Technical & Reference Section > Tech and Restoration

enginerd types- a question headtube reducers 32.5/6/7 to 30.2mm

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steve:
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question to the enginerd types....
road bike headset press fit = 30.2

bmx headtube  = 32.7

2.5mm lacking

wall thickness of 1.25mm required
brass tube is - as per the ebay advert
1-1/4" ( 31.80mm) Wall Thickness 1.5mm

the plan, cut a 8mm ring - heat it up on the cooker - brass expands well?
squezze it onto the cup in vice, file it down to 32.7

yes/no
is there a better material than brass to use?

why don't you just get a headset that fits - I here you say
1. the frame I just bought came with a welded in road headset!! - WANt to do it
2. the headset pictured was £17 delivered
3. looks ace
4. different

oldschoolace:
If the tube is 31.8 with a 1.5mm wall its internal diameter will be 28.8mm. Asking alot to get that over 30.2 with heat

steve:
I think someone needs to make some because....

then you could run campagnolo 1'' headsets
hatta swan
tange Levin
stronglite

flap wheel inside the tube first?
- I get that it will be difficult, as its a interference fit to the cups and then into the headtube
but doable somehow...

oldschoolace:
Just checked the expansion coefficient of brass and even at near melting temp it wouldnt expand to the dims you want.
Trip to a local engineers needed  ;)

john4130:
i fitted a kuwahara headset to my trm that was too small. can't remember what size the cups were but i used a small sheet of 0.7mm aluminium. i cut it to around 98mm x98mm and rolled it. pushed it into the headtube and the cups where a nice tight fit. i also did the same years ago on my standard sta 1" 1/8 frame and fitted 1" gsport forks. i used that setup for around 4 years with no problems.

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