New frame, internal headset (no cups) and dry fitted it all. There's a 3mm gap between the fork crown and the headtube. I can see the bearings, so I'm guessing water and sh1te will see the bearings as well. Is this normal?

are you using the crown race that came with the headset?

possibly. What headset is it?

I was surprised my FSA something or other had a plastic/rubber cover over the top race but nothing over the bottom one (other than the seals on the bearing itself)

edit: think it's an orbit z

I'm using all the headset parts that came with it. The frame and forks are by the same people and they also supply the (cheapy) headset into the package which is why I expected a better fit. It's almost like there's a seal missing or something. Those bearings are not going to last a week left like that.

Apologies for being obvious but if there was a crown race already on the forks did you take it off before fitting the new crown race which came with the headset?

If you were just fitting the crown race to new, bare forks is it properly seated? Is the lower bearing in the right way up?

yep,
bare fork (new) check!
bearing the right way up, check!
Nothing already in the headtube, check!
race fully seated, check!

I'm running out of ideas.

have you spoken to the supplier?

I had a similar issue at the top of the headtube on a road bike frame and was told 'they're all like that'.

I'll give them a call but I'm not going to be happy with a response like that.

you havent got the top and bottom bearings mixed up?

bearings are identical 36/45
(runs off to check as there must be a simple explanation)

Yes, they are identical.

can you get a photo of it?

I have various bikes with integrated h/sets, both Cane Creek and Campag standard. None have any additional bottom seal and rely on the cartridge bearing seals, and all have a gap between the crown race flange and bearing, although nowhere near 3mm.
Pretty poor design in my opinion, although the bottom bearings seem to be holding up ok, albeit occasionly prising off the rubber seals and injecting some decent grease in.

Someone on here a while ago used the reducer as the crown race and vice versa? They are usually different colours – are they both split?

If not email dom@upgradebikes.com he'll sort you out?

Both are split. One is a larger diameter and that the one I'm using as the crown race. I tried them the other way around out of desperation and when I did that, you could see the top bearing casing being exposed! The smaller one really doesn't make it around the steerer base.

BTW my internal headset (Ribble own) has no seals and has lasted longer than I thought (well 9 months in the winter and washings) – I also have a small gap but IIRC its smaller than yours? I'll just go and take a piccy of my gap 🙂 Back in a mo 🙂

Edit: 2mm gap here:

Is that a Tripster Decade frame Onza?

It is indeed. I didn't want to reveal what it was until I knew what the problem was but if you've spotted it, I can't really deny it now.

The other thing that you can't see in my pictures is that the crown race doesn't actually sit flush on the crown.

Sorry Didn't know it was supposed to be a secret. I'd email Dom with the piccy? I've had a look on some close up and the gap seems to vary.

But you can thank me later 8)

I did email Dom yesterday with some dodgy phone pics. The ones I posted here are the better ones I took tonight so Dom hasn't had chance to see the good ones yet. I did speak with him Tuesday when he asked for the pics, but not since. From the conversation, I'm pretty confident he'll sort it out. I'm just looking for other ideas as it's a bit baffling.

Good luck with it – yeh I'm sure Dom will sort it out for you 🙂

The donor bike is a Tricross sport. The gap on that is about 0.3mm so I was expecting similar from this. Especially as the frame and forks come from the same place.

I've been doing some research on this and it would seem like there are two different standards for the bottom of the head tube. Seems Cane Creek spec a 7mm bore on their tech documents while Hope spec a 9.5mm bore on theirs. That would explain the 2.5/3mm gap.

Anyone come across this before?

You've got the wrong crown race IMO.

The crown race was swapped out. The right sort (it came with the headset, but not quite a good one I think).

That saved about 0.5mm so the bearing is still exposed as in the pictures above.

Maybe, but it looks like the crown race lip is not seating inside the bearing as it should, this suggest to me that the lip is too tall.

I'd agree. The bearing sits very proud of the crown race. But it's done that with two different races now and been back to Upgrade for a look-see.