You know the problem, new frame, second hand forks, steerer too short.

Steerer tube length – head tube length = 53mm.
Current headset + current stem = 70mm

If I allow for 2mm of stem above the steerer, I need to lose 15mm somewhere.
Is it possible ?

Sunline all mountain v-one stem. – 25mm stack iirc

It's do-able.

Crank Bros headsets are pretty skinny

Crank Brothers Cobalt – stack height = 21mm FSA OS-150 stem = 35mm.

you may even need a spacer.

aim for 5mm between top of steerer and top of stem.

Same problem a few weeks back. Looked at a CB iodine headset but ended up going with a Spank Spike stem (25mm stack). Decent Gear are doing them fairly cheap. The Spike is very short but it makes for a nice ride.

I have a cane creek low-stack hs, you can't adjust the play out of it. FSA stems go to 35mm IIRC.

CB are the lowest but see if you can get away with something like an Orbit XL2 at something like 27.5mm stack…so much cheaper (£20 including P&P on eBay) and soooo much better. My CB headset is rough after the winter and has rust on its outer surface unlike my XL2 on another bike which is running smooth as ever.

Check before buying an FSA stem as they're not all 35mm ad the newer ones seem to be going for the more standard height of 40mm.

Can you trim the steering head of the frame? (with a facing tool)

I'm going to do this on one of my frames to fit a 29er wheel – it will drop the steering head if I trim the lower part. I figure I can take 10mm off.

In your case you would need to do it from the top to avoid changing the steering head angle.

epicyclo – well, they're your teeth.

wwaswas – Member
epicyclo – well, they're your teeth

There's plenty metal on my frame for this modification and it will simply be dropping the steering head angle closer to where it was with a 26" wheel.

I'm building a matching front fork to complete the job.

Thanks for all the information here.
That CB headset would gain me 10mm.
The spank stem would gain another 14mm, but it's very short. I guess with less engagement on the steerer they have to reduce the potential leverage.
As for the 5mm of stem above the steerer, that sounds OK if it's 40mm deep, but a shorter stack height stem would surely want proportionally more engaged. If the Spank one is only 25mm, I wouldn't want to have less than 23mm of it contacting the steerer.

And shortening the head tube, no chance.
It's a titanium frame and the head tube looks to have been machined away for most of its length, leaving the ends a bigger OD.
Shortening the head tube would take away those reinforcing bands.