what drivers needed for 1.75 backcountry track

[Mtnviper]

9 tooth
Pros
More effiecent due to the larger radius the track rides around, similar effect as larger rear axle wheels.
Less potential for thick ice build-up at the front heat exchanger, due to the lugs being closer.
Less likely to ratchet (non extroverts) because of more contact area with the track drive lugs.
Better track approach angle.
Cons
May limit track lug size on some applications
Front of slide rails may require shortening if using extroverts on some models (XTX)

8 Tooth

Pros
More track lug clearence.
More clearence for extrovert teeth to the rail tips
Gears down X 1.13 without changing chain case gearing.
Cons
Less efficent, requires slightly more horsepower to rotate the track around the tighter radius.
Steeper approach angle.
More likely to ratchet (non extrovert) and may require tighter track tension.

For best overall performance it is usually best to go with the largest driver possible, while still allowing a minimum of about a 1/2" lug clearance at the front heat exchanger.
With the FX Nytro chasis you can run a 2" track with 9 tooth 2.52" pitch drivers no problem. (Will require tunnel/heat exchanger protector removal)
XTX's require trimming approx 3/8" off the front of the rail tip, if using 9 tooth extrovert drivers. To prevent the extrovert teeth from contacting the rail tips as the front of the suspension compresses.

Bill
http://fourstrokesolutionsllc.webs.com/ ... edtech.htm

 

[Larwho]

backcountry 1.75

While your all talking about tracks.. I am planning to refit my 09 FX Nytro with the 144 x 1.74 inch backcountry track. Not a wild rider but do enjoy the hills and mountains ( but can't keep up with the 20 YO son!). For the typical rider do you think the stock drivers etc will be fine? Just replacing stock with 144, rails, and tunnel ext.
Would love some feedback from the pros but also note pushin 50 so big air days are about done. Thanks

 

[Dimebag]

I ran my Nytro 3000 kms with a backcountry 1.75/144 track with the stock drivers. No problems at all. I know many people have problems with track ratcheting, but i never had this problem on mine. Maybe i ran the track tighter then other people.. I really dont know. That being said, purchasing extroverts and installing them since you have to take the driveshaft out anyways might not be a bad idea.. Its not a big cost compared to the track/ extension kit.

 

[Supa Dexta]

So an update.. I tried to order 8 tooth avids in a 2.52 and was informed they don't make them..

So I then ordered the 8 tooth extro wahls.. But now that I dug my track out of the box, something isn't right..

The track is only punched out

- 2 holes - then A closed space - and then 2 holes...etc ---[]-[]---[]-[]---[]-[]---

So as you can see when the driver spins, its lands on a non hole every couple of holes..

The track is supposed to be a Camoplast Challenger 144x15x2 inch/ 2.52 pitch.. I notice it has polaris stamped in the rubber too..

So how does this work? I'm new to changing any of this out.

 

[sleddingfarmer]

So the track isn't fully clipped. That sucks.

You just gotta cut the holes out that aren't cut out. I'd buy some clips, and clip them. Although if you didn't want to clip it, you could just run it without clipping it, long term results I'm not sure of, but my friend did it for several hundred miles with no problems.

Hopefully a dealer or someone near you has a clipping tool you could borrow

 

[Supa Dexta]

The answer I was afraid of.. Is there something special for cutting the holes? ... Also clipping is going to be a bitch, because its going to be 2x the clips. 2 clips for each new hole.

 

[sleddingfarmer]

Not sure on the best way to cut the track. A sharp knife I guess.

I've never had to clip a track, but I have a couple friends who have done it and they weren't very happy about it. I believe they used the small tool. I think the larger tool would make the job significantly easier

 

[Supa Dexta]

Just an update for those who care, I've got a challenger 2" track/ 144 under there now..

- Avid doesn't make 8tooth drivers, needed to go with wahls (1.0625 shaft, 8 tooth/ 2.52 pitch and you will need a press to remove the old ones (4) and put the new ones extroverts (2)

- You have to remove the tunnel and cooler protectors - I used a mini grinder to start grinding down the cooler welds, then a dremel to get closer and vice grips to twist them back and forth gently so they would break loose, then grinded the welds smooth. The tunnel protectos have 4 rivets each on the tunnel mounts, then I just bent them down to pop the fronts under the fuel tank

- I didnt specify how I wanted my track exactly (windows cut and fully clipped would have been 140$ more). So I had to cut open the holes. I used a 28mm hole saw, which seems to fit perfect as the drivers come around. I also didnt clip the track any more then how it came, to save weight, and on the advice of some others this will be fine. (Helps to have 2 guys to drill the track, I used a piece of fire wood within the track to drill down into, have someone hold the track and move the wood, do both sides of the track at each stop, then you will have a lot less rotating of the track as you go all the way around it once, rather then twice. Take a propane torch and singe the new holes you've drilled.

Everything else is pretty standard and expected..

 

[moab11]

This seems like the best place to ask. How are you guys with XTX's and Extroverts trimming your rails down? I know I need to remove about 3/8", just not sure on the best procedure.

 

[PoliticalMachine]

I rode 1000 miles last year with Avid 9t extros without trimming the rails. I had no issues what so ever of the tips of the rail hitting the extros.