Build a simple mountain bike tandem - AtomicZombie

“Thanks for everything. I appreciate all that
you do. ”
~ Henry L., Florida
July 3, 2012
NEWS
Build a simple mountain bike tandem
Part 1
By Brad Graham
AZTV
I
f you have a pair of similar mountain bike
frames lying around your scrap pile, then
why not whip up a simple mountain bike
tandem?
You can complete this project in an afternoon
using a single mountain bike for parts, along
with a second frame of similar or equal size. If
you can find a pair of identical parts bikes, then
the geometry will look perfect and all of the
transmission components will match. But this is
not absolutely essential as any pair of similar
frames can be welded together.
You will need two frames, two sets of cranks, a front and rear wheel, front forks, two seats, and two
pairs of handlebars for this project.
The plan is very simple – cut and
join the front triangle from the first
frame to the rear triangle of the
second frame using the leftover
frame tubes as shown in this photo.
If the leftover frame tubing is a
different diameter, then use the
larger tube to join the lower part of
the frames between the bottom
brackets, and use the smaller
diameter tube to join the top part of the frames between the seat tube stems. Cut your frames and lay out
the tubing so you can see how your final frame will look.
Adding the 3rd loop to the four loop section
Once you have worked out your frame tubing, the top and bottom joining booms will need to be fish
mouthed at each end in order to make a joint that can be welded properly. The top boom tube will have
to conform to the seat tubes on each frame section and the bottom boom tube will conform to the two
bottom bracket shells. Both seat tubes on each frame should end up parallel to each other; this is how
you will know that your frame geometry is correct. The distance between the two seat tubes will be about
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1
“Hello from Scotland. My buddy told me to
check our your site. Pretty cool stuff.”
~ Barry W., Scotland
NEWS
July 3, 2012
(Continued from page 1)
the same as the length of
the front frame top tube
(the tube between the
head tube and seat tube).
AZTV
Weld your frame
together, making sure
that the alignment is
correct as viewed along
the length of the frame.
Weld all the way around
the joints, being careful
not to strike the inside
threads on the bottom
brackets.
You can leave the
bottom bracket cups
screwed in while you weld
in order to protect them
from accidental strike and
welding spatter. Your
tandem frame is almost
complete.
If you look at the
geometry of a bicycle
frame, then you will see
that it is made up of two
triangles - the front and
the rear. Triangles are the
strongest possible shapes
you can make from
tubing, so we will
triangulate the tandem
frame by adding a truss
diagonally across the two
sections.
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2
“Looking forward to seeing a new bike from you
guys soon.”
~ Walter N., UK
NEWS
July 3, 2012
(Continued from page 2)
You can use any 1 inch or
similar diameter tubing to
make the truss, even scrap
bicycle frame tubing or
electrical conduit. Cut the tube
to form a triangle between the
two frame sections starting at
the rear bottom bracket joint
and extending up to the front
frame seat tube joint. This
tube also needs to be fish
mouthed in order to form a
decent joint for welding.
AZTV
This photo shows the truss
tube installed into the frame in
order to split it into a pair of
triangles, making it ultra
strong. Also shown is a chain
tensioner made by welding a
scrap rear derailleur to the
center of the lower boom.
This chain tensioner will
pick up the slack in the return
chain, stopping the chain from
falling off the chain rings
when the bike travels over
rough terrain. The reason this
tensioner is needed is because
it will be almost impossible to
join together a chain that is
perfectly tight between each
chain ring since the bottom
brackets are now in a fixed
position.
Part 2 in the next newsletter.
3
“Yay! I’m off for the summer. Got your six pack
special. Gonna be a busy boy!”
~ Eric P., Alberta
July 3, 2012
NEWS
Have a safe summer
AZTV
Yay — summer is officially here! We at Atomic Zombie Extreme Machines wish everyone a
safe, happy and healthy summer. Whether you are traveling locally or abroad, please be extra
careful out there. And, don’t forget about keeping yourself safe from the sun’s ultraviolet
rays. We hope that you’ll share some of your holiday experiences in the forum, blogs or in the
AZ newsletter. We love reading your stories. ~ Radical Brad and KoolKat
Kurb Krawla
Python Lowracer
from Essex
“Hi people. Just finished
building my fourth and best so
far. It's based on a Python
lowracer and it's a one of a kind!
It's a centre steered machine
with a street/military theme.
Made from two BMXs and
Chrysler chopper (like a
Schwinn Stingray).
Only took me a month to build and (I’m)
itching to get out on it for a spin!” ~ Neil
Stanley
Read more and join the discussion.
4
“By far the best plans I’ve ever bought. Congrats!”
~ Kyle L., Australia
NEWS
July 3, 2012
Delta Wolf changing
“Greetings. A couple of years ago, my sons and I completed a Delta Wolf trike. Changes have been
made that I would like to share.
AZTV
It now has electric assist via installation of a hub motor kit. The battery and controller were
mounted up front which meant that the long direct steering arm (that we originally used) had to be
swapped out for something closer to plans. There's a swivel in the stem so that during normal riding the
handlebar can be tucked in close to the body and when you need to turn sharply, the bar is lifted to
provide clearance for full steering travel.
A handle was welded to the bolt that secures the handlebar to the stem so that its position can be
changed easily for different riders. The front hood offers weather protection for the battery, controller
and wiring, but that's secondary. The first time I saw pictures of the Hase trike with its charming partial
cover, I knew I had to do something along those lines with my Wolf and the electric conversion was the
excuse needed to get on with it. I struggled to decide between tube/fabric or aluminum construction and
ended up mixing the two, namely, chromoly frame/aluminum skin.
The windscreen is a loose interpretation of what I have seen on Stearman Biplanes and other
antique open cockpit ships. I guess it's fair to say, I was going for a vintage look on the whole trike right
from the start. I had to correct a wheel flop condition which was completely masked by the long steering
arm and just mildly irritating during the couple of weeks when I was riding the trike with linked steering
but without electric assist. When I installed the hub motor and added the weight of the battery directly
above, the problem was amplified beyond acceptance. My pedals were already close to the deck so one of
the attached photos shows how I moved the axle forward without changing height.
This change also provided the opportunity to create a nice tight fit in the thick (3/16") steel for the
slotted hub motor axle. Though not many hours have been logged, I like it real good. It's fun to ride, and
the electric assist helps get up those hills which were starting to get beyond my capabilities on a trike.
Thanks much Brad for designs that lend themselves so well to variation. Best wishes to our brothers
and sisters dealing with recent floods.
Cheers, Bill, West Virginia.”
http://forum.atomiczombie.com/showthread.php/6710-Delta-Wolf-changing
You can upload your own bike pictures to the gallery! Go to the AZ forum and join us.
5
“I’m very interested in buying any parts you will
be selling. Want to keep it in the AZ family.
Thanks for doing this.”
~ Barry T., Missouri
July 3, 2012
NEWS
Our Delta Trike Axle
Adapters are being
manufactured!
AZTV
Freewheel adapter
Disc brake adapter
Delta trike Axle Adapters - Freewheel
Adapter (left) and Disc Brake Adapter
(right).
Now that we have tested our newly anodized prototype Delta Trike Axle Adapters, a large order has
been sent to the machine shop for manufacture. Both the Freewheel Adapter and Disc Brake Adapter
are black anodized aluminum and fully drilled and tapped for a standard 6-bolt bicycle
disc brake rotor. The hardened 1/4 inch axle mounting bolt is also included with each adapter,
so they are ready to install onto your 3/4 inch axle.
We understand from your
feedback that often a local
machine shop will charge a lot
of $ to make only a few parts,
and you may have to wait
months to receive them.
Another risk is a part that may
not fit perfectly, so we are
stepping in to help ensure that
your build goes smoothly.
Delta Trike Axle Adapters made for 3/4 inch cold rolled steel shaft
These Delta Trike Axle
Adapters will fit any 3/4 inch
trike axle and allow you to
install a Shimano type
freewheel and a bicycle disc brake to the axle for drive and braking.
Our Delta Trike Axle Adapters will fit onto any cold rolled 3/4 inch steel shaft, allowing you to install
both a Shimano type freewheel and a standard 6-bolt bicycle disc brake rotor. The adapter shown on
the left is designed for a disc brake rotor only, and the adapter shown in the right will take a disc rotor
6
“Brilliant designs. Glad I found you guys (and
gals).”
~ Roger W., Australia
.
July 3, 2012
NEWS
(Continued from page 6)
as well as a Shimano type thread on freewheel. The thread
on freewheel can be a single speed BMX type, or and multispeed type with 5 to 9 chain rings. A hardened 1/4 inch bolt
(included) passes through the axle to secure the part to the
axle.
AZTV
Being able to mount a freewheel and disc brake to an axle
means that you can create practically any kind of delta trike
or quad cycle using standard bicycle components. All of our
delta trikes such as the KyotoCruiser and LodeRunner
use this adapter, as well as our StreetFighter quad cycle.
These parts can also be used on any of our other
trike plans by using a 3/4 inch axle in place of a 5/8
inch axle. All future trike and quadcycle DIY plans that we
intend to release will be using these parts as they are easy
to install and service.
The Delta Trike Axle Freewheel
Adapter mounted to the 3/4 inch shaft
Demand for our initial manufacturing run is high,
so if you are interested in these Axle Adapters,
email us right away to get on our email list. Prices
(in Canadian $) for our Delta Trike Axle
Adapters:

Freewheel and Disc Brake Adapter: $45

Disc Brake Only Adapter: $44

Both adapters include the hardened axle
mounting bolt and lock nut.

Parts are made of black anodized aluminum
and tested to fit. Only black is available at this
time.
A Shimano freehub and disc brake rotor
installed on the Axle Adapter
We expect to start taking Delta Trike Axle Adapter orders after July 6.
Proudly made in North America!
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“I love being able say, “I built it.” People are
amazed. Love the attention.”
~ Bobby G., Tasmania
July 3, 2012
NEWS
Atomic Zombie head tubes & bottom
AZTV
brackets for your bike projects
A
ttention DIY bike builders - we hear
you loud and clear!
Since we originally stated our intention to
manufacture some of our trike parts, you’ve
told us that you also want the basic building
blocks needed for practically any human
powered vehicle.
A salvaged bottom bracket
Of these basic building blocks, the two that
are most often used are the bottom bracket
and the head tube. In fact, you can build
many of our DIY bikes and trikes without
requiring any other frame parts besides a
head tube and bottom bracket.
We understand that in some parts of the world it may be difficult to salvage several frames for
chopping when taking on a project that requires several similar head tubes or bottom brackets such as
a trike or quad, so we are actively pursuing the manufacture of these raw components.
If you intend to pedal your creation, then without a doubt you will require one or more bottom
brackets, as they are necessary for holding the crankset and bearing hardware to the frame. It's easy
to simply chop one out of a steel parts frame and then grind it clean as long as you have a frame. A
tandem bike or trike requires two bottom brackets, and often matching crank hardware, so the
process of salvaging these components can take some time.
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“I love being an Atomic Zombie!”
~ Frank D., London, England
NEWS
July 3, 2012
(Continued from page 8)
As we were looking at the technical
drawings for some other parts we intend to
manufacture, I realized how simple a part a
bottom bracket really was and took a drawing
to our local shops for pricing. Thanks to those
who chimed in regarding our intent to
manufacture in our recent newsletters, we
have decided to push ahead on making
bottom bracket and head tubes available to
our community and possibly bearing
hardware in the near future as well.
AZTV
A complete bottom bracket and hardware
Our bottom bracket shells will be mild steel
and take standard threaded bearing cups or a
complete bottom bracket cartridge. These
shells will be unpainted and ready for
welding, so you will not need to spend the
time cleaning or salvaging these parts. If we
can locate a reliable supplier for the bearing
hardware, we will also offer complete sets so
you won't have to remove them from a donor
cycle or wait to order them from your local
bike shop.
With a length of metal tubing and the parts
shown here, you can carve out practically any
kind of human powered vehicle. Our goal is to
supply as many building blocks as we can so
that you can spend more time building cool
bikes and less time digging scavenging and
digging through scrap piles for donor parts.
A salvaged head tube, bottom bracket, and
supporting hardware
(Continued on page 11)
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“All I can say is perfect! Thanks for putting together such
great stuff.”
~ Winston B., Pennsylvania
July 3, 2012
NEWS
Timber Wolf (Velo Rouge) 1000km Report
AZTV
http://forum.atomiczombie.com/showthread.php/6705-Timber-Wolf-%28Velo-Rouge%29-1000km-Report
Well, I just passed 1000km on my Timber Velo. This trike is finally what I had hoped it could be.
Drive train, steering, suspension and brakes are all working well.
I ride to work and return (70km round trip) around three days a week. I use a 9C front hub motor
with 36v Lithium battery. I reach 45km/hr with a full charge and the trip average is usually about 3637km/hr.
The final parts that made this bike fast were the skinny hard rear tires and the wheel disks. The
original fenders were scrapped for a lower profile design.
I had three goals with the design (all compared to a two wheeled Burley recumbent): Better weather
protection; Better safety; Better aerodynamics.
Colorado
The weather protection is good. My feet and hands don't get cold at all. On rainy days only my
shoulders and chest get wet.
For safety, although I have been up on two wheels, I have learned to slow for the corners. I feel I
have less chance of injury. The aerodynamics are better compared to my two wheel recumbent. The
overall performance is the same and this bike is a lot heavier.
This has been a great project, I am dreaming of what will be next. Thanks to all the Zombies who
helped. ~ Pat
“My Spirit SWB is just about ready to be painted—just one cut-'n-weld to go on the seat tube,
so I am asking if it's a good idea to sand the steel frame with an 80 grit flap disc before
priming. I have some spatter and a few edges to smooth out and it would be convenient to do
both the smoothing and sanding with the flap disc.” More >>
From our Facebook Fan Page:
“Look Ma - no brakes! Well, the instructions said, "Give the Wildcat its first test ride." Thanks again, AZ, for
another great design and wonderful plans to go with it." ~ Nana Amoako Agyeman
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“Thanks for putting up with all of us. You probably
put in a lot of time and don’t get paid for it. Please
know that you are very important to the bike
building community around the world.”
~ Alex V., Germany
NEWS
July 3, 2012
(Continued from page 9)
AZTV
Head tube and bottom bracket shells are at the top of our inventory list, and we hope to add more as we
move along on this new venture. We are also going to make our head tube shells slightly thicker than
normal so that there will be less distortion in the round tube after welding it to your frame.
Parts manufacturing is a new adventure for us, so we have to work out many things such as shipping
and packaging, but we are working hard to get these parts ready to deliver. Our local machine shops are
working out a price for large quantities of head tube and bottom bracket shells and we will be taking preorders as soon as we have a firm price for the first run.
Please let us know if you want to be on the list for these parts as this will help us determine how
many to manufacture at a time, with prices being lower for larger quantities. Thanks to everyone for the
feedback!
"You guys are wonderful. Please put me down for the hardware that you will be selling. It will be such
a convenience to purchase key elements from your company. Hopefully full kits someday. I work three
jobs and have very little time to salvage bikes. Great thought, and please keep doing everything that
you do. Your website motivates, and is a refreshing step back from the establishment. I am completely
looking forward to building several of your bikes. Thank you." ~ Gerald B.
Built by Parry, Canada
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“Hi Zombies. Love your sites. Thanks for being my
Facebook friend.”
~ Petr K., Holland
July 3, 2012
NEWS
From the Builders Gallery
AZTV
Silent Speedster
Built by troynh, USA
Built by Parry, Canada
E-Cruiser by Bjofuruh,
Norway
Home made tadpole trike with
Goldenmotor Magic Pie electric motor.
Based on the Atomic Zombie, Warrior.
20"
wheeled
Python
lowracer from
the UK.
Designed and
built by Neil
Stanley.
Built by invisiguard, Australia
You can now upload your own bike pictures to the gallery! Go to the AZ forum and join us.
12
“Hi and thanks for your great chopper plans.”
~ Jessie U., Texas
July 3, 2012
NEWS
Atomic Zombie manufactured
AZTV
parts for your bike projects
By Brad Graham, AtomicZombie.com
D
ue many, many requests, we will be
manufacturing some parts that are used on
our delta trikes and quads.
We will be starting with the wheel and
transmission parts, and hope to add more to our
inventory in response to the demand. We may even
offer spokes, bearings, chains, and many other
common bicycle parts that are used on practically
every project.
Here is a description of the parts we intend to offer
and which plans they belong to.
Some of the Delta Trike parts we will offer:
Part (A) is a disc brake axle adapter, and it will allow you to install a standard bicycle disc brake
onto a 5/8 or 3/4 inch diameter steel axle. The part will be drilled and tapped for standard disc brake
rotor mounting and will include a set screw for connection to the axle.
Part (B) is a threaded freewheel axle adapter that will allow a Shimano type screw-on freewheel
to be affixed to a 5/8 or 3/4 inch diameter steel axle. This part will include a set screw for connection to
the axle.
Part (C) is a threaded freewheel axle adapter that also includes a disc brake mounting flange.
This part is basically a combination of Part (A) and Part (B) so both a free hub and disc brake can be
affixed in the same place using a single part.
Part (D) is a hub flange that will allow a wheel to be laced directly to a 5/8 or 3/4 inch diameter steel
(Continued on page 14)
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“Kudos to you and thanks for bringing so many of
us weirdoes together.”
~ Paul G., New Hampshire
July 3, 2012
NEWS
(Continued from page 13)
Projects that require axle adapters and
flanges.
AZTV
axle. These parts are sold in pairs and will
include 18 or 24 drilled spoke holes for 36 or
48 hole rims.
All of our DIY trike and quadcycle plans use
one or more of these parts, and you certainly
use these parts to design your own unique
vehicles based on our plans or from scratch.
Having these parts available means that you
can shave days off your build time or possibly
weeks if you have to wait in line at the
machine shop for your parts to be made.
Because we will be making these in
quantities, we can manufacture them for less
than what a machine shop would charge for a
single unit.
All of our parts are tested to fit on the axle
and freewheel, so there will be no guesswork
or problems when it comes time to install
them.
Our freewheel and brake adapter will allow
standard bicycle components to be adapted to
any 5/8 or 3/4 axle so that transmission and
braking can be included. A threaded freewheel
will screw on to the adapter and a standard
bicycle disc brake rotor will bolt onto the
included flange.
With these two components mounted to the
axle, you can use a standard bicycle rear
(Continued on page 15)
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“Love your web site! The videos are great. Hope you
are doing more.”
~ Quincy P., France
NEWS
July 3, 2012
(Continued from page 14)
AZTV
derailleur to add speeds and a standard mechanical bicycle disc brake to offer solid stopping power.
All of our plans that include two rear wheels make use of one or more of these freewheel and disc
brake adapters. With our freewheel and disc brake adapters, you can add a pedal transmission to
practically anything with an axle.
If you are interested in purchasing any of the parts we intend to offer, please let us know! We will
start off with a small batch of parts and then base our inventory from the response.
Here’s the list of possible custom manufactured parts again:
A.
Disc brake axle adapter, and it will allow you to install a standard bicycle disc brake onto
a 5/8 or 3/4 inch diameter steel axle. The part will be drilled and tapped for standard disc
brake rotor mounting and will include a set screw for connection to the axle.
B.
Threaded freewheel axle adapter that will allow a Shimano type screw-on freewheel to
be affixed to a 5/8 or 3/4 inch diameter steel axle. This part will include a set screw for
connection to the axle.
C.
Threaded freewheel axle adapter that also includes a disc brake mounting flange.
D.
Hub flange that will allow a wheel to be laced directly to a 5/8 or 3/4 inch diameter steel
axle. These parts are sold in pairs and will include 18 or 24 drilled spoke holes for 36 or 48
hole rims.
We are currently collecting names so that we can tell the machine shop how many parts to make in
one run. That number will dictate the unit price, so the more people who are interested, the lower the
price per unit will be and we can pass those savings along to you.
In terms of shipping costs, those will be determined once we have the prototypes back from the
shop, (within a couple of weeks). Once we have tested the prototypes, we will determine packaging
and shipping costs.
Stay tuned to the forum, newsletter , Facebook and AZ site for announcements.
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