Novice question

[greenred]

Why on the bigger Caterpillars do they mount the drive sprocket high above so that the track runs at a angle back to it?

http://img269.imageshack.us/img269/7975/catd9l14y038221.jpg (http://img269.imageshack.us/i/catd9l14y038221.jpg/)

I have a few guesses but I thought I would get the real answer from the experts.

[Scag48]

There are 2 reasons -

1) Cat claims that power to the ground is greatly increased
2) The finals are up and out of the dirt

The dirt off the finals is easy, the power to the ground is argued. Here's my take on it though. Think of pulley systems, same amount of force exerted with another point to rotate around will provide a greater amount of work done. The downside is the higher center of gravity and more wear items (extra idler).

You'll also notice that on the L series the finals were placed further back, like the dozer you pictured. The pads are more vertical coming up to the sprocket than newer N's, R's, and T's.

[bobcat_ron]

Cat did it back in the early 1980's, because getting higher horsepower components into a conventional sized drive sprocket wasn't possible, so moving it up higher gives them more room to get the extra reduction and over size parts in there.
The other reason is very simple, more power.
Think of it this way; take a pencil and put a pulley on it, and take another one and put in your hand and put a belt around it, spin it and see what it feels like.
Then take a third pulley and mount it up high and turn it, now it's easier to turn with less force.
The same is done on all new engines, 1 or 2 belts runs everything. It used to be that every function, water pump, alternator, A/C, power steering pump, air compressor, vacuum pump was all run in 4 or more belts.
By wrapping the belt 1/4 around each pulley, you don't need as much power.
Downside is there is more friction that can wear out the belt or track as there is less teeth contacting it.

[Gravel Rat]

Tracks do last longer with the final drive up and out of the way espcially working in processed gravels like sand ect that wear parts quick.


If you look at a Cat grapple skidder on tracks its tracks are almost a full triangle.

Look at this

www.mylittlesalesman.com/listingphotos/3770/e4fe514-89ad-4667-97eb-75b3380d23f_gallerybig.jpg