We tried to design the Chonus Bag to fit most headtubes, but some bike manufacturers thought it was a good idea to create some really big headtubes.
The best way to determine this is to measure the diameter of your headtube. You can do this with the following steps:
If you have a soft, flexible tape measure, use that.
If you don’t have a soft, flexible tape measure, wrap a charging cable or a strap or around the headtube.
Mark the point on the tape measure, cable, or strap where the length goes all the way around the headtube.
Use a ruler or measuring tape to measure that distance, which is equivalent to the headtube circumference.
This length should be less than 6 inches.