Difference between 39-171 and 39-315

The major difference between the 39-171 and 38-172 compared to the 39-315 and 39-316 is the style of their link arms.

On the 39-171 and 39-172, the link arm is installed under the gear arm and is offset up. The link arm also has a clip that locks onto the stud bracket.

On the 39-315 and 39-316, the link arm is installed on top of the gear arm and is straight. It also has a hole that pushes onto a stud bracket, with no clip.

These may seem like small differences, but they're important. I recommend looking over our product photos to give it a second look and determine which pair is closer to your existing hardware.