P to the 22 roller bearing delete…..

[RBalazs]

Maybe that has something to do with why they say the P85 on a Boost/9R performs better off the bottom than the P22….you actually get to start off in 1st gear versus 2nd.

Quite possibly. Thats why Burandt is always preaching belt height/deflection is so important. The roller bearing delete very well might get the “1st” gear better and bottom end of the boost.

I really can’t find anymore information on it, even on Kurts website which leave alot desired, but I get it. Small shop in Seeley….

I’m not getting too concerned until I see how my 2025 boost compares to the 22-24.

 

[carbontj]

Maybe that has something to do with why they say the P85 on a Boost/9R performs better off the bottom than the P22….you actually get to start off in 1st gear versus 2nd.

Thats a fact....

 

[carbontj]

watched the video...good idea...I am still not sure it will help with the clutch bolts loosening and our falling off...you still tighten to the sleeve then the spider, not to the fixed sheave to self....I like how they said tighten to 140ft lbs. been saying that for a couple years...I will be watching very closely to see if this helps....

the only thing I did'nt see, did he mention you wold need to put the defection bolt back in the secondary?

 

[Madtown]

the only thing I did'nt see, did he mention you wold need to put the defection bolt back in the secondary?

Yes you install the deflection adjustment bolt into the secondary just like a P85.

 

[JeffBrines]

Few things I think are worth putting into this thread.

1) If you really want to have a lower "starting gear", a gear down kit is the best way to materially do this. A slightly smaller OD bearing delete isn't going to matter enough, especially when you account for the fact your secondary is going to sit slightly shifted out because you now have to run a set screw.
2) The reason you want to run tight belt deflection has a lot more to do with belt slip and how the motor is loaded, not the "effective starting gear".

 

[mountaincat 800]

Few things I think are worth putting into this thread.

1) If you really want to have a lower "starting gear", a gear down kit is the best way to materially do this. A slightly smaller OD bearing delete isn't going to matter enough, especially when you account for the fact your secondary is going to sit slightly shifted out because you now have to run a set screw.
2) The reason you want to run tight belt deflection has a lot more to do with belt slip and how the motor is loaded, not the "effective starting gear".

I guess were going to have to agree to disagree. Not arguing the belt slip/grab point but with being in a lower starting gear in effect gives more torque which will reduce belt slip.

 

[JeffBrines]

I guess were going to have to agree to disagree. Not arguing the belt slip/grab point but with being in a lower starting gear in effect gives more torque which will reduce belt slip.

How are you actually in a lower starting gear? Explain this.

Lets say the OD of the "delete" is 5% smaller. This means the belt will engage the sheave at a point that is just a few millimeters below where it currently grabs. Run the math on this. Calculate the entire sheave shift out distance, then calculate the change. This is the "lower gear" you are now starting in

BUT WAIT

Because you got rid of the bearing and have to run more deflection (otherwise your belt will squeal), your secondary is now starting in a *higher* gear due to the fact you have to now run a set screw that "shifts out" your secondary a hair for deflection. My wager is not only does this cancel out, but you are actually in a HIGHER gear to start despite a marginal reduction on the primary side.

This is snake oil. The only reason to delete the bearing is because they do in fact fail frequently. $40 for a new one or you can do what Kurt is suggesting. There is a reason the comments are off. This doesn't pass the sniff test.

 

[mountaincat 800]

Sorry I can't run the math on that. (Didn't go to school.) I am only going off the difference in belt height in the two pictures that FT posted.
In my opinion that is quite significant. I'm not buying into the bearing delete either just observations. If you look at the two pictures, the lower the belt is in the secondary the more open it is before engagement.

 

[J270wsm]

How are you actually in a lower starting gear? Explain this.

Lets say the OD of the "delete" is 5% smaller. This means the belt will engage the sheave at a point that is just a few millimeters below where it currently grabs. Run the math on this. Calculate the entire sheave shift out distance, then calculate the change. This is the "lower gear" you are now starting in

BUT WAIT

Because you got rid of the bearing and have to run more deflection (otherwise your belt will squeal), your secondary is now starting in a *higher* gear due to the fact you have to now run a set screw that "shifts out" your secondary a hair for deflection. My wager is not only does this cancel out, but you are actually in a HIGHER gear to start despite a marginal reduction on the primary side.

This is snake oil. The only reason to delete the bearing is because they do in fact fail frequently. $40 for a new one or you can do what Kurt is suggesting. There is a reason the comments are off. This doesn't pass the sniff test.

Why are you running more deflection?? Wouldn’t the belt be able to drop lower in the primary meaning it can/will ride higher in the secondary??
Haven’t watched the video….did they have to do any shimming of the spider after removing the bearing?

 

[RBalazs]

Why are you running more deflection?? Wouldn’t the belt be able to drop lower in the primary meaning it can/will ride higher in the secondary??
Haven’t watched the video….did they have to do any shimming of the spider after removing the bearing?

It would be good for you to watch the video. It is hard to tell in the video, but I would say the belt drops minimally into the primary. Kurt does talk about it being a good quarter inch smaller than the existing roller bearing, but it doesn’t really show clear whether or not that is accurate.

As far as shimming the spider, well, if you watch the video, it will make sense. He takes off the roller bearing and slides another sleeve over that which fits into the newly pressed bearing in the spider.

 

[RBalazs]

I just got off the phone with Kurt. He said that the belt does ride lower in the primary 3/16 of an inch and although it’s not as low as the P 85 would be says it is significant enough that the belt is riding higher in the secondary. He said you can’t get it as high as we run the P 85s but he says in best case the ribs the belt are just above the secondary.

He said that he has a lot of guys running this kit, including Brett Turcotte and Dan Adams. Not that that says anything but he’s been testing it for the last year and a half and with the uncertainty of if Polaris was going to be changing the 2025 clutches he didn’t bring in a lot of inventory. He’s going to be riding with Ryan Harris, and going to do a snowest blog for the product.

One of the biggest things that it does is lower belt temperatures, the belt engagement is actually a lot smoother, more like the P85. Where on the P22 the track had to be moving about 11 to 12mph before full engagement, the delete kit allows the track to be at 6 or 7 mph. Makes for a much more responsive boost in the trees. He also mentioned that he feels that the qd2 boost are geared too high and that’s why he suggests a gear down kit and the delete kit. I know that I have some buddies that their boosts run at 8650 and he said that’s because they are geared way too high from the factory and anything over 8500 is losing top end power band. He said 8350 to 8450 is money for those sleds and thus the reason for the gear down kit.

I’d be happy to get any more answers, to questions that you guys might have.

 

[RBalazs]

How are you actually in a lower starting gear? Explain this.

Lets say the OD of the "delete" is 5% smaller. This means the belt will engage the sheave at a point that is just a few millimeters below where it currently grabs. Run the math on this. Calculate the entire sheave shift out distance, then calculate the change. This is the "lower gear" you are now starting in

BUT WAIT

Because you got rid of the bearing and have to run more deflection (otherwise your belt will squeal), your secondary is now starting in a *higher* gear due to the fact you have to now run a set screw that "shifts out" your secondary a hair for deflection. My wager is not only does this cancel out, but you are actually in a HIGHER gear to start despite a marginal reduction on the primary side.

This is snake oil. The only reason to delete the bearing is because they do in fact fail frequently. $40 for a new one or you can do what Kurt is suggesting. There is a reason the comments are off. This doesn't pass the sniff test.

But think of this…

With the delete kit, let’s say the belt is just slightly lower in the primary because that’s what it is so that we can still have some belt deflection, and no squealing. It will be in that case, slightly higher in the secondary, not all the way up like a P85 would be, but higher than it was before.

All of this does “gear down” the sled slightly.

Just like a motorcycle, the more teeth in the back sprocket, similiar to higher in the secondary the lower the gear. Again like a motorcycle, you go up one tooth in the front sprocket, it’s like installing a three tooth larger sprocket in the rear. That only creates a doggie, bottom end, but a better end.

 

[Griff]

If you are talking to him again, ask Kurt to calculate the shift ratio at idle given what he has observed with the @3/16 inch change in diameter. That could be compared to factory set up to quantify the change.

 

[RBalazs]

If you are talking to him again, ask Kurt to calculate the shift ratio at idle given what he has observed with the @3/16 inch change in diameter. That could be compared to factory set up to quantify the change.

So, to clear up the actual diameter of the stock roller bearing is (1.9895) and the new delete kit shaft insert is (1.739) So, 1/4” smaller diameter.

This means with a smaller primary shaft, they belt can ride about 3/16” higher in the secondary.

Stock p22


Belt with roller delete kit

Essentially gearing the sled down on the secondary side and the primary side. Think smaller dirt bike front sprocket drop a tooth, awesome bottom end. Or leave stock and add 3 teeth to the rear. Both make stronger bottom end.

This means engagement is between 3600-3800 if you roll onto the throttle. Shoot, if you can get the track spinning 3 inches before you slam the throttle, that makes a huge difference between likely trenching and getting stuck versus getting up on the snow and going.

That help?

 

[JeffBrines]

Oh man. This reeks of snowmobile snake oil for sure.


Some Assumptions...

1) The lower the belt sits in the primary, the lower the gear ration.
2) The lower the belt sits in the secondary, the higher the gear ratio.
3) The bearing the P22 has stock allows for no deflection.
4) With no deflection the belt rides as high on the secondary as is possible ("lowest" gear)
5) By reducing the diameter 1/4" you start the belt 1/8" lower in the sheave.
6) The entire sheave surface is 3" -
7) (1/8) / 3 = 0.041
8) This means you are effectively "gearing down" ~4.1%
9) You are going to give most, if not all, of this 4.1% up when you set your belt deflection up to not squeal. Maybe you end up with a 1-2% gear reduction. MAYBE. That is not material when there are *so* many other variables in the clutching equation. (belt condition, spring condition, spring rate, weight profile etc etc etc).

As to the whole heat argument, how is he measuring this? Is he letting the sled sit at idle and measuring belt temp at the sheave? Is he riding it? Was the roller bearing in good shape when he took the measurements?

TL;DR, if you want to lower your gear ratio, buy a gear down kit.

Side note, I've roached those bearings, so I understand the real desire behind the kit here. But lets just be clear as to what it is/does. It gets rid of the P-22 roller bearing that is prone to failure and allows you to retain a similar "starting gear". That's it.

 

[JeffBrines]

EDIT: I just saw you suggest the belt rides higher in the primary? How? I don't get that. The stock P-22 does not require a set screw at all so should be running at the the highest possible spot on the sheave. Is it because the smaller diameter creates belt deflection and it essentially "floats" atop the secondary? Interesting, but now I am curious if you have enough surface area to engage the secondary without slipping.

One other thing I forgot, less deflection = less slip. Less slip = more load on the turbo faster = better performance.

I've run a lot of turbo sleds and the number one thing I used to do to my sled or a customers was decrease belt deflection until it was *almost* squealing for best performance. There is a reason Polaris wanted the roller bearing in the P-22 for the boost (despite the engineering flaws with that clutch).

 

[RBalazs]

Oh man. This reeks of snowmobile snake oil for sure.


Some Assumptions...

1) The lower the belt sits in the primary, the lower the gear ration.
2) The lower the belt sits in the secondary, the higher the gear ratio.
3) The bearing the P22 has stock allows for no deflection.
4) With no deflection the belt rides as high on the secondary as is possible ("lowest" gear)
5) By reducing the diameter 1/4" you start the belt 1/8" lower in the sheave.
6) The entire sheave surface is 3" -
7) (1/8) / 3 = 0.041
8) This means you are effectively "gearing down" ~4.1%
9) You are going to give most, if not all, of this 4.1% up when you set your belt deflection up to not squeal. Maybe you end up with a 1-2% gear reduction. MAYBE. That is not material when there are *so* many other variables in the clutching equation. (belt condition, spring condition, spring rate, weight profile etc etc etc).

As to the whole heat argument, how is he measuring this? Is he letting the sled sit at idle and measuring belt temp at the sheave? Is he riding it? Was the roller bearing in good shape when he took the measurements?

TL;DR, if you want to lower your gear ratio, buy a gear down kit.

Side note, I've roached those bearings, so I understand the real desire behind the kit here. But lets just be clear as to what it is/does. It gets rid of the P-22 roller bearing that is prone to failure and allows you to retain a similar "starting gear". That's it.

Thanks for all that You’re correct that there are tons of variables..

I never suggested that the belt rides higher in the primary, the belt rides higher in the secondary simply because it can be adjusted with their added set screw. I will go back and see if I mixed that up and if I did I’m sorry because that’s not what I intended.

Heat- He rode a “deleted” 165 boost side by side to another “stock” 155 boost. After a handful of steep pulls, his deleted clutch was usually 1 -2 degrees cooler than the stock 155 belts, when measured at the top of the the climb

I’d took that he recommends the gear down kits for sure. Regardless of the delete.

You may be correct. At the end of the day, it makes the roller bearing go away, it reduces heat and has better engagement. All good things, but at what cost

 

[RBalazs]

EDIT: I just saw you suggest the belt rides higher in the primary? How? I don't get that. The stock P-22 does not require a set screw at all so should be running at the the highest possible spot on the sheave. Is it because the smaller diameter creates belt deflection and it essentially "floats" atop the secondary? Interesting, but now I am curious if you have enough surface area to engage the secondary without slipping.

One other thing I forgot, less deflection = less slip. Less slip = more load on the turbo faster = better performance.

I've run a lot of turbo sleds and the number one thing I used to do to my sled or a customers was decrease belt deflection until it was *almost* squealing for best performance. There is a reason Polaris wanted the roller bearing in the P-22 for the boost (despite the engineering flaws with that clutch).

Don’t shoot the messenger You did see that they are adding an adjustment screw in the secondary to adjust deflection, and therefore they can get the belt up higher in the secondary, with the gained 1/8” more play in the primary. No!?

And he didn’t disagree at all that the P22 isn’t a great clutch. It’s lighter than the P 85 and it just has a “couple” issues.

 

[rmk8001]

How are you actually in a lower starting gear? Explain this.

Lets say the OD of the "delete" is 5% smaller. This means the belt will engage the sheave at a point that is just a few millimeters below where it currently grabs. Run the math on this. Calculate the entire sheave shift out distance, then calculate the change. This is the "lower gear" you are now starting in

BUT WAIT

Because you got rid of the bearing and have to run more deflection (otherwise your belt will squeal), your secondary is now starting in a *higher* gear due to the fact you have to now run a set screw that "shifts out" your secondary a hair for deflection. My wager is not only does this cancel out, but you are actually in a HIGHER gear to start despite a marginal reduction on the primary side.

This is snake oil. The only reason to delete the bearing is because they do in fact fail frequently. $40 for a new one or you can do what Kurt is suggesting. There is a reason the comments are off. This doesn't pass the sniff test.

Wow. Do you know how a cvt system works you know infinite gears so yes a few mm does make a difference. The lower you can get in the primary and the higher you are in the secondary is gonna get you into the lowest “gear” possible. Go look at a bicycle it will all make sense

 

[turboless terry]

Thanks for all that You’re correct that there are tons of variables..

I never suggested that the belt rides higher in the primary, the belt rides higher in the secondary simply because it can be adjusted with their added set screw. I will go back and see if I mixed that up and if I did I’m sorry because that’s not what I intended.

Heat- He rode a “deleted” 165 boost side by side to another “stock” 155 boost. After a handful of steep pulls, his deleted clutch was usually 1 -2 degrees cooler than the stock 155 belts, when measured at the top of the the climb

I’d took that he recommends the gear down kits for sure. Regardless of the delete.

You may be correct. At the end of the day, it makes the roller bearing go away, it reduces heat and has better engagement. All good things, but at what cost

1 to 2 degrees is in the margin of error. Meaning not a nickels worth of difference. Ride it the way it is or get rid of it altogether. Why put money in a turd.