Loose Crown Race

rjsterry

I'm replacing the headset on my 1997 Giant (from 1" threaded Shimano STX - to cheapo VP 1" threaded - cheapo so that if I make a mess of it, it's not the end of the world). Anyway, the old headset came off without any problem, but I've just dropped the new crown race on to the forks and it's not a tight fit - i.e. the crown race has a slightly larger ID, maybe a couple of 10ths of a millimetre. Oddly if I flip the race over and slide it on upside down, it does then fit tightly, although this maybe because there is a slight taper to the bottom inside edge of the race. I've held the old and new races up together and the difference isn't really discernible (to my eye anyway). Have I unwittingly bought a slightly different size headset or is there some other explanation. Also, is there any easy fix, assuming that riding with the crown race loose is not a good idea.

Thanks in advance.

desweller

There are different sizes of crown race. Do you have a set of calipers?

nicklouse

rjsterry
it can happen especially when the first is at the tighter end of the tolerances and the second is on the looser end.

fit and see how it is in use.

a good (very good) bike shop should have a fork steerer raiser. it is a tool that putts a knurling on the wider part of the steerer allowing a tight fit to be achieved.
Please note this is a once only operation and usually is a action of last resort before replacing the fork.

TBH I would fit it and see. you my "take up the small movement with grease

rjsterry

Thanks both of you. The old STX headset was 26.4mm ID, but I wondered whether the new VP one might have been 27.0mm ID, as I'd read on Sheldon that some headsets do use this measurement. I managed to make myself a shim from some very thin plastic - one of those little flowerpots that garden centres put seedlings in, cut into a thin strip - which worked pretty well. Unfortunately after getting the whole thing together, it turned out that the stack height of the new headset was slightly too low (about 1mm) even with an extra washer, so I couldn't tighten the locknut against the top race without pushing the rubber seal out. So, the whole thing had to come out again and the old STX put back in. The STX crown race really was a snug fit when it came to refitting.

Still, on the plus side, I've had some good practice with my home made headset press, and have managed to get the old headset running better than it was before. Glad it was only a £10 headset I 'wasted'.

Thanks again.