_____________________ SPROCKET CONUNDRUM
By, Kevin Toole
Sprockets play an important role in heavy equipment. After all, without them the machines wouldn’t move. This article is going to focus on some aspects of rubber tracked machines and some information that can be helpful to you when ordering sprockets. Many times it is not all cut and dry and even the guy behind the parts counter may not be aware of an unexpected situation.
First off, when replacing your rubber tracks it’s typically a good idea to replace the sprockets. This is not always the case with mini excavators. With them a good rule of thumb would be to replace them with every other track change. Given this rule it is always best to at least inspect them though just to head off any premature problems with track failure. It doesn’t take much for a sprocket to rip a lug out of a track and at that time the track is finished.
Mini Excavator Sprockets
So what should I be looking for you might ask. There are actually only a few small differences in rubber tracked machine sprockets. I will touch on mini excavator sprockets first. We will focus in on mini excavators that utilize a 300 millimeter wide track and larger. These tracks are generally manufactured with two different width guides which correlate to the corresponding sprocket widths. Beyond the dimensions, there is a quick method to ascertain whether your track is a wide guide or a narrow guide. The narrow guide can be determined by laying two fingers into the tracks guides and the wide guide can be determined by laying three fingers into the guides. The narrow guide is approximately 1-9/16 inches and the wide guide is approximately 2-⅜ inches.
Compact Track Loader Sprockets
Let’s jump over to compact track loaders or CTL’s which they are commonly referred to. Bobcat CTL’s in particular utilize a dished or bowl type sprocket. Specific models can use a different depth bowl with a serial number breakdown. This can get very tricky if your not careful. The first thing that you need to do is determine the bowl depth of your current sprocket. You cannot rely on the parts counter salesman to use your serial number only to determine this. The reason for this is that some machines may actually have two different final drives on them requiring two different sprockets. To determine the bowl depth simply set the sprocket on the ground and measure from the ground to the top of the teeth. It may be a little more difficult to do while installed, but you generally only have to be close. There are basically only about two sizes. In some cases a spacer may be utilized to make the final fit.
Takeuchi CTL Sprockets
With Takeuchi CTL machines specifically TL140 and TL150 as well as the respective correlating Gehl and Mustang models. You will need to know the inside opening diameter where the sprocket slides over the final drive. There are actually only two dimensions which are 200 mm or 242 mm. Beyond this you would not need to know much more to replace them.
Another question that you need to be prepared to answer is the number of teeth and the number of bolt holes that your sprocket has. Many sprockets will have more bolt holes than your machine requires but keep in mind that typically a manufacturer will try to cover as many machines as they can with one part. This is very common throughout the industry with all parts. It holds true with all machines and not just rubber tracked ones for that matter.
Beyond what I’ve mentioned, there really isn’t a whole lot more to know. Unfortunately, not all machines are standardized so it can be a daunting task to keep up with all that is available in the world today and virtually impossible to stock it all.
For more information or help with understanding your parts needs, please visit us at www.traxnm.com.