Hawkegirl

A friends bike got awfully vandalized, and her fork was DOA. She has a peculuar [large] size old fuji and had no luck finding a replacement fork with the right size tube. So we got her one that was too long, and tapped another cm of threads into it. I assumed we'd then cut a little off the top, though my only saw guide is threadless (I thought that likely to still be okay figuring I could bevel the top edge as needed for it's not an important spot to have actual threading should it even have the top ring of thread damaged from the guide in the first place) however, she opted to use spacers instead. Other then it being odd to have spacers on a threaded, any reason that isn't a decent option?

MichaelW

I use spacers on the threaded steerer of my replacement fork. No problems at all but make sure that you use a keyed washer somewhere to prevent rotation.

HillRider

I have a bike that I had the threaded fork intentionally left extra long and added spacers to to get the bars a bit higher. I couldn't find a stem with an adequately long quill so increasing the fork height was the best option.

operator

That is not good advice, use all non-keyed washers.

MichaelW

There is usually a keyed washer between the upper race and the locknut so you can tighten the locknut without too much movement of the race. There is a slot on the thread for this purpose.
Why is it bad to use these washers either above or below the spacer ring?

rosiewoodboat

Because even though that notch is 'designed' as an anti-rotation device, keyed washers can and do rotate and then jam themselves. Then when you try to adjust the headset the washer isn't free to move and it ends up making the headset adustment for you. Replace all keyed washers with non-keyed washers in general.