How to Adjust a Threadless Headset
Learn how to check the adjustment of a threadless (Aheadset) and align the handlebars.
In today’s tutorial, we’ll learn how to adjust a threadless headset, otherwise known as an ‘Aheadset. For this job, you’ll need either a 5mm or a 6mm allen key, depending on your stem.
To loosen the stem, simply turn the allen key on top counter-clockwise a few turns. Don’t remove it completely. Then loosen the two bolts on the side. Now your stem should turn freely.
To check if the headset is tight, lift the front of the bike off the ground. The handlebar should rotate freely and fall to one side or the other. If it doesn’t, you’ll have to loosen the top bolt a little bit and try it again.
To check for play, hold the front brake, place one hand on your headset, and rock the bike forward and backward. If the headset is loose you’ll feel it, and you’ll have to tighten the top bolt a little bit.
Once the adjustment is set, check the alignment. I find it easiest to line up the stem with the front wheel while you’re sitting on the bike. Once the handlebar is straight, tighten the two stem bolts and check the adjustment again just to be sure.
- Park Tool: Threadless Headset Service
- Sheldon Brown: Servicing Bicycle Headsets
- Bicycle Torque Specifications
- Park Tool HXS-1.2 Hex Wrench Set
- Park Tool AWS-1 3-Way Hex Wrench
- Park Tool AWS-10 Folding Hex Wrench Set
- Park Tool WTK-2 Essential Tool Kit
- Park Tool SK-3 Starter Mechanic Tool Kit
- Park Tool PK-3 Professional Tool Kit
Discuss this topic in the Bicycle Repairs and Mechanics Forum
Handlebars are either too loose or too tightLatest post 1 hour ago
Hello, I've had my bike from teenage years in the garage with the wheels off for a few years now. Put it all together and instantly remembered why it was in storage. The handlebars either move without the wheel turning or the handlebars get REALLY hard to turn (with the wheel ofc). Its a matter of maybe a quarter turn on the top bolt from loose to tight, there's no inbetween. I think when I was y...Read more
Patching a tireLatest post 3 weeks ago
In the past I have had a lot of punctures. When they happened, I patched the tube, but the holes in the tire were so small, they did not need patching. After many more kilometers, rubber started coming away around two of the holes in the tire, exposing the chords. If I did not do anything, a rock could cut the chords, destroying the tire. I wanted to get more use out of the tire. I cut patches fr...Read more
Schwinn Meridian Drive Wheel Missing Feather KeyLatest post 4 weeks ago
Hi, So I bought a used Schwinn Meridian sight unseen online auction for $59 & drove 8 hours round trip to get it. It appears to be brand new actually. When I got it home, the next day I checked out my score. When I sat on it and pressed on the pedals, they moved but the bike did not. I inspected the bike and realized that whoever put this trike together, forgot to put what appears to be ...Read more
I fell off my bike and slightly damaged my hand brake, resulting in a weak front brakLatest post 1 month ago
I had a previous incident with my bike, and the front brake got bent. Now when I try to use the front brake, it is very weak (when I ride the bike and fully depress the front brake, the bike does not stop quickly). I tried to fine-tune the disk brake caliper (I did it many times before), and it looks good and tight, but the front brake. What could be the reasons for this?...Read more
Full Rebuild vs ServiceLatest post 1 month ago
Hi, I've had my Giant Defy for two years now and have done about 4000 miles on it. I keep it clean and generally only ride in dry or damp conditions (never pouring rain). Apart from a potentially stretched shifter cable (won't go in highest gear despite adjusting barrel adjuster and limit screws) the bike rides fine. I keep on top of basic maintenance, cleaning, checking for chain wear etc... an...Read more
Sloppy front deraullierLatest post 1 month ago
Hi there how do i tell if my front deraullieur needs to be replaced on my hybrid it has a ton of play back and forth....Read more
Cracked shimano DI2 front derailleurLatest post 2 months ago
Hi, I got a cracked shimano DI2 front derailleur (see picture attached). I try soldering it but no luck (probably don't have the right solder). Any suggestions on how to fix that please? Thanks 20230206_170038.jpg (Size: 47.7 KB / Downloads: 35) ...Read more
Calculating bottom bracket spindle widthLatest post 2 months ago
Hello, I’ve got an old set of square taper FSA tempo cranks (2x) that I want to swap from a single speed 120 OLD bike to a 1x10 135mm OLD one. Any tips on how to calculate the spindle width for correct chain line? I can’t find anything for that model on the manufacturers website, and i don’t think measuring the one on the single speed will work with the different chain line....Read more
Help with headset preloadLatest post 2 months ago
First time adjusting a headset and I'd like to get it right. Brand new giant reign with a carbon frame, that I do not want to damage I finally have the preload set to where there is no play but I'm concerned that it is to tight... Stage 1- obvious play/clunk Stage 2- no clunk, but if I lock up the brake and push and pull hard, I can feel some very slight movement Stage 3 - no play or movemen...Read more
8 Speed on 7 Speed Freehub BodyLatest post 2 months ago
Awhile back, I was able to hack a 7 speed freehub body and get an additional speed out of it by using a 9 speed cassette with the narrower spacing. Note that these older freehub bodies are 7 speed exclusive. They do not typically have the space to fit a larger cassette on them. To do this, I took a 9 Speed Dura Ace 11-23 cassette and I simply removed the final combination cog from the back, then...Read more
How often do you wash your bike?Latest post 2 months ago
Ciao. I know that some bike riders overexaggerate the 'cleaning part' and wash (or spray) their bikes at least once a week. I know, it's mandatory after a muddy trail ride. But I'm thinkging more about daily commuters. It gets dusty here and there, but how long is too long without a shower for a bike? For a bike that rides almost every day....Read more
What's Wrong With My Bike? Squeaking or Squealing Noises?Latest post 2 months ago
I made a video of what my bike is doing. Can someone please watch and help? https://youtu.be/NTu-831CuGM...Read more
How to lubricate my bike's D-lock?Latest post 2 months ago
Looking for advice. I have repeated problems with my D-lock sticking. I've used standard light bike oil which then leaks all over my hands when I handle the lock. I have some 3-in-one PTFE spray: would that be better?...Read more
Best way to thoroughly clean a chain?Latest post 3 months ago
Hi everyone! I hope you're enjoying a great start to 2023. I'm curious to hear your go-to method for getting a chain truly clean. I don't mean, just looks shiny or is good enough for a quick clean after a ride. I want to know what you do when you want to get every last morsel of ground-up, link-destroying, roller-eating, tooth-gnashing crud out of your chain. The Best Chain-Cleaning Recipe Ever?...Read more
700c Wheels on a 26er or 26" Bike FrameLatest post 3 months ago
Obviously, this doesn't speak for them all, but they certainly might fit! And not even just barely (as suggested by some sources), but with a lot of room to play with. This is another GT Tempest frame that I recently purchased. It's originally a 26" alloy touring bike. As you can see, there's lots of head room, and plenty of clearance to increase the tire size up to probably 38c—maybe even 40c....Read more