I just installed a detachable backrest on my Sportster and the backrest posts are now not wide enough to slide into the new sideplates. Anyone have a similar problem? Parts I used are - detachable chrome sidplates-53913-04, and docking hardware 53529-04. It's on a 2010 XL1200C with no saddlebags. The docking hardware was installed just as the instructions say, pretty straightforward. The new sideplates are angled inward to compensate for the quick release mechanism but looks like they're not angled in enough to use the original backrest. I shouldn't need a different style backrest but that's the only thing I can think of. anyone have this problem??

 

Looks like the wrong backrest to me.

 

Yep, wrong sissy bar. Too narrow.

 

Or, the sideplates should be mounted inboard rather than outboard as they are now.

 

The sissybar you got is for the non-detachable side plates. The docking hardware/sides plates are installed correctly...just the wrong sissybar.

 

This is the correct answer. You have the wrong sissy bar for the detachable side plates.
Non-detachable side plates mount inside the rails and use the narrow sissybar.