Pretendr: Blendr-Style Accessories Mounting for Trek Bike

Motivation

I wanted to a way to mount a GoPro to my (Trek) road bike handlebars, and I didn't like how other 3D-printed mounts that tried to mimic the Blendr system either required a lot of support material (or weak printing orientation) and/or required a flexible filament to be able to wrap around the handlebar.

The pretendr mount can be printed in the ideal orientation for maximum strength without any supports, and instead requires a bit of M3 hardware (or glue) to be assembled and a couple of zip ties for mounting to the handlebar.

Description

• There is a ‘straight' and ‘hooked’ version of the design, with the difference being that the hooked version has a slight offset in the accessory mounting hole.
• The design has 2 main body pieces which can be glued or screwed together with a M3x12 screw and locknut. The ‘bottom' body parts are meant to be mounted under the handlebar while the ‘top’ bodies are mounted above.
• There are also 2 insert pieces which can be slotted into either base piece, depending on which side you want the thumbscrew of your accessory to be on. The inserts can also be glued in place or screwed in with an M3x16 screw and lock nut.
• The accessory mount itself is built for M5 hardware (ie. GoPro hardware). You will need an M5x18 screw (ie. GoPro thumbscrew) and nut (square or hex) for mounting an accessory.
• For mounting to the handlebar, you will need 2 zip-ties that slot into the base pieces and wrap around the handlebar. Note that you should be able to mount 2 Pretendrs to a single handlebar to get a dual-mount.
• This design is made for the Trek/Bontrager (Legacy) Elite Stem, used for 2015-2018 model year bikes. The spacing between the stem plates should be 16mm. The system should still work as long as you can wrap zip-ties around the handlebar through the stem between the stem plates, it just may be a bit looser.

Printing Tips

• I recommend printing these in something like ABS or PETG for their superior mechanical properties compared to PLA, but PLA is not a bad option, especially if you don't plan on mounting anything too heavy.
• No supports should be necessary.
• Recommended slicing setup in the photos.

Assembly Tips

• When assembling, if you are gluing parts together it may still be useful to insert M3 screws into the empty holes for better alignment of the parts.
• When mounting to the handlebar, it is useful to kink the ends of the zip-ties a bit so the form a hook-like profile; this will make it easier to loop them around the handlebar through the stem.
• When mounting to the handlebar, the rear tab piece of the main body inserts into the stem behind the handlebar. This tab should be inserted first and at an angle, then the main body can be secured with zip-ties.