Power through it..

Here is a topic of conversation. And when I say conversation, at times more like a heated debate. It could also be phrased as: Which axles does most of the work… forward or rear?

Most people immediately guess that it is the rear axle that does most of the work. Their evaluation is based upon tire wear. The rear axle tends to wear tires faster, so the assumption is that it works harder. While increased tire wear is a concern, the cause is not related to power division. This is one of many situations where the evidence does not support the theory.

Looking at the picture we see that the housing on the forward axle is quite a bit bulkier. This is because it contains the power divider, and all the gearing associated with that. In all, this could make the forward axle up to 200 lbs. heavier than the rear drive axle.

When unloaded, the pivot point of that group moves slightly forward, creating scrub on the rearmost axle as the chassis turns. Scrub creates tire wear. In reality, the gear housing, or pumpkin, is offset on the axle, making one outer end lighter on each drive axle as well. Typically, the lightest loaded axle is the right rearmost of the group. Most operators know this is the position where tire wear is the greatest.

We featured spider gear functionality in a previous post. Spider gears ensure that power goes to each outer end evenly, as long as the surface resistance is the same for each tire. When this is not the case, the outer end encountering the lowest rolling resistance breaks traction. It could be any of the outer ends within a group. However, the axle with the lightest load will exhibit the tendency first, with all things being equal on the road surface.

And now…

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Believe It OR Not

111,111,111 X 111,111,111 = 12,345,678,987,654,321.

Aren’t numbers amazing?