TRA settups...attn clutch guru's

[tollen77]

First things 1st the spring preload and its side force is what sqweezes the belt. The question is how well it works in conjunction with the torque sensing secondary at WOT where the helix/spring than takes over.... Primary 160/320 or 130/320 at 6500 rpm isn't much of a comparison..How's about a 130/320 vs 200/320 or 200/350 climbing wot in deep snow where sqweezing the belt is very critical and belt slippage often occures due springs with not enough preload ability .

One way to mitigate the harsh engagment of a spring with a high pre-load would be to have a look at you ramps.....A taller ramp at the engagment point of the ramp = higher engagment. Ramps like 419,427 and 435 at the engagement point are notched and not as tall which help in decreasing the harsh engagment when running heavy primary springs.. A lot of racers will custom taylor there ramps just to address the harsh engagment.

OT

"Primary 160/320 or 130/320 at 6500 rpm isn't much of a comparison..How's about a 130/320 vs 200/320 or 200/350 climbing wot in deep snow where sqweezing the belt is very critical and belt slippage often occures due springs with not enough preload ability ."


The differences would be smaller for 130/320 vs. 160/320 though they would still be there. I agree, to see more of a pronounced difference you'd need to compare springs with larger differences in rate (130/320 vs. 200/320). Tough to compare 130/320 vs. a 200/350 since they have both a different starting and finishing force.


"One way to mitigate the harsh engagment of a spring with a high pre-load would be to have a look at you ramps.....A taller ramp at the engagment point of the ramp = higher engagment. Ramps like 419,427 and 435 at the engagement point are notched and not as tall which help in decreasing the harsh engagment when running heavy primary springs."


This one I'm not sure about and I'd love to hear another opinion on it... my thinking re: taller ramps to cure harsh engagement is taller ramps will simply reduce clamping forces further. Can someone clarify this.

A spring with high initial force and a ramp that diminishes clamping forces should lead to an even higher point of engagement and an even harsher take-off, no???

 

[banditpowdercoat]

Doesn't the secondary determine how the primary is going to PINCH the belt?

Ok bear with me. Without a belt on, the primary closes WAY before the peak RPM, say 7000RPM. WHen a belt is there, and the clutch closes, the belt wants to Ride up in the primary and down in the secondary. Now, if the secondary did not resist this, the primary will shift out completely at 7000RPM, correct? Now change secondary helix, load, or spring, whatever. Change to increase the secondary resistance to opening. Now, where is the belt sitting in the primary at 7000RPM? Lower, correct? Without add more secondary resistance, belt goes lower. BUT still @ 7000 RPM, so the primary MUST be making the same force, rigth? Same weights, same RPM. F=MA BUT, less spring force, due to the clutch being open more. So same roller force, but less spring force should be more belt clamp. which was derived by changing the secondary, Not the primary.


When I started typing this, I knew what I meant, but Ive been up since 8pm last night...... Am I right though? ballancing a double edge sword on a razor blade???

 

[banditpowdercoat]

"First things 1st the spring preload and its side force is what sqweezes the belt."

In the secondary! Not in the primary. The only thing that squeezes the belt in the primary is the arms pushing on the ramps!

But ONLY IF the secondary is squeezing back the same amount to keep the belt at the same shift height

 

[tollen77]

But ONLY IF the secondary is squeezing back the same amount to keep the belt at the same shift height

There does have to be equal and opposite forces between the two clutches to acheive optimum efficiency, no doubt, though I wouldn't go so far as to say the secondary helps provide belt pinch in the primary. It does provide resistance so the belt doesn't just fly out of the primary as soon as you touch the gas, though even if there wer no spring in the secondary, there would still be resistance in the secondary at full shift. The effective pulley diameter only gets so small and then stops.

If the secondary transferred zero load to the primary it would be like having a tug of war with your imaginary friend.

To be honest, I'm not totally following where you're going in your posts. Could you clarify a little?

 

[YamaDoo PolCat]

I don't see almond, but gold is 120/270. These are just Polaris lists, not the after market.

Lots of strange ideas about clutching the skido forums. Most of it centers around high spring pressures. In the primary the higher the spring pressure the more force it robs from the horizontal force developed by the centrifical action that moves the weights of the clutch. It is interesting to see so many people believe the harder you keep the sleaves apart the harder they will pinch together! Crazy!

How weird is that? What happens of course is the harder you keep the sleaves apart with big springs, the harder it is to push them sheaves together, (which has nothing to do with pinch force,) so why waste that pressure? Just run with enough spring to provide some sort of reasonable RPM engagement, and let the weights pinch the belt. Weight is what pinches the belt in any case, unless of course you have simply too much spring and all the clutch can doo is open a fixed amount at each RPM and sit there spinning. Naturally a fixed opening of the sheaves would not be very effective ........HEY, silly me! That's what you guys are doing right now! Heehee!! No wonder there are so many posts of people doing everything right, but the TRA don't deliver. What doo you expect from tuning like that?

 

[tollen77]

banditpowdercoat;

I think I get where you're going now. Let me know if I screw something up or put words in your mouth.

You're saying that the pull from the secondary is neccesary for the primary to create belt squeeze, right? This is somewhat true, though to a much smaller degree than I think you're getting at. The sheave is going to apply force on a vector perpendicular to the clutch sheave. If you think about the clutch sheave this way you can see what a small percentage of the force vector is pushing the belt up in the primary. Approx 90-95% of the force provided by the sheave is squeeze.

Compare this to the secondary. The sheave is at approx. the same angle as the primary trying to keep the belt from moving lower in the secondary. If there were no secondary spring at all the primary sheave would still place 90-95% of the force it creates towards squeeze, with the remainder to moving the belt higher on the sheave.

The secondary does the same thing. 90-95% of the force from the spring still pushes inward on the belt with only 5-10% of the force apllied to keeping the belt high in the clutch.

So in this way, the secondary does supply some force to keep the belt in the primary, but does not provide any of the squeeze.

I hope I've made sense here. Let me know if I'm off.


.

 

[Throttle Junkie]

I don't see any spring that stiff listed in my book for the P-85. The hardest spring is the Silver/Gold at 168/300, but just about useless for regular riding. The most popular is the Blue at 110/280. The stock TRA starts at 160/230, but spring kits for our ridning area all use 230/390 or 230/410. Hardly comparable, so don't kid a kidder. The TRA uses a spring nearly double the compression of what a comparable Polaris would use in the mountains. The Polaris spring is also smaller in diameter.?

Sounds like you need to update your spring list. That old junk you are mentioning they used to run in the 80's. (400's and 500's.) THere is a black/green that came stock in the 700/800's that is 120/340. Update your list to the 21st century.

Blue 120 300
Dark Blue 120 310
Almond 140 330
Almond/Gold 150 290
Black/White 140 320
Almond/Black 165 310
Almond/blue 150 310
Almond/Red 165 310
Black/Green 120 340

 

[banditpowdercoat]

There does have to be equal and opposite forces between the two clutches to acheive optimum efficiency, no doubt, though I wouldn't go so far as to say the secondary helps provide belt pinch in the primary. It does provide resistance so the belt doesn't just fly out of the primary as soon as you touch the gas, though even if there wer no spring in the secondary, there would still be resistance in the secondary at full shift. The effective pulley diameter only gets so small and then stops.

If the secondary transferred zero load to the primary it would be like having a tug of war with your imaginary friend.

To be honest, I'm not totally following where you're going in your posts. Could you clarify a little?

Im not sure exactly where I was going with it really, It's 3:30 now, I got OFF work at 8AM LOL. Sleds all loaded, greased, ready for Yanks Peak tomorrow.

But i think I was more trying to determine the exact reason for belt pinch. Pinch is a relationship between the Primary sheaves separated distance, and the feedback force from the secondary trying to Pull the belt down and open the primary.
The effect of the arm weight and RPM really doesnt not pinch the belt. it merely trys to close the primary to a set position, determened by the arm weight, Ramp profile fighting the spring resistance. This resultant force is Constant in the primary at a given RPM. Unless acted upon by the secondary.

make sence?

 

[winter brew]

I will TRY to explain why I prefer a bit more spring and weight than some. I have tried soft spring with light weight, along with steeper helix's....in both P-85 and TRA's. In EVERY case I saw similar results from both settups on the flat, like drag racing, BUT when you put the sled on a hill the lighter weight settup was always more inconsistant with maintaining RPM (it would fluctuate more) and the heavier weight settup would show higher and more consistant track speed and stabilized RPM. I agree that both settups may squeeze the belt similarly and produce similar amounts of heat, if you could calculate or measure the force generated it may be similar....BUT the real world results show the difference in the 2 theories and I go with what I find works.
I consider my settups very moderate, I use middle of the road springs and amounts of weight, nothing extreme. Unless it's a turbo

 

[fatguy1]

Hey Yamadoo Polcat!

I think the horse is dead!,

we get the point, you have some kind of weird hate for the TRA. (it's like it took off with your wife)

You don't want to listen to anything anyone else has to say. Hey ya know what, maybe the TRA is not the best clutch. But I spend more time in the mountains than I do on my computer and while in the mountains I've seen all kinds of sleds (pol,cat,yama,doo) pull all kinds of crazy chutes and slopes, and the you guessed it the ski-doos all had TRA clutches.

The TRA is not a big POS like you make it out to be. If you want to start a Who hates the TRA thread please go ahead, other wise please stop wrecking this thread that most of us enjoy reading.

Thanks,

 

[Original Tetonice]

"Primary 160/320 or 130/320 at 6500 rpm isn't much of a comparison..How's about a 130/320 vs 200/320 or 200/350 climbing wot in deep snow where sqweezing the belt is very critical and belt slippage often occures due springs with not enough preload ability ."


The differences would be smaller for 130/320 vs. 160/320 though they would still be there. I agree, to see more of a pronounced difference you'd need to compare springs with larger differences in rate (130/320 vs. 200/320). Tough to compare 130/320 vs. a 200/350 since they have both a different starting and finishing force.


"One way to mitigate the harsh engagment of a spring with a high pre-load would be to have a look at you ramps.....A taller ramp at the engagment point of the ramp = higher engagment. Ramps like 419,427 and 435 at the engagement point are notched and not as tall which help in decreasing the harsh engagment when running heavy primary springs."


This one I'm not sure about and I'd love to hear another opinion on it... my thinking re: taller ramps to cure harsh engagement is taller ramps will simply reduce clamping forces further. Can someone clarify this.

A spring with high initial force and a ramp that diminishes clamping forces should lead to an even higher point of engagement and an even harsher take-off, no???

In your search for an opinion make sure you inquire as to why ramps such as the 419, 427 & 435 have a notch aka engagment notch. Ramps profiles also control the shift character as well. Ramps with a shallow profile shift slow vs ramps with a slight profile shift fast. In deep snow i prefer ramps with a small profile because of the fast clutch shifting = trackspeed and in deep snow trackspeed RULES. The trackspeed is maintained because we run heavy pinweight in the arms to hold and maintain the roller on the correct shift curve of the ramp, "holding the throttle steady helps maintain trackspeed & rpm.....It takes the correct weight of the arm assembly, the correct profile of the ramp and the correct preload of the spring to acheive the correct belt sqweeze in deep powder.... More of an art than a science

Clutching is all about setting up for the riding condition

OT

 

[tollen77]

In your search for an opinion make sure you inquire as to why ramps such as the 419, 427 & 435 have a notch aka engagment notch. Ramps profiles also control the shift character as well. Ramps with a shallow profile shift slow vs ramps with a slight profile shift fast. In deep snow i prefer ramps with a small profile because of the fast clutch shifting = trackspeed and in deep snow trackspeed RULES. The trackspeed is maintained because we run heavy pinweight in the arms to hold and maintain the roller on the correct shift curve of the ramp, "holding the throttle steady helps maintain trackspeed.....It takes the correct weight of the arm assembly, the correct profile of the ramp and the correct preload of the spring to acheive the correct belt sqweeze in deep powder.

Clutching is all about setting up for the riding condition

OT

Well that's interesting and makes a lot of sense, though I sure never thought of it... both you and winterbrew have found that the clutch is less sensitive with an increase in weight, I assume, due to more inertia in the arms.

I'm with you on track speed in the pow and that what works in the real world is what matters. Just trying to understand things a little better.


As for ramps, I can see why you'd want a faster shift pattern in the hills and I suppose for a lake racer or whatever as well. But why would you ever want a ramp that shifted slower... pulling a sleigh????

Thanks for the input OT. If you know of anywhere to point someone to learn a little more about ramps and how they effect clutching, please let me know.

 

[Original Tetonice]

2-UP Touring sleds and entry level trail sleds don't need fast shifting clutches....One of the nice things about the TRA is its broad range and ability to tune to all level of riders.....Perhaps the most challanging of tune is for the mountains/deep snow.

Also keep in mind that mountain sleds make up a very small % of sales....plus the factory also knows regardless of what the provide the mountain segment of riders we will always find a flaw and consider the stock setups garbage.....My friends trail ride in michigan and they never even open the hood.

By the way i believe the TRA is "very sensative" . If not it would not respond to so many setups.

OT

 

[YamaDoo PolCat]

2-UP Touring sleds and entry level trail sleds don't need fast shifting clutches....One of the nice things about the TRA is its broad range and ability to tune to all level of riders.....Perhaps the most challanging of tune is for the mountains/deep snow.

Also keep in mind that mountain sleds make up a very small % of sales....plus the factory also knows regardless of what the provide the mountain segment of riders we will always find a flaw and consider the stock setups garbage.....My friends trail ride in michigan and they never even open the hood.

By the way i believe the TRA is "very sensative" . If not it would not respond to so many setups.

OT

Exactly OT. BRP likes to advertize their sleds with lots of mountain pictures, because taking a picture of a sled on the trail is boring. But the % of sleds sold to people that know the mountains is a real small part of the market. Plus there are so many novice "experts" yapping that BRP really doesn't know how bad the TRA is in the mountains. You can't really tell the dummies from the tuners on sites like this, so BRP could be a little confused about how real the limitations on the TRA are in a vertical environment.
Plus there is a lot of blind brand loyalty, like people that never had sex with anyone other than their mommy. Some people just don't know any better and think you are a heretic for speaking out.
I have no problem believing that the TRA may be as good as any other clutch on the trail, but that's just because I don't spend enough time on trails to know any different.
I wonder how long it is before BRP comes out with a new primary? You only have to look at the problems people are having with this one component to wonder what's up.

 

[fatguy1]

I find it funny that you speak of how real the limitations of the TRA are in the vertical enviroment, and then post a picture of your sled up on Alexander. (Is that your sled?)

Last spring I went there with two M1000 cats (with minor mods) and at the lower elevations on the way in they were beating me on every highmark we made by 20-30 feet. But once we were up in the area to the left (not shown in the picture) were it's 9000' everyone (the cats, the doos, the yama) was not pulling there peak RPM. I just smiled as I opened up my clutch cover and turned my quick clickers up one setting, all the sudden I was out marking them by 15-20 feet.

I'm not sure how I could of done that with a P-85 or a Polar???

 

[YamaDoo PolCat]

I find it funny that you speak of how real the limitations of the TRA are in the vertical enviroment, and then post a picture of your sled up on Alexander. (Is that your sled?)

Last spring I went there with two M1000 cats (with minor mods) and at the lower elevations on the way in they were beating me on every highmark we made by 20-30 feet. But once we were up in the area to the left (not shown in the picture) were it's 9000' everyone (the cats, the doos, the yama) was not pulling there peak RPM. I just smiled as I opened up my clutch cover and turned my quick clickers up one setting, all the sudden I was out marking them by 15-20 feet.

I'm not sure how I could of done that with a P-85 or a Polar???

Here a picture with the hood open. No TRA. The sled is stock except for a can. I have also ran the TRA and the Comet 109. The Polar is by far the best.

I probably know the guys on the 1000 cats if they are from BC. There's an independent varification for you. Those guys know when I show up with a TRA or the Polar primary installed. The Polar puts the 800R in with their class. It rocks!

When I run the TRA I end up just giving the Cats my spare fuel, because the TRA is so disappointing. It's like running a sled that just ran out of NOS.

I have found the Polar holds the RPM better than any primary I have ever seen. I run it with no changes from 3,200 feet to 9,500 feet and the RPM is rock solid until 9,000 feet. Then I noticed it was down about 100 RPM to 8150 RPM. So I don't bother tuning for a drop like that for the amount of time we are at that altitude.

 

[winter brew]

Any pics of the polar after it exploded....last year or the year before? Just trash talkin, hopefully it works good for you and proves durable this time.

 

[Original Tetonice]

I've always felt the TRA primary was a descent clutch and easy to tune once you understood how to blend the ramp profile, weight of the arm assembly and spring. The issue in the mountains above 9000' was the secondary and getting the torque senseing secondary to work in harmony with the primary above 6000 rpm.....My answer to that even with the best setup i can throw at the clutch was to be a better manager of the throttle knowing full well that if i backed off the throttle the arm/roller/pinweight assembly would fall off the power curve of the ramp and would than have to recover the LOST RPM and TRACK SPEED.

And there is still the heat, just ask TurboAl he packs a gun to check for heat spots onthe TRA which just don't seem to go away regardless of how you vent the clutch for deep powder mountain riding.

OT

 

[fatguy1]

Hey YamaDoo Polcat!

Don't take anything I say personally.... I get the feeling we got off on the wrong foot. (my coment about the TRA and your wife was in bad taste).

I guess what I'm trying to say is summed up best by OT, I too have found the TRA to be a DESCENT clutch. I don't have any blind faith to any brand and have even rented a stock RX-1 from time to time just to go riding when my sled has been down. I'm happy for you that the Polar is flawless, I have never ran one. But at the same time I'm not going to toss my TRA in the dumpster and take up dialing in a new set up. Who knows hopefully this winter I will run into you up at alexander and maybe based on your sleds performance I will be a new polar fan, then rush right out and buy one. Until then I'm just trying to learn for others posting on snow west as to what works for them(TRA set ups) in thier areas and thier riding styles.

I like your pics of Alexander, we all need to stick together to keep that area open regardless of what brand of sled/primary we run.

cheers,

 

[YamaDoo PolCat]

Hey YamaDoo Polcat!

Don't take anything I say personally.... I get the feeling we got off on the wrong foot. (my coment about the TRA and your wife was in bad taste).

I guess what I'm trying to say is summed up best by OT, I too have found the TRA to be a DESCENT clutch. I don't have any blind faith to any brand and have even rented a stock RX-1 from time to time just to go riding when my sled has been down. I'm happy for you that the Polar is flawless, I have never ran one. But at the same time I'm not going to toss my TRA in the dumpster and take up dialing in a new set up. Who knows hopefully this winter I will run into you up at alexander and maybe based on your sleds performance I will be a new polar fan, then rush right out and buy one. Until then I'm just trying to learn for others posting on snow west as to what works for them(TRA set ups) in thier areas and thier riding styles.

I like your pics of Alexander, we all need to stick together to keep that area open regardless of what brand of sled/primary we run.

cheers,

We are just waiting for a letter from BC Parks regarding some Kakwa Park issues they agreed to look at, from our meeting on PG in April. We werte looking for opening timing and elevation changes. Next year is the start of a new review for BC Parks management and planning, so the pressure is always on. There is some real impact from the summer users happening in the park, especially around Kakwa lake, and I can't understand why BC Parks is OK with that, but not OK with people on sleds.

Like Brew says I am the BC mountain test pilot for the three post Polar and it has changed lots. As I said the Polar is like riding with NOS, so I was entirely willing to run it to death. I killed it a couple times but it's worth waiting for. It is amazing what it does for the Rotax 800R performance. What we doo to make BRP look good, eh?

I like your comment about the TRA being a DESCENT clutch, but we need a CLIMB clutch! Heehee!

Here's an interesting picture for you. Ever wonder what would happen if you slipped and didn't make the traverse around Sir A to the base of the Spire? It can get windy and icy right there. You are at about 8,400 feet and the McGregor is at 3,800 feet. Thought you would like that pic!