Photos of MDS weights

You have put a lot of effort into this post.

I am curious what the clutching experts will come up with.

Thunder

Just have to say it Flange...this is a bloody exellent thread!

I have for weeks been curious on the mds stuff.

You did put in a lot of time into this.

At any point in the shift, the weight is applying force in the direction that it is contacting the roller. Different weight profiles will change this angle. To get the most force on the belt, the closer this angle is to the direction the sheaves move, the better. But without even doing some serious measurements, I'm sure there is a happy medium of a weight profile giving you the most force at certain percentages of sheave closure.

Also, the location of the mass on the weight changes things as far as the amount of force on the roller at certain points in the shift.

I'm not sure if anyone has done it but there could be VERY complex calculus and physics to do to maximize the profile of the weight and the location of the mass on the weight. I would hope that the engineers at the sled manufacturers would figure this out for each type of sled. Sadly, I highly doubt that this happens.

hey i just got my weights from steve and had a question if you had tried the weights with the polaris black spring that you could get from him? going to the big horns next monday and thats what he recomends for 6k to 10 k.

thanks

FLANGE:

You HAVE put a lot of effort and time into this. What an excellent post. Kudos to you!!!

1 thing you should compare, is to hang the weights from the same pin. This will give you the center of gravity of the weight, as opposed to setting them flat on the table as your pic shows.

If I remember correctly, when the COG is towards the bottom side of the weight, the weight will shift more aggressivly at the start, and less aggressive towards top end. D&D's big Dod weights change the COG to the bottom side.

If the COG is towards the top side (where the roller runs), it shifts less aggressivly on the bottom end, and more on the top.

The reason the weight with more COG on the bottom side shifts more aggressivly on the bottom is as the weight swings open, the COG pushes the force against the roller, shifting the clutch out. As it swings out, centrifigual force has more mass to "pull" on the weight. as it nears the end, the main mass is past center and thus shifts slower. The opposite is true for the COG on the other side.


As for profile, a flatter profile usually shifts slower, as the roller has to travel further on the weight to close the sheaves. The more aggressive the profile is (curved from pin to tip), the faster is closes the clutch. Culter's profile is very aggressive, and shifts the clutch closed very fast. With a weight that closes the clutch fast, it shifts the belt higher, quicker, and can actually cause you to bog down. It simply shifts up too fast and puts too much load on the motor.

As I see it, the big mass on the bottom will shift very fast, and lug the motor. To overcome this, the profile had to be flattened out, so that the motor can "keep up" with clutches.

Hanging the weights side by side on a pin will tell you the COG. With them hanging, draw an imaginary line through the center of the pin, straight down to the floor. Which side of this line is there more mass on?



DTR

From grinding and burning up about a zillion weights always testing; yes, he has more weight toward the shift-out making it more agressive. Except the curvature is flatter than a stocker making it less aggressive. Just like the example in Aaens book.
Solution-get a set of Heavy Hitters or STM adjustables. As Lonn told me once years ago, you could almost make the curvature of a weight flat as long as it would turn the roller and you placed the weight bolts and washers in the correct positions to hold the desired RPM. There is nothing new here, just the 'newest' thing to extract max $$ from your wallets.

Great job! I have been wondering about the way the weights are profiled, the pics with the different sheaf travel versus the weight profiles really helped me understand the interaction of the two.
Thanks again for your work.

When I read MDS threads for a couple of months I was skeptical of impromvment claims based on the last 10 years of the explosion of aftermarket weight makers with the various methods of adding weight all kinds of ways, with pins, bolts , rivets, washers, allen bolts..........same thing you can do with a welder in a few minutes back at the shop.

My experience with a lot of weight sets I bought and sold.

1. suspect material quality, read material Too Soft, couple of thousand miles on a mtn sled, face of the weights wore out / roller surface.

2. pretty subtle shift changes moving weight from tip to middle etc etc. Yes..........some change or improvement at times, but never what a customer wanted..........never a wow!

3. swore off more $250 weight sets and went back to sturdy cat weight and a welder as best option, since the ole firecat era.

When Steve @ MDS said had used a chassis dyno to develope weight profiles to put up bigger to the track numbers without increasing engine hp, I was encouraged. Why? Becase 10 years of buying aftermarket weights, the weight profiles haven't changed since the first comet 102 clutch's. So...........one weight profile is correct for the last 20 years of sleds ? That what we have been fed. " Buy our weights and with a few nuts and screws it works on 340's or tubo 1200's""............yeah right.

When I got Steve's weights I was skeptical because I expected to see more profile change. The added mass hanging under his weights, I had played before without dazzling myself or anyone else.

Steve's weight's backed up one of the oldest hot rodding axioms, GOOD TUNING is RESULT fueled, not DESIGN FUELED, meaning no matter how you think you should get the results, you have to follow the results backwards.

I installed the MDS weights with a profile I wasn't really sold on. Woops ..........the results were unmistakable. Results I hadn't gotten with a lotta dollars worth of secondary clutch's/weights/and lots of mix and match springs n dem helix's. So some guy in Ellensburg WA has seriously one upped my best efforts. Pizzes me off in a way, now my M8 has the best tuned clutch's of the 30 or so sleds I've owned, and I didn't figure it out on my own.

Some good comments so far. Thank-you for those that have posted already.

With that being said I have a question about loading up the MDS weights.

First some background discussion to why I am asking this question. Correct me if I am wrong but one can argue that Arctic Cat uses the same "theory" of clutching on their stock setups for the M1000, M8 and M6. In the secondary they are all running a 36° helix with the orange spring (I am assuming that they have the same number of shims under the helix but I don't know for sure) and in the primary they all run the yellow/white spring and a light-tip profile weight with varing weight for the different engines / power. For the purposes of this discussion I am not considering the gearing because for what I am asking I don't think it will matter.

So with that in mind lets fast forward to the MDS weights. To me it appears that the recommended way of loading up the weights varies with the model of sled they are going into. In the M6, M7 and M8 setups it appears that the common recommendation is to load the MDS weights in the tip according to your elevation and change out the spring to a similar engagement rating as the yellow/white but with a higher finishing rate. On the M1000 the spring of choice would appear to be the same as the M6, M7 and M8 setups but the recommendation of loading the weights up is quite different. On the M1000's I have seen, a plate is used to add mass across the whole weight and then use the same (or very close to the same) weight setup in both the middle hole and the tip. To me that seems like a significant difference and I am curious if one setup or the other is leaving something on the table??

Comments.

Tee-Kay said:

Some good comments so far. Thank-you for those that have posted already.

With that being said I have a question about loading up the MDS weights.

First some background discussion to why I am asking this question. Correct me if I am wrong but one can argue that Arctic Cat uses the same "theory" of clutching on their stock setups for the M1000, M8 and M6. In the secondary they are all running a 36° helix with the orange spring (I am assuming that they have the same number of shims under the helix but I don't know for sure) and in the primary they all run the yellow/white spring and a light-tip profile weight with varing weight for the different engines / power. For the purposes of this discussion I am not considering the gearing because for what I am asking I don't think it will matter.

So with that in mind lets fast forward to the MDS weights. To me it appears that the recommended way of loading up the weights varies with the model of sled they are going into. In the M6, M7 and M8 setups it appears that the common recommendation is to load the MDS weights in the tip according to your elevation and change out the spring to a similar engagement rating as the yellow/white but with a higher finishing rate. On the M1000 the spring of choice would appear to be the same as the M6, M7 and M8 setups but the recommendation of loading the weights up is quite different. On the M1000's I have seen, a plate is used to add mass across the whole weight and then use the same (or very close to the same) weight setup in both the middle hole and the tip. To me that seems like a significant difference and I am curious if one setup or the other is leaving something on the table??

Comments.

Click to expand...

I'm no expert so I might be way off, but I think it's because they use the same base weight between all engines. The 1000 with more power and spinning around 800rpm lower requires alot more mass to pull down the rpm.