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Rotating weight reduction
- Thread starter Bauer112
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I added 8 lbs on my last 5 sleds and I really noticed a huge difference. Sled really feels light especially going uphill. Although sometimes it's a real handful. I wouldn't trade that 8 lbs for anything. It's called BOOST. I think you should try it. Pretty sure you will like it. Once you add that 8 lbs you will add it to every sled you ever own. Just saying!!!
This has to be one of the least productive threads in the history of the forums.
You must not have been around for the great counter steering debate.
Wow man really?? First off, I wasn't "taking you on" but I am challenging the thought process and the theories presented. If you want to take those challenges personally, that's your bit. I'm fully aware I'm a rookie and have things to learn, but I will not just succumb to the ramblings of those that are "smarter than me" without challenging just because you've been doing it longer. It takes real world testing of on paper theories to set my mind.
I listed the biggest assumptions I had in question, and although I fully agree that "it's appropriate" to use an assumed value for track traction and use it for an on-paper calculation, it still doesn't mean that I agree with it or believe that it fully represents real-world scenarios. I don't care that you think its splitting hairs and in fact I agree with you but then again that's the point of what I was trying to convey, you can't use assumed values and averages to make a formula work and then expect the outcome to be the exact same in real life. I read the articles and understand them and that they CAN carry over in certain situations, but in trying to achieve a "best of all worlds" scenario again I don't believe they're fully applicable.
"How did that feel"? What the actual **** man are you just going out to try and make people angry now? Well let me put it this way to tell you how I feel: I don't have a degree in engineering, I'm fully self taught and have been able to bridge my real-world experience as a mechanic and fabricator into the "on paper" world and have been very successful thus far. My degree is in Rangeland Management, but my passion has been in motorsports since I was 3. I have the engineering job I have now because I beat out 49 other top candidates because my employer believed that I was best suited for the job, and have just been given my third multi million dollar project to fix after the "actual" engineers screwed it up in the first place because again, they only believed what was on paper and once the project was built, it was an utter failure.
I commend you on your years of service and experience sir, but I still believe that as far as the topic at hand applies, I still don't agree with you. But then again, that's the beauty of continuous learning, when enough facts are presented, state of minds can change and usually we all benefit from the result. See you on the hill someday!
I listed the biggest assumptions I had in question, and although I fully agree that "it's appropriate" to use an assumed value for track traction and use it for an on-paper calculation, it still doesn't mean that I agree with it or believe that it fully represents real-world scenarios. I don't care that you think its splitting hairs and in fact I agree with you but then again that's the point of what I was trying to convey, you can't use assumed values and averages to make a formula work and then expect the outcome to be the exact same in real life. I read the articles and understand them and that they CAN carry over in certain situations, but in trying to achieve a "best of all worlds" scenario again I don't believe they're fully applicable.
"How did that feel"? What the actual **** man are you just going out to try and make people angry now? Well let me put it this way to tell you how I feel: I don't have a degree in engineering, I'm fully self taught and have been able to bridge my real-world experience as a mechanic and fabricator into the "on paper" world and have been very successful thus far. My degree is in Rangeland Management, but my passion has been in motorsports since I was 3. I have the engineering job I have now because I beat out 49 other top candidates because my employer believed that I was best suited for the job, and have just been given my third multi million dollar project to fix after the "actual" engineers screwed it up in the first place because again, they only believed what was on paper and once the project was built, it was an utter failure.
I commend you on your years of service and experience sir, but I still believe that as far as the topic at hand applies, I still don't agree with you. But then again, that's the beauty of continuous learning, when enough facts are presented, state of minds can change and usually we all benefit from the result. See you on the hill someday!
I apologize for the rancor. Many here would rather "eat the teacher" than discuss issues in a civilized manner.
Cinno
Gyroscopic effects of rotating mass
Several people have posted in this thread about how by increasing the rotating mass, it increases the gyroscopic effect that may make the sled less "flickable". I read an article, about that very same issue, on how the gyroscopic effects of the rotating wheels of a bicycle should make it easier to ride and balance. You push a riderless bike down the driveway and it travels a long way before falling. You remove a tire and spin it and you can hold it up with only one finger on one side of the shaft. Very difficult to pivot on its rotating axis. Several quotes:
"The problem with the forces generated from the gyroscopic effect on a typical bicycle is that they simply aren’t very powerful when considering the physics involved in having the majority of the center of mass of the bike at the top (with you on it)."
"so the gyroscopic effect will only help me if I don’t tilt more than 2 mm from being perfectly upright"
The jist of the article is you just have to learn to ride and balance the bike as the gyroscopic effects on a bike are minimal.
Heres the article, you can do the math as it relates to riding a snowmobile and determine the real gyroscope forces and maybe find out how little you have to shift your weight while standing up to compensate for a 5 lb change in track weight at any speed you wish to test at.
http://www.todayifoundout.com/index...thing-to-do-with-your-ability-to-ride-a-bike/
Cinno
Several people have posted in this thread about how by increasing the rotating mass, it increases the gyroscopic effect that may make the sled less "flickable". I read an article, about that very same issue, on how the gyroscopic effects of the rotating wheels of a bicycle should make it easier to ride and balance. You push a riderless bike down the driveway and it travels a long way before falling. You remove a tire and spin it and you can hold it up with only one finger on one side of the shaft. Very difficult to pivot on its rotating axis. Several quotes:
"The problem with the forces generated from the gyroscopic effect on a typical bicycle is that they simply aren’t very powerful when considering the physics involved in having the majority of the center of mass of the bike at the top (with you on it)."
"so the gyroscopic effect will only help me if I don’t tilt more than 2 mm from being perfectly upright"
The jist of the article is you just have to learn to ride and balance the bike as the gyroscopic effects on a bike are minimal.
Heres the article, you can do the math as it relates to riding a snowmobile and determine the real gyroscope forces and maybe find out how little you have to shift your weight while standing up to compensate for a 5 lb change in track weight at any speed you wish to test at.
http://www.todayifoundout.com/index...thing-to-do-with-your-ability-to-ride-a-bike/
Cinno
At the end of the day, personal experience will prove to you if you think rotational weight reduction is the real deal or not. Just ride a 600 Pro and a 800 Pro. Although they will be almost the same weight on the scale, by riding I would have sworn the 600 weighed 20 lbs less than the 800 and it felt like that weight was in the front end. I cannot explain this other than rotational mass. Also if you are rider that pays attention to your sled, I bet you will find it easier to pull up on the left ski than the right ski. Unless your clutch is way heavier than your can, it can be attributed to the gyroscopic effect of the clutch on the left side actually pulling that side down on acceleration.
^^^its pretty fully illustrated during a jump too
I heard that the axis rmk is heavier on the left than the right. The sled weight is not balanced in the center. It makes the sled harder to sidehill right. A reputable aftermarket company told me that. Anyone confirm that?
It's totally true. That's why I lightened up the left side.
And added ballast to the right side.
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I have not noticed any appreciable side hill difference from right to left. I think side hilling on the right is made marginally more difficult due to it being the throttle side but with proper bar height and width, it is almost the same. Just one old guy's observation. I lightened my Axys a lot on the right side with an SLP pipe and a Diamond S Titanium muffler.
And added ballast to the right side.
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Those shocks though ???
Track Weights as per camso
This thread has been an interesting read. There seem to be a lot of different opinions on the topic so I thought I'd share the following article below for those that are still reading, it has a lot of good information on how mass and rotational inertia apply to vehicle physics. While they make a lot of assumptions on no slip from the “tire” to the ground I think the same principles apply to accelerating the engine and track whether it is slipping or not in deep snow. There are a few major differences but the concepts would still apply. With a CVT you have infinite gear ratios and I think roughly the changes to the flywheel could apply from everything directly coupled to the crank (i.e. primary clutch, etc.).
I don’t think anyone will argue that the QuickDrive system by Polaris and the weight reduction in key places changed the way the sled responded in many aspects.
http://hpwizard.com/rotational-inertia.html
I’ve also copied a few of what I believe to be “key” statements below:
Shaving a pound from your tires is equivalent to shaving at most 2 pounds of non-rotating weight.
All that having been said, the calculator below will show you that the equivalent mass of the flywheel is HUGE, especially in lower gears. It's not uncommon for the equivalent mass of a flywheel to be 10x its static mass. Mitigating this somewhat is the fact that the equivalent mass is most significant in 1st and 2nd gears, and you may be traction limited there anyway.
So as you see, rotational inertia effects can add ~30% or more to the effective mass of a car in lower gears. In higher gears, it can be as little as 5%.
A flywheel won't increase horsepower. The typical wheel dyno doesn't measure horsepower...it measures the rate at which the car's engine can accelerate a rotating drum of known inertia. The engine has to accelerate the drive train components as well, so a reduction in drive train rotational inertia will show up on a dyno run as a perceived horsepower increase.
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I don’t think anyone will argue that the QuickDrive system by Polaris and the weight reduction in key places changed the way the sled responded in many aspects.
http://hpwizard.com/rotational-inertia.html
I’ve also copied a few of what I believe to be “key” statements below:
Shaving a pound from your tires is equivalent to shaving at most 2 pounds of non-rotating weight.
All that having been said, the calculator below will show you that the equivalent mass of the flywheel is HUGE, especially in lower gears. It's not uncommon for the equivalent mass of a flywheel to be 10x its static mass. Mitigating this somewhat is the fact that the equivalent mass is most significant in 1st and 2nd gears, and you may be traction limited there anyway.
So as you see, rotational inertia effects can add ~30% or more to the effective mass of a car in lower gears. In higher gears, it can be as little as 5%.
A flywheel won't increase horsepower. The typical wheel dyno doesn't measure horsepower...it measures the rate at which the car's engine can accelerate a rotating drum of known inertia. The engine has to accelerate the drive train components as well, so a reduction in drive train rotational inertia will show up on a dyno run as a perceived horsepower increase.
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No engineer here but seems an engine producing 100 ft lbs of torque at the drive shaft will spin a 40 lb track a whole lot faster than a 50 lb track.
It will spin both at the same speed...
It will ACCELERATE/Decelerate the lighter track at a faster rate than the heavier track.
This is what is known as "throttle response" to most.
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One of the other BIG benefits of reduction of rotating mass....is reduction of inertia.
The Gyroscopic effect of all of those parts, rotating in the same direction... will have a noticeable affect on how nimble the sled feels.
If you reduce the weight of rotating parts... especially if that reduction is away from the centerline of rotation (ie, further out from the center line you make your weight reduction)... you will have make the sled more, dare I say, "Flickable"....this is in addition to the responsiveness that you will feel in the sled.
In the new AXYS... you have a lighter crank, a belt drive, a lighter track... more "flickable" eh !
Make the Primary clutch lighter, make the track and drivers lighter... You will notice it for sure!
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The Gyroscopic effect of all of those parts, rotating in the same direction... will have a noticeable affect on how nimble the sled feels.
If you reduce the weight of rotating parts... especially if that reduction is away from the centerline of rotation (ie, further out from the center line you make your weight reduction)... you will have make the sled more, dare I say, "Flickable"....this is in addition to the responsiveness that you will feel in the sled.
In the new AXYS... you have a lighter crank, a belt drive, a lighter track... more "flickable" eh !
Make the Primary clutch lighter, make the track and drivers lighter... You will notice it for sure!
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