Hey forms. From my experience of working in a bike shop, headset spanners are often innacurate, or the headsets are, either way. I just fitted a 105 headset and the 32mm didn't quite fit it, despite fitting other headsets fine.
Try really gently sliding the spanner on, if that doesn't work then yes, file the spanner a bit, but you need to do quite a good job so that there are no burrs or sharp bits to damage the headset.
Hey forms. From my experience of working in a bike shop, headset spanners are often innacurate, or the headsets are, either way. I just fitted a 105 headset and the 32mm didn't quite fit it, despite fitting other headsets fine.
Try really gently sliding the spanner on, if that doesn't work then yes, file the spanner a bit, but you need to do quite a good job so that there are no burrs or sharp bits to damage the headset.