Clutching with 3" track

[High Velocity]

I've got three rides now on my '12 Pro with the 162x15x3" track and although I'm very happy with the track, it does need a little clutching help. My current setup is 3"P 7T drivers, 20/45 gearing, PAR 13.1:1 head. 68g MTX's with 2g in the middle and 2g in the tip and SLP blue/pink (140/340) in the primary, Carl's helix (60/40) and gold/black (170/240) in the secondary. Sled feels very responsive and good backshift when tree riding, but it will drop to 7900 when pulling a hill and trackspeed (corrected for driver size) is about 36mph.
Riding altitude is from 3500-7500 ft. Any suggestions that will help both rpm and trackspeed would be greatly appreciated.

 

[Murph]

That much track and that low of track speed I would start with a 19T top gear.

I run 19/45 with the stock 163" track.

You need as much mechanical advantage as you can. At 36mph you aren't shifted out very far in the primary. Is it slipping in the primary?

 

[High Velocity]

Murph, I was running 19/45 with the stock track, but went to a 20 when I did the 7T drivers for the 3". I thought I would end up geared too low because of the smaller drivers. I may have to try the 19. Belt does not appear to be slipping in the primary, but I am only using about half of the primary.


Sent from my iPad when I should be sledding.

 

[High Velocity]

Anyone else running a 3" with 7T drivers that wants to chime in ?


Sent from my iPad when I should be sledding.

 

[Jeff K]

I am running a 3" on a 2013 pro. I am geared down ~10% from the 7T drivers and IMO its perfect. I am running MDS weights @68gm, Black primary spring (100/340) and Black/Purple secondary spring with a PAR 13.1 head. This combo rocks. Awesome back shifting, very sanppy and hold RPM perfectly. Buddies that ride my sled comment that it feels like it has 10-15 more HP then theirs with similar setups except the track/gearing.

 

[winter brew]

HAve done a few 3" on the Pro's and kept the stock gearing (not much choice with the belt drive) and it seems to work good. With the bigger/heavier track you definatly want a little shallower helix than stock....a XX/38.36 or .41 would be my choice along with eithe 10-arms or MTX's.