SoulPuppy

I don't know if I have a problem or just a minor irritation. When I go over bumps, I feel a rattle in my handlebars. It feels like something below is loose, but I can't find anything to tighten. The stem it tight. I have no idea what it could be & it doesn't seem to give me any trouble except being annoying. Does anyone have any ideas what could be going on? Thanks!

FYI, I have a Specialized Sirrus Comp.

jimc101

Headset? Park Tool Co. » ParkTool Blog » Threadless Headset Service

12strings

Just a thought, the stem could be tight down onto the steerer, but there could be space for movement if the spacers are not fit right. Try this, in this order:

1. Put bike somewhere where it won't fall over, and the front wheel is resting on the ground (if you put it up in the air the front fork will fall out when you do this).
2. Loosen the top bolt (the one pointing straight down into the steering tube...there might be a small rubber plug covering it)...take it completely off, along with the top cap. (make sure the fork is not allowed to drop out...this will make a mess with lots of parts falling off)
3. Loosen the stem. See if you can push it down any farther. Once it is as far down as it goes, there needs to be about 1/8" of space where the top of the stem is HIGHER than the top of the steering tube inside...this space allows the top cap to press everything together when it is tightened...(some people have the stem lower down the tube with some spacers on top, but the principle is the same...there needs to be space to tighten everything up).
4. If you have this space, leave your stem loose, and re-install and tighten the top cap. This should hold everything together, and make your stem fairly snug, but still able to be moved to align your wheel with the handlebars...
5. Last step is to tighten the stem itself, which will elminate any spin.

SHORT VERSION: Loosen stem and top cap...tighten top cap FIRST, then stem.

Could be something completely different rattling, but if the stem is tight, that's what I'd check next. If someone tightened the stem first, then the top cap, the stem would preven the top cap from squeezing down like it needed to.

rmfnla

Hold the front brake engaged and rock the bike back and forth to see if the headset is loose.

If it's just a small rattle it might be the shifters; they have little parts in them that will make noise as you describe (mine do)...