Raptor SD deck spring

Kremeneon

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With past talk about springs and belt tension I present for discussion the factory RSD tension spring and the spring used on many/most other models, x-one, fastrack, etc...
 

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mooch91

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Direct replacement with noticeable improvement???
 

Kremeneon

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OEM Raptor SD Spring (Hustler 604291)
Alternate spring (Hustler 781302)

The alternate spring is larger wire, and less coils, which increase tension. It also has a much larger wind diameter, which decreases tension. The larger wind also means it makes contact with the deck in one spot at the far anchor from the idler. Raising that anchor a hair (bending) should resolve the contact.

I have not mowed with it, Wet grass. adding any links (I only have 1" chain at the moment, and one link is too loose) reduces tension below what the factory spring provides. With no links, direct drop in, there seems to be a slight increase in tension as measured by belt deflection from the idler to the clutch. I also marked the idler slider and the alternate spring does bring it in 2-3mm more than the factory spring.

Blade engagement/running all seem about the same, wobble might be improved a bit by feel. I need to have someone sit in the seat with blades on so I can observe belt and spring activity.
 

djdicetn

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With past talk about springs and belt tension I present for discussion the factory RSD tension spring and the spring used on many/most other models, x-one, fastrack, etc...

I hope that everyone that is making modifications to the springs on their Raptor RSD's are getting the blessing of Hustler and/or their dealer on these mods!!! IMHO, I would be hesitant to arbitrarily change a tension spring from the OEM on my ZTR because I'm certain that a spring with "too much" tension could potentially be as bad as a spring with "not enough" tension. Too much belt tension could "possibly"cause premature idler pulley bearing failure or even spindle bearing problems......don't you think????
 

RaptorSD

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The belt is supposed to dance around when running. I'd be worried about belt wear and spindle bearings with the commercial spring installed anchor to anchor, the difference in tension from stock is not even close.

I maintain that the stock spring is perfectly fine on this mower.
 

djdicetn

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The belt is supposed to dance around when running. I'd be worried about belt wear and spindle bearings with the commercial spring installed anchor to anchor, the difference in tension from stock is not even close.

I maintain that the stock spring is perfectly fine on this mower.

I completely agree....I've noticed a "wobble" in my belt when running since day one. Gotta be "normal". As long as the grass is being cut cleanly and the belt isn't coming off I don't even give it any thought.
 

Kremeneon

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The belt is supposed to dance around when running. I'd be worried about belt wear and spindle bearings with the commercial spring installed anchor to anchor, the difference in tension from stock is not even close.

All valid.

On the spring difference though, did you measure it? Appearance on springs can be deceiving. I do intend to measure pull force before trying it for real. I need to build a jig in the woodshop with my fish scale.

Here's a snippet from the FasTrack SD service manual, this is the entirety of its content on deck belt adjustment:
The spindle belt tension remains constant by means of a tension
idler and spring. The spring tension should be such that the
belt does not slip under normal operating load conditions,
assuming the belt is not excessively worn or damaged. As the
belt stretches and wears in, adjustment may become necessary.
To increase belt tension, move the spring chain one (or more)
link(s) at the anchor point on the deck frame.

IMPORTANT: Do not over tension the spring to compensate
for a badly worn belt or pulley.

Spring length after tensioning new belt. Measured from outside of hook to outside of hook with deck set at 3¼" cut height: 8.3"-9.3"

So the instructions are: belt slips, make it tighter, but not too tight. Start at specified tension resulting from 8.3-9.3" end to end on spring.


The issue I'm having is that my center blade slips in thicker stuff. Leaving a trail of half cut yard. The left and right are cutting the same thing perfectly. The center pulley has the least amount of belt contact so it would of course slip first. This slip happens and I don't hear the engine load up at all. I know the Kawa's are good, but not that good. What use (other than for marketing) is a 23, 50, or 1000 HP engine on the back if power delivery is limited to less than what can be generated?
 

djdicetn

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All valid.

On the spring difference though, did you measure it? Appearance on springs can be deceiving. I do intend to measure pull force before trying it for real. I need to build a jig in the woodshop with my fish scale.

Here's a snippet from the FasTrack SD service manual, this is the entirety of its content on deck belt adjustment:


So the instructions are: belt slips, make it tighter, but not too tight. Start at specified tension resulting from 8.3-9.3" end to end on spring.


The issue I'm having is that my center blade slips in thicker stuff. Leaving a trail of half cut yard. The left and right are cutting the same thing perfectly. The center pulley has the least amount of belt contact so it would of course slip first. This slip happens and I don't hear the engine load up at all. I know the Kawa's are good, but not that good. What use (other than for marketing) is a 23, 50, or 1000 HP engine on the back if power delivery is limited to less than what can be generated?

Slippage of the belt on the center pulley has got to be deck design/components. I have the same Kawa engine(691v) on my Gravely(except it's the FX series rather than the FR series) and I don't have that problem(and I cut through 8" windrows before installing my mulch kit). It's definitely not the Kawa engine.
 

Carscw

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Running a spring that is to strong will wear out the bearings on idler pulleys and spindles a lot faster.
As long as the belt does not slip in thick grass then leave it be.

You should be able to see the idler pulley arm moving when the blades are running.

. If the spring is to strong it will not let the idler pulley loosen the belt when under a heavy load.
 
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