I had my installer check what size my front door speakers were and turns out they are 6X9's. They also require brackets to fit properly. Anyone know where to find the proper brackets. Also, what size are speakers are the rears?

 

They are the same as the adaptors on the 2015-2018 F150 and they can be found online from various sources like Sonic Electronix, Crutchfield, etc, etc. including Amazon.

You can also visit Metraonline.com

More than likely they won`t have all of the items available for the 2018 F250`s listed but you can just type in 2017 F150 and it`ll bring up all of the items that are available including speaker adaptors, speaker sizes, and part numbers for the adaptors.

These will be the same for your F250.

Hope this helps.