Handlebars not staying correctly in position

[Mooruk]

Hi everyone.
Got a second hand bike with straight-style handlebars. Been fine for a couple of years, but during my journey yesterday, the wheel and handlebars rotated so they are no longer perpendicular with each other. Tried tightening everything that looked like would work, but I can still rotate the handlebars without the wheel moving.

Any advice please?

 

[further]

Tighten the Allen screw in the top of the headset.

 

[Ian H]

Tighten the Allen screw in the top of the headset.

If that is tight & there's still movement, then suspect something considerably more serious.

 

[screenman]

Please get a cycle mechanic to have a look at it, for your safety, if tightening the large allen key in the middle does not work.

 

[fossyant]

Warning, your stem looks quite some way extended out of the fork steerer, please check the minimum insertion lines/markings. I'd undo the allen bolt on the top, pull the stem out, clean and check it, grease it, then put it back in, align with wheel, and tighten up.

 

[screenman]

What we have to consider is the OP has very little if any knowledge of the parts we are talking about. Safety first every time.

 

[Mooruk]

What we have to consider is the OP has very little if any knowledge of the parts we are talking about. Safety first every time.

Thanks for your justifiable concern! Much appreciated!

 

[Mooruk]

If that is tight & there's still movement, then suspect something considerably more serious.

It is as tight as it goes.....

 

[Mr Whyte]

I`d say get it checked out, as better safe than sorry if it was me.

 

[MichaelW2]

You to have the stem removed to inspect the wedge and see what is happening.

 

[Ian H]

Ok. Loosen it 4 or 5 turns. You might have to tap the top of the bolt so that it drops back down. Pull the stem right out to inspect. The bottom should have a wedge of some kind which expands to lock the stem in place. If that looks correct, re-insert the stem, push it in at least 80mm and re-tighten the bolt. If it still isn't tight then something serious is wrong.

 

[Ajax Bay]

Wot Ian says ^^^ (plus @fossyant 's "clean and check it, grease it") including the inside of the steerer tube, on the way. There are lines on the side of the stem (say 80mm up from its bottom/the wedge) like this: ||||||| (minimum insertion lines/markings ). Those must be out of sight below the level of the locknut before tightening the bolt.

 

[Mooruk]

Brilliant advice guys. Thanks so much. I'll let you know how I get on.

 

[Mooruk]

Not much success, I'm afraid.

Took everything apart, cleaned and oiled. Couldn't see anything that obviously expands. And a few of the ball bearings were missing at the bottom.

Tightened everything up. All seemed ok but when standing either side of the wheel I could rotate the handlebars again when applying some force. Pics attached.

 

[figbat]

We need to see the rest of the stem. The expanding bit is the wedge-shaped 'nut' at the bottom of this picture:

...which you have shown in a couple of your pictures. It works by being pulled up against the angled lower end of the stem itself - as the bolt is tightened the wedge pulls up and the whole assembly tightens inside the steerer tube of the fork. There was no need to undo all the bearings and such, although it's not a bad idea to clean and regrease these anyway.