I tested several manufacturers primary springs on a spring scale today . I had a total of 12 springs ,they were all brand new .

My readings may vary from the manufacturers , but the whole point of this is to show springs relations to each other . My scale is repeatable to a variance of about 3 pounds , I have checked this by retesting the same spring several times . I do find springs (of the same color code) can vary often by more than that.

I always thought an EPI red and a polaris white were identical . The two springs appear to be the same , and maybe they are , I may have gotten a wimpy white spring . I tested several EPI reds and they all tested close together , the polaris white is just a little lower . I have another new white spring coming to test tommorow .

My scale is not a high quality certified scale , I am using a common bathroom scale in my press with a tool I made to hold the spring and allow me to compress it while I read the calibrations on the side . The poundage may be off but the tests are repeatable with in the variances I have previously mentioned .

I put this list together so at least we can all see how these things measure on the same day , on the same tester . I hope this helps you all in tuning your clutches .

Color 2.5" 2.25" 2.0" 1.75" 1.5" 1.25"
Polaris blue/green 5 24 46 66 90 117
Dalton plain/white 13 30 47 65 86 105
Polaris white 34 52 72 93 116 140
EPI red 37 57 76 97 118 140
Dalton black/white 39 57 77 100 122 144
Polaris green 43 61 78 96 116 140
Dalton black/orange53 71 88 106 125 150
Aaen green 54 73 91 112 130 154
EPI orange 79 91 102 118 130 145
HPD plain 32 65 102 145 185 235
Polaris orange 72 92 115 141 166 196
HPD red/yellow 118 139 161 187 214 243
HPD red 135 162 183 206 229 253
Dalton Black/red/white147 177 204 234 267 298 <--NEW JUST ADDED
EPI maroon 199 228 245 277 303 330

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The previous post I copied and pasted from another thread . The spring I sent Lukester is an EPI red . Same top rev as green , just a little earlier engagement .

For what he is going to do I think it was a good call .

Thanks ,

Rick Ritter

 

Thanks for all the information but I was wondering if you suggest buying new clutch weights as well seeing all the clutch kits I've looked into sell them as part of the packageand is there that much invlovedin swapping out the spring if you have decent mechanical knowledge.

 

Changing the primary spring and weights is very easy to do. Usually if you go with a stiffer spring then weights should be changed also.The spring will give more resistance to engage and the weights will give more force to clamp on to the belt. Just changing to a stiffer spring can cause more slippage thus the reason for heavier weights. HPD agressive kit is a red/yellow primary with 58g weights. I would go with a complete kit and not mix and match parts. This way everything works together and takes the guess work out. Rick can also set you up with a system that matches your riding style. Your secondary will also determine how fast you want it to shift out. With a full kit it will give you both springs,weights,spacers and/or helix.

 

Mudizfun24,
I replied to your topic up top. I'll be getting my 03 TBoss back this week and will ride it out this Friday - I'll reply to this thread on how it does. 2manytoys is giving you good info - I am comfortable with changing out stock to the red spring alone (no other clutch mod). Also, when I was checking on it in the shop last weekend we noticed the 1-1/2" tall air box vents I listed above were too tall to clear under the seat bottom - had to go with short vents.