On Thursday, October 12, 2017 at 7:36:15 AM UTC-7, Joerg wrote:
On 2017-10-11 18:16, jbeattie wrote:
On Wednesday, October 11, 2017 at 2:36:03 PM UTC-7, Joerg wrote:
The adapters to increase rotor size in a post-post situation (which
I have front and back) look like this:

http://i.ebayimg.com/images/g/oK8AAO...Au/s-l1600.jpg

My MTB has a factory one from 160 to 180mm up front but I am
considering 203mm. That would make the thing even more extreme,
like this where the screws would look more cattywompus or out of
line than they already do:

https://i.ebayimg.com/images/g/w4MAA...bTa/s-l500.jpg

Why are the spacings so different on both sides while for 160mm
their are not?

The angle of the caliper changes as you get into the larger rotor
sizes and thus the disparity.


Understood. This is also what Ralph wrote. However, many calipers such
as mine have round pads where it doesn't matter if the angle is slighlty
different.

I don't know your brakes, but the rotor might hit the internals if the caliper is not angled correctly. You want the mechanism following the arc of the rotor, which is what you will get with your spacer. You also want to engage as much of the rotor as possible. I don't think any of this is optional, is it? You just put in the spacer, and you're done.

-- Jay Beattie.