On The Pegs February 2018 - Volume 3 - Issue 2 | Page 148

On The Pegs
graph and it allows you to see what
kind of characteristics the spring has
through a given distance.
P 148
chrome silicone alloy and weighs a
porky 3lbs!
I do need to explain the unique and
marvelous design of the AER air forks
TWO MAJOR DIFFERENT SPRINGS
balance or negitive chamber. In the
EQUALS TWO DIFFERENT METHODS picture on page 137 you will notice the
FOR TESTING
circle drawn around what appears to be
How a straight rate spring is tested is
sharpie mark in the shape of an “I”. Its
to do an international compresion test. actually a protusion/dimple convexed
Take two points, 1 at 20%=L1 and the
out of cartridge that allows the fork
2nd point at 80%=L2 of stroke/travel.
to equalize pressure between the “A”
Then take L2 subtract L1 and divide by main spring chamber, which is trying
the distance inbetween them and that to extend the fork and the “B” balance
gives you rate.
or negitive chamber which is trying
Seeing how the air spring doesnt work
to collapse the fork. The “A” chamber
like a metal coil spring in any shape or
is roughly 4 times longer than the “B”
form, I will be testing them both like a
chamber. Air is very progresive and if it
progressive spring. I am going to test
wasnt for the balance chamber the air
both of these springs the exact same
spring would be extremely progressive.
way. The data points will start at 50mm, The simplistic design of one schrader
and will be every 50mm over a 300mm valve at fork cap in combo with this
distance, equalling 6 data points.
notch makes a very user friendly car-
tridge air fork.
LETS MEET OUR CONTESTANTS
On the graph on the next page
On page 136, we have the AER air
we have force on the vertical line in
spring. It can produce multiple spring
kg(kilograms), and displacement/dis-
rates of .76kg/mm to 1.20kg/mm “plus” tance in mm(millimeters) on the hori-
depending on psi. The Cartridge is 37
zontal.
to 38mm in diameter made from an
Above is the AER air spring at 140 psi.
high grade of aluminum alloy and is
Using my conversion method 140psi
hardcoat annodized. Total length is
would be equal to a .98kg/mm metal
590mm, the internal plunger is 34mm
coil spring.
in diameter which is connected to the
Regardless if the spring was tested
smaller 12mm diameter rod protruding at 100psi or at 170psi, the graph/curve
out at the bottom of the cartridge, and for all intesive purposes is identicle to
the entire spring weighs in at an amaz- this shape. This is a great visual tool
ing 1.5lbs!
for when somebody tells you, “air is
On page 137 is a factory showa spring. progressive” and that statement would
44mm in diameter by 660mm long,
make a lot more sense if this graph
6.7mm wire diameter with 42 total coils started at the 100mm mark, but it
and 40 active coils, producing a fixed
doesnt. There is the slightly high intial
rate of .99kg/mm made from high tensil rate at 50mm of 1.049kg/mm, then