How long are these meant to last? Changed 18/12 ago and now there seems to be a bit of play again. Am I doing something wrong?

12/18 months? how much riding are you doing…? more info is needed but, if the bearings themselves can be replaced, ie: cartridge style, then the cups should be fine unless the cup itself (the part pressed into the frame) is horribly corroded or distorted.

FWIW I’ve replaced sealed cartidge bearings in a FSA headset top assembly after 5 years use + and the headset is like new unsurprisingly. Top cup was undamaged. Saw no reason to knock it out and replace that part itself.

XC; ten mile loop once a week, though the last mile is down a cobbled hill which gives everything a bit of a beating.

Hope headset. Original 44mm external cup and replacement 44mm internal top cup.

you using a traditional star nut or Head Doctor? I’ve read of some people experiencing slipping with Head Doctors which might contribute to a lack of compression on the bearings but i’ll be honest here and bow out of this one. There are bound to be more experienced Hope Headset bods out there. Nice bit of kit and i’ve only heard good things with the headsets. Hope you get it sorted!

I’m using a traditional star nut. I’d like to think I might be able to (temporarily) fix this by increasing the preload, but…

What do you mean by “top cup” exactly? Do you mean you’re wearing out bearings quickly, that the cup is moving within the frame, or something else?

Not sure. Cup doesn’t seem to be moving but there’s a definite knocking on rocking the bike forward & back with the brakes on – I assume that will be bearings?

I’m using a traditional star nut. I’d like to think I might be able to (temporarily) fix this by increasing the preload, but…

Yeah.. best avoided lol. FWIW I once rode for almost two years with a slight knocking in a headset I could never ‘cure’ and typically tightened the nut pre ride to get me through. Not clever. Thought the whole headset was shot. Turns out I’d missed an entire component of the top assembly during a fork fitting- a conical wedge, CRITICAL to the bearing preload.. ended up with seized lower bearings that rotated on the crown race-thew whole brown rusty unit rotating on the race.. got away with it but the lesson is, you shouldn’t have to crank the preload any more than to stop play. If steering tightens, you’ve got it far too tight.

Have you tried turning the bars 90degrees and rocking the bike back and forwards?

when you grasp the top headset assembly, can you feel a part of the assembly moving when rocking the bike on the front brake? knocking can be MANY things but headsets are normally pretty easy to diagnose. That said, doing it via the internet is hard.. Don’t be afraid to take it apart, give yourself time and re assemble re grease etc and see if the prob still exists. Its entirely possible it is shot bearings but it could be fork bushings…wheel bearings..

Mate thought he had a loose headset, turned out to be rotor bolts were loose 🙄

could be rotor bolts, caliper bolts, or even just movement in the pads in the caliper.

Try as suggested above – rotated bars 90 degrees and see if it still does it.

Turning the bars 90 deg says it’s not the headset.