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The suspension and steering
are clearly very important components to consider BEFORE you
start the build. We have many items on the crawler that could
interfere with one another as the suspension cycles through its
path. To get a crawler to steer the full 45 degrees plus
articulate fully is not an easy task when you’ve got an engine,
shocks, steering box, and link arms to consider. The
Blue Torch Fabworks chassis was designed with the front
rails just narrow enough to have the
West Texas OffRoad steering box mounted and still clear the
tires. The engine was pushed way back to give room for full
compression and turning yet still allowing a LOW mount for
better CG.
For the front suspension,
we have to deal with a steering box because the
WE Rock Pro Modified class vehicle specifications say a
working mechanical steering box must be used (hydro assist is
ok). This means we have a drag link to contend with. Because
of that, we’ve chosen to use a three link plus a panhard bar
that matches the angle and length of the steering draglink.
Bender is telling me that odds are we will be able to use a
three link but until we get everything in place, we won’t know
for sure. If the three link won’t work, we’ll make it a radius
arm.
The rear suspension will be
setup for the climb. Becca’s current rear suspension sets the
IC (Instant Center) FAR in front of her RockHer I. We’re
talking about 15 feet. The setup of the crawler gives her an
amazing climb and stability while on the throttle. The link
configuration will be a triangulated four link with the lowers
configured as slightly triangulated and the uppers at full
triangulation. The lowers will be 38” in length and will be
fabricated units (instead of straight tube) so we can gain
addition ground clearance. They will actually look like big
“J’s and will be give us an additional 7 inches of clearance
that has been afforded us by making the jump to the
Hi 9’s. Bender will try to set the roll center and the
shock angle to a stable enough configuration to eliminate the
need for a swaybar. If that cannot be done properly, we’ll add
one after some testing.
Matt will again go to work
in SolidWorks and model all of the suspension and steering so we
can preview it there first. That’s a big advantage to using BTF…they
have Matt. Not only is he a fabricator with an engineering
background, but he understands how and why things in this sport
work…adding that experience to his complete understanding of how
that program (SolidWorks) works, we can fully take advantage of
it. Drawing something up is one thing. Making it work and
understanding the numbers it kicks out and how that relates to
rockcrawling is another thing entirely.
Since making the jump to the
RaceRunner air shocks two years ago, we’ve heard rumblings
of new brands and new ideas coming out that were going to change
everything…yet still, here we are, with the exact same air
shocks we switched to. An obvious sign that all of those rumors
we nothing more than hype. The
Sway A Way RaceRunner air shocks have proven themselves as
the most stable choice. |
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Their larger piston in the
same size body uses lower pressures to support the same weight,
in turn offering a better spring rate curve and less unloading.
Their 110 pound return spring also helps keep the shocks from
unloading at the top end. Their finish looks great and is far
more durable than the shocks we’ve had in the past. A little
polish with 000 steel wool a few times a year keeps them looking
perfect. We will be running 14’s in front and 16’s in the
rear. All of them will be the RaceRunner 2.0 version which
basically means they have 2” bodies…by far the most common size
for air shocks in rockcrawling. We will have to dial in the
pressures and oil accordingly…we’ll get back to you with our
adjustments once the RockHer II is through with its “dial-in and
testing” phase.
Also, knowing the big
dropoffs we are seeing in competition nowadays, we’re looking
into AirBumps from Sway A Way for the rear end. Odds are high
we’ll install them and we’ll try to get them as close to the
shock mounts as possible.
Something you may have seen
mentioned a couple of times so far is the position of the
engine. It is set far back in the chassis, with the front of
the crank pulley a full 11 inches behind the centerline of the
front axle. Also, it is set off to the passenger side with the
driver’s side of the engine sitting straight over the centerline
of the chassis and angled so that the passenger side of the
transfer case sits on the chassis centerline. This affords us a
number of things. First, we wanted the engine back to make it a
more technical vehicle. With more weight in the center of the
chassis, it tends to maneuver and balance better, making the
tight, off-camber, and twisting sections of the courses easier
to drive. The engine position puts the back of the engine block
about 7” in front of the
MasterCraft seats. Because the engine is so far back, we
need to give Becca legroom. Pushing the engine over to the
passenger side affords that. The other benefit of the way we’ll
se the engine up is that Becca will have full visibility on the
entire left side of the Red Bull RockHer, simply by looking
under the hood. She’ll have nothing in the way as the engine is
off to the right half of the crawler. The
WARN 9.0R winch will be slung low and she’ll look straight
over it. The
Ron Davis radiator is sized so it has enough cooling for
this engine yet is small enough to actually turn sideways
(running longways front to rear) and fit in front of the engine
on the right-hand side of the chassis, completely out of her
field of view. The
Dedenbear SuperGlide tranny will be crossing the centerline
of the crawler so will be clearly out of the way of the full
swing of the driver’s drop
JE Reel driveline. The rear output of the
Lovell transfer case will be right at the back of the seat,
pointing in the direction of the pinion yoke on the rear
Diamond Axle. Pretty slick and the way things will be set
up, the chassis, with Becca in it, should be well balanced left
to right, with a target of a 55/45 weight split front to rear,
not including tire ballast.
To steer the RockHer II,
Blue Torch Fabworks asked me to get a steering box that sat high
on the frame with a reverse geared sector shaft so we could
point the pitman arm facing forward. I called Matt at West
Texas OffRoad and told him I wanted something lighter, that sat
up higher for clearance of axle components, that was geared
correctly for the forward pitman, and that could be plumbed for
Hydro Assist. He said he could custom build “just the box I was
looking for”. We’ll have more details on this box once Matt
chimes in with what he used.
Wow, it’s 5:20am…time for
another
Red Bull…and maybe a bowl of Lucky Charms! |
