Riding off road you almost never need more braking power; at least more than most good race based Enduro bikes come with as standard these days. The era of shit brakes that needed hands of iron and faded away on the 5th corner in MX are gladly gone. Anyway most of the the time the surface will not give enough grip to let you use the brakes in a deep ” fade the fuck away” sort of way, thus upgrading the discs to a larger diameter is not really worth the expense and weight for most post 2000 enduro bikes. The exceptions are fast parked motocross tracks when you are hard on the brakes every corner, high speed events with huge downhill sections (erzaberg!), supermoto style sections on tarmac, and of course the one or two bikes that are over weight and come with crap no feel brakes- mentioning no names….
The other reason to change the brake discs at least, are that some of the wavy designs clear mud and sand a lot better than a plain disc, and some disc designs save some weight relative to the standard fitment. The most important thing you can do is get better feel and a smoother more progressive braking, I have found that the discs made from the correct steel can help a lot (after a change of pads to something first rate like SBS and a good bleed has got your anchors as good as they will go with out changing the standard set up).
This oversize disc below is by a company called Hollis, it is made almost 20% larger than a standard KTM or Husberg disc but is almost the same weight, also the outer part of the disc is made of hi carbon steel, this is stronger and has more friction than the easy maintenance stainless standard discs, but of course it will rust a little. The other cut V shapes aid cleaning considerably and help to reduce the total weight at the same time, having holes in the disc will obviously reduce the pad to metal area, but the use of HC steel balances that out and the better cooing improves race conditions efficiency again. The floating disks are very precisely made on the hollis offering and made the brakes feel a lot more progressive.
I guess i have sold them to myself… but they still cost money… but what the hell does not?
The is the standard replacement quite a decent £30ish pounds…