Hi, I replaced my headset and when I tried to install the 1 1/8″ crown race on my 1 1/8″ steerer tube it didn’t fit? It seems to flare out right at the bottom making the diameter about 5mm bigger than my crown race? Not sure what do do now?

put the crown race on?

It’s supposed to flare out there – the corwn race is an “interference” (i.e. very tight) fit

you need a crown race setter or ‘equivalent’ tooling.

yeap crown race settter and a hammer!!

OR if the headset uses “cartridge” bearings, you can remove any seals on the crown race, cut a “slot” with a hacksaw (just one cut with the saw)
debur refit seal and fit to forks, (it make it easier to remove at a latter date as well.)

DO NOT DO IF HEADSET USES LOOSE BEARINGS/CAGE (if the bearings run straight on the crown)

i have a split crown race and it fits very tight but my cartridge bearing doesnt fit over it when the crown race is fitted?

check bearing correct way round and check you not mixed up with top bearing (shouldn’t be diff but some are)

other than that diff headset there is so many “standards” out there!

the steerer is ‘how they all are’ can you do pics with the race and bearing fitted?