Why don't BMX plugs fit on MTB riser bar? In a previous question, I have been told that the grip diameter of a MTB riser bar is 22.2mm. From research I did, the grip diameter of BMX handlebars is also 22.2mm. In fact, it's possible to use BMX grips on MTB handlebars. I thought this would allow to use also BMX bar plugs on MTB riser bars. As I experienced first hand, this is not the case, see picture below. Is that because the internal diameter of MTB bars is smaller than in BMX bars? ![see picture](

The outer diameter of bars is the same. Internal diameter can vary a bit between manufacturers, but you're going to have an ID of around 20 mm for road bars and 17 mm for mountain bars (source). A BMX bar is somewhere in between -- if you get the right MTB bar and the right BMX plugs, they'll probably work.

That being said, if you can't get those in with a bit of twisting and turning, you could probably shave them off. Or, go for an expander style plug.