Headset problem

I put a C-Record headset onto a frame I'm building up, but there's only enough fork thread to get about half a turn on the top nut before I hit the top race - obviously not enough. This is because on this headset, the washer is normally recessed into the top nut, so there's a couple of millimetres where there are no threads on the nut. And as the fork thread has no "guide" for the washer (which has a small stub on the inside), the washer is useless.

So can anyone recommend a compatible "thin" top nut that would look the part for C-Record? My other option is to get a machinist to skim the bottom of the nut to remove the area where the washer is recessed, but I think that'd look a bit silly as the nut has nice rounded edges.

I'm keen to stick with period parts on this bike (circa 1988-1990) so another option might be a Campag headset with a shorter stack height?

Here are some pics to illustrate:

Is the top race down ? I think I can see ball bearings.

Shaun

Yes, I have a crown race installation tool and a headset cup tool too, it's just slightly off the cup because I was taking photos.

Even with a thin nut you will only have 3 threads which is asking for trouble. 5 is usually a minimum IIRC. You might have another turn if you tighten the top a bit as it looks slack - the gap around the bearing shouldn't be visible.

hamster":3oz27z87 said:

You might have another turn if you tighten the top a bit as it looks slack - the gap around the bearing shouldn't be visible.

Click to expand...

It isn't slack, it just unscrewed a bit when I removed the nut to take the photo.

Re:

look for a headset with a low stack height.

If you want to stick with Campag, then try looking for a campag pista (track) version which has a lower stack height.

There is a shimano 105 version (poss 1051) which is reknowned for having a low stack height

Ok I announce my candidacy for idiot of the week. The top bearing came (Ebay) with the wrong carrier, so I removed the ball bearings from the carrier and inserted them manually (I probably need another 3-4 to fill the gaps). One ball had become trapped in a slightly incorrect position, meaning that the bearing wasn't quite closed. I'd looked at the pictures and just assumed the nut had unscrewed, so apologies to those who pointed this out and then read my replies saying they were wrong.

Anyhow, I've fixed that and now managed to get about 2 turns on the locking nut. I don't think that's enough though so perhaps I'll replace the headset with something that fits the fork.

Two whole turns of the lock nut

Shaun

I had a similar problem with a Ribble frame I was building up I took the frame and forks to a machinist and had them turn down the top of the fork crown where the crown race sits and then had the head tube turned down each end as well. Only had a 1mm taken off each surface but it gave me enough thread to sort the lock nut out
you could probably get this done by a decent bike shop if they have the right tools.

It's a good idea but this is a TVT carbon frame with aluminium lugs, so I don't think it'd work

I'll just have to resign myself to spending more money I can't bring myself to modifying the headset, it wouldn't be right