mal wrote:Sometimes you can remove the crown race by tapping it gently from underneath, and working round with a flat blade screwdriver (cover the tip with cloth or a bit of old inner tube to prevent marking), work your way around and go steady.
Hmm, on closer inspection, it clearly is a separate bit because there's air between the flange and the steerer tube. Having had a look at this image of a headset the bit I have pulled off is the seal, and the bit that's still fitted to the old fork is the crown race, and a bit of googling tells me those things are pretty well fitted to forks and are a bit of a bugger to get off and on. Oh well, might have to make a visit to my (not very L) LBS when the snow clears, assuming a bit of the old gentle persuader (aka a plastic mallet) isn't up to the job.
You can use a similar technique to reinstall on a new fork. Tap it round the top part of the crown race collar to slowly drop it in place. Do not strike the bearing surface.
It's a 10 minute job for an LBS with a crown race puller and an installer, however.