Hi
I’m making a balance bike for my little girl for Christmas and was wondering if some helpful frame builder may be able to give me the dimensions required for the head tube bores for standard sized head sets?
I’ll be going with something like this: http://www.chainreactioncycles.com/fsa-no-10-internal-headset/rp-prod108136
So what size/tolerance should I be aiming for for the cup bores?
Thanks
Steve

34mm

http://sheldonbrown.com/cribsheet-headsets.html

But best to go slightly undersized and run a reamer through it after the frame is built. You can buy stock head tube material from Ceeway.

Edit: misread the headset you were using – the FSA website has bearing dimensions I think, but definitely go undersized and find someone units a reamer.

there’s images of two posters on this page that give the tube dimensions for most of the headset standards available;

http://www.moredirt.com/stories/FSA-Orbit-Z–Orbit-IS-2-Coloured-Headsets/1806/

Thanks Ben.
Going to be making it out of aluminium. Will be CNC turning my own head tube, CNC milling the rear stays and doing all the welding myself too.. 😯
Will get the LBS to ream the bores when everything is finished.

If you’ve got the kit, go for it 😉