note the added bolt spacer to
support the passenger footrest at its proper height. Your footrest arrangement may be quite
different than mine.
The aft
extent of the frame, however, was determined by the need to clear the rear
fender while avoiding interference with the rear turn signal lights which
extend laterally some distance.
After
selecting dimensions that appeared to provide appropriate clearances, I cut out
a cardboard pattern of the planned frame just to verify the fact. Fortunately,
the nominal frame height passed just beneath the rear turn signals.
Metal Shopping:
I visited Industrial Metal Supply in Irvine, CA to
actually lay my hands on the metal that I planned to use in the design. A thick walled (1/8 inch 11 Gage) mild steel square
tube 1-1/4 inches outside dimension looked sturdy enough for the frame since the
basic bike’s frame is 1-1/4 inch circular tubing. This size gives enough meat to support
drilling 7/16 inch holes to accommodate 3/8 inch bolts.
While
there, I checked out the steel strap and precut metal gussets (3/16 inches
thick) that would also be needed. For
anyone not familiar with the term, gussets are small triangular plates welded
inside the frame or strap at the corners.
These substantially increase rigidity and reduce the flexing of a welded
joint.
The price for the metal was surprisingly inexpensive
and accounted for only a minor portion of the project’s final cost.
I bought two good 7/16 diam. metal drill bits and
several metal cut-off wheels along with a can of black metal primer while at
Industrial Metal Supply, I also bought
two metal “rod end” fittings for use in the “torque adjustment” assembly which
I will discuss later.
Bracket Fabrication:
I bought
several standard pre-cut 3/16 thick 4 x 4 and 6 x 6 steel plates, a short
length of 1‑1/2 inch thick wall tube and some scrap 2”x 2”x ¼” angle while at Industrial Metal Supply. This was the material I needed to fabricate
the brackets that were to join the outrigger frame to the bike. It is desirable to use 4 inch and 6 inch
dimensions for the plate designs whenever possible to minimize the amount of metal
cutting required. I made a drawing of
the plates and then cut them out and held them up to the bike where they were
intended to go, looking for any possible interference.
The Road
Star passenger footrests are secured to the bike’s frame by several large
metric bolts which make an ideal attach point for the outrigger frame. A 1‑1/2 inch tubular bracket ending in a 2 x
2 x ¼ inch angle mates the footrest plate to the outrigger frame. The right and left side are of the same dimensions
(except for dimension X) but the mirror image of one another.
Once
I removed the existing passenger foot rest hardware, I made an overlay tracing
of the bolt holes to get their exact
location. Before starting to cut metal,
I again rechecked all of the dimensions for accuracy. I then completed the final drawings of the
plates (see Passenger Footrest Plate Drawing). The dimensions shown are specific to my bike
but illustrate the process. I drilled slightly
oversized holes to accommodate the metric bolts and to provide a little “wiggle
room” for small errors.
I
needed two sets of plates, one on top of the other. The “passenger footrest plate” supports the
heavy gauge 1-½ x 1-½ thick walled square tube at its top that directly
supports the outrigger frame. The second
“lateral brace” bracket supports a diagonal strap that reaches under the right
side exhaust pipes and connects to the outrigger frame in such a manner as to
give it added rigidity. At first
glance, one might think that a single plate supporting both brackets would
suffice; however, it would then not be possible to assemble such a design
without actually removing and
replacing the exhaust pipes in the process!
In hindsight, I now feel
that this second supporting diagonal lateral member is optional as the frame
proved remarkably rigid on its own.
This diagonal lateral brace also protrudes about as much as the
saddlebags when reverting back to the basic motorcycle configuration and is
awkward. Doing away with this diagonal lateral
brace also eliminates its associated mounting plate and further simplifies the
design. I did not consider the lateral
brace on the lighter Honda adaptation and eventually removed it from the
Roadstar as well. On the other hand, if
you encounter any low speed shimmy,
this added rigidity may help minimize
it. It is your call!
By making
a cardboard pattern of the mounting plates first, I was able to confirm those
areas that required cutouts to avoid interference with other parts of the
bike. I then made print copies of these
patterns and pasted them onto the metal stock before drilling and cutting. I rounded and smoothed all edges and used a
counter sink head to smooth out all drilled holes to give the finished product
the quality machine shop look I desired. I then fine sanded and cleaned up the
metal with acetone to remove grease and other oils and prepare them for
eventual priming and painting.
Delay Decisions Were Possible
I next sat down and considered the sequence that I
should do certain assembly tasks, anticipating that the “as built” frame would
probably slightly vary from the “specified frame”. I concluded that I need not commit myself to
certain bracket dimensions until I had the frame in hand. Then I could accurately specify those
dimensions with confidence and finish the job.
However, by delaying these decisions, I would have to make two trips to
the welder rather than just one. The “Flow Charts” provided in the Folder 3 reflect this sequence.
In particular, the “exact” distance from the
passenger’s footrest plate to the outrigger’s frame connecting bracket (dimension
X in the earlier sketch) is best determined “after” the frame has been welded to allow for minor assembly
variations. It turns out that for the
Roadstar, X is not the same dimension right and left side. It is important that the outrigger frame slip
easily but accurately into place to
make the “on-off” option viable. It is
also essential that the frame be in perfect
alignment with the motorcycle to preclude unwanted dynamics. This is especially true for frame elements B
since they support the suspension components.
Purchase Material
I felt
that I was now ready to cut out the frame elements so I purchased the basic
frame 11 GA. 1-¼ inch tube stock (20 feet) from Industrial Metal Supply.
Stock comes in 10 ft. lengths, two of which are within inches of being
adequate for the frame I had designed. The
additional few inches came from the remnants bin. Surprisingly, the steel for this part of the
frame cost less than $35.
I was
concerned about the openness of the simple frame design to the roadway and was
pleased when I came across 16 gage perforated steel plate stock sold in 24” x
48” sheets with a ¾” hole pattern. They
also had preformed edge channel in 10 ft. lengths to give a finished look to
what would become the platform of the outrigger frame. I eventually had this
platform tack welded to the finished frame.
This is a luxury in that it is not structurally necessary but the total
cost of the platform materials came to only $90 and it certainly looks great! Welding the platform in place added some very
small additional cost that was buried in the total welding bid.
The total cost of the metal used in all elements of the
frame was approximately $125 with the optional platform being the major contributor. The
metal is obviously a relatively minor portion of the total project cost.
Frame Cutting:
I carefully
laid out the frame members for cutting in a specific
order so that I would not waste material.
This took about 20 minutes of juggling segment combinations to most
efficiently use the stock at hand. (See the cut length layout diagram). If you don’t enjoy puzzles, just forget it
and buy some extra tubing … it’s cheap. As
it turned out, I used all but two or three inches of the two 10 ft. tubes I had
purchased. I purchased several metal
cut-off abrasive discs to use on my Makita hand held grinding tool. These seem to work quite well. I also tried an abrasive cut-off blade on my
10 inch miter saw but this worked poorly, heating and melting the metal while
leaving a poor edge. Cuts were also much
slower, the blade seemingly less effective compared to the higher speed
handheld tool.
It proved quite difficult to accurately cut exactly
22.5 degree and 45 degree angled ends with the hand tool. I had to finish each angled cut on the
grinding wheel to properly square the ends.
I found it more accurate to first mark and tape and then cut the periphery of the tube rather than trying
to cut straight through the member. As
instructed by the welding websites I visited, I slightly beveled the outer
edges of the frame members that were to be joined to prepare for the weld fill.
I am not
familiar with cutting metal so I was very cautious and wore a good face mask,
heavy gloves, an apron and a shirt with thick sleeves. Cleaning up the metal dust afterward was a
chore. The hot grinding debris from the
handheld tool actually burned out the threads in the fingers of my gloves after
several hours. Small hot metal corner
cutoff pieces landed on my rubber floor pad and promptly melted into the
mat. I made such a racket that I eventually
bought my neighbor a bottle of champagne in appreciation of her patience and
endurance.
When I
finished cutting each frame member, I labeled it with its identifying letter
and marked an arrow to identify its orientation (i.e.: forward or inside
direction as may be the case). I laid
out all of the members and found a minor error in one of my measurements. I had used the wrong reference for the
dimension. Fortunately, correcting the
problem only required “shortening” the members in question which was relatively
easy. (Metal does not stretch well)
I took digital
photos of the assemblies to help the welder visualize the final product when
giving me a bid.
I next laid out the perforated metal sheet platform and
its associated metal edge channel for cutting and assembly. The perforated sheet came in a width of 48
inches which was perfect in that I needed two 24 inch wide panels. Unfortunately, the channel edging is only
sold in 10 ft. lengths and is expensive ($31 per 10 ft.) and none was to be
found in the remnant bin. I ended up
with about 5 ft. of edge channel scrap.
Frame Bolt Holes &
Gussets:
Once the frame sections have been welded together,
drilling bolt holes would have to be done by using a hand drill which is slow
and arduous. Since I was confident of
the location of the main passenger footrest and rear saddlebag bracket bolt
hole locations, I went ahead and drilled these holes on my drill press while
the frame members were easy to handle.
These holes are all on the innermost rail of the outrigger frame
(element A) and would not be affected by minor frame distortion stemming from
the heat of welding.
I also drilled the holes for the suspension system
swing arm and pivot bolt. Be very careful to insure that these holes are drilled
true and aligned properly otherwise the entire suspension will be askew and a
multitude of problems will ensue.
I did goof
on one hole location but plugged it with a black plastic 7/16” insert to be
found in the specialty drawers at most good hardware stores. I also found black plastic square plugs properly
sized to fit the open ends of the 1-¼ x 1-¼ 11 GA steel tubing. I secured these with “goop” to prevent rain
and moisture from collecting inside parts of the frame. This nice touch added only another $7 to the
project.
One word of caution. The edge channel for the perforated platform is
only 1” wide while the tubular frame is 1-¼” wide. To obtain the cleanest bolt holes, I drilled
them ½” from the edge to center them on the edge channel rather than centering
them on the frame.
I next cut the eighteen 2” x 2” corner gusset plates (from
the 4” square plate stock) that would eventually be welded in place for added corner
strength.
Rod-End Provisions
The hardest task was cutting a slot in the bottom of
frame element B to accommodate the “swivel rod end” that is part of the
suspension torque adjuster. This is a useful
load bearing item incorporating a center swiveling bearing that is securely
mounted by a 3/8” bolt inside the 1-¼ tubular frame as shown in the adjacent
sketch. It fits perfectly! (The
adjustment link shown in the sketch is rotated 90 degrees to best illustrate
the connection details. These link
brackets were made from 3/16” x 1” strap material. Be sure to leave
enough clearance for a box wrench on the inside nut).
The gap
through which the 3/8 inch diameter threaded end protrudes must accommodate some
angular adjustment range hence the hole must be slotted. It must also be wide enough to accommodate
the width of the end bearing at its
center so it can be easily inserted into the frame. I drilled three 5/8” holes in a row and patiently filed the edges to create the required
rectangular slot. The high strength 3/8”
swivel rod ends, which I purchased at Industrial
Metal Supply, are conventionally used in rigging projects and were relatively
expensive costing $11 each.
Nuts, Bolts and Washers:
I stopped at McFadden
Hardware in Santa Ana and bought the nuts, bolts, washers and lock
washers that I needed. McFadden is one of the better industrial
hardware stores in Southern California with an extraordinary inventory of
fittings. I used “loctite” to secure all
bolts on final assembly.
Ray Miller at Special
Interest Motorcar Restorations advised me to use Grade 8 bolts on the frame
for added strength and durability. Ray
felt that lock washers were a better fastener choice than nylon nuts for high dynamic
load applications like mine. He also
advised me to use stainless steel bolts for the fender attachment as they would
show and would otherwise be prone to rust.
The total cost of all of the nuts, bolts, washers and
lock washers was a surprising $45 … much more expensive than I had expected.
Reworked Passenger Foot
Rests:
I removed
the original passenger footrest hardware to facilitate the connecting brackets
that would bolt to the outrigger frame.
To restore a passenger footrest option, I had to fabricate new
attachment items. This was simply done
by making two small U-shaped brackets for the footrest pin and welding them on
to the outrigger frame support bracket. If
you are going to do this sort of adaptation, have your parts to be welded at
hand to avoid a second trip to the welder. Your hardware will most likely be different
than mine.
I added a short metal spacer to extend the outrigger attachment bolt in order that it
could raise the footrest to the correct riding height. I put a glue-on plastic bumper atop the bolt
to prevent rattles.
Rear Fender Saddlebag
Brackets:
Clear Bike Suspension
& Exhausts
|
In
addition to the forward passenger footrest attach point, I made two vertical
brackets on each side that ran from the outrigger frame to hard points on the
rear fender where the saddlebags attached to the bike. These additional brackets help distribute the
outrigger frame load to the bikes frame and added additional rigidity. I welded gusset plates at each bend of the
bracket to further increase their rigidity.
These brackets also serve as a standoff support for the saddlebags both
in the “quad” configuration and in the basic motorcycle configuration,
replacing the stock chrome saddlebag standoff bars I had previously employed. The brackets are obscured by the bags when in
place. These vertical brackets were dimensioned
to clear the bikes rear suspension swing arm and the exhaust pipes when the bike’s
suspension was fully compressed.
Pre-weld Swing Arm
Hardware
|
Final Drawings and Specifications for
Welding
When I had accumulates all of the items
to be welded (frame elements, brackets, straps, gussets, footrest supports and
suspension items) I began to shop for a welder in earnest. I hoped to get nearly all of the welding done
at one time rather than traipsing back and forth with small (more expensive
jobs). I had earlier decided to hold off
on specifying the length (X) of the main brackets that connect the outrigger
frame to the bike until the outrigger frame had been welded thus allowing for
small dimensional anomalies. This would
become the final welding task.
I compiled the final drawings and photographs that I
thought would be useful to the welder and went about getting three
estimates. My metal supply house (Industrial Metal Supply) recommended a
local welder as did my auto expert, Ray Miller at Special Interest Motorcar Restorations.
I chose the third local welder (Specialized
Welding & Fabrication) from local ads and reviews on the internet. I was pleased that I received the most
reasonable estimate of $500 from David Stiles at Specialized Welding &
Fabrication since he was my first choice and is clearly a heliarc craftsman
and artist when it came to metal fabrication.
David Stiles - Welding
Craftsman
|
I took all
of my miscellaneous parts to Dave’s shop and we started the welding process at
9 am. on a Saturday morning. We finished 9 hours later! We worked together, keeping the parts
straight and carefully squaring up the sections before welding. I was careful to
properly fish my tail light messenger wire through the frame elements as they
were welded together. It is also crucial
that frame B right and B left be parallel as these elements support the
suspension which must track perfectly to avoid dynamic problems. Some builders have added additional
forward or side LED running lights to the fenders. If you want internal to the frame wiring,
additional messenger wires and passage holes will be needed. PLAN AHEAD!
The job
took a lot longer than either
one of us anticipated. The welds were
beautiful and the frame was perfect in dimension! I feel that you would be fortunate to get the
same job done for twice the price … so be prepared for higher bids. I also walked away with a lot more knowledge
about welding plus some great past project war stories from Dave.
Powder Coating:
I had originally planned to prime and paint the frame;
however, Dave Stiles convinced me that powder coating would result in a far
more durable weather proof finish. He
suggested that I get hold of Bob Goldberg at Performance Powder in Anaheim, California and check it out. This is quite a large company with substantial
facilities. Dave was optimistic that I
could tag on to the coattails of some larger job if I’d settle for the coating
color they were applying that day and, by so doing, get a reasonable price.
This is exactly what happened. They were running a large black semi-gloss
fast cure job the morning I arrived. Bob
Goldberg had done a number of coating jobs for Dave Stiles and he was always
impressed with the outstanding quality of Dave’s work. He gladly tagged my small frame coating job
on to the larger batch, charging only $100 for the process. Here again, I’d be prepared for a higher cost
if you simply powder coat the frame as a standalone item.
I had my frame back the next day and it was beautiful! Bob did suggest, however, that I run a bead
of black silicone based sealant along the channel edge of the perforated
platform as it is very difficult to effectively get into such a small crevice
where water could collect. He also assured
me that semi-gloss black spray paint would touch up any future road damage and
that it would blend and adhere perfectly well.
I did not powder coat the other plates and
brackets. Instead, I gave them hefty
priming with a multiple semi-gloss black paint final finish.
Final Assembly &
Alignment
Wheels to Frame
Attaching
the wheels to the now assembled frame and suspension was a real milestone! This contraption was finally starting to look
like a “Quad”!
Frame to Bike:
This is a
crucial step. For the sake of
discussion, let us assume that your frame is not perfect. Let us assume that it is not exactly square
or some of the elements are not quite parallel with one another. What part of the frame do you align with the
bike? Your best choice is to concentrate
on the frame elements B on which the wheel suspension unit is mounted. If both the right side and left side frame B
elements are parallel to the bike’s centerline, the wheels will likely also be
in line. If they are not parallel, split
the difference and you will minimize the amount of wheel track adjustment that
will be required later. In the end, the frame
and wheels must be properly aligned for good safe riding properties. This may require reworking the rear fender
support strap brackets to exactly match the final frame position.
An
easy way to check this frame alignment is to place a long level or other
reliably straight member atop frame element B.
Then measure the right and left equidistant standoff distance from some
symmetric part of the bike, such as the outer edge of the crash bars as shown
in the adjacent photo. When you’ve got
this right, measure XRIGHT and XLEFT and finish the footrest
connecting brackets.
Wheel Height (Torque) Adjustment
Range:
It
is desirable to be able to adjust the outrigger wheel height to some
degree. By raising or lowering the
wheels relative to the frame, you can shift the amount of weight being carried
by the motorcycle’s rear tire which in turn affects the bikes steering and rear
wheel traction. This is a unique feature
of a “Quad” with independent rear suspension, unlike a “Trike” which has only
limited suspension adjustment options.
I spent some
time developing a swing arm scheme to allow the adjustment of the outrigger
wheel height (pre-load). My goal was to
keep it simple and use as little “custom” hardware as possible. One of the commercial kit schemes is rather
complicated and results in a member protruding well below the rear wheel
assembly. That protrusion significantly
reduces the ground clearance of the bike.
(Remember your swerving ability will now be limited and you will have to
deal with debris on the highway). However,
that system covers a wide adjustment range probably to accommodate a variety of
motorcycles. I am dealing with only two
bikes so the adjustment range requirements are lessened.
I
have chosen to use a 13 inch (24 inch outside diameter) trailer wheel. The axle of the side wheels will actually always
be 12” above grade as the wheels will always touch the ground. Only the pre-load distribution between the
motorcycle and the outrigger changes.
The
lowest point for the outrigger wheels relative to the motorcycle would
correspond to no load on the bike’s rear tire
(bike’s swing arm drooping fully extended below fender) and the total rear end weight resting on the outrigger
wheels only. This would be analogous to jacking up the
bike’s rear end by using the outrigger wheels.
Call this Condition A. In this
extreme condition, the front end would be heavily loaded resulting in solid
steering and front braking. However, the
motorcycle’s rear wheel would have no traction whatsoever. This also results in the stiffest ride.
The
outrigger wheels will be at their maximum
height relative to the bike when the bike’s own suspension is fully loaded and
compressed (bike’s swing arm pushed high into the bike’s fender) and the
outrigger wheels are not carrying their own weight. The outrigger assembly’s total weight(including
wheels) is 164 lbs. The bike’s rear end is essentially carrying
the entire weight of the outrigger assembly and the overall center of gravity
correspondently moves aft. All normal
riding conditions require the outrigger wheels to be lower than this position. Call this Condition B. In such an extreme situation with most of the
weight on the motorcycle’s rear wheel, the front end would be comparatively
lightly loaded and the steering would be soft and unresponsive. However, the rear wheel would have maximum
traction and braking ability... This
configuration results in the softest ride.
(My final setting was biased in
this direction).
Suspension Swing Arm
Assembly
|
All possible
outrigger wheel adjustments will fall between these two extremes of condition A
and condition B. This establishes the
absolute maximum usable adjustment range.
For my heavy Road Star, 3 inches of adjustment proved adequate to cover
the useful range. You may wish to
consider a larger range to cover other contingencies unique to your design. If you feel you need more adjustment range,
you can always fabricate longer or shorter height adjustments
links.
Although
I like to think of adjusting the outrigger wheel’s height, in actuality what is
being adjusted is the at-rest
suspension unit’s torque. The
wheel height above the ground remains unchanged but the outrigger torque suspension
is pre-loaded to transfer
weight to or from the outrigger tires.
The
mechanical principle of this “Suspension Torque Adjustment system” is quite simple. The suspension unit has a strong base plate angled
at 45 degrees from horizontal. I built a
swing arm with a mating plate welded to it to allow this entire unit to swing
in an arc from a 3/8” pivot bolt on the outer frame element B. Note the added reinforcing plates to be
welded to the upper end of the swing arm and the frame at the pivot bolt
bracket. It is
crucial that this assembly be “square” from the beginning!
At the
lower end of this “swing arm”, I attached an height adjustment link
leading to a swivel rod-end which is interior to frame element B. As illustrated in the adjacent sketch, one
can raise or lower the outrigger’s wheel axle position relative to the frame
(preload the suspension torque) by lengthening or shortening this adjustment link. Shortening the adjuster preloads the
outrigger wheels, placing less weight on the bikes own rear suspension. About 3 inches of adjustment covers the range
of interest for my situation. If you
feel the need for a greater range, change the dimension of the adjustment link
to suit you.
You’ll
notice that an “overextension stop” has been welded to the bottom of frame
element B to arrest the suspension axle arm before the wheel would hit the top
of the fender when the rig was under extreme load. For my particular application, a 1‑½” square
steel tube yielded the correct overextension stop position. Other designs may require different stop
dimensions.
Complete
your wheel height (pre-load) adjustments before
taking the next step of wheel alignment.
Wheel Alignment:
The
next task is to insure that the outrigger wheels will run true. To accomplish this, I provided two other
adjustments that allow the suspension unit to be aligned vertically (cant …
lean in or out) and horizontally (track … right or left). This results in three
dimensional
alignment control … height, cant and track.
I fabricated a series of bolt brackets that are bolted at their lower
end to the innermost lowest corner of the “suspension base plate”. The upper end of the first bolt bracket leads
to a welded bolt tab under the frame at the main passenger footrest attachment
bolt of frame element A. The second bolt
bracket leads to a bolt tab under the frame at the bolt location for the foremost
rear fender mount support strap on frame element A. By adjusting these two bolts, one can change
the cant and track of the wheel.
Because
of the three dimensional aspect of this assembly, it is difficult to clearly
illustrate. The bolt tabs at the upper
end are welded to the underside of the inner frame element A while the lower
end brackets are bolted to the most outboard lower corner of the suspension
base plate. In forming these brackets
and tabs and welding them in place on frame element A, one must make careful
note of the three dimensional alignments required. The bolt tabs are welded in place in order
that the frame may be temporarily removed from the bike without effecting the wheel
alignment. Welding of these tabs would not be necessary if the outrigger frame was to be permanently attached to only a single bike.
The
wheel cant is changed by shortening or lengthening both adjusting bolts. The wheel track is changed by shortening one
bolt and lengthening the other. Wheel
height is adjusted as previously described and should be done prior to any other adjustments. When making these adjustments, other bolts
(such as the swing arm pivot bolts) should first be slackened to allow the
entire assembly to relax and easily adjust to the new settings. Jumping up and down on the platform and
rolling the bike back and forth during the process helps the adjustments settle
in as you work. When everything is true,
lock down all of the bolts.
The
detailed procedure for checking the alignment is discussed in a later section
relating to the bike’s dynamic performance and potential shimmy problems (Section 7.1).
Fender Bolt Brackets:
The base
of each plastic fender is secured by using three fender bolt tabs welded to the
frame. Stainless steel ¼ “ bolts
and lock washers with backup stand-off nuts secure each end of the fenders. A narrow steel face plate distributes the
bolt load least the plastic become overstressed and crack. I took care to angle the bolt tabs about 10
degrees so that the bolts would squarely meet the slightly curved fenders. Have these tabs ready for the welder when the
frame is to be assembled.
Fender Tail Light Wiring:
Once the frame is assembled and welded, it would be
extremely difficult, if not impossible, to fish wires from the bike’s tail
light area to lights on the fenders.
Most of the commercial designs simply secure exposed wires to the
underside of the frame. To facilitate
cleaner internal wiring, I made sure a hole was drilled in those frames where
the wires must pass through before
assembling and welding the frame elements together. This means a hole must be drilled in frame
member A where it meets member E and a hole must be provide in frame member H
near the bikes tail light assuming this is where the wires will enter.
I fished a
messenger wire through the frame elements from the center hole near the tail
light to each of the fender locations as the frame was being welded
together. After the frame had been
welded and powder coated, I simply joined the messenger wire to the electrical
wires and pulled them through, saving a lot of grief. In the photo, you can see the finished wires
extending from a hole I drilled in the plastic cap at the end of the fender
support frame E. If you are planning
additional lights and would like internal frame wiring, you should include
additional messenger wires and passage holes in the frame at the appropriate
junctions.
After
endlessly shopping for suitable tail lights, I decided to save some money at
bought a pair at Big Lot discount
store for $18 compared to the $100 each
deluxe versions on line. They are “good
enough” as I am interested in Go, not SHOW!
While I was at it, I took another builder’s idea and installed yellow
LED running lights from Pep Boys auto store on the front of each fender
(another $16). The running lights were
an unanticipated addition hence I had to run the wiring externally beneath the
edge of the platform to reach the front of the fenders. Ah yes, plan ahead! I do have blue LED engine illumination lights
on the Yamaha Roadstar but decided against putting one or two under the fenders
of the outrigger … just “too much trouble now”!
You will
note that I applied 3M reflective tape to the rear of the outrigger frame to
maximize night visibility. I
subsequently pinstriped the tape and the fenders as well. It may not be the “coolest” thing to do but
after 50 years of riding experience, I’ve had enough rear end close calls as to
be very conservative. Fortunately, the quad presents a much larger
image to the point that even cell phone/texting distracted drivers just might
be more likely to notice me.
The Final Touch:
After six weeks of part time work and the total investment
of approximately $1500, I proudly applied my name plate to my Trike+Plus!
The Finished Product First Ride:
Yamaha Road Star
Trike+Plus
|
I
completed the final assembly and carefully rolled
out of my driveway for the first test ride of this new creation … quite an
experience. When I say “rolled”, I mean
it. With no kickstand, the quad easily
rolls away on even the slightest incline.
I quickly learned to leave it in gear when
parked. I fired up the bike, slipped into gear, let
out the clutch and almost ran into the
home across the street! Wow! The handling is totally different from a
motorcycle! I was accustomed to the
feather touch of a motorcycle and push-to-steer. I’ve said it elsewhere in this narrative but
I’ll say it again … riding a trike is so
different that it is like starting all over again. The street smarts carry over but the handling
is completely new.
I had
initially set the wheel height (torque preload) adjustment to maximize the load
carried by the outrigger wheels. My
first test rides exhibited an overly stiff feeling at low speed. I eventually solved this problem shifting
more load to the bike’s suspension and by truncating the torsion suspension
system which significantly softened the ride (See
Section 9).
I
also encountered a slight low speed front wheel shimmy at exactly 22 mph. when
I hit a bump or encountered rough pavement.
I progressively unloaded the outrigger wheels thereby placing more load
on the bike’s rear wheel. By doing this,
I smoothed out the ride somewhat but was unable to totally eliminate the low
speed notch shimmy. I discuss this in a
separate section entitled “Shimmy Problems (Section
7.1)” I finally did mitigate the low
speed notch shimmy but it required very careful alignment and the addition of a
front fork damper.
True to
plan, it took me about 15 minutes to install or remove the outrigger frame from
either of the bikes (Yamaha or Honda). This
is a major motivation and essential feature for doing a Trike+Plus conversion.
The
real test and my principal reason for undertaking this whole project, was to
achieve a satisfactory stable camping vehicle.
This is the reason that I favor the wider platform even though it could
have been made narrower. I have full
saddlebag compatibility and I was delighted with my new found flexibility and
bulk storage capacity. No need to tow a
trailer and no reason for a skimpy sleeping bag and mat. At last, luxury was ours!
Remember,
added volume capacity is great but to
It is a pleasure to have
the space to now carry bulky (not heavy) items such good sub-zero sleeping bags
and comfortable thick sleeping pads. The
outrigger platform provides numerous options for “junk”. There is enough room
to use a large plastic bin on each side rather than the saddlebags when going
to the market or bringing back firewood to the campsite. Nevertheless, we remain purists believing
that less is more.
