What's the Best Aftermarket Secondary (Driven) Clutch?

Well, one thing I think that has to be considered is these are "M" sleds for Mountain sleds. I think their is a give and take that needs to be thought about when buying a sled. I think a lot of guys that ride M's would be better off on a crossfire/firecat. It's like having a drag car made for the strip and wanting to take it on the road. You are giving up something to achieve something else. To be honest, at first I was almost regretting gearing my sled down. Yea, it made it fun (kinda like dropping the front of the rear skid to the lower holes. Fun, but not efficient hillclimbing) but I sacrificed my doing 70 on the trail getting to the powder. But then, after seeing how awesome it hillclimbs and boondocks, I realized I sacrificed one thing for another that I wouldn't give back. I think it all depends what you want in your style of riding. As far as the bigger clutches, I think you can do it either way. You can gear down or buy bigger secondary sheaves. Both accomplish the same thing I think. JMO

Aaron

I have a Cutler secondary on the M1000 and I am much happier with it than the stock setup, letting the secondary do more of the work helps for the M1, not sure about an 8 though.

i run the 11" STM secondary on my stock M8. Less belt heat and more consistent shifting when you have the flapper wideopen in the pow. i really think it pulls harder, but i never ran the two clutches back to back. i do know it still climbs higher then both the revs i ride with so i know i didnt lose anything.

Right now my setup is 75g weights w/ yellow/white in the primary
11" STM secondary with green sno pro spring and a 52/44 helix @ 0-5000'. The STM is identical to the pre-diamond secondaries on the Mcat. I believe they are called reverse cam? (please correct me if i am wrong)

I am not confident enough in my clutching knowledge to tell you this is the best thing ever, however my sled runs very well with it. i just havent taken the time to swap helixes on the hill. I pretty much set the deflection and let'r rip.

I did have to drop 2g from my weights and i now run a XS 809 belt which seems to work well.

I have a 48/44 helix i want to try, just havent put in the effort. I got some clutchin recommendations from a thread i started a while back asking what people had for a setup, but everyone that replied had the clutch on the m1000 or m7. so i took what i thought would be in the middle and went from there. I'll send the original thread i stated to the top so you can read other responses.

overall though i really think its a big improvement over stock, belt runs cooler, and the sled pulls hard. but sometimes i dont think its loads the motor correctly and i have to let off then get back on the trottle Like when i initially grab handful of throttle at the bottom of a climb, and then it feels like it pulls like it should and the RPMs shoot up to above 7000. and thats where my inexperience comes in. i'm not really sure what shift charateristics i should be looking for with the secondary to get it to shift the most efficiently.

You will probably get similiar results with RKT or Cutler kits, they basically turn the stock secondary into a torion spring setup which is what the STM is, only with 11" sheaves.

hope this helps

I am running the Supreme tool 11" secondary on mine and so far I am very pleased with it. Belt temps at way down, clutches are cooler, and it shifts well.

On the little time I have on my TM1000, I have taken back to back pulls (about 4-6) that would typically get any belt quite hot, but after making the pulls I was still able to place my hand on it and leave it there...I was impressed.

This clutch was on the sled when I got it, but if I was going to put another secondary on another sled this clutch would probably be it.

The bigger the socondery the more likely to get hit by a rock, its already very close to the belly pan and I have had rocks get up in that area twice, just something to think about:beer;

My $.02. Get the stock clutches setup so they perform good. I have been satisfied with the stock clutches on my M's since 2006....once they are set up for my preference. Next, would be the turbo if you want to keep up with the other guys on boost.

I'll bet next year we see something completely different in the clutching.

I am thinking that if you're having belt issues, something simply isn't right with your clutch setup. I, and most others have no issues. I haven't even checked my alignment from the factory as I have had no issues. Put vents on before I really even rode the thing. I think that's the main issue. Engine heat has nowhere to go, and there's barely any intake vents.

I think its due to spring bind. I am woundering about taking both plastic washers out of my secondary to see if it helps. On my 07 m1000 with a 4 post it would rip up to 95 mph in seconds and when we would ride in the gosples (25 mile trail ride) I averaged 85 mph most of the way and was always over 90 at some point. My 09 hits about 82 and feels like thats the end but slowly climbs until the belt go's boom. I think the 4 post put more force on the primary making the secondary work. I have taken one plastic shim out of the secondary and need to check i, if It goes quick past 82mph i'll know if its spring bind in sec.

Frostbite said:

The stock secondary with stock gearing on the M series just can't shift out far enough to keep up with the shift out of the primary. The primary keeps shifting out and if you keep it pinned the belt eventually spins on the secondary creating lots of heat and BAM there goes your belt, again.

So, what's the fix? Higher gearing?

If you go to higher gearing your mountain prowness declines, right?

Click to expand...

You bring up a couple good discussion points. I would be interested in the clutching experts reply to your fix question. In my experience, the secondary spring is key to find balance with the primary on a stock M sled. I have only personally experimented with the 36 degree helix. I am running the Goodwin Blue spring in my stock 2009 M8 currently and it is a noticeable improvement over the AC Orange. I can't quit looking for more so have a spare secondary assembled with a progressive 42/36. We'll see how that works out. I have not had belt issues with my M8 or previous M7. I do feel on the stock M8 the best on snow performance comes if you clutch to take advantage of the wide torque band of this motor. Light weights and higher rpms seem to underperform a set up that lugs this motor.

You may want to draw a picture. This may not be perfect either but my math says this.

I just started doing some clutching and noticed black all over my primary (all the way to the outside of sheeve) and thought how the H did that happen as I never went above 70mph, if that. So I started punching numbers. My belts measure( may not be perfect measurements but close) from 44.25-44.6. If you measure the clutch sheeve where the belt would be in full shift out 8.25 (driven) and 5.5 (secondary) and 11.5 from center to center. At full shift it is 44.58. So if everything stays where it should. Its near perfect.
If measurements count then the top of the belt should engages in the primary at 5.25 across and finish at 8.25, the distance the belt travels in the primary is 1.5". The secondary measures 10.4 and full shift is 5.5, total movement is 2.45.

Optimal belt to sheeve contact is at a 1.1 ratio on the m1000 at 7800rpm you would be turning 78mph with 60/60 gearing.

At a 1.1 the belt would be riding 6.87" across the clutch in both clutches. Now I am going to cut that in 1/2 because the belt only covers half the clutch. So from center a 1:1 is 3.435 and 3.435 to get to a 1:1 the the belt travels in the primary .81" and 1.765" in the secondary at an increasing rate.

Here is where the demand on the clutches after 78mph
from 1:1 to full shift out the belt moves .69 in the primary and .68 in the secondary.

so after 1:1 the belt move the same amount across the clutches,(or am I wrong) all though it is increasing (shifting it overdrive) in my mind this means that the force of the primary must be greater than the force in the secondary, but by how much. a softer finish rate might play a big factor in either clutch.

My 07 did it flawless with stock clutching and a 046 belt leading me to beleive the 4 post clutch has far more force in the primary when needed. Never blew a belt either but changed them out every 300 or so hard miles.

But if my clutches have black all over and I never went above 70 it means my belt either stretched greater than .7" or my motor is moving that far, and if this is happening any more engagement (speed) would just walk the belt right over the top of the clutch and boom. I am installing motor mounts as soon as possible. I will also be running my belt tension loose in the mountains to get it closer to a 1:1 and tighter if I want to go fast. (and looking for a 4 post for testing)

I'm not sure what the bigger secondary is supposed to play but I do know people gear down for the extra grip in the clutches as it gets you closer to a 1:1 ratio.

Frostbite said:

The stock secondary with stock gearing on the M series just can't shift out far enough to keep up with the shift out of the primary. The primary keeps shifting out and if you keep it pinned the belt eventually spins on the secondary creating lots of heat and BAM there goes your belt, again.

So, what's the fix? Higher gearing?

If you go to higher gearing your mountain prowness declines, right?

Click to expand...

Hmm. I haven't had that happen yet, on any of the 8s I've owned/tuned (qty 3 so far). Last year with my 09 162 I had some full throttle pulls that lasted 30-40 seconds in Montana and this year I rode it at 85 mph for long stretches at a time and some good hill pulls at 100% throttle. No clutching issues other than hard engagement after changing to the SLP green/yellow primary spring. I now I have 700 miles on the sled and it's still on the stock belt. I use some side vents to cool things and have never experienced abnormal belt/clutch temps. I've always been told that the 09 m8 gearing is pretty darn good and not to mess with it.

By the way, you're gonna love your SLP perf edition kit. I finally had a chance last weekend to really test it out at Mt Bachelor and it definately runs way stronger than with the pipe only. You'll see what I mean

I think the problem is more with modded m8 and m1000's

chaning a helix on a cat secondary is the worst!!!

but the clutch works great and came with the sled

i would love to have a TEAM, very easy to work with clutch:beer;

Changin a Helix on the STM clutch is a snap. less than 10 minute procedure, and thats doing it in the field.