… on CRC http://www.chainreactioncycles.com/Models.aspx?ModelID=30592

How the hell do I work out which ones I need for my bike????

08 Yeti 575 with 2007 Lyrics

Can’t see anything in my manual that would say I need PM 6″ / 7″ / 8″

Also, are they any good? I’ve always had Hope or Shimano and been happy with both. Anything to be aware of?

PM = post mount
IS = International Standard Mount

EDIT: Looks like Lyriks are post mount rear is IS mount
Edit – not sure what size in inches refers to

I’d go with RH lever PM 203mm rotor for the front and LH Lever – 180mm – IS for the rear.

The inches will be the rotor size at a guess.

AIUI The metric number (160mm, 180mm, etc) is the disk size, the imperial number (6″, 7″, etc) is the mount size. Most forks are 6″ and use an adapter to go bigger (I suspect yout Lyriks are). Some forks, including Maguras, have direct mounting for the bigger sizes. Maybe that is why the 6″ ones are expensive.

EDIT, just done a quick google in case I was talking nonsense. These magura Thors are listed as having a 7″ post mount http://www.magura.com/en/products/suspension-forks-2010/prod/thor-3.html Postmount 7″ disc mounts, i. e. direct mount of the caliper without adaptor to run with a 180 mm/7″ rotor.

George, your Lyrics are PM6. If you put the brake straight on to the fork it will fit a 160mm rotor perfectly, you need adaptors for every other size. It’s the 8″ one you want, for an 8″ rotor.

Maguras are always sold assuming that you have the standard 6″ Post Mount standard and you would need to order a QM7 adaptor separately if you had Magura Thors with the PM7 standard.

Incidentally, this kind of pricing really irritates:

http://www.chainreactioncycles.com/Models.aspx?ModelID=52240

Sorry rocky I’m still confused. If I buy the wrong size, can I make it right with adaptors? Or do I just change the rotor size?

So at the moment…

Front 203mm hope disc on post mount lyric
Rear 183mm hope disc. Frame is is mount, but then I’ve got mount b on which converts it to post mount.

Is there something I need to measure?

Please can someone just tell me what to buy?