Ever wanted to build your own rock buggy but didn't know where to
start? Here's one way to jumpstart your project. I am
offering the plans for the chassis I designed and built as
here. Advantages of my designs include:
The ability to pull the transmission and transfer case without
pulling the motor (via the lower skid plate).
No bars near your head (unlike many homebuilt chassis designs).
A cockpit that is big enough to keep you from hanging outside of the
chassis when seated.
A suspension that works excellent for both crawling and climbing (I
have seen at least one person crawl Upper Helldorado in one of these
This chassis was originally designed as a 3
seater with room for two full sized Beard (or equivalent) seats up front and a
smaller child sized seat out back.
Don't need 3 seats? You can easily shorten
the roof, realign the rear down bars and have a 2 seater with plenty of storage
space for camping gear or spare parts. Or shorten the back end even more
and make it smaller and lighter.
Here's a few more pictures of one possible 2
seater configuration. You are really only limited by your imagination as
far as how short/long to make the back end.
Here's the basic parts I designed
this chassis around:
Motors - As per the FAQ:
Suzuki: 1.3, 1.6 or 2.0l motor should fit
with a Samurai or Sidekick 5 speed and Samurai transfer case. I used to
run a Toyota 5 speed transmission (85 4x4 Pickup) mated to a 1.6 16v motor via
adapter. A stock Samurai radiator fits perfect up front.
Toyota: 22re (2.2l), 2rz
(2.4l), 3.4l, 2rz(2.4l) or 3rz (2.7l) motor found in various Toyota
pickups could also be used with a 5 speed transmission and dual
Toyota transfer cases. If you run an automatic a 3.4l Toyota V6
should also fit.
Domestic: A Pontiac 3.8l V6,
Chevy 4.3l V6, Chevy 4.8/5.3/5.7/6.0/LT1, Ford 5.0l to name a few.
An automatic transmission is preferred as it makes the drive train
length shorter and allows you to push the motor back to leave enough
room up front for a good sized radiator.
A 26 x 19" double pass Ron Davis radiator fits if you lay it back at
an angle (this particular radiator keeps my supercharged 3.8l motor
plenty cool). A manual transmission will work but wheelbase will
need to be 102" or above.
Larger motors have been installed by other builders (including big
blocks). Really if you think about it the difference between a
4.3 V6 and 5.3 V8 is only a few inches in length and the chassis is
very easy to modify if you want to make the fenders a bit wider to
accommodate whatever it is you want to use to power this chassis.
In addition, the belly pan of the chassis is left wide open to allow
the transfer case and transmission to be removed from the vehicle
without pulling the engine.
and build up notes for a Supercharged 3.8l install can be seen here.
Axles: I am running Toyota
truck axles from an 85 4x4. Pretty much any solid axle can be
made to fit. I have personally run 1985 Toyota truck axles as
well as narrowed D60's (60" wms to wms) under this chassis.
Suspension: Suspension: The skies the limit. I ran a
dual triangulated 4 link front and
rear utilizing 2.0" coilovers and provide the numbers to duplicate this
link setup. Wheelbase in the plans is approximately 111" and with 39" tires the
belly is approximately 23" above the ground. The wheelbase and belly clearance
can be changed to suit your needs. For further suspension information
see the FAQ.
Moab Hot Tub video clip.
Upper Helldorado waterfall
Steering: Full hydraulic via a double
ended steering ram. A single ended steering ram could be used but you will
need to modify the front link setup.
Tires: With the Toyota axles and 2"
backspacing on the rims up to a 39" tire should fit fine. A narrow 42"
tire also fits. With full width axles a tire larger than 42" in diameter could
Outside of rocker to outside of rocker is 58.2", outside of door bar
to outside of door bar is 53.6". Belly to highest point on the
roof is 54" and length from front bumper to rear most tube is
133.4". Estimated chassis weight is 250-330lbs depending on bracing.
The plans you will receive are laser printed on 11 x 17 sized sheets of
paper. I have broken down the entire chassis into stages and include a
suggested order of assembly guide to help you build your chassis. The
guide lists how I would tackle the chassis build and notes when you should mock
up major systems and suggests other systems that need to be considered at that
stage. The sheets in the above example are from stage 5 and show the suggested
roof bars and bracing. 8 of these sheets are drawings of some of the link
mount plates and tabs, switch mount box, seat rails and the rear upper link
mount bracket. These should help you if you want to duplicate the
suspension I used. Also, keep in mind, at any time you can change the angles or
bracing for a different look if desired.
*** Note - I am not releasing the solid models at this time.
Things to keep in mind:
1. I make no warranties of any kind for the performance or durability of this
chassis. You are buying plans only. If you chose to fabricate something
using these plans you assume all risk in the fabrication and operation of the
2. You will need a basic knowledge of tube bending and access to a tube
bender, welder, chop saw, etc. Access to a plasma cutter or cutting torch would
be very helpful but is not required. The chassis is designed around 1 5/8 tubing
with a bend radius of 4.5"***. Larger tubing or bend radii could be
used with some minor adjustments to the initial tube lengths. There are no
bends over 90 degrees.
*** It has been brought to my attention that the 4.5" radius die is no longer
available from JD2. See
the FAQ here for information on compensating for different die sizes. It is
actually a very quick and easy adjustment to accommodate larger bend radius
3. The plans are meant to be a guide. Since there is no way to
get the bends to match the plans %100 expect to have to make small adjustments.
Even as I built the first chassis I would double check dimensions when I started
on the next tube and if in doubt I would leave a little extra for the cut
length. The plans do have suggested cut lengths and start points for the
bends. It will be your responsibility to cope the tube ends. In
spots where there are straight braces I usually provide a recommended tube size
and length, however in most cases your best bet is to measure the distance
between the nodes to determine the cut length.