How to work out headset stack height

ok i have been through a shed load of different posts but still cant seem to find exactly what i think i am looking for.
i am trying to work out what stack height of headset i need to order. from what i can gather i need to measure the steering column and the headtube length so the difference between these two should be my stack height. Correct??
my issue comes when i do this and the stack height comes out at 46mm (headtube 11.9cm and steering column 15.3). this seems pretty high to me for the stack height or am i just wrong??

stack height of a headset is height of bottom cup, plus the height of top cup and any lockring (if threaded)

obviously, spacers may make the steerer tube longer.

yeah i got that much from what i have been reading thanks velo. my issue is working out the size i need to order using the measurements that i can take from my frame and forks

well is it threaded or threadless headset?

some headsets have the stack height in the info.

sorry its a threaded headset

so measure the height of the bottom cup, plus the height of the top cup including any spacers and the locknut, and this is the max stack height of the headset you should order. smaller stack heights can be compensated for by adding more spacers. larger stack heights can't as the locknut won't engage the thread.

sorry i obviously haven't been clear i dont have an existing headset so i need to work out the size i need from the frame and forks that i have.

The stack height is pretty unimportant with regards to frame+fork fit. It becomes important if you like to have your bars as low as possible.

Once you have the headset, you chop the steerer tube to size, or add headset spacers beween the top race and the lockring if you want to keep some length on the steerer. The steerer should not be too long as to prevent tightening of the lockring onto the top race. Neither should it be too short so the lockring has too few threads engaged. The easiest way of doing it is to install everything and measure the gap between the top race and the lock ring (which has a top lip, so stops on the top of the steerer). cut the measured amount off the top of the steerer, add this distance in spacers, or do a combination of both.

If (as it sounds) your steerer has already been chopped. Then you just need to make sure you dont buy a headset with too large a stack height.

ah ha now all is kinda clear!! i'll just by the headset i reckon will kinda fit then cut the steerer to size.
thanks

it is not strictly necessary to cut steerer if the stack height is shorter than your current one as you can just add more spacers, but if you do, thread on the lock nut, cut the steerer, then unthread the the locknut to ensure the threads are nice, other wise you may have trouble threading the locknut back on.

Going for something like 45mm, using spacers to take up any extra, will mean you can get virtually any replacement headset on there in future. Many 1990s road bikes had the steerers cut right down for 33mm stack height Shimano 105/600 headsets. They were crap headsets* which didn't last long, and replacements are both difficult to find and expensive.

*there was a quiet revolution in headset design around 1995 when people started using loose races or cartridges that could move relative to the pressed-in cups; this pretty much eliminated the "indexed steering" problem that used to kill headsets. It took about 150 years to work this out.

1) Measure the length of the steerer from the shoulder that the bottom race sits on to the top of the threaded part.
2) Measure the length of the head tube from end to end (without any cups inserted).
3) Subtract 2 from 1.
The result is your stack height. However, if your headset had exactly the same stack height as (3) you risk not being able to adjust it perfectly, so in practice you need (3) to be a millimeter or two less than the stack height of your headset, or:
a) you can add a spacer to create room for adjustment, or
b) you can file down your steerer to create the adjustment margin.

z) I hope that's all clear!

THREAD DREDGE

Can anyone recommend some 1 1/8 threadless headsets with as low a stack height as possible? I've seen some crank bros ones but they are prohibitively expensive.

Do we have a headset list on here?

and one more thread dredge. Where would one find 1" headset spacers?

googled it
http://www.ribblecycles.co.uk/sp/road-track-bike/Headset-Spares-and-Accessories-CSN-Headset-Spacer-Alloy/CSNAHSTZ275

I have some you have have for free if you want:

4x10mm Alloy, 3x5mm Carbon
pic here

cheers Pifko but I'm not local (posting from the Wales over the bridge)

Neither am I (Bournemouth). I don't have a problem posting. I have no use for them and don't really want to bin 'em.

Thread re-dredge.

I've just bought myself a nice Concorde frame and fork from a forumger and am getting the parts together. This included a new Campag Record headset. Like a fool, I didn't check the stack height before I spent the cash. I've ended up with a headset with a stack height of 36.5, but find I need 45 mm of height. So a list with some 1" threaded headset details, hope it helps ...

BTW, does anyone have a Velo Orange Grand Cru headset fitted - if so how do they find it?

1 Inch Threaded Headsets (in stack height order)
Headset / stack height (mm) / weight (g) / bearings / Aprox. price (£)
Tange Passage / 30.2 / * / cup and caged bearings / £14
Tange Levin CDS / 33.3 / * / cup and caged bearings / £17
Campagnolo Record / 36.5 / 104 g / cup and cone bearings / £45
Chris King 2nut headset / 37.4 / 94 g / cup bearings / £120
Shimano Dura-Ace headset 7410 / 37.6 / 101g / cartridge bearings / £80
Chrus King GripNut headset / 33 to 38 / 93 g / cup bearings / £120
Stronglight A9 / 38 / * / needle bearings / £35
Cane Creek Classic 110 / 38.75 / 93 g /external cup bearings / £100
Velo Orange Grand Cru / 42 / * / sealed cartridge bearings / £35
Miche Primato / 42 / 90 g / cup and needle roller bearings / £25
Tifosi / 45 / 95 g / ball bearing and needle bearing / £17

http://freshtripe.co.uk/Freshtripe/Handlebars,%20Headsets%20%26%20Stems.html

ta, that's where I was planning to get the Velo Orange headset from.

The VO headset looks quite chunky, but as my frameset is Columbus Max and the forks are chromed I think it should work well. I was just wondering if anyone had one of those headsets fitted and if so how they rated them.

Can't you just use spacers to make the stack height up?

could do, I just want to avoid using ~10mm of spacers on a threaded headset. Having done a bit of research on currently available threaded headsets I thought I'd put up the info for others ...

Did you get the VO headset? If so how are you finding it?

I did. It's certainly shiny. The split fork crown race works a treat and the sealed bearings look good quality, but I've still not fitted it yet (I'vel not sorted a groupset for the project yet) so unfortunately I can't tell you how it runs ...