Ramps in the TRA, how they work and how they effect performance.

[YamaDoo PolCat]

I realize that. What I meant is that since a CVT has two sheaves that are on each side of the belt and a washing machine has just a pulley(with not much for sides, other than a little ridge) it's different. I guess I didn't explain my point very well.

Like I said I guess I didn't explain my point very well. What I meant is that since a CVT has two sheaves that are on each side of the belt and a washing machine has just a pulley(with not much for sides, other than a little ridge) it's different. Yes I do know how they grip the belt but your assessment that slipping of the belt plays no part in the heat generated is wrong. I guess you could say overtension in the secondary is causing the belt to slip in the primary(or vice versa the example). It could just be the fact that there's not enough weight(or in the case of the TRA, the correct roller or clicker position) in order to balance out the tension between the two clutches. What I am getting at is that you can't just say it's overtension, every sled and setup is different.

FYI I ride a Polaris at the moment.

Hey dude, we already have OT on here for entertainment! Do you mean to say that a pulley is not a sheave because it is smaller? You are on a pretty lively forum here and someone is going to call that silly. Heehee!

Now about that statement that overtension in the secondary is causing the belt in the primary to slip. You want a minute the think about that? Were you thinking that the secondary is stickier and the belt got stuck in there? The tension (and side pressure) has to be the same in both pulleys at the same time, you understand that? You doo realize that if the primary weights cause more pressure on the belt in the primary that the belt will squirt up in the pulley to equalize the tension again, don't you? And the same in the other direction. It how clutches work.

It's interesting that you run a Polaris. I used to never think about the primary clutch either. You picked a good forum to learn clutch principles as everyone that has a Ski-doo has a question about why the TRA doesn't work all the time. Biggest subject on all Ski-doo forums.

 

[DaveB]

 

[winter brew]

Thanks Dave....that pretty much summarizes this thread.

 

[banditpowdercoat]

The REV is a great sled. As long as you are a flatland rider you will like the TRA, but if you ride mountains you are in for a bit of a disappointment. Not in the sled, just the TRA. I never ran the TRA in the past as people had warned me against it, but when I bought my first 04 REV I had my first introduction to the TRA in the mountains.

Like you I had certain expectations of the primary, but the TRA is very limited in what you can doo with it in the mountains. Took me a few years and a waste of money, but I had to try. Anyway I run an aftermarket primary now on my 07, and you are just going to have to decide what you will put up with, and the level of performance you need. The TRA lives under the bench now. I keep it for a spare just in case, because a ride on the TRA is better than no ride at all! And that's as good as it gets.

It's not ALL that bad YDPC. Sure the TRA has some issues. Especially with up Mtn guys. BUT, I still see more TRA sleds up the hills than ANY other brand.

 

[DaveB]

Has anyone got some 415 (stock 08 TRA XP) ramps they would like to part with? Preferably an Alberta boy.....

 

[shortstop20]

Now about that statement that overtension in the secondary is causing the belt in the primary to slip. You want a minute the think about that? Were you thinking that the secondary is stickier and the belt got stuck in there? The tension (and side pressure) has to be the same in both pulleys at the same time, you understand that?

Yes I do realize that the tension has to be the same in both clutches for proper operation of the clutches, I'm just giving an example where it would not be and what a person might do to correct it. Do not turn my one example into a generalization. You aren't trying to infer that every sled has the same tension/belt pinch, whatever you wanna call it between the two clutches are you?

You doo realize that if the primary weights cause more pressure on the belt in the primary that the belt will squirt up in the pulley to equalize the tension again, don't you? And the same in the other direction. It how clutches work.

LOL, that's exactly what i was getting at in my post. That the tension on the belt between the two clutches has to be the same in order for the clutching to be as efficient as possible. Otherwise there will be some efficiency losses happening. I know how a clutch works.

It's interesting that you run a Polaris. I used to never think about the primary clutch either. You picked a good forum to learn clutch principles as everyone that has a Ski-doo has a question about why the TRA doesn't work all the time. Biggest subject on all Ski-doo forums.

So now you're inferring that I don't think about how the primary clutch works? I know plenty already but I can still learn just like everyone else, I'm certainly not gonna try and learn from a guy that honestly thinks the same clutch setup delivers maximum efficiency over an 8K foot elevation change. I change my clutching setup according to elevation like most people that want maximum efficiency. You may think you're dealing with some bozo kid that doesn't know jack ****, but you are not. My clutches run cool to the touch from 1000 ft. all the way to 13,000 ft. with setups I have come up with all by myself, but yeah I don't know what I'm doing.

 

[winter brew]

Has anyone got some 415 (stock 08 TRA XP) ramps they would like to part with? Preferably an Alberta boy.....

413? or 415's? '08 was 413. 415 is '07 and older Rev 800.

 

[banditpowdercoat]

One thing you gotta ask yourself is "why shouldn't a clutch be the same from 0Ft to 10000Ft?" Why does the TRA NEED adjusting as we change elevation.

OK Lets talk out what changes with elevation.

Does the spring change it's force between the elevations?
No
Does the Flyweight force change at XXXXRPM between the 2 elevations?
No
Does anything in the track, suspension change between elevations?
No
Does the engine HP change between elevations?
YES

OK so engine HP changes, It gets less, at higher elevations. Now lets dissect a climb. and what SHOULD happen

You tape the throttle to the bar and point the ski's skyward.
Engine races to 8150, and holds there. Clutches start to shift out all is good.
Clutches are shifted out as much as they are going to, engine still running 8150.
Now we climb higher, clutches are the same, but engine HP is falling. Load on track is the same, were still climbing the hill.
Same load on track, but lower engine HP, RPMs start to drop. Here's where it gets interesting,
RPM drops, whats SHOULD happen? clutches should backshift, right? But do they? If they did, the RPM would pull back up to 8150 and all would be good...

This should all happen seamlessly, you shouldn't even notice a fall in RPM. But again, we do. And usually the fall in RPM is permanent, untill we change something. IE reduce elevation to bring HP back up, change clickers to adjust clutch to handle lower HP.

Now, and I have no wat to test, or prove this but, could all this be because of the internal Friction inside the TRA and the secondary? I mean, engine RPM has to fall, or load HAS to change for the clutches to react. But How much of a change before they do react? If the amount needed exceeds the engines power curve and ability to regain rpm's??
You all know what sticky buttons do in a button secondary. Why do they all use rollers now?

In theory, the TRA shouldn't have any more internal friction in it than a P-85, or a Polar. BUT, running the heavy springs, and heavy pinweight will put more force on the rollers. Just like you can push a car by hand, but try to push a semi truck... They both are on tires, but one has more force on the ground.

Thing I'm trying to get at is maybe were all looking in the wrong area's? We keep adding weight, adding springs. More squeeze, more pinch. maybe more is not better?? How many grams is an average P-85 weight? Are they the same as the TRA rollers and arm? I know the P-85 rollers are stationary(dont even start OT) But the Polar uses a arm like the TRA??? Wait, the polar, the arm pivots from the inside, and the TRA has the pivot on the outside of the clutch???



Just some more stuff to think about in our allready clutter'd melon's

 

[DaveB]

413? or 415's? '08 was 413. 415 is '07 and older Rev 800.

Ya...WyoTA pointed out the error of my request as well...LOL. Now I don't know what I want. hahaha. I think I'll have a beer though.

 

[tollen77]

OK, first off, I apologize to all those annoyed with me in Winterbrew's "Attn Clutching Gurus" thread. I've been gone the last couple days and came back and found three pages of arguments re: the ramps moving with OT. I had a similar argument with him in the other thread, some people gave me sh!t and I got annoyed. I now see, they were right. I was wrong.... way wrong.

All those in favour of ignoring every single post OT makes from here on out, raise your hand.... :raises-hand:

Hey dude, we already have OT on here for entertainment! Do you mean to say that a pulley is not a sheave because it is smaller? You are on a pretty lively forum here and someone is going to call that silly. Heehee!

Now about that statement that overtension in the secondary is causing the belt in the primary to slip. You want a minute the think about that? Were you thinking that the secondary is stickier and the belt got stuck in there? The tension (and side pressure) has to be the same in both pulleys at the same time, you understand that? You doo realize that if the primary weights cause more pressure on the belt in the primary that the belt will squirt up in the pulley to equalize the tension again, don't you? And the same in the other direction. It how clutches work.

It's interesting that you run a Polaris. I used to never think about the primary clutch either. You picked a good forum to learn clutch principles as everyone that has a Ski-doo has a question about why the TRA doesn't work all the time. Biggest subject on all Ski-doo forums.

Next up, had to address this as I don't want anyone new to the TRA to get confused. YDPC had highlighted the folloowing;

"overtension in the secondary is causing the belt in the primary to slip."

and then went on to say this doesn't happen. Let me assure you folks, it does. But lets go back to the washing machine belt for a minute.

Newton's Law (can't remember which number is was) For every action there is an equal an opposite reaction.

The washing machine pulley is basically a groove for the belt to wedge itself into. The more you pull the belt into the groove, the more force it exerts on the sides of the pulley. Newton's first law states they must push back with the same force. If they didn't, the pulley would explode and you're dirty clothes would start to pile up. It's this contact area on the sides of the belt that are what allows the washing mashine moter to impart force on the rest of the machine.

In the TRA, as RPM increases the sheaves begin to close and squeeze the sides of the belt - more squeeze than is required to hold the belt in the same position. Let's call this over-squeeze, though I'm sure there is a better name for it. A washing machine pulley does not have the ability to impart 'over-squeeze' as the distance between it's two 'sheaves' is fixed. Any increase in side force comes as a direct result of increased belt tension. The TRA though continues to squeeze the belt harder the faster it spins which pushes the belt up higher between the sheaves, making effectively a bigger drive sprocket.

Now imagine the secondary (QRS) has only a pen spring in it and so cannot squeeze the belt very hard. Without this clamping pressure, the belt would simply be pulled down further and further into the QRS. The QRS wouldn't spin, the jackshaft wouldn't spin and your sled would go no where.

Now for case # 2, imagine that instead of the pen spring you have a coil over spring from your front shock. Now, as RPM increases, the TRA tries to close but it can't overcome the force provided by your shock spring in the secondary. One of two things happens... either the TRA spins but the belt simply slips between the sheaves (creating heat) or the TRA graps really hard on the belt and the engine lugs since it doesn't have enough power to pull the belt down in the QRS.

There's much more to this and I'd love to get into it, but unfortunately I've gotta go. Bought a new house and I'm moving this morning.... what fun, grrrrr.

Anyways, I'm sure you'll disagree with this YDPC so leave your response and I'll get to it Monday.



.

 

[ReTodd]

Now about that statement that overtension in the secondary is causing the belt in the primary to slip. You want a minute the think about that? Were you thinking that the secondary is stickier and the belt got stuck in there? The tension (and side pressure) has to be the same in both pulleys at the same time, you understand that? You doo realize that if the primary weights cause more pressure on the belt in the primary that the belt will squirt up in the pulley to equalize the tension again, don't you? And the same in the other direction. It how clutches work.

I have to agree, the only way the primary is creating belt heat from slipping is from the secondary being too soft causing the primary to want to shift out further but instead slipping. Any other point in the gear curve and the secondary tension=primary tension. Maybe that is why people are saying you should use a stiffer secondary. If the secondary was over-tensioned, the primary would not shift out as far/secondary would not shift out as far and you would be stuck in a lower gear. We are pretty sure that isn't what is happening hear.

However, I have marked my primary and still had plenty of marker left until I went with a stiffer primary spring and more weights while the secondary was shifting out most of the way.

Rt

 

[fatguy1]

Hey! anyone seen Joey?... I haven't seen him in this thread since about page 4 or 5. I think that's pretty much when everyone kinda gave up on the subject of how the ramps in the TRA effect performance.

The trash talk is still very entertaining! YDPC comes up with the funniest stuff, I asphalt race in the summer and seen the polar clutch on the jr. dragsters comment coming from a mile away. too funny

YDPC you make mention of climbing an area you call the box? is that near Mt. Sir Alexander?

 

[shortstop20]

I have to agree, the only way the primary is creating belt heat from slipping is from the secondary being too soft causing the primary to want to shift out further but instead slipping.

Define what you mean by "too soft".

Any other point in the gear curve and the secondary tension=primary tension.

If the tension/belt pinch/grip, whatever you wanna call it is equal, then exactly how is the excess heat in the clutch created?

 

[Dynamo^Joe]

The 413, 414, 415, 419 are all the same ramp, made out of a 414.

The 419 produces highest engagement because of a notch then transition to a 414.

The 415 is less aggressive than the 413, 414 (in this order) Producing highest rpms under sustained throttle position.

The 413 is more aggressive than the 415 and produces lower rpms than the 415 but higher rpms than the 414. (under sustained throttle position)

The 414 is the most aggressive, produces lowest rpms under full throttle in low ratios, the clutch pushes hardest. (under sustained throttle position)

Depending on gearing you can safely say that around (lower gearing)30mph~(higher gearing)40mph track speed all the ramps blend into the same curve right to full shift.
Remember the picture comparing the 441 vs 413 and the "ramp angle" at the start of the shift?
The 441 is nearly like the 414 when you put them up side by side...the 414 has slight higher angle, merely a few thousanth.

 

[banditpowdercoat]

Just got to say, went up to the hills today, not alot of snow, but a heavy base. gOOOD enough to test some theorys and YES, I have figured some stuff out. I need a lil lighter pins, 1/2 gram maybe? 200 RPM, AND more helix, less preload??? |Cluthces even temp on pulls, but lacking RPM above 6500Ft

 

[Original Tetonice]

Theres a reason many of you complain about your TRA and how it can't this & can't that. Face the FACTS many of you are NOVICE when it come to clutching the TRA. An example of that is how many of you are frazzled over the FACT that the TRA ramps MOVE.

By the way its very clear to me that many of you have never taken the TRA primary apart. If you have you would clearly see that the ramp move.

OT

 

[Original Tetonice]

The 413, 414, 415, 419 are all the same ramp, made out of a 414.

The 419 produces highest engagement because of a notch then transition to a 414.

The 415 is less aggressive than the 413, 414 (in this order) Producing highest rpms under sustained throttle position.

The 413 is more aggressive than the 415 and produces lower rpms than the 415 but higher rpms than the 414. (under sustained throttle position)

The 414 is the most aggressive, produces lowest rpms under full throttle in low ratios, the clutch pushes hardest. (under sustained throttle position)

Depending on gearing you can safely say that around (lower gearing)30mph~(higher gearing)40mph track speed all the ramps blend into the same curve right to full shift.
Remember the picture comparing the 441 vs 413 and the "ramp angle" at the start of the shift?
The 441 is nearly like the 414 when you put them up side by side...the 414 has slight higher angle, merely a few thousanth.

This is the kind of confusion that im talking about.....The 413,414,415,419 are all the same ramps made out of a 414

But But But the 419 produces a higher engagement because of the notch

But But But the 415 is less aggressive, blah,blah,blah

But But But the 414 is most aggressive , blah,blah,blah

But But But the 441 is most aggressive, blah,blah,blah

Folks there are similar ramps YES the same NO. The only thing the same is the steel there made from

 

[banditpowdercoat]

I think I heard a squeak or something? Any of you hear that???? No, I didn't think so, Musta been the wind

 

[Original Tetonice]

I think I heard a squeak or something? Any of you hear that???? No, I didn't think so, Musta been the wind

I heard the squeak as well, aren't you one of the 3 Blind Mice ?

OT

 

[banditpowdercoat]

You just can't take a hint, can you Please GO AWAY AND NEVER POST IN THIS THREAD AGAIN