Ask Einstein, Headsets: What’s that knocking noise?

So you've noticed a knocking sound when you brake or hit a bump? Sounds like a clunky metal sound coming from the forks? Well, most of the time when this happens it's the headsets fault. Most of the time. A few checks will help you determine the problem and with a simple guide you can avoid the mechanic and sort it yourself.



So let me begin (scratches ear, licks nose and shakes head violently):

There are several different types of headsets out there but for this short guide we'll focus on the two most common: threaded and threadless. One way to determine if your headset is loose is to brake hard and listen out for the 'clunk' sound or lift up the bike by the headset to see if there is any play or movement in the headset. If you've definitely got a clunk sound or movement, your headset might need adjustment.

Here's how:

  • For threaded headset you'll need 2 large adjustable wrenches or 2 headset wrenches.
  •  Place first wrench on top lock nut and loosen it a little (anticlockwise). Then place second wrench on bottom locknut and tighten slightly clockwise. Check again if there is any play in it the headset. If there is, tighten lock nut on top tight, and check again. Remember there's tiny adjustments so you might have to go through this a few times to get it right.
  • For threadless headset like with most road, hybrid, and mountain bikes, it is a little easier to adjust assuming it just needs a tighten. You'll need a allen key set. Like with the threaded headset, check if there is any play/movement in the headset (and not the brake) before you begin.
  • To adjust: First loosen your stem bolts at the side of your stem. Loosen each a bolt a little at a time. Wiggle stem side to side to ensure that it is loose. Then loosen top bolt. Check again if headset is loose by gently dropping the bike.
  • Gently tighten the top bolt until you feel resistance. Pull the brake and see if there is any play. If there is, gently tighten top bolt again and repeat until no play is felt.
  • Once achieved align the stem with the front wheel and tighten the stem bolts. Check stem again and make sure it turns freely.

Remember if you are unsure or if you think that there is another problem (stem is seized etc) bring it to a bike mechanic to check to be on the safe side. I  know a few mechanics here at The Bike Institute that are happy to help.

I'm off to chase squirrels now but catch me again next week for more advice on bike repair and maintenance - Woof!

Einstein The Dog


Butt sniffing, nose licking, bike shop floor hound who loves cuddles.