Bike Stem Phone Mount

UPDATE 1: As requested in the comments, I’ve added larger Square Stem mounts that fit up to 50 mm wide. Enjoy!

This accessory lets you securely attach your phone to your bike. It fits phones from 63 mm to 93 mm in width. 

This is an alternate version of the Bike Handlebar Phone Mount, which was design to mount directly on the handlebar. 

There are six versions included in the print profile, each designed for different tube sizes:

• From 23 to 26 mm
• From 27 to 30 mm
• From 31 to 34 mm
• From 35 to 38 mm
• From 39 to 42 mm
• For Squared Stem (max 38mm width – adjust depth with screw length)
• NEW For Large Squared Stem (max 50 mm width – adjust depth with screw length)

The clamping jaws are the same for all tube diameters. Two knob styles are included: a smaller one for quick position adjustments, and a larger one for easy mounting and removal of your phone. Both knobs are interchangeable, allowing you to customize the setup to your preference. To install, simply snap the knobs onto the clamping jaws.

I’ve also included optional TPU parts (common for all versions):

• 2x phone pads – useful if your phone doesn’t have a soft case (e.g., if you’re clamping directly on metal).
• 2x clamp pads (for cylinder clamps only) – optional, but they help with grip and reduce slipping on smooth surfaces.

To mount it on your bike, you’ll need:

• 2× M4 × 20 mm screws (AA068) (select a proper length if you use the squared clamp)
• 2× M4 nuts (AB028)

If you prefer, you can use heat-set inserts instead. M5 screws and nuts may also work, but you’ll need to slightly enlarge the holes.

---If you like this bike accessory, I recommend checking out the B-Rail — an ecosystem I designed for mounting interchangeable accessories on your bike.