I'm looking to replace the front and rear rotors and I have a question. Are the fronts 11.8" (300mm)? Will 11.5" fit in the front? And is the rear a 11.5"?
Also are Full Floaters worth the $$ (pro's & con's) or can the fronts be one piece? Thanks

 

I had these on at one time and never had a problem. Just depends how much you want to spend really.

https://www.summitracing.com/int/sea...illocation=int


Edit: You should throw in new pads to give em a fair shot a proper bedding.

 

Front are 11.8" and a 11.5" rotor will not fit (and be dangerous since pads will sit further than the rotors)

 

I don't know what your riding style is, but here are my thoughts. Full floating rotors are a good investment if you really use your brakes, spending time running mountain roads, anything that involves braking from high speed repeatedly. Floating rotors have less of a tendency to warp under these conditions as the braking surface is thermally isolated from the disc hub by buttons that hold the works together, this allows the braking surface to expand freely as heat is generated.
Floating rotors are not maintenance free, the buttons must be kept clean or binding may occur which will feel like a warped rotor as collected brake dust binds up the the movement.
Your choice depends on your usage of the motorcycle, you're FXDF is equipped with floating rotors on the front. There is controversy on whether or not the the Harley rotors are actually floaters. They are floating rotors, the side to side movement is controlled by very stiff wave springs behind the buttons, you can't move the rotor by hand as you can on most aftermarket floating rotors, and that is where the controversy comes from.
In the end its your choice, I would not recommend trying to save money here as the brakes are the single most important system on the entire motorcycle.

: Mike

 

All I know is if your Fat Bob was in my garage there'd be dual Arlen Ness Big Brake rotors on the front and an EBC free float rotor on the rear with Lyndall Z+ pads all 'round...

Edit: But wait, you've got 16" wheels front and rear; those Big Brake rotors are 15"; damn close, I dunno now. Still think I'd try and see if they'd fit...

Second Edit: I just did some measuring on my Big Brake rotor; they won't fit on your Fat Bob. Damn, that would have looked incredible and hauled your bike down with a quickness I'd still consider full/free floating rotors for your ride. Too bad the Big Brake rotor won't work...

 

yep it's bad it won't work
I personnaly prefer CL brakes or EBC HH (both sintered, CL Brakes are easy on rotors) ower Lyndalls

 

Fun reading
https://www.hdforums.com/forum/touri...ke-rotors.html

 

Per your measurements I assume an 18 inch front rim on a fatty would be fine for clearance?

 

Honestly, as I've never done it I can't be sure if it would work with an 18" wheel or if you'd run in to some clearance issues.

With my Big Brake rotor on a 21" wheel I can only measure and guess, but this is cvaria's Sportster running dual Big Brake rotors on a 19" wheel to help give you a visual of how they sit...

 

Yeah looks pretty close hey?