the service
• The way a power spring works is it holds the
clutch in low gear longer allowing the motor to rev
higher, giving the cart more power. If everything
is assembled correctly the power spring cam not
have less power than the stock spring. As it simply
makes the driven clutch harder to spread apart
which raises the engine rpm increasing torque.
With that said, here are some ways you CAN lose
torque when installing a power spring. Sometimes
something as simple as installing the belt in the
opposite direction from what it was originally or
getting even a tiny bit of grease, oil or even plain
dirt on the drive belt. It will work just like putting
flour on the counter to keep the cookie dough from
sticking.
The belt will not be grippy. Now the reason a ma-
chined clutch makes a more dramatic difference
when installing a spring is it actually has a lower
gear to start off in (like granny gear). These num-
bers are just approximate but will show the differ-
ence.
• Diameter of drive clutch at engagement: 2”
• Diameter of driven clutch with belt 1/4 down in
driven clutch 8”
That’s a 4:1 ratio now multiply that through the
12:1 gear ration in the gearbox
A standard cart drive ratio. 48:1 complete drive
ratio
Now the same thing with a machined driven clutch.
The diameter of drive clutch will actually go down
some because the machined driven clutch will
pull the belt tighter pulling it farther down in drive
clutch.
• Diameter of drive clutch at engagement: 1 7/8”
• Diameter of driven clutch that’s been machined
with belt sticking 1/8 above the outside diameter
of driven clutch 8 3/4” that gives you a 4.6:1
ratio, now multiply that by 12:1 gearbox ratio.
Machined clutch gear ratio of standard cart 56:1
That’s over a 15% increase in gear ratio!!
What’s it all mean?
Take a standard cart and chain it to a tree. Install a
load scale in chain between the cart and the tree.
Now with a standard cart try to pull the tree down.
Let’s say the scale reads 500 lbs. Now try to pull the
tree down again with a cart with a power spring in
the driven clutch.
It will still only pull 500 lbs. The reason is the cart
never moves so the spring slowing the shift of the
driven clutch does not apply yet. You still have a
48:1 starting ration. now, if you try to pull the tree
down with the machined clutch WITH or WITHOUT
the power spring it will pull well over the 500 lbs.
Because it has a 56:1 starting gear ratio. The power
spring can only help once the cart is moving. By
slowing the upshift of the clutch. Where the spring
will really help is, let’s say you have a steep hill and
when carts going uphill the cart slows way down to
5 mph and the engine is struggling at 1500 rpm due
to the heavy load.
Same hill with a power spring, the cart will slow
down but usually not as much because the driven
clutch will downshift faster due to the stronger
spring. So now go to 5 mph the motor is running
at 2500 rpm. The motor makes way more power
at 2500 rpm as 1500 rpm so it should climb the hill
faster and have much more reserve power.
& repair hub
I hope this all makes it easier to understand.
This applies to all brands and shows how even a
machined 36 degree E-Z-GO clutch will out pull a
28-degree power clutch. The different ramp angle
just changes the upshift but the starting ratio is the
same for both clutches where the diameter of the
machined clutch is larger them either of the stock
clutches. •
JUNE 2019
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