Mikeyp wrote:definately a convetional threaded headset in that case then, that is what it looks like anyway, ok, but according to that site the Park site, I am supposed to measure the diameter on the outside of the steerer ?? I guess it will all make sense when I take the biatch apart
Yep it's pretty likely that you'd have a conventional one. The Semi IS and IS are relatively new (someone help me out with years) and if you read the Chris King spiel on IS systems, you'd never buy one. The say
'All bicycle frames that use integrated headsets will ultimately have substantial performance and reliability problems due to the inherent flaws in this design. The largest flaw is a bearing system that does not positively attach the bearing to the frame, leaving the bearing to "float" resulting in wear and impact damage to the frame. As an additional complication, each manufacturer seems to be doing their own thing, with no real standardization to date. As a result, there are multiple bearing types and sizes (some of which have been discontinued with no replacement options) and the frame builders and bearing makers are not all working from the same drawings.
Lack of standardization is a bad thing for everyone. It means that you may not be able to get replacement headset bearings for your bike, and you will need them.'
This is from a company that also actively states not to use carbon spacers either.