Why use the offset hole in a flip kit bracket

[44boggers]

I know this has been discussed a bit before, but I dont really understand why flip kits that you buy come with the offset hole to move the axle back. Is it simply so you do not need to shorten the driveshaft and somewhat adjust the pinion angle?

I am in the process of flipping my axle now but I will be using real spring perches, set my desired pinion angle and weld them in. But my plan is to weld them in the stock center hole. Then shorten my driveshaft accordingly.

So what is the reason behind the offset hole? Wont it make your wheel not centered in the wheel well?

Am I missing something?