Handlebars come in all styles and sizes so here’s a quick guide to choosing the right size Knog Oi bell for your bike(s).

Watch this video to understand where and how to attach your Oi bike bell.

If your handlebar is any bigger than 22.2mm then you will need to choose the LARGE bell. The Large Oi comes with spacers that will allow you to attach the bell to handlebars with diameter of 23.8, 25.4 and 26mm.
– If your handlebar in the middle looks ‘normal sized’, it’s probably 25.4mm = LARGE bell
– If your handlebar looks overly big in the middle, it’s probably 31.8mm = LARGE bell


The easiest way to measure your handlebars is with a set of digital or vernier scale callipers.

measure your road bar diameter

measure handlebar with verniers

If you don’t have callipers then you can use a simple measure tape. Just wrap around the bar at the point you want to attach the Oi to get the circumference size and then divide by pi to get your diameter e.g. 99.9mm / 𝜋 = 31.8mm.

measure handlebar road

measure handlebar with tape

If you have no tape, then use a piece of paper (or string). Same as above, just wrap the paper around the bar at the point you want to attach the Oi, make a mark with a pen where the paper intersects and then measure against a ruler. This will give you the circumference and to get the diameter just divide by pi.

measure bar without tape

measure your circumference

measure handlebar with paper

measure your circumference 22

As a general rule of thumb:

–  Road Bike – Handlebars generally come in two clamp sizes 26mm (older style) and the newer ‘oversized’ 31.8mm. The area where you attach the Oi bell will most likely be either 25.4mm or 31.8mm = LARGE bell

–  Commuter/Cruiser Bikes – These handlebar sizes do vary due to the wide variety of styles, however most bar sizes would be either 25.4 or 31.8mm = LARGE bell

–  Mountain Bikes – Handlebars generally come in two clamp sizes 25.4mm (older style) and the newer ‘oversized’ 31.8mm. On some bars there will be a bulge in the middle and the bars will thin out towards the brake levers. If you want to attach your bell here, then please make sure you measure as it could mean you move from a large sized bell to a small. For instance the grip area on some of these bars will be 22.2mm, whereas the bulge is 25.4mm = LARGE bell

–  BMX – Always 22.2mm = SMALL bell