Just wanted to see if anyone could offer any advice here. I currently have an XTR front calliper (M975) I.S with a 160mm rotor. My new forks are post mount so I will need an adapter. However all the I.S to post mount adapter I have seen so far increase the rotor size by 20mm so I would need to purchase a 180mm rotor. Is there such a thing as an adapter that wont push up the rotor size as I am quite happy with 160mm ?.

Thanks in advance.

I looked at this a while back and couldn’t find anything. Not much help but it might save you looking for hours. Thinking about the layout of bolt holes I struggle to see how you could make one.

WAITS TO BE TOLD HES WRONG…………..

There is one. Unhelpfully, I can’t remember the brand. It might be kcmc. It was red and only works with some combinations of fork and calliper.

Don’t you just remove the adapter as the caliper is post mount?

THIS is what you need.

( Link shamelessly stolen from a similar thread started yesterday )

EDIT: It is the one that onzadog mentioned.

“Don’t you just remove the adapter as the caliper is post mount?”
The problem is that his caliper is IS mount, not post mount

Giant used to do one for 164mm rotors (though giant MPH-3 rotors were also about twice the width of normal rotors, so 160mm should also work)
The giant MPH-3 caliper is also pretty fat, so a chance other calipers might fit
JeJames had them in stock at least in the rotherham workshop, though back in 2007 .. Might be worth a call if th KCNC one doesn’t work for your combo.

The link to the adaptor from clee cycles is absolutely what you need. I can provide a pic of it in situ if you want to know how it looks on the bike (’twas me that posted it up in the other thread

Pic might help

😳 I googled the caliper and found the PM one on a IS adapter.

Looks like you’ve found your adapter!

Thanks for all the replies. That KCNC adapter looks exactly what I need. Will order one and see how it goes with my caliper and fork combo.

Thanks again.

As I pointed out yesterday – that adaptor is the only solution BUT it won’t fit all forks.

Witness here on 2011 RS revelations – especially you bigG !

Don’t waste your time & money if your forks look like those. It’s all very well people posting a fancy picture of their set up being OK but maybe they should take the time to make it clear that it won’t work on all forks.

Steal4real. It works for me, it doesn’t work for you. That’s just the way it is sometimes. Sorry if my enthusiasm for showing a successful application get on your tits.

I’ve never suggested this is the silver bullet to this issue. But it works for me and for a lot of people. I’ll continue to put forward that advice, safe in the knowledge you’ll be along shortly afterwards to scream from the rooftops that it didn’t work for you so it’s the work of Satan!

Nice to know that someone else is making one of those. Giant used to make one while they still did the old MPH brakes, but never sold it aftermarket.

Steel4real: I reckon you could possibly space that out with a couple of washers underneath, and do a little filing in sensible places and it’d work. Depends on how much space on the outside of the rotor you’ve got. As long as the pads don’t end up hanging right off the outside of the disk you’ll be fine.