Rotor sizing

[NicoBoshoff]

I am currently running 200/180mm setup on my bike.

 

Ordered some new rotors but want to run 180/160mm setup.

 

Can I simply move the caliper adjusters from the rear to the front and run the rear with no adjusters to make the caliper sit at the correct height?

[merwe]

Depends on the disk brake mounts on the frame and fork. There are two standards, IS (international standard) and post mount. On the rear you'll typically have IS, and at the front post mounts are more common. Check out this article: http://www.bikeman.c...74mm-post-mount

 

If you have IS mounts you will always need an adapter, but for post mounts you would not need one if you are running a 160mm disc.

Edited September 18, 2013 by merwe

[NicoBoshoff]

As I understand it the post mounts are standard unadjusted for 160mm so for anything bigger you need adjusters. So it would make sense then to just remove the rear adjusters on there now to the front and then go 180/160, no?

[merwe]

The IS mounts always need an adapter since the holes are at a right angle to what the caliper's needs to be. Post mounts do not need an adapter for 160mm discs since the post holes are in line to what the caliper's needs to be.

If you have post mounts at the back, you would not need an adapter. but if you have IS at the back, you would need a 160mm IS to Post mount adapter.

 

If you have IS both at the front and rear, you need to get a 160mm IS to post mount adapter for the rear and you can possibly move the 180mm adapter at the back to the front. If you have post mount rear and back, you can mount the rear caliper directly on the frame, and move the 180mm adapter to the front. If you have post mounts at the rear, and IS at the front, you can mount the rear caliper directly on the posts, and you need to buy a 180mm IS to post mount adapter for the front. And finally, the most common scenario, if you have IS at the back and post mounts at the front, you need to buy both the 160mm IS to post adapter and the 180mm post mount adapter.

[NicoBoshoff]

I have post mounts front and back so it's a simple move of the rear adjuster to the front.

 

Thanks!

[Unknown MTBR]

Sorry wrong button.. nothing to see here!

Edited September 18, 2013 by Dewald ZA

[no calves]

The IS mounts always need an adapter since the holes are at a right angle to what the caliper's needs to be. Post mounts do not need an adapter for 160mm discs since the post holes are in line to what the caliper's needs to be.

If you have post mounts at the back, you would not need an adapter. but if you have IS at the back, you would need a 160mm IS to Post mount adapter.

 

If you have IS both at the front and rear, you need to get a 160mm IS to post mount adapter for the rear and you can possibly move the 180mm adapter at the back to the front. If you have post mount rear and back, you can mount the rear caliper directly on the frame, and move the 180mm adapter to the front. If you have post mounts at the rear, and IS at the front, you can mount the rear caliper directly on the posts, and you need to buy a 180mm IS to post mount adapter for the front. And finally, the most common scenario, if you have IS at the back and post mounts at the front, you need to buy both the 160mm IS to post adapter and the 180mm post mount adapter.

 

Didnt the XTR brakes of old use the IS standard and in orderto centre them yiou had to use washers and spacers??? It was a pain in the ass