I’m planning on building a bike for my disabled brother. I’m using a trekking/XC frame with standard 1 1/8″ integrated headtube and want to fit cromo rigid forks with V brake mounts. Now, there are loads around with 1 1/8″ steerers, but many of them have threaded steerers, or at least portions of steerer. Can you clamp a threaded steerer with a normal stem?

You may be better off with something like this if using a threaded fork – http://www.chainreactioncycles.com/brand-x-quill-adaptor-alloy/rp-prod6254

Well, I’d rather use a fork with a non-threaded steerer if you’re telling me you can’t, or shouldn’t clamp a threaded one.

If you’ve the option of using non threaded that must be better. I’ve used quill adaptors on retro bikes to fit an aheadset (all though brandx one wont do as can’t adjust preload as no recess for star nut) . if you don’t need to bodge it dont so get plain steerer but make sure it’s long enough for the frame. Good luck, sounds like a worthwhile project.

Sorry, in response to your last clamping a stem on to a thread sounds dodgy as much reduced surface area due to only touching the tops of the threads. May be ok for light use but not good, and would make a mess of the stem. Threaded 11/8 headsets can be ok if you get the stack height right but then need the right quill stem which may be trickier.

Can you clamp a threaded steerer with a normal stem?

No, definitely not – the threaded section isn’t strong enough for that, and the threads will act as perfect fracture points.

Straight it is then, thanks for the replies.

Depending on the disability obviously but would using a quill stem and having much better adjustability be a useful feature?

ignore me. Integrated headset.

SO I went with On One Cromo fork in the end, just finished this- great frame and wheels from the Planet X spring clearout, some internet bargains and spares box raiding, plus Ton’s old sq taper cranks and a rattle can:
Rigid 26″, 1×10 with Zee shifter and SLX mech all in for £297 and at 11kg should suit his short ride to work perfectly: