Changing drivers from a 2.52 to 3 pitch

[sweidall]

How will my top rpm change from going to a 3 pitch driver from a 2.52 driver? I'm currently in the process from going from a 144x15x1.5 2.52 track to 144x15x2.5 3 pitch track.

 

[sweidall]

I'm changing from a 9 tooth driver to a 7 tooth.

 

[natedawgedog]

How will my top rpm change from going to a 3 pitch driver from a 2.52 driver? I'm currently in the process from going from a 144x15x1.5 2.52 track to 144x15x2.5 3 pitch track.

I'm changing from a 9 tooth driver to a 7 tooth.

I dont think the pitch has as much to do with the gearing change as much as the diameter of the drivers, how much bigger/smaller are the drivers going to be would affect gearing and clutching more than the pitch of drivers. to find it out measure from center of your old drivers and your new ones and see how much bigger/smaller they are that will give you a better idea of how much is going to change

 

[MTN_VIPER]

Some info from my tech page,http://fourstrokesolutionsllc.webs.com/snowmobilerelatedtech.htm

Snowmobile driver diameter specifications

2.52” pitch drivers inches (Metric rounded to nearest mm)

10 tooth 8.021” diameter 204 mm

9 tooth 7.219” diameter 183 mm

8 tooth 6.417” diameter 163 mm

7 tooth 5.615” diameter 143 mm


2.86” pitch drivers

8 tooth 7.283” diameter 185 mm

7 tooth 6.373” diameter 162 mm


3.00” pitch drivers

8 tooth 7.639” diameter 194 mm

7 tooth 6.685” diameter 170 mm

Changing driver size will also effect over-all gear ratio. For example when changing from a 2.52” 9 tooth driver to a 2.52” 8 tooth driver. You would multiply your 9 tooth ratio by 1.13.

Example: 20/40 gears with 9 tooth drivers would be 2.00 to 1. When switching to 8 tooth drivers with the same gear set the new ratio would be 2.26 to 1. (2.00 x 1.13= 2.26)

Note: the 1.13 multiplier only applies to 2.52” pitch sized drivers. Although the 2.86” is fairly close to the 2.52" and could be used for a 2.86" driver to get a general idea of ratio change.