I need my steerer tube to grow by about 2 cm i tried wearing and fertilizing it i even left it in the sun to no avail.

So My alternative is to get lower stack height height

i currently run a race face dues head set,
and a
race face evolve xc stem,

My issue is I’m on a tight budget budget. so what parts should i look at,i have no idea what is good and what isn’t as i haven’t bought anything mtb wise in 3 years

Presuming this is on a mountain bike then 20mm is a massive amount to lose!

Have you removed all the spacers?

You could possibly shave off 7-10mm of overall stack height with a lower stack headset (for regulat 1 1/8 i think crank brothers do one) and a new stem (sun line do one at 35mm) but 20mm IMHO will not be possible.

Head Set (21mm stack height)
http://www.chainreactioncycles.com/Models.aspx?ModelID=24980

Stem (35mm stack hight)
http://www.chainreactioncycles.com/Models.aspx?ModelID=41211

Superstar do one at a similar stack height of 35 mm
http://superstar.tibolts.co.uk/product_info.php?cPath=67&products_id=416

So basically the steerer tube of your forks will need to be

Head tube lenght + 21mm + 35mm – 3mm(to allow for preload on bearings)

if it is not this length then it will be a no go.

Integrated headset and lower-stack stem perhaps.

Like Rusty says tho 20mm is alot.

Ragley stubbing stem from CRC are on offer. They have a 30mm stack height.

Cane Creek Zero Stack headset? You’ll need to make sure it’s compatible with your headtube, but they have virtually flush cups. Various models, some so pricey it would be cheaper to change your fork.

Sunline V1 stems are about 30mm stack

Anyone use a zero stack head set, i understand the cons of them not lasting to long however my brother in law works as an engineer and can get bearings to fit most things

you can only fit zero stack if the head tube is built for it.

they last fine – I have a donkeys year old WTB innerpeace headset in my Giant NRS frame.

Anyone use a zero stack head set, i understand the cons of them not lasting to long

Don’t know where this has come from? but is definately not my experiance of them. I had a FSA Orbit Z that lasted 2 years with no maintnenace and then longer when i re-greased the bearings.

Zero Stack / Semi Intigrated / Integral / 44mm headsets like any others can come with good or bad bearigns dependant on type and model.

What will limit you in the decision to use one of these is the dimentions of the head tube on your bike. The below link takes you to a hope document that will help explain the diference in types of headset for the types of head tubes on bikes.

http://www.hopetech.com/webtop/modules/_repository/documents/HOPEHEADSETS2011Web.pdf

If you have a traditional 1 1/8 head tube a zero stack headset will not fit.