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RKT dual spring secondary set up

stocksucks!!

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Dec 6, 2008
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fort st john b.c
www.powderking.com
just got mine in the mail installed some of it and found i was missing some parts..as i am not familar with clutch components..talked to kelsey and the rest of the stuff is on the way the install is pretty striaght forward.. small hole to drill for the ear of the spring.. other than that ordered a 15 hp bolt on head from rkt and it fits awsome and looks good too.. canèt wait for snow..well have to wait for clutch part @ least..
 

backcountryislife

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It looks to be a good idea. We played with different combos a few years ago & got some decent results, but now it sounds like Kelsey got some custom springs so he can get them made to his specs. It should do good things & allow you more tuning options as well.
 
N

Nubulin

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Oct 26, 2005
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Flatlands USA :(
Can anyone explain what they are doing? Is it a compression spring and a torsion? Or post a pic?

I am curious what they have done.
 
B
Nov 27, 2007
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Rovaniemi, Finland
One dude here in Finland asked about the RKT dual spring kit for his stock CF 7 SP -06. Kelsey recommended (if I remembering right) 36-34 angle helix. Sounds really shallow angles as we drive below 3000ft (usually around 1500ft). I bought just 48-40p helix for my sled so there's huge difference and feels weird to put so shallow helix for our elevation?
 
R
Feb 2, 2008
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Grande Prairie
so i already have the torsion secondary conversion on my sled with a cutler red/white spring. Im not too crazy about the back- shift but man does it rip. Wondering if i should go for the double and what changes will i see if any.. Im kinda thinking lower belt heat by being able to back the spring tension off and run lighter weights???

id like to know if this will improve it or not because i think there is room to improve..


What ya think?

i got the40/36 helix
 
N

Nubulin

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Oct 26, 2005
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Flatlands USA :(
So let me get this straight?

Compression secondarys suck, so 15 different aftermarket companies change them out to torsion springs. Now this years "upgrade" is to go back to half compression and half torsion? Now we are half way back to the original design?

I guess I have never understood the "physics" of why a torsion spring applies any different force in a fully encapsulated helix than a compression spring. The helix only moves one way, and other than spring rates, the net force in the helix is the same regardless of type of spring. Try it on a press with a compression scale. Sure, you get different rates with a torsion, but it would seem to me that just building the correct rate compression spring wound do the same thing? Perhaps they were not previously available?

I know these kits get good reviews and I had one myself. It worked, but no different than a spring/helix change and I was not sold on it. Like a lot of aftermarket parts, I just wonder how much of the "better performance" is the placebo effect?

No bash, just trying to get an intelligent explanation that uses physics not salesmanship. I am curious to see RKTs new kit. He is the only one that seems to have any innovation out there. It's changed a lot since the first year. They rest just look like a copied 1st gen RKT end cap design.
 
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J

Jeff K

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Jan 26, 2008
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Calgary, AB
So let me get this straight?

Compression secondarys suck, so 15 different aftermarket companies change them out to torsion springs. Now this years "upgrade" is to go back to half compression and half torsion? Now we are half way back to the original design?

I guess I have never understood the "physics" of why a torsion spring applies any different force in a fully encapsulated helix than a compression spring. The helix only moves one way, and other than spring rates, the net force in the helix is the same regardless of type of spring. Try it on a press with a compression scale. Sure, you get different rates with a torsion, but it would seem to me that just building the correct rate compression spring wound do the same thing? Perhaps they were not previously available?

I know these kits get good reviews and I had one myself. It worked, but no different than a spring/helix change and I was not sold on it. Like a lot of aftermarket parts, I just wonder how much of the "better performance" is the placebo effect?

No bash, just trying to get an intelligent explanation that uses physics not salesmanship. I am curious to see RKTs new kit. He is the only one that seems to have any innovation out there. It's changed a lot since the first year. They rest just look like a copied 1st gen RKT end cap design.

The way I understand it is this:

The helix twists as it travels. This is why a lot of people put the shift assist under the secondary spring to prevent spring bind. A torsional conversion uses the twisting action to apply a torsional force (twisting) to the spring and ultimately the helix (since they are bound together). This helps with backshifting because the helix now has 2 forces applied to it. Where a regular compression spring may not have the required force to provide quick backshifting, a torsional setup has the added "torque" built up in the spring to give full backshift.
 

WyoBoy1000

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everyone seems to like the torsional setup but I would rather have optimum up shift rather than limiting it for better backshift, I also understand the need for backshift to maintain optimum rpm. But why don't some of these clutch guru's make a tied clutch that works on a dd.
 
B

bigcat_ak

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Nov 27, 2007
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everyone seems to like the torsional setup but I would rather have optimum up shift rather than limiting it for better backshift, I also understand the need for backshift to maintain optimum rpm. But why don't some of these clutch guru's make a tied clutch that works on a dd.

If you mean the TEAM, engineers who tested it say it has 30% less back shift than the old TEAM.

But I agree with you. Seems someone could get it right?!
 

WyoBoy1000

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thats not what I read in a magazine( can't remember which one ) that had a 2 page article.

In fact if they don't back shift as good how do they get the hold back effect on the auto atv's and side by sides.??? No twisting on the sheeves smooth transitions. maybe you can enlighten me on how it would not, its all new to me.
 
D
Nov 28, 2007
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The problem with the DDrive secondary is a group of problems.

1) end cap for open ended helix was way to weak.

2) friction washer in the secondary stock would not let the spring spin and it would belly hanging the shift.

3) primary spring bind had guys looking at the secondary....... yet this secondary was used on the T660 and ZR900 for a year before with no problems. DDrive offset bar was off and the secondary is fixed and will not float.


The torsion spring puts loads on the end cap too. Most of the performance gains are if you use the new stronger end cap. This can be achieved with the dalton billet end cap and compression spring. When the end cap bends the bearings bind in the secondary cutting the shift back. The closed ended helix was to stop this end cap by taking it out.

To gain more back shift I always added more secondary spring rate. When doing this the end cap was the problem. The compression spring set up rocks once you take out the bellying of the spring and keep the end cap from binding the bearings.

The primary spring cup is to tight and the primary spring needs a shift assist as well. You guys all can check your primary springs and you will see the OD of the spring all the paint worn off the inner three coils of the spring.

Fix all this and it will out run any after market goodie you can put on the sled other than NOS..

Cheers Don.
 
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