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How to assemble and adjust bicycle handlebars and stem correctly

To change bicycle handlebars and stem you need the following tools: 

You don’t need any special tools to correctly assemble or adjust your bicycle handlebar stem. If you have an average tool kit, it should have everything:

  • The most important utensil is an  Allen key or an Allen key set, the size of the clamping screws of your stem, and the head cap.
  • A  torque wrench provides the correct torque and guarantees that no components or screws break.
  •  A tape measure or folding rule is required to align the brake and shift levers on the racing bike or gravel bike at the same height.
  • A bicycle assembly paste is strongly recommended for carbon parts.

Changing bicycle handlebars and stems on road bikes and gravel bikes 

Changing the stem of a gravel bike

Changing the stem 

In principle, changing the stem on your racing bike or gravel bike is relatively easy and you don’t need to be afraid to try it yourself.      

1. First you dismantle the handlebars using the four screws on the stem clamp, loosen the two screws on the stem on the side of the steerer tube, and unscrew the Ahead cap. Now you should hold the fork if your racing bike or gravel bike is not on the ground, otherwise, the fork can slip out.

2. Pull off the spacers and the old stem and slide the new one onto the steerer tube. Make sure that the height of the new stem matches the dimensions of the old model. If the new stem is lower in height, an additional spacer or shortening of the steerer tube may be necessary. If this is not the case, put the previously installed spacers back on and hand-tighten the Ahead cap back into the steerer tube.

3. Next, mount the bicycle handlebars on the stem with the four screws. Pay attention to the crosswise tightening and the correct torque. Next, you set the right distance of the headset with the Ahead screw. To do this, pull the front brake and move your bike slightly back and forth. With your index finger on the lower headset, you can see if there is still play between the fork and the headset. Minimal turns of the head screw can be enough to fix the backlash. Never tighten the ahead screw too much, otherwise, you will crush the headset. 

4. Finally, align the stem straight to the front wheel and use a torque wrench to tighten the two side screws as recommended by the manufacturer.

Mount and adjust a new handlebar on the racing bike and gravel bike

Mountain bike handle bars

1. Before you can mount a new drop bar on your road or gravel bike, you must remove the brake and shift levers and other accessories.  To do this, fold the rubber overlaps of the brake handles up and loosen the locking screw (only loosen, do not unscrew).

2. Now you have to completely unwind the handlebar tape and detach the brake and shift cables from the bicycle handlebars. These are usually fixed to the handlebars with insulating tape. Now pull the brake shift levers down and put them down carefully. They are held to the bike by the cables.

3. Now you can loosen the four screws that fix the old bicycle handlebars to the stem and dismantle the old handlebars. Center the new racing bike handlebars in the intended clamping area of ​​the stem and screw it tight. Make sure not to tighten the four screws completely and first align the handlebars horizontally. Next, thread the brake levers back onto the handlebars – don’t mix up the left with the right! You only have to put them roughly in the right position for the time being and then only slightly tighten the locking screws of the brake levers. 

4. In the next step you align the levers correctly and equally. For the height you can use the imprint on the handlebars, a spirit level, or a tape measure, both should be mounted at exactly the same height on the handlebar bend. Also, note the angle of the brake levers. They should run like the drop of the handlebars. For handlebars with a flare (outward bend), for example, turned slightly outwards. Correctly aligned, the brake lever will cover the lower link when you look at your bike from the front. 

5. Once you have set the appropriate positions, you can tighten the locking screws of the levers and tape the cables to the road bike or gravel handlebars. In the case of handlebars with internal cable routing, you must of course route the cables through the handlebars at this point. Only then do you wrap the new handlebar tape around both sides of the handlebars and finally fold back the rubber grips on the levers.

Changing the handlebars and stem on a mountain bike

Mount and adjust the stem on the mountain bike

1. In order to change your stem on the MTB and be able to mount a new one, you must first dismantle the old one. To do this, take a 4mm or 5mm Allen key and loosen the four screws on the connecting clamp between the handlebars and the stem.

2. As soon as you have unscrewed all four screws, you can remove the handlebar and carefully lay it forward. It is now held in place by the brake and shifter cables. (See Full Suspension Bikes for Sale)

3.  Next, loosen the two screws on the stem that are on the side of the fork. About 1.5 turns should be enough. Before you can now loosen the large ahead screw in the third step, it is important to check whether the fork and your front wheel are hanging freely in the air. If this is the case, be sure to hold your fork tight when loosening the ahead screw, otherwise, it could fall out. If your bike is on the ground, this step is not necessary. Now loosen the ahead screw, remove the spacers (if there are any) and pull the stem upwards off the steerer tube.

 4.  Now you can proceed backward in almost the same way to assemble the new stem:

Put the new stem on the steerer tube and the ahead cap with the screw from above and tighten the ahead screw slightly – the large ahead screw is an adjustment screw and not a locking screw! Now plug the handlebars back in and fix them to the stem with the four screws. Use a torque wrench for the last few turns and always follow the manufacturer’s instructions, you can find them either on the stem or in the user manual. Always tighten the four screws crosswise.

 5.  Next, slowly rock your bike back and forth with the front brake on. With your index finger, you can feel at the lower transition between fork and frame whether there is still play. If nothing wobbles there anymore, you can also tighten the side stem screws. A torque wrench is also recommended here. However, make sure to straighten the handlebars first. To do this, stand in the middle of your bike, look down at the suspension fork or fork of your bike and compare the visual distances between the handlebars and fork. If the distance is the same on both sides, your handlebars are optimally aligned.

6. If there is still some play in the headset, tighten the ahead screw a little more. Most of the time, minimal turning movements with the Allen key are sufficient.

Mount and adjust the handlebars on the mountain bike

Fitting a new handlebar to an MTB is usually quick and easy.  

1. First remove the grips and then the brake and shift levers from your handlebars. You can carefully put the brake and shift levers down and let them hang by the cables, or wrap them around the frame with cable ties or insulating tape.

2. In the next step, loosen the four screws on the stem, remove the handlebars and attach the new ones in reverse order. When tightening the four screws you have to pay attention to the correct torque again and tighten the screws alternately crosswise. Make sure that the gap dimensions of the handlebar clamp are the same at the top and bottom.

3. Finally, thread the shift & brake lever and the grips back onto the handlebars. Be careful not to mix up the brake levers and mount them as you have ridden them before. You can use a spirit level to align the brake levers evenly, but a visual check from the side of the handlebars is usually sufficient.

The peculiarities of assembling carbon bicycle handlebars and stems

If your new bicycle handlebars or stem are made of carbon, a few special rules apply when changing your components. On the one hand, it is essential to pay attention to the correct torque. In order to tighten all screw connections correctly, you absolutely need a torque wrench. In most cases, you will find an imprint with the exact values ​​in Newton meters (NM) on the carbon handlebar or carbon stem. If this is not the case, the operating instructions will surely help you. 

It is also advisable to use special bicycle assembly paste  –  in this case, carbon paste – when assembling carbon parts such as road bike carbon handlebars and mountain bike carbon handlebars.  

Caution: Carbon Paste is not the same as lubricating or anti-corrosion grease. Carbon pastes do not reduce adhesion but increase it.