CHART FOR COMMON GEAR RATIOS, AND "AT TRACK" RATIOS FOR 7 Tooth 3" PITCH DRIVERS.

[mountainhorse]

CHART FOR COMMON GEAR RATIOS, AND "AT TRACK" RATIOS FOR 7 Tooth 3" PITCH DRIVERS.

With the arrival of the X3 tracks and the 2.6 Powerclaw... 7 tooth Drivers have become common place.

:bowl:EDIT: Oct 2016....
Most people base their "feel" for gear ratios based on stock gear ratios of the sleds when they were 8-tooth 2.86"-pitch drivers on the drive shafts... now that we have many 3"-pitch tracks... and using 7-tooth drivers... a "translation" for comparison... has been posted here. That is, if I change out to a different pitch driver or track... how would that compare to my ORIGINAL gearing.

BUT... if you are keeping you stock driver diameter...then this is a moot point as you are NOT changing the diameter of the drivers on the driveshaft.
. For example, you have a 2016 AXYS with the 3"-lug with 3"-pitch-drivers... and you switch out to a Conquer 280 track... which also has 3"-pitch drivers... then your gearing will NOT change... unless you change the sprockets on the drive/jack shafts... easy to do on a chain drive.
. If you have a QuickDrive™ equipped sled (belt drive on the jack/drive shafts), for those with the series 6 (2.6"-lug) or series 5 (2.4"-lug) that has the 2.86"-pitch, you will need to change drivers to the 3"-pitch, then you will need a kit like C3 or TKI etc on a

Many of our members are curious about gear ratios with this driver, so I thought I'd put together a list of Comparative (realized) drive ratios... That is, what is the real ratio at the track taking into account the correction factor of .92 for the smaller diameter of the 7tooth 3" pitch driver.

EDIT: Comparative (realized) drive ratios are ALSO listed for 2.86" pitch 7 tooth sprockets.

To calculate the comparative 'final' drive ratio for a 7-tooth, 3" pitch driver equipped sled, use this formula (B ÷ T)÷.92=Final Ratio. Where B is Bottom gear tooth count, T is top gear tooth count and .92 is the correction factor for the difference in the diameter of the sprockets.

I will not list the 18t top sprocket as I'm not at all a fan of that small of a sprocket.

Now...For the STOCK 2013/14 owners with the QuickDrive™ belt drive equipped PRO RMK's, you are limited to a final drive ratio with 7tooth 3" pitch at 2.27:1 (ie 2.09 ÷ .92 = 2.27)... Which is not bad... I personally prefer, as does my "Gear-Guru" TRS... around 2.35:1.

I'm running the 19/41 gearing with a stock 72 link (pitch) chain and AVID 7 tooth 3"-pitch combo drivers for a realized ratio of 2.35:1
As a comparison, the factory 8 tooth x 2.86"-pitch drivers ... a gearing combo of 19/45 gives me approx the same ratio of 2.36:1

For the same approx 2.35:1, the 20/43-74p may be more "ideal" as it puts more teeth in contact with the chain... but heck... I'm cheap and have plenty of 19/41 tooth sprockets on hand... and stock chains (72p)... and none of the others.

Chaincase PRO RMK models:

Factory gearing 20/42-72p

A) Gearing top/bottom
B) Ratio (gearing alone, factory drivers)
C) Realized (at the track) 7t, 3" pitch Ratio
D) Realized (at the track) 7t, 2.86" pitch Ratio.
E) Pitch count (IE... How many links in the chain)

--A-- -> --B-- -> --C-- -> --D-- -> --E--
================================

20/41 -> 2.05:1 -> 2.23:1 -> 2.33:1 -> 72p

19/41 -> 2.16:1 -> 2.35:1 -> 2.45:1 -> 72p

20/42 -> 2.10:1 -> 2.28:1 -> 2.39:1 -> 72p FACTORY

19/42 -> 2.21:1 -> 2.40:1 -> 2.51:1 -> 72p

20/43 -> 2.15:1 -> 2.34:1 -> 2.44:1 -> 74p

19/43 -> 2.26:1 -> 2.46:1 -> 2.57:1 -> 72p

20/44 -> 2.20:1 -> 2.39:1 -> 2.50:1 -> 74p

19/44 -> 2.32:1 -> 2.52:1 -> 2.64:1 -> 74p

20/45 -> 2.25:1 -> 2.45:1 -> 2.56:1 -> 74p

19/45 -> 2.36:1 -> 2.57:1 -> 2.68:1 -> 74p

20/46 -> 2.30:1 -> 2.50:1 -> 2.61:1 -> 76p

19/46 -> 2.42:1 -> 2.63:1 -> 2.75:1 -> 74p



















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[philsummers21]

How big of a difference for 7 tooth 2.86.

Sent from my galaxy note3 via tapatalk

 

[R_8_N]

Thank you!

This should be a sticky

 

[philsummers21]

I agree. Throw out some 2.86 numbers and 8 tooth for both 2.

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[mountainhorse]

For 7 tooth 2.86" pitch, Factor .88 (rather than .92 for the 3" pitch 7 tooth)




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[philsummers21]

This is interesting. I might be geared way low. Pretty sure I'm running 19/43 7 tooth 2.86 for 2.57:1. This was with a turbo

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[mountainhorse]

You dont say what track you are running??

With 7 tooth 2.86" pitch drivers.

IMO... Run 20/41-72p... gives you 2.32:1 at the track... with a turbo might be ideal.

Stock, 20/42-72p, gives you 2.38:1 at the track... and you won't have to buy anything if you kept your stock stuff... def an improvement over the 19/43 .... cant hurt to try.

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[mountainhorse]

I've added the info for 7 tooth 2.86" pitch as well.








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[philsummers21]

Awesome. Thank you mh. One last question what's the factor for factory 8 tooth.

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[mountainhorse]

Awesome. Thank you mh. One last question what's the factor for factory 8 tooth.

Factory 8 tooth is the baseline reference... so... ZERO.

 

[BILTIT]

Very informative and helpful, much thanks!

 

[die hard poo]

So I want to strive for around 2.4:1 gear ratio this year, wonder if it would be essentially the same thing to install 7t 2.86 avid drivers with stock gearing vs. stock drivers and the Kurts Polaris belt drive kit? Thoughts?

 

[mountainhorse]

That would give you 2.37:1 realized ratio... and give you some more lug clearance... Run it and see how you like it..Fairly cheap mod to gear down IMO.

the 14's did not see the problem level that the 13's had with the QD's... SO.... I think that the majority of the durability issues have been corrected in the stock QD.

That being said... i believe that the aftermarket QD mods/replacements are more robust than stock.

With the arrival of the X3 tracks and the 2.6 Powerclaw... 7 tooth Drivers have become common place.

Many of our members are curious about gear ratios with this driver, so I thought I'd put together a list of FINAL (realized) drive ratios... That is, what is the real ratio at the track taking into account the correction factor of .92 for the smaller diameter of the 7tooth 3" pitch driver.

EDIT: Final (realized) drive ratios are ALSO listed for 2.86" pitch 7 tooth sprockets.

To calculate the FINAL drive ratio for a 7-tooth, 3" pitch driver equipped sled, use this formula (B ÷ T)÷.92=Final Ratio. Where B is Bottom gear tooth count, T is top gear tooth count and .92 is the correction factor for the difference in the diameter of the sprockets.

I will not list the 18t top sprocket as I'm not at all a fan of that small of a sprocket.

Now...For the STOCK 2013/14 owners with the QuickDrive™ belt drive equipped PRO RMK's, you are limited to a final drive ratio with 7tooth 3" pitch at 2.27:1 (ie 2.09 ÷ .92 = 2.27)... Which is not bad... I personally prefer, as does my "Gear-Guru" TRS... around 2.35:1.

I'm running the 19/41 gearing with a stock 72 link (pitch) chain and AVID 7 tooth 3"-pitch combo drivers for a realized ratio of 2.35:1
As a comparison, the factory 8 tooth x 2.86"-pitch drivers ... a gearing combo of 19/45 gives me approx the same ratio of 2.36:1

For the same approx 2.35:1, the 20/43-74p may be more "ideal" as it puts more teeth in contact with the chain... but heck... I'm cheap and have plenty of 19/41 tooth sprockets on hand... and stock chains (72p)... and none of the others.

Chaincase PRO RMK models:

Factory gearing 20/42-72p

A) Gearing top/bottom
B) Ratio (gearing alone, factory drivers)
C) Realized (at the track) 7t, 3" pitch Ratio
D) Realized (at the track) 7t, 2.86" pitch Ratio.
E) Pitch count (IE... How many links in the chain)

--A-- -> --B-- -> --C-- -> --D-- -> --E--
================================

20/41 -> 2.05:1 -> 2.23:1 -> 2.33:1 -> 72p

19/41 -> 2.16:1 -> 2.35:1 -> 2.45:1 -> 72p

20/42 -> 2.10:1 -> 2.28:1 -> 2.39:1 -> 72p FACTORY

19/42 -> 2.21:1 -> 2.40:1 -> 2.51:1 -> 72p

20/43 -> 2.15:1 -> 2.34:1 -> 2.44:1 -> 74p

19/43 -> 2.26:1 -> 2.46:1 -> 2.57:1 -> 72p

20/44 -> 2.20:1 -> 2.39:1 -> 2.50:1 -> 74p

19/44 -> 2.32:1 -> 2.52:1 -> 2.64:1 -> 74p

20/45 -> 2.25:1 -> 2.45:1 -> 2.56:1 -> 74p

19/45 -> 2.36:1 -> 2.57:1 -> 2.68:1 -> 74p

20/46 -> 2.30:1 -> 2.50:1 -> 2.61:1 -> 76p

19/46 -> 2.42:1 -> 2.63:1 -> 2.75:1 -> 74p



















.

.

 

[mountainhorse]

That would give you 2.37:1 realized ratio... and give you some more lug clearance... Run it and see how you like it..Fairly cheap mod to gear down IMO.

the 14's did not see the problem level that the 13's had with the QD's... SO.... I think that the majority of the durability issues have been corrected in the stock QD.

That being said... i believe that the aftermarket QD mods/replacements are more robust than stock.

With the arrival of the X3 tracks and the 2.6 Powerclaw... 7 tooth Drivers have become common place.

Many of our members are curious about gear ratios with this driver, so I thought I'd put together a list of FINAL (realized) drive ratios... That is, what is the real ratio at the track taking into account the correction factor of .92 for the smaller diameter of the 7tooth 3" pitch driver.

EDIT: Final (realized) drive ratios are ALSO listed for 2.86" pitch 7 tooth sprockets.

To calculate the FINAL drive ratio for a 7-tooth, 3" pitch driver equipped sled, use this formula (B ÷ T)÷.92=Final Ratio. Where B is Bottom gear tooth count, T is top gear tooth count and .92 is the correction factor for the difference in the diameter of the sprockets.

I will not list the 18t top sprocket as I'm not at all a fan of that small of a sprocket.

Now...For the STOCK 2013/14 owners with the QuickDrive™ belt drive equipped PRO RMK's, you are limited to a final drive ratio with 7tooth 3" pitch at 2.27:1 (ie 2.09 ÷ .92 = 2.27)... Which is not bad... I personally prefer, as does my "Gear-Guru" TRS... around 2.35:1.

I'm running the 19/41 gearing with a stock 72 link (pitch) chain and AVID 7 tooth 3"-pitch combo drivers for a realized ratio of 2.35:1
As a comparison, the factory 8 tooth x 2.86"-pitch drivers ... a gearing combo of 19/45 gives me approx the same ratio of 2.36:1

For the same approx 2.35:1, the 20/43-74p may be more "ideal" as it puts more teeth in contact with the chain... but heck... I'm cheap and have plenty of 19/41 tooth sprockets on hand... and stock chains (72p)... and none of the others.

Chaincase PRO RMK models:

Factory gearing 20/42-72p

A) Gearing top/bottom
B) Ratio (gearing alone, factory drivers)
C) Realized (at the track) 7t, 3" pitch Ratio
D) Realized (at the track) 7t, 2.86" pitch Ratio.
E) Pitch count (IE... How many links in the chain)

--A-- -> --B-- -> --C-- -> --D-- -> --E--
================================

20/41 -> 2.05:1 -> 2.23:1 -> 2.33:1 -> 72p

19/41 -> 2.16:1 -> 2.35:1 -> 2.45:1 -> 72p

20/42 -> 2.10:1 -> 2.28:1 -> 2.39:1 -> 72p FACTORY

19/42 -> 2.21:1 -> 2.40:1 -> 2.51:1 -> 72p

20/43 -> 2.15:1 -> 2.34:1 -> 2.44:1 -> 74p

19/43 -> 2.26:1 -> 2.46:1 -> 2.57:1 -> 72p

20/44 -> 2.20:1 -> 2.39:1 -> 2.50:1 -> 74p

19/44 -> 2.32:1 -> 2.52:1 -> 2.64:1 -> 74p

20/45 -> 2.25:1 -> 2.45:1 -> 2.56:1 -> 74p

19/45 -> 2.36:1 -> 2.57:1 -> 2.68:1 -> 74p

20/46 -> 2.30:1 -> 2.50:1 -> 2.61:1 -> 76p

19/46 -> 2.42:1 -> 2.63:1 -> 2.75:1 -> 74p



















.

.

 

[mountainhorse]

That would give you 2.37:1 realized ratio... and give you some more lug clearance... Run it and see how you like it..Fairly cheap mod to gear down IMO.

the 14's did not see the problem level that the 13's had with the QD's... SO.... I think that the majority of the durability issues have been corrected in the stock QD.

That being said... i believe that the aftermarket QD mods/replacements are more robust than stock.

With the arrival of the X3 tracks and the 2.6 Powerclaw... 7 tooth Drivers have become common place.

Many of our members are curious about gear ratios with this driver, so I thought I'd put together a list of FINAL (realized) drive ratios... That is, what is the real ratio at the track taking into account the correction factor of .92 for the smaller diameter of the 7tooth 3" pitch driver.

EDIT: Final (realized) drive ratios are ALSO listed for 2.86" pitch 7 tooth sprockets.

To calculate the FINAL drive ratio for a 7-tooth, 3" pitch driver equipped sled, use this formula (B ÷ T)÷.92=Final Ratio. Where B is Bottom gear tooth count, T is top gear tooth count and .92 is the correction factor for the difference in the diameter of the sprockets.

I will not list the 18t top sprocket as I'm not at all a fan of that small of a sprocket.

Now...For the STOCK 2013/14 owners with the QuickDrive™ belt drive equipped PRO RMK's, you are limited to a final drive ratio with 7tooth 3" pitch at 2.27:1 (ie 2.09 ÷ .92 = 2.27)... Which is not bad... I personally prefer, as does my "Gear-Guru" TRS... around 2.35:1.

I'm running the 19/41 gearing with a stock 72 link (pitch) chain and AVID 7 tooth 3"-pitch combo drivers for a realized ratio of 2.35:1
As a comparison, the factory 8 tooth x 2.86"-pitch drivers ... a gearing combo of 19/45 gives me approx the same ratio of 2.36:1

For the same approx 2.35:1, the 20/43-74p may be more "ideal" as it puts more teeth in contact with the chain... but heck... I'm cheap and have plenty of 19/41 tooth sprockets on hand... and stock chains (72p)... and none of the others.

Chaincase PRO RMK models:

Factory gearing 20/42-72p

A) Gearing top/bottom
B) Ratio (gearing alone, factory drivers)
C) Realized (at the track) 7t, 3" pitch Ratio
D) Realized (at the track) 7t, 2.86" pitch Ratio.
E) Pitch count (IE... How many links in the chain)

--A-- -> --B-- -> --C-- -> --D-- -> --E--
================================

20/41 -> 2.05:1 -> 2.23:1 -> 2.33:1 -> 72p

19/41 -> 2.16:1 -> 2.35:1 -> 2.45:1 -> 72p

20/42 -> 2.10:1 -> 2.28:1 -> 2.39:1 -> 72p FACTORY

19/42 -> 2.21:1 -> 2.40:1 -> 2.51:1 -> 72p

20/43 -> 2.15:1 -> 2.34:1 -> 2.44:1 -> 74p

19/43 -> 2.26:1 -> 2.46:1 -> 2.57:1 -> 72p

20/44 -> 2.20:1 -> 2.39:1 -> 2.50:1 -> 74p

19/44 -> 2.32:1 -> 2.52:1 -> 2.64:1 -> 74p

20/45 -> 2.25:1 -> 2.45:1 -> 2.56:1 -> 74p

19/45 -> 2.36:1 -> 2.57:1 -> 2.68:1 -> 74p

20/46 -> 2.30:1 -> 2.50:1 -> 2.61:1 -> 76p

19/46 -> 2.42:1 -> 2.63:1 -> 2.75:1 -> 74p



















.

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[jonasumb]

Okay, learning here sorry if I ask a dumb question.
I have a 13 pro with the 7 tooth avid drivers and X3 track, so I am below the 2.37:1, how do I use your graph with the Qd?

 

[mountainhorse]

QD

Now...For the STOCK 2013/14 owners with the QuickDrive™ belt drive equipped PRO RMK's, you are limited to a final drive ratio with 7tooth 3" pitch at 2.27:1 (ie 2.09 ÷ .92 = 2.27)... Which is not bad...

...

 

[2mileshigh]

I have a 2014 pro with a 3in track, 7 tooth drivers. Where would I be if I put on Kurts Polaris gear down kit? would it be to low? Run 10 to 12k elevation

 

[mountainhorse]

Same formula... divide the ratio by .92....

With Kurts kit at 2.41÷.92=2.62

So your realized ratio would be 2.62:1... pretty steep IMO... Target 2.35:1 to 2.45:1
would be ideal.




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[Kcjepperson]

Thanks for all the info in this post MH, what has been your experience with the 7 tooth driver? Do you notice a difference in efficency? I am running a cmx belt drive at 2.14 for 8 tooth driver and have contemplated trying a 7 tooth driver and gearing down to around 2.33ish. I thinking the gearing would be great, especially for playing in the ditches and trees, just worry I might be losing some efficency with wrapping the track that tight

Thanks