Threadless handlebars will also have additional screws on the back of the handlebars. Look for these if you’re unsure of what type you have.
Read the product details on the bike to determine which size Allen wrench you need. The most common sizes of Allen wrenches used on bikes are 4mm, 5mm, and 6mm. [3] X Research source
If your handlebars don’t have spacers above the stem and your steerer tube is too short to add some, then you may need to use a threadless stem raiser instead. This attaches to your handlebar stem to raise it higher. However, if you raise your handlebar stem too high, you may need to install longer cables and housing.
If you don’t like the new height of your handlebars, remove your handlebars again and place fewer spacers below the handlebars.
A 6mm Allen wrench is a common size for the top bolt.
There are usually markings on your handlebar stem that designate how high the handlebars should go. Don’t raise them higher than these lines or your bike will be unsafe to ride.
If you don’t like the new height of your handlebars, loosen your handlebars again and readjust them until they are at a height that feels comfortable.
In an ideal position, your shoulders should feel relaxed and your core should feel engaged. You should lean forward at the hips but your spine should be straight. [13] X Research source Your handlebar placement can create a neutral, relaxed, or aggressive posture. For a neutral posture, keep your handlebars level with your seat. If you want a relaxed posture, raise your handlebars higher than your seat. To get an aggressive posture, lower your handlebars below your seat. Keep in mind that most riders prefer a neutral or relaxed posture.
If your handlebars are too high, you won’t be able to lean forward and it can cause saddle soreness or soreness in your back.
If you have to strain to reach your handlebars, they are too low.
