This is the original manuscript as it was submitted to National Kart News
for Publication. It is being used with their permission.
TESTING THE CRG HERON OVAL TRACK CHASSIS by Mark Bergfelt
CRG calls it the Heron Offset Oval Chassis.
Heron? When a company chooses a name for a race kart, it's a common
practice to choose a name that sounds intimidating. A Heron is a bird
that hangs out around the water; by the beach. Ah, how relaxing, and
beautiful. Hardly a name for a race kart. Then for kicks I looked
up birds in an encyclopedia. I came across a picture of a Heron.
Not a bad looking bird. Then I also noticed that his beak was pearcing
a fish. Those birds dive bomb unsuspecting fish and spear then.
They are vicious toward their prey. The thought of a Heron is most
certainly intimidating to fish. Likewise, the CRG Heron Oval Chassis
is beautiful to look at, but is intimidating and vicious toward it's competition.
During the early summer of 1997, the people at SSC
Racing contacted me at BRE Small Engines and Family Motorsports and asked
if we would be interested in becoming the Pennsylvania dealer of CRG karts.
The proposal was interesting, after all, CRG is the largest volume, and most
successful, manufacturer of race kart chassis in the world. Right away
images of Formula A, Super A, Formula C, and other asphalt warriors flashed
through my mind. Drivers with names like, Schumacher, Zanardi, Manetti,
Rossi, Justus and Long also come to mind. What great company! I immediately
told the salesmen that I was definately impressed with the success that CRG
karts have had on the asphalt all over the world and was just as impressed
with the quality and appearance of their machines, BUT, Western Pennsylvania,
where my shop is based, is dirt oval country, which is no place for those
pretty Italian karts. The salesmen then told me that CRG was currently
working on a design of an oval track kart. ("Yeah, right", I thought)
I said, "Give me a call when you have one to show me."
Later that fall, I got the call that the CRG, Heron
Oval kart was available. After seeing them I was confident that these
were karts that could be easily made to work. I signed on with SSC
and CRG. I was anxious to find out first hand if the karts were as
good as they looked.
Over the past twenty six years I've been racing karts
on the Western Pennsylvania and Ohio dirt ovals, and a whole bunch of other
places as well. During that time many chassis were put to the test,
many were my own creations. From that I learned, several things; don't
build your first kart yourself. You may be inclined to do that
sort of thing, but resist. Buy your first kart. If you find you
have some better ideas, only then should you build one of your own.
Only build it if you can't buy it unless the cost is outrageous and you are
sure you know what you are doing. The racer who intends to race often,
and is pressed for time, will find it challenging to make the next point
race if they have to remanufacture every component, every time one needs
to be replaced. The CRG Heron Oval Chassis is much like the next one
that I might have built for myself, but I did't have to. CRG already did,
and they did it with style.
The plan was for me to run one of the karts in the
Pittsburgh Circle Track Club, BRE Small Engines-Unlimited Circuit with an
alcohol burning Komet K-30 two stroke and my son Matt would compete with
his on the local tracks in the rookie alcohol class. Unfortunately,
my other job, a technology education and vocational teacher did not allow
me the extra time I needed to get my own new kart ready so I had to run the
first half of the season with my old kart that was already ready to go.
It was a very busy spring in the shop, working on other peoples equipment
almost every evening. Matt did get to run his new kart all season
though.
Setting up a kart for a rookie class driver is always
a challenge. Meaningful feedback from a ten year old is sometimes tough
to come by. That's why gages with a memory are so popular in that class.
No matter where you mount the seat, a rookie drivers feet always wind up
in the same place as the tie rods. We made it work by making up metal
blocks to mount the pedals to the floor pan. We used a cable to activate
the master cylinder and shortened the throttle cable. Some roll bar
foam, wire tied to the tie rods, completed the initial set-up. Matt
was very happy resting his heels on the tie rods. Burris D-21 tires were
mounted on Douglas rims. These work very well on most of the tracks
around this region, especially for night racing.
Matt's performance improved a great deal immediately
with his new kart. At first the kart seemed a little loose coming off
of corners. We later found that this loose appearance was induced by
a driver who was a bit too aggressive with the steering wheel. Steady
coaching and working with the set-up resulted in his first feature win.
In June school was out and I finally had enough time
to set-up a new kart for myself. Out of eight races entered with the
kart my record was; three wins, one second, one third and two dnf.
All but two events were Unlimited All-Stars events. When I began using
the kart I was in second place in season points and with the help of the
CRG kart managed to maintain that position. The following is a brief
summary of those events and what was learned from them.
In my haste to get ready for the first outing with
the kart at Good Hope Speedway in New Springfield, Ohio, I overlooked a few
items in preparation. As a result I experienced clutch problems but
in spite of that I found myself runnig second to the point leader in a heat
race. During the feature a fould spark plug put me out of the running
but the important thing to be learned was that handling was not bad and the
kart had not been on scales yet. I did experience the illusion of understeer.
Later that evening it dawned on me that the steering ratio was a lot different
to what I had been using for the past 15 years. For someone else, especially
a new driver, this would probably not have been a problem at all. In
fact, arm fatigue is less of a problem with such a set-up because the steering
requires so little effort It's just that old habits are hard to break.
When getting set-up for the next race at Pine Hill
Speedway, in Shippenville, PA, I relocated the point on the spindles where
the tie sods attached to speed up the steering. Much better. The
flat, hard baked abrasive dirt required the use of Burriss M-22 tires.
I wouldn't say that it was perfect, handling, but it was very good.
Good enough to win. Did someone say that Italian karts don't work on
dirt?
We rolled into the driveway at home that evening
at 7pm. I dropped off my wife and kids at home. They had had enough
racing for one day. I then hurried over to Naugle's Speedway, near
Coraopolis, Pennsylvania, just in time to change tires and hot lap during
intermission before the features. The kart stuck like glue to
the soft high banked clay track and I never even had to let off of the throttle
even slightly. I tagged onto the tail of the Open 2-cycle feature and
to my amazement, sixteen laps later I was carrying the checkered flag around
the track. The kart cornered so well that the G-force was making me
roll out of the seat. Repositioning of the seat was in order when setting
up for the next race. The quick cornering also made me aware of where
my right foot was. I discovered that the side of my right foot was
activating the throttle, when I didn't intend to, by pushing sideways on
the throttle cable. I did this a few times in traffic but managed to
discipline my foot to stay tight against the heel rest to eliminate the problem.
This was an attribute of the kart that was worth getting accustomed to.
At the Unlimited All-Star race at Slippery Rock
Pennsylvania the kart handled superb and was very fast. Unfortunately,
I expected the impossible and driving errors resulted in a DNF and blemishes
in the front and rear bumpers.
The next scheduled outing was the first annual Unlimited
Invitational at Naugle's Speedway. I settled down as a result of the
last outing which was a contributing factor to finishing second to the track
points leader. I was later disqualified because the twenty pound lead
brick that I foolishly expected the neat little weight mounting tabs to support
broke off in the heat of competition. Lesson learned was no more that
five pounds to a tab. The engine was tired and seemed down on power but the
kart handled very good.
The Unlimited All-Stars visited the Good Hope Speedway
for the final time of the season. Many times I have raced here and
lead only to succomb to some sort of mechanical failure, usually sheared
teeth on the engine sprocket. I was able to hold off two very
good drivers who had slightly more horsepower that night by having a kart
that could comfortably run on the inside all of the way around the corners.
I finally got to carry the checkers at Good Hope.
The finale for the Unlimited All-Stars was at Naugle's
Speedway. Because of the luck of the draw I started the first heat
of group one on the pole and won. The CRG kart nandled very good but
not as good as it was in hot laps when the track was "heavier" In the
second heat, the track was much harder, and I could not get side bite and
could not move up in position. We made three chassis adjustments that
dialed the kart right in to be just about as fast as it could be. They
were: pulled right rear in approximately one inch, dropped the right rear
tire pressure from 10 psi to 6, ran the left at 6 and the fronts at 5.
Finished off the adjustments during the warm up laps for the feature with
the weight jack. A third place finish was the result after a very tight,
twenty lap, four way battle for the lead after starting in fourth.
Any of the top four could have just as easily won. It was fun and isn't
that what it's really all about .
One thing experience has taught is, that no
matter how good that you think your set-up is, there is always a way to improve
on it, even if only a little. The thing that impressed me most about
racing the CRG Heron Oval kart is that even when the set-up was off, the
kart was still competitive. In a half of a season of competition, never
on the same track two events in a row, only during one heat race was the
handling unacceptable. It only took a few minor adjustment to make
it one of the quickest machines at the event!
The CRG Heron Oval chassis is very consistent and
easy to dial in for changing track conditions. As with setting up any
race kart getting the seat mounted in just the right place is probably the
most important factor. The one on my test kart was moved three times
and will probably get one more minor position adjustment before I'm completely
satisfied.
Beside getting the seat in the right position, there
are many adjustments that are possible to optimize handling. They include;
Rear axle bearing cassettes that can be raised or lowered, rear wheels can
be moved in or out, additional seat struts can be added, rear axle stiffness
(an axle change is needed), various tabs are provided for changing the position
of ballast, front spindle height, front wheels can be moved in or out, adjustable
castor, and a really nice weight jack.
The test karts were never put on scales until the
season was ovver. This was done because no recommended weight percentages
were given and we did not want to be biased by a recommendation. We
wanted to take the time to find out for ourselves. After one half of
a season of racing, the weight percentages that we have wound up with so
far are; with front wheels held straight, LF 22%, RF 15%, LR 38%, RR
25%,
with the front wheels turned full lock to the left: LF 34%, RF 7%, LR 26%,
RR 33%,
with the front wheels turned full lock to the right: LF 12%, RF 29%, LR 45%,
RR 14%.
Why did we show the percentages when the wheels were turned? Well,
that's something that's best left for a future article. Tire pressures
wound up a around 5 psi in the front and 6 to 8 psi in the rear.
From an appearance stand point, the Heron Offset
is second to none. The fit and finish is typical of the chassis that
find their way across the Atlantic ocean. The beefy 1 1/4 inch
and 1 1/8 inch frame tubes are finished with a high gloss and durable bright
yellow powder coat. All of the components that are bolted on are either
bright chrome, if they are steel or anodized gold, if they are aluminum.
The front bumper is made up of two sections.
The lower section is welded to the frame and is also the mounting point for
the pedals, The upper portion of the bumper bolts on and is replaceable.
Moving back along the kart, a small tab is welded to the frame making
mounting a fairing easy. A chrome bracket , that attaches with the same
bolt as the upper steering bushing, for mounting the top portion of
a fairing, also comes included with the kart. Molded plastic heel
cups are attached to the aluminum floor pan to keep the drivers feet in place.
The brake pedal is attached to the cnc produced billet
master cylinder, with a steel rod. All of the mounting hardware is
first rate. The master cylinder is plumbed to the billet brake caliper
with plastic coated braided steel brake lines. The massive four piston
brake caliper will lock up the rear wheels at the drivers desire but will
give him good brake feel as well. The design allow quick brake adjustment
with removal of what CRG calls a security pin which retains the brake shims.
The pin is easily removed with out tools. The brake rotor is vented
and is cast and machined iron. A light weight version is also available.
It is mounted to an anodized aluminum hub, or "boss" as the CRG parts catalog
prefers to refer to hubs. The brake system is indeed one of the most
impressive parts of the kart.
The throttle pedal is linked up with the carburetor
with a cable that runs directly from the pedal to the carburetor in typical
European fashion. This arrangement allows plenty of pedal
travel to fully operate the throttle on any carburetor. The throttle
pedal is also equipped with an adjustable stop bolt to eliminate carburetor
damage from a heavy right foot. There are also adjustment bolts on both
pedals that allow drivers to adjust the position of the pedals when they
are in the at rest position.
Moving back along the right side, the observer will
find that the right spindle is attached to its hanger with an adjustable weight
jack screw (refer to NKN July 1997, "Weight Jacks"). The handle of
the screw is a beautiful piece of anodized , billet aluminum. The weight
jack also has a locking clamp that makes it possible to set it and forget
it, if that is what the crew chief, or the rules demand.
The chrome spindles are hefty enough for oval style
racing. The axle portion of the spindles are 5/8" (definately not a
metric size) to accomodate the wheels used by American racers. Plenty
of machined aluminum spacers are provided to get just the right front wheel
offset.
The castor angle is adjustable. There is an
eccentric flanged bushing that the kingpins are inserted through that have
four hols drilled into the flange that accept a lock screw. The castor
is adjusted by removing the screw, rotating the bushing to the desired location
or hole, and then replacing the lock screw. It is also very wise to
use a thread locking chemical on these screws. They did come loose
on our test karts but some blue threadlocker did the trick.
The steering shaft of the Heron Offset is different
from its American counterparts. No it isn't a different diameter.
It's made from a solid steel shaft 5/8 inch in diameter. Yes,
it is spined to lock the steering boss, um, hub from turning.
It does utilize a steering wheel center nut as well. All of the above
to comply with WKA and IKF requirements. What makes it different from
many American karts is that the tie rods are attached with two separate bolts,
utilizing the ackerman steering principle, instead of a single bolt securing
both.
The large plastic, see through fuel tank is molded
to fit in between the steering wheel support tubes and is retined by the
floor pan. It is my understanding that future production may use some
other method of securing the fuel tank.
Behind the fuel tank are the tubes that accept the
forward seat mounts. These tubes feature lock screws to secure the
forward seat mounts. It is interesting to note that the
ends of the seat mounting tubes as well as the nerf bar stubs are machined
to a taper to give thm a more finished appearance.
The CRG Heron Offset is much the same design as
the Heron that is produced for 100cc and shifter competition on asphalt
sprint courses with the exceptions that make it legal and more suitable for
American oval track competition. One of the obvious differences
is the offsetting of the frame in the seat mounting area. The frame
brace on the left side allows the stiffness of the chassis to be adjusted.
That brace has had two smaller tubes welded to it on either side. The
brace was then cut, including the two small tubes. Bolts were then
placed through the smaller tubes. Tighten the bolts and the frame is
stiffer. Loosen them for more chassis flex. We took the bolts
out for dirt racing.
Along the left side of the main frame rails are
mountng tabs. These were provided for adding lead ballast to meet minimum
weight requirements and to balance weight percentages. A similar tab
is found on the right side of the frame at about the center of the kart.
This tab can be used for ballast as well, but is was originally intended
as an attachment point for an intake silencer box support brace.
The karts that we tested used a 1 3/8 inch axle.
Equipped this way, the kart usually had good to exceptional side bite.
1 1/4 inch axles are available and will be provided on later production units.
The 1 1/4 axle allows the use of the large variety of components that American
oval track racers have collected and are available. Axle and rear chassis
stiffness can be adjusted using different stiffnesses of axles as well as
varying the length of the rear wheel hubs (bosses).
The rear axle spins in bearings that are housed in
billet aluminum cassettes. The bearing hangers ar slotted allowing the
rear ride height to be adjustable. The sprocket hub is billet aluminum
that is anodized gold.
Chain tension can be maintained by adjusting the
engine mount stop screw that is provided. The screw features a knurled
oversize head to insure contact with the engine mount and to provide that
totally finished look.
Heavy duty chrome seat struts allow the racer to
mount the seat in the manner that works best for him. This is very
unusual for a European manufactured machine. Three struts are provided
instead of the usual two. We only used two on our test kart and only
one of the front seat mounts as well. The one on the right. This
allowed more chassis flex.
Mounting tabs are welded to the ends of the frame
tubes on the right side. These are for mounting full length, chassis
mounted chain guards. Additional mounting brackets are also supplied.
The rear bumper and nerf bars are nice chrome pieces
and are easily replaced. These parts feature mounting tabs for easy
installation of side panels and number plates.
The CRG Heron Offset Kart is a high quality kart
that combines strength with quality and good looks, In the hands of
the right driver, this bird can be viscious and intimidating to the competition.
You may even win enough prize money with the Heron Oval Chassis to take a
vaction at the beach.