Originally Posted by
dnomel
The setup would probably work ok and serve it's purpose as a temporary low cost solution until a new fork arrives. Seems like the main question is if it might mess up the nice threadless headset. Maybe some locktite or something in the threads of the steerer where it may sit would help.
Different from this situation, but I did a pretty desperate modification to allow riding a too short threaded fork with threaded setup. I cut off the top of another threaded steerer and slipped it inverted onto the quill stem and used the threads at the bottom for the upper race, then shoved the stem with it down into the fork and tightened the quill. The overall length of the cut off steerer section and the length of the threaded part of it were dependent on where the stem ended up as far as it's height and acceptable insertion into the fork steerer (this section buts up against the crook of the stem and can't hit the top of the fork steerer). Kind of hard to explain and visualize, but it "works".
This was only meant as a very temporary fix to allow testing the ride to determine if it was worth keeping and looking for another fork, and it is, I really like the ride with this fork as a reference for a replacement. It's a secondary bike and I don't consider it very safe (if I loosen the stem bolt the fork falls out) and ride it accordingly while keeping my eye out for an acceptable longer fork.
Anyway, whatever you do try not to mess up the new headset.
Hi - There`s no doubt that it MIGHT be a workable solution. But no chance that it could be considered low cost unless you consider your time worth nothing. The `LOW COST` solution would have been to have the threaded headset replaced with another threaded headset at a shop equipped to do the job.
But instead he saw a `deal` on a threadless headset and thinks he eventually wants a threadless fork anyway - so why not?
Your point about the threads being a problem is right on, particularly if there is a rubber seal in the top cap. Ideally the complete threaded area except for the part that would inside the locking nut should be filled with epoxy and the profile sanded smooth. And the locking nut should be drilled and tapped for two grub screws to keep it from coming undone since it now has no other threaded nut to lock against and bearing preload pressures are minimal.
If this was a prototype or an R&D project with an equipped workshop the whole thing would be a lot more likely to come together successfully - but if that was the case, then the OP wouldn`t be on a forum like this askink some pretty basic questions.
So why do I have so many reservations? Because the last guy that brought a BMX into the shop because he couldn`t get the threadless headset adjusted properly had tried to do the installation himself. In his case he had used a 2 x 4 and a hammer too install the bearing cups. But that was only part of the issue. The profile on the crown race originally installed on the forks didn`t match the new bearings and since he didn`t know you had to change it -he didn`t. But since there aren`t supposed to be any parts left over P the new crown race got added in somewhere else.
And then he took the bike down to the skate park (where he was actually an excellent rider) and started doing jumps with it.
No money saved - he needed a new headset.
Forums can be fun, but I`m thinking that if people start to be held accountable for what they post and were open to lawsuits for injury or damage resulting from what they post or encourage, they`d be a lot more conservative.
Sometimes the best advice to give in some situations wher the poster has limited experience is: Take it to a shop!