I recently got a fatback and swapped the brakes over to so Hope M4's I had but the front pads only cover about 3/4 of the disk
I'm using a J mount and 183mm disk on an IS fork, can anyone think of a reason why as I can only think the IS mount on the fork is slightly out
ps if I flip the mount it rubs the disk so I've ruled that out
[img] 
[/img]
pic is about as good as I could get
thanks in advance
J mount is the correct one. Are you sure that you have a Hope 183mm rotor? From your picture it looks to be too small.
yeah I double checked after posting, its a new floating one
Got to cover the simple stuff first. Is the wheel fully located in the drop outs?
yeah its been ridden like that for a couple of weeks, I ordered the new disk as I wasn't sure about the old one, I used the mount and calliper a couple of years ago on some revelations and don't remember there being a problem
the mount shows no indication as to which way round it should go but as I said I flipped it and it rubs the disk slightly but also I cant get proper adjustment on the calliper so I'm pretty sure its the right way
Its not uncommon to have to file a mil or two off of the tabs to gain clearance - I had to take about 1.5mm off a Mono M4 to get a brake to fit on Maverick SC32s.
so I flipped the mount again today and the same problem is there just with added rub issues as I've lost side to side adjustment, I was reluctantly going to grind up the mount but there's no point as the pads still don't cover the disk correctly
If I were you, I'd find some pictures of the mount on other bikes to check it's on right. It could be that the position where it rubs is correct and maybe it needs a washer to space it out. Easier than filing.
Might be worth posting a side picture on here as well.
Are you sure it's the top of the rotor rubbing the caliper when it's the other way up? Could the rubbing be somewhere else?
When it's fitted correctly, the letter J should be facing outwards. May be worth looking at an F mount for a 180mm rotor, won't be a huge difference, but might be enough.