TRACK PITCH DISCUSSION AND PADDLE COUNT

[mountainhorse]

Good topic for discussion... in this new world of wide pitch tracks.

Ski Doo, with the release of the 2017 G4 Summit platform, has made another industry first with the use of the 3.5"-Pitch track (pitch=space between paddle centers)...this new a 22% increase in space between the paddles... and driver window length.

Opening up the pitch ... is certainly a way to lighten a track...AND... possibly change some other performance characteristics of the track.

I'm wondering if the 3.5" pitch is a "plus" or a "minus".... less paddles on the snow, and also less shear stress on the snow with each "bite" of the paddles...but what is the tipping point for number of paddles in the snow vs traction and forward progress of the sled???

In the words of BRP

New 3.5 in. (9 cm) pitch reduces weight, and keeps snow between lugs for added performance.

A 165 is actually a 164.5" track at 3.5" pitch... which translates to 47 rows of paddles.

A 163" track, at 2.86" pitch is 163.2" actual... 57 rows of paddles.

Say, for arguments sake, that 50% of the paddles are in the snow...
That puts 23 rows of paddles in the snow for the 165" and 28 rows of paddles in the snow for the 162"...

What are the performance aspects of this change?

How does snow type affect this etc etc.???

Given the same track track design... say the new Conquer 280... one in a 156" x 15" x 2.8"-lug w/3"-pitch... and a 154" x 15" x 2.8"-lug w/3.5" pitch...same paddles, same duro, same belting, same clips... (or a 165" vs. 163 Conquer 280 15")

All other things equal on the sled... save the different pitches...
On a nice fresh bottomless 'blower' day, which one will trench more?
What if that were bottomless fresh coastal snow, which would trench more??

What is the "optimal" pitch for a given paddle design... say in deep 'blower' pow... or in Coastal snow... what would give you the best "swiss army knife" kind of compromise, taking ONLY pitch into consideration.

HMMMMM????:spider:

POWDERMAX™ LIGHT TRACK WITH FLEXEDGE
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[turboless terry]

That is exactly what I want to know before I choose between the 154 and 156. Burandt says the 3.0 trenches less. Will the 3.5 trench more. Seems like there is a fine line there. Ski doos have always had a tendency to trench. The 3.0 is supposed to be 45 pounds and have heard the 3.5 is possibly 40. That sounds appealing if it doesn't trench but my gut says it will in deep powder. Questions I would love answered.

 

[volcano buster]

I question whether there will be a decrease in durability as there are fewer lugs to share a load when the sled is only on a small foot print.

Would hifax wear be better or worse?

I imagine the lugs would need to be built firmer on a wider pitched track to handle the load, if so, it may tend to trench more.

 

[skierh2o]

With more snow mass between pitch, it should provide more forward thrust in any snow = less trenching.
To me the snow is going to shear at the bottom of each lug regardless...so more snow between lugs = more mass to thrust against=more forward momentum.
Now with that said some of you will say there is the same amount of snow under the track regardless, and you are correct......it is just easier to move when broken in to smaller pieces by a smaller pitched track!

6-8 more weeks and we will have our theories tested IRL!

With more power per lug, torn lugs may be an issue, hopefully not!
Ryan

 

[summ8rmk]

Not a snowmobile but the same concept.
I ran both of these tires snow wheeling.
Tell me which tire u think performed better and why.

GS6

 

[tuneman]

Truck tires are quite a bit different, because the lugs are rigid. If close together, the spaces will fill up quickly and you get a slide. Much like locking the brakes up on your sled as you slide down a mountainside.

I don't believe trenching and pitch are as closely related as previously discussed. You get float from a track by allowing the lugs to bend/fold. By folding, they pack the snow downward and push the sled upward. Rigid lugs trench because they push the snow straight out the back of the sled and just keep digging. The optimum all-around design is a lug that's rigid at the base for acceleration in set up snow and soft at the tips for floatation.

Now reduce the number of lugs and you reduce the amount of lift. It's well known that the lower the pitch, the higher the track speed. A higher pitch will reduce weight and rolling mass, but you sacrifice track speed and lift.

My guess is that the 3.5" pitch will not perform well.

 

[mountainhorse]

This is an interesting point... and I would imagine that the TYPE of snow plays a big role.

Fresh 'blower' pow acts more like a liquid than coastal pow... and thus has a very low 'shear' property... more like water skipping than "hooking up"... would that be better or worse with a wide pitch... HMM.

With more snow mass between pitch, it should provide more forward thrust in any snow = less trenching.
To me the snow is going to shear at the bottom of each lug regardless...so more snow between lugs = more mass to thrust against=more forward momentum.
Now with that said some of you will say there is the same amount of snow under the track regardless, and you are correct......it is just easier to move when broken in to smaller pieces by a smaller pitched track!

6-8 more weeks and we will have our theories tested IRL!

With more power per lug, torn lugs may be an issue, hopefully not!
Ryan

 

[mountainhorse]

It's well known that the lower the pitch, the higher the track speed. A higher pitch will reduce weight and rolling mass, but you sacrifice track speed and lift.
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Expand on this more please (sincere question and not sarcasm).



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[summ8rmk]

Yes, please explain how a heavier track equates to faster speed.


GS6

 

[turboless terry]

The larger pitch will dig down quicker. Doo claims 10 percent more traction. I can believe that but it will have less lugs to provide lift. This leads me to believe it will dig down or trench more in certain conditions. Probably a trade off like everything else.

 

[mountainhorse]

My impression (opinion).

Is that the wider pitch will work better in denser snow.. and not so much in dry powder... all other things being equal... like a Conquer 280 comparison in same lengths but diff pitches. (3.5" vs 3" pitch)



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[summ8rmk]

Boggers dug straight down, very little forward propulsion.
IROK had just enough dig with massive forward propulsion.

GS6

 

[joshkoltes]

What about my 166 2.52 inch track? 66 rows of paddles 33 in the snow off the throttle and five in when I cob it!

 

[tuneman]

Expand on this more please (sincere question and not sarcasm).



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With all other things being equal (same # of lugs, driver diameter, etc.), a smaller pitch equals more teeth to drive the track. So, you get less sliding friction as the track moves around the teeth of the drivers. That gives you more track speed.

On a side note, I believe Indy Dan makes roller drive drivers, which would negate the sliding friction. Would be sweet to try those things out.

 

[capulin overdrive]

Don't know if it equates, but sand paddle tires add more paddles per specific tire as horsepower goes up.

 

[DDECKER]

Boggers dug straight down, very little forward propulsion.
IROK had just enough dig with massive forward propulsion.

GS6

my vote is for Krawlers red label preferably unless its wet

 

[warreng417]

Larger pitch gives more area to pack the snow before grabbing it? I dunno. Like someone else said, probably less effective in dry snow

 

[rkm]

Smaller pitch makes a huge difference when you're talking 100+ mph. Never did the testing to quantify an effect at 40-60mph track speeds.
Heavier tracks climb better, but react slower. Thats from Camoplast and verified by my testing.

 

[roni87]

I'm going to try cutting out every other center lug on my m9104 ce 2.5. 54 pitches so 27 heavy center lugs. That would be about 11.5" between the remaining center lugs.
I believe the idea is to trap the snow for the longest time...just as a longer track does.

 

[89sandman]

I think about the very front of the track just as it comes off the drivers to where the bend in the front rails go straight. I would think that this is the area most of the "lift" is created. The paddles are coming down at an angle instead of horizontal. Attack angle plays a major role in how much lift you get from this area and how much forward momentum you gain. From there back is where most of the forward momentum comes from. Sure there is a sweet spot where each paddle gets enough fresh to give the most lift, they need to figure out the optimal spacing to get this sweet spot as much as possible. Many varibles, snow conditions, stiffness/height of lugs, suspension setup, ect. So unless you could build a track for the exact condition you are in at the time, they will need to find a happy medium where it will preform in many different conditions. Depends on where you are willing to give in one area to take in another.