I'm working on putting a fatboy front tire on by Street Bob. It'll be the 140/75R17 Dunlop D408F which I beleive is actually 145mm wide at its widest point.

I've been measuring the space between the fork sliders and it's 155mm mostly with a small section about 160mm where there is a sort of shallow cutaway in each slider. The wider part is round about where the sidewall of the tire will be although I can't say for absolute certain being as I've not had the front wheel built yet.

So is 10mm clearance enough, i.e. 5mm per side between the tire and the sliders?

 

Anybody help with my clearance worry?

 

Doesn't the fender mount on the lower legs....If so, the fender will move at the same tire does. Only things to worry about are the tire changing circumference from speed and rocks/debris from the road.
AS far as side to side goes...if it fits you should be good to go.

 

On Metzler's tire site they specify .25" clearance each side and .5" at top of the tire. Scroll to the bottom of this link.
Your clearance would work out to about 3/16" each side.
http://www.us.metzelermoto.com/web/p...s/default.page

 

might have to consider the mounting bolts for the front fender