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Discussion Starter #1
This is for us underpowered 550 owners. You 700 guys are in different ball park. I have 28” Zillas on MSA 14” Rims. Total weight per the scale is 162 on all four corners. I feel like I went to big. Curious if other 550 owners have a similar setup and if they are having any issues.

I am clutched, gold spring, 1mm shim. But I was thinking of dropping to a purple spring. I think the gold is overkill. If you have a similar setup what spring are you using.

Thanks, Jason
 

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Welcome from Colorado.
Measure the roll-out for true tire diameter.
1 mm is not enough to return the low end performance if your tires are 27"s true. You'll need a machined sheave and some shim in combination.
Depending on you ride style and trail conditions, the purple spring should be more than you need.
There are many threads about C.V.T. mods, and the theory for the 550 is the same as for the 700 and 660 grizzlies. Go slow and learn what the different mods do.
What was your stock ratio?
 

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I copy and pasted this from the other thread.

I have a 550 and with 28” Zillas on 14” MSA M20 Rims. Looks great but drastic performance difference from stock. I am clutched which helps for sure but if I did it again I would choose 26” since im underpowered.

Total weight per the scale is 162 on all four corners. I feel like I went to big. Curious if other 550 owners have a similar setup and if they are having any issues.

I am clutched, gold spring, 1mm shim. But I was thinking of dropping to a purple spring. I think the gold is overkill. If you have a similar setup what spring are you using.

Thanks, Jason
I strongly suggest you send your primary sheave to Coop45. In my case I use an EPI Orange spring and added another 0.5 shim to Coop's machined sheave to get an initial CVT ratio of 3:1.

I run heavy 26" Pitbull Growler tires. Mounted they weigh 38 lbs for the fronts and 46lbs rears, so 168lbs total. Freestanding they measure 27" @ 6psi.

My little 550 has zero problems pulling these tires. I have amazing off the line torque in HIGH range and a top speed of 61mph on GPS.
 

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Discussion Starter #4
Thank you Vincent. That’s exactly the kind of response I was looking for. I have been considering the modded sheave as well. I’m still researching the forum for opinions though to see if I want the hunter works mod or the coops mod. It seems they both are similar but I like the theory behind hunterworks seal movement trick. I know a lot of people recommend coops mod. I’m still searching for responses for those that have the “new” hunterworks sheave with the new seal.
 

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Hey...JC766..Welcome to GC from Wisconsin.

As indicated above..That gold is way too much for your rig it will eat you power and belt. Drop down to a purple. Add some extra shims, As Vincent suggested. You might be able to run 2mm. You get get a little housing rub at 2mm.

BTW what year is your 550?
 

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If you go higher than 1.7 and the bolts hit the cage you can do a little grinding on the cage also.
 

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Discussion Starter #8
Thank you. Mine is a 2011. The Zillas are a true 27.5. The EPI kit with gold was installed before I bought it and it was for 28”+ tires. So, I appreciate the feedback on the purple spring which I would like to try next. especially if I move in the machined sheave direction. 80% of the time I trail ride so I don’t want too much shim. But I can try 1.5 next. I just need the lower start up gearing the most. It does fine when I get over 20 mph.

Does anybody ride two up on a 550? Or will the weight of an extra rider plus massive tires kill a 550? I’m about 175 and the lady is about 110. Maybe an extra 30 lbs in gear with tools and winch.

Excuse my ignorance too on capabilities. I grew up with race quads. Still have a 450 MXR. This is my first 4x4. While I know they are vastly different, I don’t know/can feel the difference of when I’m truly “straining” the 550 yet. I obviously don’t want to blow it up by overloading it with to much stress.
 

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For trail riding a machined sheave is the best option.
If you feel that you are bogging the 550 down use low gear more for slow riding.
 

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They handle a passagers without issue. I've had many and one was 250lbs. As reogem has stated when in doubt use Low range. As a general rule when ever my average speed is below 12 mph (alone or with a passager) I use Low range. But my area is full of rocks and hills so this method works excellent for me.

Now that I have a Coop's machined sheave with the equivelent ratio of 2.5mm worth of shims, my High and Low range were completely transformed for the better.
 
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