Can I fit a 18x 3.5 hd blade wheel on a 03 Electra glide??? If so what do I need to change and is it worth it

 

You can answer your question in part by looking at Harley's website. It is designed for 04 and on bikes, which means it may fit your bike, but you will need different rotors and possibly adapt or change your calipers. Not a bolt-in, but not impossible, with determination! Someone over in the Touring forum may have a better answer.

 

An 18x3.5 will fit either the front or rear. What size are the bearings and what year bike did it come off? You can do up to a 21" wheel on the front and up to an 18x4.25 on the rear as long as the hub is configured properly.