The headset on my merida ride 100 has come loose. I watched a few videos to see how to tighten a threadless headset. They all say loosen the stem then tighten the top cap. However on my bike the top cap seems to do nothing, it's not threaded or anything and there's nothing inside.
How do I go about tightening the headset on a setup like this?
I was curious about your bike brand, Merida. I learned via Googling, that the Merida Ride 100 has a headset called "Big Conoid semi neck pro." Googling that mouthful led me to a Q & A from another bike forum which may shed some light onto your problem. It seems that while the bearings are loaded with the use of a bolt (after the stem bolts are loosed), it is located under the top cap. I've tried unsuccessfully to find instructions specific to big Conoid semi neck pro, though a plethora of how - to videos are out there on the subject of threadless headset install and adjustment.
On threadless headsets the top cap has a bolt passing through it that threaded into either an expansion plug or star nut that is pressed into the steerer tube. Tightening the bolt pulls the top cap down which compresses the headset bearings.
I'm guessing your top cap bolt is missing. Any local bike shop will be able to provide a replacement. Perhaps the expansion plug, no longer attached to the top cap, has dropped down into the steerer tube. Have a look down the steerer tube with a bright light. You may be able to fish it out with a length of coat-hanger wire.
