Tamiya Track kit...extra parts?

[mjbeals]

I'm in the process of building up my first robot using a Tamiya track kit.  After putting everything together, I have some extra pieces that are not referenced in the documentation at all.  They look like a pair of linkage arms and some stand offs, but I have no idea what they are supposed to be used for.  I know the kit comes with other wheels and extra track, so I'm assuming these are for something else as well.