1 inch threaded headsets

douglaslaird · Post by **douglaslaird** » 9 Nov 2008, 12:06pm

I am looking for a 1 inch headset JIS size i.e. 27.1mm crown race dia, not the 26.5mm usual standard, it is for an elderly Dawes touring bike I can get them in USA but cant find one in GB.

rogerzilla · Post by **rogerzilla** » 9 Nov 2008, 1:08pm

Can you just get the crown turned down to ISO?

rjb · Post by **rjb** » 9 Nov 2008, 5:43pm

You have a PM

GrahamG · Post by **GrahamG** » 9 Nov 2008, 8:49pm

If you can only find a US supplier and they won't ship to the UK, try www.myus.com

stephen · Post by **stephen** » 9 Nov 2008, 11:30pm

I had exactly the same problem also on an old(ish) Dawes. It is possible to get spare JIS and ISO crown races for some Shimano headsets from St john St, these are to enable a JIS fork to be fitted to an ISO headtube.

http://www.sjscycles.co.uk/category.asp?cat_id=588&pf_id=&jump=24&sfile=1

However they don't sell a JIS headset.

More important than the crown race is the headtube, JIS has an internal diameter of 30.0 mm while ISO is 30.2. So it is possible to force an ISO headset into a JIS frame, but the headtube is likely to subsequently crack.

http://www.living-room.org/50buckbike.html about 2/3 of the way down.

I ended up buying one from the states on e-bay but in retrospect it probably would have been easier to have the head tube reamed out, you could do this if you trust your LBS.

Stephen