Lightweight press-fit MTB handlebar plugs

Simple bar end plug for MTB handlebars which is very lightweight, but requires measuring the inner diameter (ID) of the bars accurately to get a good fit.

The design is minimal - the outer diameter of the plug is 22.2mm (7/8") which matches the outer diameter of MTB handlebars.This allows the plugs to stay in place when grips are installed or removed. The design is sized to the inner diameter of the handlebars, which you'll need to measure. (or print several and see which fits) For instance, the 17mm size fits my ENVE bars, as well as my wife's Bontrager XXX bars. The aluminum bars that came with my XC bike has thinner walls and so they use the 19.5mm diameter size. The design is parametric, but to make life easier, I've included STL files in a range of sizes from 16.5 to 20mm. The Fusion360 F3D file is included if you wanted to make any further changes. (see the section below for notes on that)

These things are light - see the photos, a current set of ESI plugs is about 4g and these come in at 2.5g in the 20mm ID size in PLA. Yes, this is ridiculous weight weenie territory, but I'm not aware of any option that's lighter, aside from running no plugs, which is a bad idea as that's kinda dangerous.

Print instructions

I've printed using PLA, PETG, ABS, ASA, PC, CF PETG, CF PC, nylon and CF nylon. Pretty much anything but PLA is best if your bike is subjected to high temperatures (like sitting in a car on a hot day) but any of the materials should work.

I've even printed this on my MSLA (UV resin) printer and they worked, but not as well as the FDM printed ones. One perk was I as able to add debossed texted that I then filled with paint, so they looked awesome, but broke quickly.

No supports are needed, and you can use whatever layer height you wish. Two shells are usually fine.

How I Designed This

Design process

The design of these plugs evolved over several months as I tested them on several bikes, both mine and my wife's. They've been tested over several hundred miles of riding, in the deserts of Utah and Arizona, Kingdom Trails in Vermont, and various Cat 1 and endurance MTB races in the northeast.

My initial prototypes were printed in PLA, and I had issues with them getting loose and falling out. I thought this was due to the less than perfect properties of PLA, so reprinted in PETG and ABS, but those wound up falling out as well. Turns out I had designed them too thin, and after a while, the plastic would reshape to no longer be a press fit into the end of the bars, at which point it would get loose. Adding a small taper to the inside of the plug thickened the walls slighly and prevented this. The current design has been in use on several bikes with no issues.

I also ran into issues where the plug would break quite easily if I hit a tree with the bars. The obvious solution is don't hit a tree with the bars, but adding a fillet to the inside increased the strength and made this less of an issue.

The current design has been in use on several bikes for well over a month with no issues.

Custom Section

Notes for modifying in Fusion360

If you download the F3D file and import it into Fusion 360, you can use the "Modify" "Change Parameters" command to open the little spreadsheet where you'll be able to modify the user parameter "Bar_inner_diameter"

In the old version of the Fusion 360 file shared here the text is static so you need to update the diameter and then update the text to match. I've since added the parametric text plugin and that drives the text in the newer versions, but have not uploaded it as it won't work if you don't have the plugin.