Threaded conversion to Threadless - Ghetto?

[Rampage]

These adaptors are designed to be used with a threaded headset, with an ahead stem. Therefore they don't need to allow for preload as there won't be any if used for the purpose they were designed.

 

[Rampage]

You could possibly drill out the wedge and insert a longer stem bolt the wrong way round (so the allen head is against the flat of the wedge). Where the bolt comes out of the top of the quill it would have a washer and nut on it (to hold the quill in in the steerer) the bolt would then extend to the top of the stem and pass through an ahead top cap which had been drilled out also. There would be another nut on top to set the preload.

Bit of a bodge through.

 

[old_coyote_pedaller]

These adaptors are designed to be used with a threaded headset, with an ahead stem. Therefore they don't need to allow for preload as there won't be any if used for the purpose they were designed.

That's true, but the one I have the bolt does not go to top of adaptor. It is recessed down inside the adaptor tube. Wish I knew where it was just in case I'm really just talking pish.

You can get 1 inch aheadsets, plus I found a site selling a shim that fits on the threaded part of steerer allowing you to fit a 1'1/8th ahead stem. Then you can pre-load the bearings with an ahead cap with a star nut in steerer. For this to work you would need a significant amount of the threaded part of steerer sticking up above the aheadset. On most threaded steerers I've seen they are cut so they are flush with top nut of headset so a shim won't work.

There's no way I'm going outside just now to my bike-shed to find the adaptor I've got and if I don't find it, I won't need to admit it if I'm wrong.

 

[oldave]

Perhaps I'm misunderstanding the terminology here, but one of my Kilis has been running a threadless extender/adaptor with threaded P2s for some 4-5,000 miles with no problem.

 

[old_coyote_pedaller]

Ahaaa (a bit Alan Partridge there, I do apologise), it does work.

 

[pete_mcc]

To use it with an aheadset on a threaded steerer tube that is too short as the OP is suggesting is daft. You can do it by buying:

1) ahead stem
2) aheadset
3) quill to ahead converter
4) use ringo-star ring based preloaded

But there is no guarantee that this whole bodge will work for any length of time as using an aheadset on a section of weakened thread where the outer diameter of the steerer tube is reduced to the point that the original threaded locknut no longer holds surely is going to result in rocking and damage to the bearings and the races. But then I don't really have an engineering mind so maybe I'm missing something.

Add all that to the fact it won't work it will probably cost more than sorting out the original problem. Bit pointless really. But if people don't value front teeth or wallet then go for it!

 

[Rampage]

Ahaaa (a bit Alan Partridge there, I do apologise), it does work.

It the adaptor is recessed enough you might be able to use Hope's bung thing (alternative to star wrangled nut) in the recess. That would work. As long as preloading the stem still allows the stem to sit on the correct part of the adaptor.

 

[old_coyote_pedaller]

oldave's bike shows that it does work.
The top race of an aheadset usually has a tapered or cone-shaped wedge to take up slack between steerer and race. This would solve the worn thread problem.

 

[pete_mcc]

oldave's bike shows that it does work.

In which case, OP go for it, it's a proven great idea.

 

[old_coyote_pedaller]

oldave's bike shows that it does work.

In which case, OP go for it, it's a proven great idea.

Hmm, I sense from your reply you are not entirely convinced.

I agree that what we are talking about is, to put it politely, not best engineering practice. In fact it's a bodge but I've committed much worse bodges in my time on mechanical devices, usually when I've had no other option. Most have survived, as have I. I can sympathise if you are uncomfortable with it. Some of the things I've done made me wince at the time.