49mm fork's
 

i want to put a 3deg rake on a 06 dyna glide, what i want to know is what is the differance between 49mm and the 41mm forks (apart from the size). :icon_denk:

Plenty of difference. You can't just slap 41mm on 49mm trees if thats what you're thinking. Why would you want to go to a thinner fork? I also believe the 41mm forks/lowers will be 3/4 axle so you'll be doing some work on your wheel either changing bearings (not sure if they are sealed) or buying new wheels. Also, you'll be doing something with your fender as the late model fender may or may not fit due to the small fork size and change in overall width.

Do you have a wide glide? If so, you have 2* trees now so you're looking at a nice chunk of change for +1*.

Not sure I understand what you are looking for, since to swap to different diameter forks you will need to change out the entire front end, trees, forks, axle, perhaps axle bearings, wheel spacers, etc...
I have not actually done this swap, but have investigated it, wish it was in my budget...

The size is all that matters. Hard to shove a 49mm tube through a 41mm hole.