Mounting track chains in the correct direction
Chains are increasingly mounted under machines by users themselves. And let’s be honest, you don’t need to be a genius to screw a track shoe onto a chain. And yet we still receive multiple calls asking us in which direction the chain should be mounted under the machine. So there remains some confusion with regard to mounting chains.
The machine’s direction of travel
Before we do any mounting of the chains, we need to know the difference between the front and the back of the undercarriage. When the levers in the cab are pushed away from you, the undercarriage always moves forward and therefore also in the direction of the tension wheels or idlers. The sprockets or final drives are then located in the back of the undercarriage. The sprockets run across a ladder motif of the chain that is laid out on the ground by the front wheel.
** tip: this direction of travel is the least sensitive to wear for the undercarriage parts. **
Direction of the chain
Everyone has their own way of seeing it; “the pin pulls the bus” is used often, but there are many other tips to help you remember. I’ll collect a few of the most useful reminders to recognise the right direction here.
For example, firstly: When the chain is open on the ground. The chain is in the machine’s direction of travel if you can see an arrow on the links pointing in the direction of travel. Each link has a narrow side and a wide side. The wide side should be on the sprocket side and the narrow side on the front wheel. In this case, the chain is positioned in the correct direction under the undercarriage…
When viewing the undercarriage from below, the whole undercarriage looks like the drawing below. The link on the narrow side on the idler side, and the wide side on the sprocket side.
Here’s a second reminder: if the chains are closed around the undercarriage and you drive the machine forward, i.e. towards the front wheel, the wide side of the link should hit the ground first. In most cases, chains have a trapezoidal bolt hole pattern with which the track shoes are mounted. The bolt holes of the chains are close together on the side where the link is narrow and therefore also wide on the wide side. See the photo below for clarification.
The wide side of the link or the wide distance of the bolt holes clearly comes into contact with the ground first when the machine drives forward. The front wheel is always at the front of the undercarriage.
Mounting the track shoes on the chain
The trapezoidal bolt hole pattern makes it difficult to incorrectly mount the track shoes to the chain. There are however also chains with a square bolt hole pattern. The chains can then be correctly closed around the undercarriage if we look at the wide and narrow side of the link, but the track shoes can still be mounted incorrectly.
There is an angled strip at the front of a track shoe that prevents sand entry when the undercarriage is driven. This side should be positioned on the wide side of the link and should reach the ground first during rotation of the chain. If the track shoe is mounted upside down, the sand will flow more easily between the plates in the chain.
A crawler undercarriage can be easily mounted by anyone. As long as the machine keeps running well, that’s not a problem. You can order the correct crawler undercarriage parts at www.vematrack.com, such as rubber tracks, sprockets, idlers and rollers. Do you have any questions or do you have any issues? We’ll be more than happy to share our expertise with you. Please contact us if you need any help.