Track Clearance discussion

[byeatts]

The 2010 XP 800 Summit X in my shop right now has the stock drivers /track.

With the XP having front bulkhead heat exchangers and full length U-coolers in the roof of the tunnel... I'm not at all worried about ice build up there from "too much" clearance.

It has 1" front clearance and 5/8" at the top...with the stock 2.33" lug.
The top is the tight clearance spot.

The 7 tooth, 3" pitch drivers increase clearance by .30" (about 5/16")
A 3" track lug on the 7 tooth drivers will take the clearance down to 5/8" front, and 1/4" on the top.

A 3" wont rub on the top unless you run the track loose.

Running the 3" track at anything less than factory tension will, IMO, lead to early track failure and delam from from the excess heat buildup.... not to mention diminished performance from more friction across the hyfax and the paddles "laying down" because, without proper tension, the leverage of these tall paddles will flex the track belting and lay down because there is not enough tension to keep them standing up

"Not Rubbing" and giving proper performance are not necessarily the same thing.

The XP has pretty good clearance for a modern mountain sled.

Drag from lack of clearance is more of an issue in heavy/wet snow than light/dry snow.

A 3" paddle will move more snow thru the tunnel than a 2.5" paddle. More snow, less clearance... more drag.

Here is my take on the topic from another thread in the Poo section... but it applies here IMO.

Good info .Damn Thought I had my decision made

 

[lookup]

I just ordered a 162" 3" paddle for a xp 880 and avid 7 tooth drivers.This post had me scared off, but how many failures are actually out there compared to the amount of tracks sold, only bad news travels fast. Only time will tell how it will hold up.DANG the want factor!

 

[byeatts]

I just ordered a 162" 3" paddle for a xp 880 and avid 7 tooth drivers.This post had me scared off, but how many failures are actually out there compared to the amount of tracks sold, only bad news travels fast. Only time will tell how it will hold up.DANG the want factor!

As suspected many different opinions on clearance,Spoke with many who have had no issues with the 3 in, They did have a bad batch!I wonder how the Doo 2012 with a 2.5 and little clearance will perform when it gets deep? In addition I just received a set of Wahl Bros 7 tooths. They are larger than the 7 Avids. Just another option

 

[byeatts]

As suspected many different opinions on clearance,Spoke with many who have had no issues with the 3 in, They did have a bad batch!I wonder how the Doo 2012 with a 2.5 and little clearance will perform when it gets deep? In addition I just received a set of Wahl Bros 7 tooths. They are larger than the 7 Avids. Just another option

I,m finding out some interesting facts which i will post soon, The unanswered question, Has anyone observer the amount of ice buildup above the drivers?

 

[byeatts]

I think the gains are from the shallower attack angle (generally a good thing for the deep) and being able to run a bigger driver might add a little efficiency/reduced rolling resistance.
I am not sold on "just" the additional clearance being of any measurable benefit......but when someone goes "all-out" with a dropped or extended chaincase they are generally also accomplishing these other things which are, without a doubt a benefit for a deep snow sled.
I have heard talk of air pressure being built up and possibly slowing track speeds.....I don't buy into that at all. In my "normal" job we have done several tests that I can relate to this, and what it takes to build up any sort of air pressure or resistance and from what I have seen using huge volumes of air and sensitive equipment, it is just not going to happen.... way too many escape routes for air on the sides of the track and through the driver windows. No more resistance than it will see just from the nature of the paddle/air friction....if that makes any sense.
Given the choice I think the added clearance has more benefits than drawbacks....the big factor is the effort and expense involved to accomplish this.

Another thought....many years ago I had helped build some sleds with huge clearance....like 2"+. Depending on your cooler configuration, what I generally saw was huge amounts of snow/ice buildup in the tunnel and the track would carve a path through the snow....so in reality the clearance was virtually zero most days....plus the added weight. With the right cooler layout this would not be a factor.

There have been many credible opinions on the clearance issue and the benefits. After discussing this with many long timers ,I Agree with your post.Too much Extra clearance will ice up and create weight and the approach angle will be the best benefit.Looks like ill stay with the 8 tooth. i will have 5/8 inch clearance on top of the drivers and one inch through the cooler,Also thinking about removing the fins to allow better snow flow at the cooler. Also I feel much more comfortable about the 3 inch after talking to many that have no issues at all and Love the track.Commonly hear stories about stock sleds with a 3 inch and is a contender with a turbo with stock track.Thanks everyone for your thoughts on a subjective issue.sure looking forward to running this full Mod 880/extended chaincase 3 inch with this setup

 

[sledsrock]

There have been many credible opinions on the clearance issue and the benefits. After discussing this with many long timers ,I Agree with your post.Too much Extra clearance will ice up and create weight and the approach angle will be the best benefit.Looks like ill stay with the 8 tooth. i will have 5/8 inch clearance on top of the drivers and one inch through the cooler,Also thinking about removing the fins to allow better snow flow at the cooler. Also I feel much more comfortable about the 3 inch after talking to many that have no issues at all and Love the track.Commonly hear stories about stock sleds with a 3 inch and is a contender with a turbo with stock track.Thanks everyone for your thoughts on a subjective issue.sure looking forward to running this full Mod 880/extended chaincase 3 inch with this setup

Well get on it...and hurry up! I think mother nature is holding off until you're ready. While some of us have been ready...