You don't need to be an 'investor' to invest in Singletrack: 6 days left: 95% of target - Find out more
I had some vague recall there were 2 post mount standards but never had fitment troubles so didn't look further into it. I see 6,7 and 8 inch post mount options are sometimes offered against a single disc size ie 6 inch 203 7 inch 203 or inch 203 which is confusing me . what do these measurements in inches relate to?
May I also ask why rotors tend to be 160 ,180 then 203...why not 200? I know hope had some different sizes like 183 but why?
6, 7 and 8” disc sizes are an American thing. In mountainbiking terms they don’t really exist but apparently American heads explode when millimetres are offered as a size.
For all intents and purposes they’re 160,180 and 200mm. 183, 203... attempted standards lock-in IMO. Usually different enough to cause trouble if trying to use other components not the same size.
PM: yes, two normal sizes - PM160 and PM180. PM180 isn’t common on older or shorter forks. It refers to the native rotor size that can be accommodated without an adapter shim - hence the majority of forks being PM160 want a +20 adapter for a 180mm rotor.
Thanks for that..it is somewhat confusing with all the different sizes standards and mixing metric with imperial + conversions being way off ."Does your head in" is a phrase that comes to mind!