One of the key things we do to make our test bikes handle better is adjust the handlebar height. Often, the off-the-shelf bar height doesn’t lend itself to optimal handling. With that in mind, here’s our guide on how to adjust handlebar height.
Riders will often experiment with saddle height, tyre pressure, bar angle and suspension settings, but few are aware of the benefits of adjusting bar height, despite the handlebar playing a crucial role in the way your bike handles.
Bar height is also known as saddle-drop which is the measurement of how far the top of the saddle sits above (or below) the bars.
Generally speaking, a lower handlebar height reduces your centre of gravity. By placing more weight over the front wheel, you increase traction.
Additionally, a lower bar height provides a more centred position between both wheels to improve bike control, especially during climbing. These traits are even more noticeable off-road, especially with 29ers.
There is a limit; going too low can make the bike difficult to control. A lower handlebar can also negatively affect handling in steep terrain.
On the road, elite riders normally have a significant drop, where their bars sit below the saddle. This is typically done to provide a more aerodynamic position.
Recreational riders are usually best served by a handlebar that is in line with the saddle or above it. This usually gives a very comfortable position.
Luckily, experimenting with bar height is easy and most often free, so you can adjust to your heart’s content until you find the right position for you.
How to adjust the handlebar height on your bike
The guide below applies to modern threadless style stems and headsets. If your stem has bolts pinching it onto the steerer tube, it’s most likely threadless.
We also cover how to adjust the height of a quill-style stem below.
Time: 15 minutes
Skill rating: Easy
Tools you’ll need
- A multi-tool or a set of Allen keys
- A torque wrench or pre-set Torq key is recommended, especially if working with carbon or lighter parts
- Some stems, such as those from Zipp, Ritchey and Syncros, will use Torx keys rather than Allen bolts and so a T20 or T25 Torx key will be required
- Possibly a hammer for some quill stems
How to add or remove headset spacers
This bike features four headset spacers. The piece below the fourth spacer is the headset bearing cover and should not be removed. Oli Woodman/Immediate Media
The first and easiest way to adjust handlebar height is by moving headset spacers.
Headset spacers sit on the fork’s steerer tube and help pre-load the headset bearings during adjustment.
Generally, most bikes have 20 to 30mm of headset spacers that can be moved freely above or below the stem. All bolts in the stem are standard-threaded (i.e. ‘lefty-loosey, and righty-tighty’).
Loosen each of these bolts, a little at a time, one after the other until you feel no resistance. Oli Woodman/Immediate Media
Start with the bike’s wheels firmly on the ground and then loosen the clamp bolts on the back of the stem.
This is a good time to add a little fresh grease to the top cap bolt, which can easily become seized in place.
The top cap bolt will most often require a 4mm or 5mm Allen key. Oli Woodman/Immediate Media
Remove the top cap that sits on top of the stem.
Slide the stem off of the steerer tube.
This is what the top cap and bolt look like when undone. These pieces thread into an item called a star nut.
On a carbon bike, an expanding wedge called a bung is usually used. You do not need to remove either of these.
Even a small change to the height of your handlebars can make a big difference, so don’t be afraid to play with this arrangement in the future. Oli Woodman/Immediate Media
Decide how much you’d like to lower or raise your bar and add or remove the appropriately sized spacer(s).
If there’s a large stack of spacers above the stem, consider whether flipping the stem could achieve the same effect to the fit. Oli Woodman/Immediate Media
Slide the stem back onto the steerer tube and replace the spacers you just removed into position above the stem.
If this gap is not present, check that you have not misplaced any spacers. Oli Woodman/Immediate Media
Ensure there is a 3 to 5mm gap between the steerer tube and the top of your stem/spacer. This will ensure there’s enough space for the headset topcap to clamp down and pre-load the headset bearing.
Too tight and your handlebars won’t turn freely, too loose and you will feel a rattle and vibration through the bike. Oli Woodman/Immediate Media
Now replace that top cap and bolt, and tighten until you feel some resistance. This top cap bolt is used to pre-load the headset bearings.
This step may take some patience – it helps to straddle yourself over the top tube of the bike. Oli Woodman/Immediate Media
Next, align the stem with the front wheel, so the bar is at a right angle with the wheel. This may take some patience – it helps to straddle yourself over the top tube of the bike.
It is worth investing in a decent torque wrench for jobs like this. Oli Woodman/Immediate Media
Once the wheel and stem are aligned, evenly torque the stem clamp bolts to the manufacturer’s recommended value using a torque wrench. This is often around 5 to 8Nm.
If you’re struggling to eliminate play, make sure all headset spacers are accounted for. Even a few millimetres can make a difference. Oli Woodman/Immediate Media
Check your headset adjustment.
An easy trick to get this right is to hold the front brake and put one hand on the headset, then rock the bars gently back and forth. Feel for the steerer rocking back and forth inside the head tube of the bike.
If you feel this, loosen the stem clamp bolts and tighten the top cap bolt another quarter-turn, then re-torque the stem clamp bolts.
Repeat until all signs of bearing movement have disappeared and the handlebars still turn smoothly. If you’ve tightened the bolts too much, you’ll feel a tight spot when turning the handlebars.
If your headset feels rough, it may be time to service or replace your headset bearings.
How to flip the stem on my bike
If spacers aren’t enough to achieve the affect you want, you can flip the stem to make a further change to the bar height.
Most mountain bikes will be set up with the stem in a positive position, creating an upward angle, but you can use it the other way round.
This uses all the steps above with the addition of unbolting the handlebar from the front of stem.
If you feel an excessive amount of resistance when loosening the faceplate bolts, don’t be afraid to put a dab of grease on their threads. Oli Woodman/Immediate Media
With the bike’s wheels firmly on the ground, make a mental note of the handlebar angle and the brake lever angle.
Matching up a piece of masking tape on the faceplate and bars will make sure you get the angle spot on when refitting.
Undo the bolts that hold the handlebar to the front of the stem. Remove the stem’s faceplate and store it somewhere safe.
A second person to support the bike can help here. Oli Woodman/Immediate Media
Let the handlebar gently droop to the side and now follow the procedure for swapping spacers, outlined in steps 1 to 4 above.
You can see that the stem has reversed its slope. Oliver Woodman/Immediate Media
While the stem is off the bike, flip it over and then slide it back onto the steerer tube.
Uneven spacing can lead to failure of the bolts in the future, pay particular attention to this step.
Reinstall the handlebar, replicating the previous brake lever and handlebar angle.
Tighten the faceplate to the manufacturer’s recommended torque (generally between 4 and 8Nm). Ensure that all bolts are done up evenly, a little at a time, and that there is an even gap top to bottom with the face plate once they’re tight. If the gap isn’t even, the handlebar is being pinched.
(While it’s usually the case, not all stems suggest having an even gap at the top of the faceplate. Check your user manual if you are in any doubt.)
Proceed with steps 3 to 7 above to pre-load the headset and tighten the stem.
How to adjust the height of a quill stem
A quill stem slides into the steerer tube. Jack Luke / Immediate Media
Quill stems were the norm before A-head/threadless style stems hit the market. They are still commonly seen on bikes of all styles and disciplines.
Quill stems slide into the steerer tube of the fork and are secured with either an expanding bung or sliding wedge that presses against the inside of the tube.
Adjusting their height is slightly different – but arguably much easier – than a threadless stem.
Loosen the bolt on the top of the stem. Jack Luke / Immediate Media
Begin by loosening the bolt on the top of the stem. Most use a hex head bolt, but some will use an external bolt.
You may have to tap the bolt with a hammer. Jack Luke / Immediate Media
Once loosened, you may be able to freely move the stem.
If the stem hasn’t been adjusted in some time, you may need to gently tap the bolt with a hammer to free the wedge or bung.
If the bolt is sitting proud of the stem, strike this directly. If it is flush with the top of the stem, you can use your hex key to gently tap the bolt.
Pay attention to minimum and maximum insertion heights. Jack Luke / Immediate Media
The stem can now be adjusted to your heart’s content. Be sure to check for any minimum and maximum insertion marks on the stem and adhere to these.
It is good practice to periodically grease the shaft of a quill stem because they frequently seize if left dry.
Once set, re-tighten the bolt to secure the stem. Jack Luke / Immediate Media
Once you have set the height of your stem and lined it up with your front wheel, you can re-tighten the wedge bolt to spec.
You’re now good to hit the trail and/or road to test out the bike’s new handling characteristics.
It may take some trial and error along with patience to find that perfect height, but once you’ve got it, you’ll be far closer to realising the bike’s true potential.