Track Tension

[CPearce]

I was installing a new track (144" / 2.52 track) and have the tension set at 1/2". I have always had the tension set at 1/2" and my buddy questioned why my track was so tight b/c his king cat is at suggested mfg. of 2" and all I had to say is that's what the mfg. said and i have had no slippage from the drivers.
So it had my head spinning if it was all right to loosen the tension. I know the looser the track becomes the less sensation and ratcheting occurs. I'm sure most of you have converted to 3 pitch tracks and have it looser. Out of curiosity what does everybody have their track tension set at?

Also, why is the fusion tension set so different?

The '05 Deep Snow Service Manual:
Tension Test: 10'bs weight & 16" in front of the rear idler shaft:
IQ RMK/Switchback - 3/8" - 1/2"
Fusion - 1 1/4" - 1 1/2"

 

[ghostwhite]

I would venture to say that the difference between the two is in relation to where the weight is placed. On a longer track the weight has less leverage at 16", where as on a short track it would be closer to center and have more leverage. Otherwise it is probably in the suspension design.

I would recommend just setting it to factory specs for your sled, MountainHorse had a write-up or post that highlighted exactly why, I will try and find it. It is best to run it to spec, regardless of ratcheting.

Thats just my opinion though, others may say otherwise!

Edit- I have mine set at 1/2 on my 151

 

[CPearce]

Couldn't find MH's post regarding the reason for track tension. If someone could guide me in the right direction it would be much appreciated.

You'll be home just in time for the champagne pow!

 

[ghostwhite]

From a previous post...
Some stuff I've learned from the diff engineers in the sled world.

Looser tracks allow the paddles to fold over easier... a part of the equation that most dont think of and is the MAIN reason why (I think) Jack Struthers says that a tight track works better than a loose one...it hooks up better, expecially in more setup conditions like on a track or hill-drags, or spring time climbing (or our average Sierra cement)

The people with Extrovert (AKA combo) drivers seem to want to run the track real loose and feel it frees up HP...a loose track allows for distortion of the track as it leaves the driver and makes the track more suceptable to "stabbing"... With the extros, I dont look at them as a way to allow a track to be run looser... I look at it as a prevention of ratcheting in the high-demand situations.

I think the "combo" drivers are the best option, but run almost as tight as the stock drivers AND run the more slippery hyperfax as well as popping back on some idlers for spring conditions as well.

Extros, IMO, are mandatory on high hp sleds... BUT they should be run at the correct, not loose, tension... similar to normal tracks/stock-drivers.

When they are running normally, not ratcheting, the teeth of the extro are not even contacting the track or the clips and only drive from the involute portion on the inside of the track.
The first of the M-series cats had poor geometry that tightended up the track when it worked thru the travel and caused all kinds of problems that was the big factory push to extros and the one that gave the extros and stabbing a bad rap


Do NOT run the track too loose.... many people do with extros and end up stabbing the rails thru the windows... IMO, too loose of tracks by people with Extrovert drivers is the main cause of stabbing track windows with the rails ("stabbing")... most sleds do not, IMO, need anti stabbing kits...

There is a difference between an extrovert and a combo driver... unless it is ratcheting, the teeth on a combo driver never touch the track.

Here it is

 

[94fordguy]

Great find on that old post... I was thinking of that very one as I read the first post.

I also run my track at factory spec and have never had a problem with ratcheting.

I would think the reason the longer RMK tracks need to be so much more tight is as the longer the track is, the less force is needed to stretch the track enough for it to jump on the drivers and ratchet. A 10 ft long track is gonna be a lot harder to stretch a half inch than a 14 foot long track.

 

[mountainhorse]

PLUS...

Also, with the Combos on ANY Polaris RMK>....Run STOCK tension specs if you want the track to perform well...especially on the lightweight single ply tracks....The myth that a loose track will turn easier and use less hp is just that... a myth... Loose tracks are more prone to stabbing, the paddles lay down easier, the track balloons out and rubs on the tunnel or decreases clearance, and there is more friction along the hyfax when the sled is in motion with the wieght of the rider and sled on it....Turning it on a stand with the track off the ground is NOT representative of what is happening with a sled on the snow and in motion. This comes from Camoplast as well... they make most of the tracks, including the Power Claw, that we run on our RMKS!..... Jack Struthers, owner of Carls cycles also supports this position.

 

[CPearce]

Well done finding the post! I do remember reading this post from MH in one of the anti-ratchet driver threads.

This is starting to sound like school when the teacher asks you a question and you say "Oh, f*ck I know this" and nothing comes to mind.

At first, I was using a bike chain as an analogy to compare track tension, because if the bike chain is too tight in turn needs more force to turn around. But when a chain is so loose it’s basically inoperable because the chain wants to fold/flex prematurely or come off the chain.

Having the track snug makes the track move in a unison motion which creates less energy and resistance. I'll be leaving my tension at 1/2", thanks for slapping me straight.