[cparky]

Can you help me find the right Adaptor to fit my disc brake callipers to my new front forks?

I have:

160 mm Disc

B4 Formula Calliper IS Mount

Rock Shock Post Mount disc brake standard

I bought an adapter from a bike shop for Post Mount to an IS Mount. This is a very similar one except the one I bought was for 160 mm discs: http://tinyurl.com/36qw65w
This didnt work as the calliper would not fit on.

This is a discontinued brake but I found the user manual and parts diagram:

User Manual
B4 Brakes: http://www.propelbike.com/tech-docs/manual_b4.pdf

Parts Diagram: http://www.propelbike.com/tech-docs/formula-exploded/older-systems.pdf

Picture of them: http://tinyurl.com/28twe5k

This is a picture and description of the new forks im using:

Rock Shox Dart 3: http://www.jejamescycles.co.uk/rockshox-dart-30mm-item97107.html

Any help would be greatly appreciated.

 

[Mr Jones]

That's a toughie. The calipers you are using have integrated adapters to International Standard (IS) brake mounts. I'm sorry to say that you may either have to get new brakes or change your fork to one that has IS mounts.

 

[moff_quigley]

You should be able to find a Hope +20mm post to IS adapter. You 'll need a 20mm larger rotor than what you are currently using too.

edit: Magura makes them also.

 

[NuMexJoe]

That sounds right. Or a Magura QM3 adapter and a 180mm rotor. I did the same thing recently when I got a Reba w/ post mounts. Lots of places are blowing out Magura adapters for <$10, but the QM3 is hard to find. I had to go the ebay route.
- Joe

You should be able to find a Hope +20mm post to IS adapter. You 'll need a 20mm larger rotor than what you are currently using too.

edit: Magura makes them also.

 

[Lelandjt]

I'm trying to sell 2 sets of IS brakes and this is the problem potential buyers are having. The adapter needed is very rare and I've never seen one.

 

[gearskip]

I ran into this with my previous generation XTR calipers on a Fox fork. Like everyone above, I ended up with a 180mm rotor. That's fine but I wish you could still get a decent fork with IS mounts.