For the first time I have a frameset with integrated headset bearings i.e they go straight in the frame without any additional bit of metal getting in the way. Which to me is a good thing.

However, I was somewhat perturbed when I went to press them in, in that they didn't need pressing in, they fell in and are a rattling fit. I get that they have tapers to centre them but this seems wrong to me and my instinct is to reach for the high strength loctite bearing fit.

I take it I'm just being paranoid? However my thought is that if the bearings become loose, they will be bashing around in the headtube which is going to knacker the tapers in short order. (I'm not in the habit of riding bikes with lose headsets, well not if I can help it, but if it comes lose mid ride this isn't ideal.....)

Any advice welcome!

No great insight, but I can tell you the ones in my full-sus are the same loose fit. Struck me as sub-optimal too, but I stuck them in and promptly forgot about it

They'll be ok fitted with some grease as normal but you're right about a risk if ridden loose for long or ridden hard like that. A press-in cup might ovalise the HT in that case, here you might get some distortion of the seat taper - but the taper can be tolerant of some imperfections.

I'd just pay attention to how well it all fixes up and beds in. Bikes with carbon steerer forks and integrated HSs can be a bit flaky here as the steerers can stretch and flex enough for the bearings to shift a bit. But you know what I think of carbon steerers.. the headset's the last of my concerns

Tah, I'm overthinking it as usual!
Steerer is alloy and the lump of carbon attaching it to the fork blades is reassuringly chunky so fingers crossed....

'Rattly' suggests a red flag for me, I'd check the replacements are actually the right size. There's an annoying variety of bearings, and I've got it wrong in the past not being super accurate with the calipers and getting say a 51.8mm OD when the original is actually 52.0mm*

*if you're wondering why both those sizes exist, that makes two of us!

AlexGold wrote: ↑Mon Aug 05, 2024 9:08 pm 'Rattly' suggests a red flag for me, I'd check the replacements are actually the right size. There's an annoying variety of bearings, and I've got it wrong in the past not being super accurate with the calipers and getting say a 51.8mm OD when the original is actually 52.0mm*

*if you're wondering why both those sizes exist, that makes two of us!

Should be OK as its a Salsa frameset which included the headset....
(grabs Vernier calipers and heads for the shed)