7 or 8 tooth drivers on IQR 155"??

[rydningen]

Im in the process of getting drivers for my IQR mountain conversion, and now im not sure to go with the 7 or 8 tooth avid drivers?!
The track is an series 5.1 155" of an 2009 rmk, there is some clearance for the paddels with the 8t but i wanted to know if I would be better of running a 7 tooth instead of an 8 to get more clearance??

Would be great to get input from someone whos already done this and hear what setup you are running

 

[autolodge]

8 tooth

Supposedly the 8 tooth drivers put more power to the ground because the track doesn't have to make such a tight corner around the drivers. The opposing argument would be that with the 8tooth drivers you would only have a little track to tunnel/front cooler clearence which would increase snow pack in the deep and rob horsepower. The 7 tooth drivers would increase that clearance and supposedly save horse. I run all 8 tooth 2.86 with a 2.4" track it seems to work really well. Hope this helps, Craig

 

[rydningen]

ok, sounds good...i guess i will be runnig the 8t.
Thanks alot autolodge

 

[mountainhorse]

The 7 tooth 2.86" pitch drive sprockets are fairly new... they are pretty small diameter 6.37" diameter (3.19 radius) (Wahl bros mfg)

The 8 tooth 2.86" pitch is 7.28" diameter (3.64" radius)

This will give you approx .45" more clearance in your tunnel...

Do not confuse this with the larger diameter 7 tooth, 3" pitch drivers.

If your track is the 2009 Dragon SINGLE ply track... I'd say it would be pretty GTG... But the 2 ply tracks do resist bending around the smaller diameter more.

Another thing to look at is that when you decrease the diameter of the driver... you also bring the top inside of the track .45" closer to the front torque arm as well... you could have rubbing, maybe even constant, against the wear bars on the top tube.

You may need to lower (relocate) the front swing arm in the tunnel and suck up the limiter strap... this will decrease the travel of the skid slightly and change the geometry slightly ....I do not know HOW it will change it... maybe not noticeable...maybe really noticeable.

AGAIN... If someone has run the 7 tooh 3" pitch drivers... it is not the same thing as far as clearances/rubbing nor needing to move the arm down as the 2.86" pitch

 

[rydningen]

If i lowered the front arm of the rear suspension (which i most likely will have to do anyway) and run the smaller diameter 7t drivers wont I get an even steeper approach angle than with the 8t?
And since im not running a drop and roll i think that would cause a problem.