Post mount adapters, confused?

reaperactual
reaperactual Posts: 1,185
edited May 2020 in MTB workshop & tech
Straight forward adapter. I have fitted one to my bike and it is fine. Fit it to a 180mm native post mount fork to work with a 203mm rotor. A +23mm (SM-MA-F203P/PM) Adapter Front (180mm) to 203mm.


This adapter is causing a lot of confusion.
(I-SMMAF203PPA)


Is the above adapter used for fitting a 203mm rotor to a 160mm post mount fork or not? Does the slightly different design change the orientation and distance of caliper by +43mm? Not looking for the brainiac, long winded answers about radius/diameter measurement (for simplicity sake).

Has anyone used this adapter or anyone know for sure if it works? Searches have conflicting views and mixed up serial numbers for both and caused a lot of confusion? Thanks for any clarification on this certain adapter and how or if it works for 160mm forks with 203mm rotors.

Comments

  • whyamihere
    whyamihere Posts: 7,713
    Yes, that adapter works for fitting a 203mm rotor to a 160mm post mount fork. You can see that it pushes the caliper out by around 10mm in the same way as the 180mm adapter, but also moves it up by around 10mm, and in combination, these add up to it working with a 203mm rotor - The 21.5mm difference in the radius of the rotor is taken up by the 21.5mm movements of the caliper by the adapter.
  • reaperactual
    reaperactual Posts: 1,185
    Makes perfect sense the way you explained it! Out and up, not confused any more. Thank you whyamihere! ;)