stackheight is too large (threaded headset)

Hi,

I bought myself a new headset some time ago for my GT GTB Track frame.
I wanted to keep the original fork, but the original headset was damaged so I had to replace it.
I tried replacing it with a Chris King 2nut, but I didn't measure the stackheight, and after assembling the stackheight was way too large so I couldn't fit on the locknut. (the fork's steertube was too short)

Now I got in a brand new Campa Record headset (threaded 1") and it only fits just..
If I don't use the washer under the locknut and after grinding down the adjustable race from the top and grinding the locknut from the bottom to remove the small edge I have about 1mm of thread that is 'caught' by the locknut.
Though it only uses about 0.5 round of thread now, it does 'lock' the race, but I'm afraid the thread will break.

I might be able to grind down the adjustable race a bit more so the locknut can use a bit more thread to lock on to (about 1-1.5mm of thread), but I'm not sure if it will be enough anyway to be able to really lock the race.

My questions:
Is this dangerous, and if so, why?
Is there another solution without buying a new headset?

I've never done it, but can't you actually take material off the headtube at the top to shorten it if its only a couple of mm?

2nuts are about 37.4mm off the top of my head, so if it's way too high you haven't got much to play with.

Have you thought about, um, measuring what stack height you need, to avoid having to grind anything?

Tange do headsets with low stacks, around 32mm I think.

And remember you can mix and match tops and bottoms.

I had this recently and ground my headtube to make it work. Took most material from the top to avoid affecting the geo as much, but do have to take 1.5mm from the bottom, and that noticeably changed my saddle angle, so has obviously changed the geo a fair bit

Though it only uses about 0.5 round of thread now, it does 'lock' the race, but I'm afraid the thread will break.

Is there another solution without buying a new headset?

Possibly silly question: have you properly tightened this all up, or just assembled it hand-tight?

I has similar issues recently trying to get the right number of spacers for a new headset. When I assembled it, the locknut only seemed to catch about half a turn's thread. But when I actually tightened it up with some spanners it went on 3 turns, which was plenty. This may have been partly due to the headset cups settling slightly and everything straightening up.

I'd rather not take anything of the headtube, cause I'd like to keep it original..

And I'm scared I'll break the thread cause it only went around almost 1 turn, and if I tighten it up too much it just feels like it will break.

Also, I've already grinded down some parts of the campa headset, so it's already modified.

Also, does anyone know what the danger might be when the locknut isn't tightened enough?

Also, does anyone know what the danger might be when the locknut isn't tightened enough?

Couldn't say for sure, but it sounds less terrifying that riding a bike fitted with a headset that has had bits ground off it. A loose headset is pretty easy to notice as you'll get a clunk every time you use the front brake. If you're worried about sudden dramatic failure then go and spend less than £20 on a Tange Levin (which has a 33mm stack height vs. 39ish for Record Strada) and try that before grinding anything off anything else.

Couldn't say for sure, but it sounds less terrifying that riding a bike fitted with a headset that has had bits ground off it. A loose headset is pretty easy to notice as you'll get a clunk every time you use the front brake. If you're worried about sudden dramatic failure then go and spend less than £20 on a Tange Levin (which has a 33mm stack height vs. 39ish for Record Strada) and try that before grinding anything off anything else.

I don't have a front brake, so that won't happen.. I'll just try it like this, if the locknut will come off I will notice it and try thinking of a solution..
Untill then I'll just keep it like this.
Thanks for the replies!

That could be a recipe for disaster if your front tyre/downtube clearance is small. I can imagine a scenario in which the locknut pops off, the front wheel hits the downtube and you get chucked off.

I don't have a front brake, so that won't happen.. I'll just try it like this, if the locknut will come off I will notice it and try thinking of a solution..
Untill then I'll just keep it like this.
Thanks for the replies!

You misunderstand. A front brake won't cause the headset to come loose, it will just throw up a nice clear symptom that it is loose. Do you have a rear brake by any chance?

Also, what ncjlee said.