How short is too short for steering tube

Have got enough bits to build up my new (secondhand) Bfe frame, I find out I have made school boy error!! The steering tube only comes out of the top of my headset by 20mm, is this enough?

Even without spacers it will only be half way up the stem that I have. Can I leave a gap? What is the problem? Can I get a narrower stem?

Any experience and or advice would be good. Already kicking myself so no more of that is needed.

Thanks.

Even without spacers it will only be half way up the stem that I have. Can I leave a gap?

That’s no good. I wouldn’t go any more than 5mm from the top of the stem if I were you. 20mm is nowhere near enough for any stem I know of. Unless you can get a lower stack headset you’re buggered.

Some stems go as low as 35mm stack height, although not ideal, this will work, personally I’d fit a lower stack headset top cup too (if possibe)

what make of headset is it? – may be able to find some room there

Some stems go as low as 35mm stack height, although not ideal, this will work, personally I’d fit a lower stack headset top cup too (if possibe)

Nah. That’s still little more than half way up the stem. Just don’t.

Spank spike stem is 35mm can you find 10mm or so with a lower stack headset?

20mm no.

Half way up the stem I’ve done without death though.

Thanks for the responses.

The headset that I only fitted an hour ago is a Octane One Warp 1 Sealed Headset 2013. The profile isn’t that high, so not sure I will gain much.

The stem could be smaller, but don’t think I will get enough.

You should be able to fit a zero stack headset in there if you’re running 1 1/8 steerer

You’ll need 35mm minimum for your stem – does your current headset give that ?

Zero stack sounds good, but may not be enough. I for think I have that much spare to find.

May have to change forks.

New uppers for your forks may be required…….

I’m well aware of how fractions work thanks Peter. 🙂
What catastrophe do you think will happen with only 20mm clamping surface and 15mm free at the top,?
And do you realise some BMX stems have as little as 22mm stack/clamping surface?

The stem won’t hold, the steerer with quite so much force, which may cause loosening of the headset adjustment.

If you’re really worried, run a headlock

Kore used to make a stem with 30mm stack height. I’ve still got one but it’s for 25.4mm handlebars unfortunately..

It’s ok, I’m here to save the day

http://www.wiggle.co.uk/bbb-bhp-22-steerer-tube-extender/

Some Syntace stems only need 30mm of steerer. It might be cheaper to get new forks though…
http://www.syntace.com/index.cfm?pid=3&pk=2050

i used a steerer extender similar to the one posted above. Not ridden it yet, but it would easily be robust enough for general trail duties i reckon. Basically its just like a quill stem

I run one about that short once.
I put a peice of cut steerer on top so the stem wasn’t clamped with only one bolt & unevenly stressed. An Ameoba headlock kept it all tight, but some forks have a blanking plug in the crown so you’ll need to check.
Was some RC31’s I picked up cheap due to a short steerer.
Ran it for a Winter SS.

Nobody died etc.

Cheap bike builds never work out cheap.

Thanks for the help. I will look at changing to zero stack and see what I’m left with. If I can do that and get 30mm then I will be able to make a go of it. If not then, forks will be up for sale and see what else I can find.

I suppose the other question is, how hard to you expect to beat it? A BFe could be a general bike or it could be for jumping over houses.

kaboom, i’m running a ragley stubbing stem which has 32mm stack height

davidtaylforth, yesterday

I think this is what mightyDT was looking for

Cheap, good looking and super light (123g !) stem from Funn, with only 30mm stack

http://www.chainreactioncycles.com/funn-funnduro-stem-2014/rp-prod91491