Brake boss threads

jawa

Dirt Disciple
Hi all,
I have a 1993 Kona Hei Hei frame and I would like to put some new brake bosses on the frame. I have brought a set from a local bike shop and the threads don't seem to match with the frame. I have tried to screw the brake bosses into the frame and they seem to require far too much force to screw them into the frame and so I don't want to force then if they have the wrong thread.
So, does anyone know if there are different threads possible for the brake bosses? Or what sort I need for an old Hei Hei frame?
 
the difference would be in the " pitch " of the threads

as in the amount of threads per inch , definately dont force them !!
 
Try and find a bolt that will fit your frame bosses then take the bolt to the bike shop or another shop and get the canti posts to match.
 
Are we talking the actual brake boss mounts that the canti's slide onto that are only removable on certain frames or the mounting bolts (brake boss threads are a standard size and pitch. Size M8 IIRC, but they are quite a narrow pitch compared to a bog standard hardware store M8 bolt. Any cantilever brake bolt should fit and any decent bike shop should have some lying about).

If it is the actual removable mounts try a decent frame builder - Yates, Roberts etc.
 
Thanks for the suggestions. To clarify, I am talking about the removable brake boss mounts that screw into the frame, not the brake mounting bolts.
I will try and find a bolt that fits first and see if I can get the right brake boss else I will try one of the frame makers suggested. And here was me thinking that these things are always standard......oh well lots to learn yet it seems!

Adam - You will be pleased to hear I rode my 97 Explosif to work today so I can bring the 92 Explosif home tonight and start getting it dismantled ;)
 
May be worth an ad on the classifieds here or on STW - a lot of people have removed these over the years to fit discs and someone is bound to have some in the 'spares box'. In contrast to the mounting bolts there are only a couple of variations I think (the blanking bolts for instance only come in two sizes) but the pitch is much wider.
 
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