Giant OD2 50mm stem for Mountain Bike.

thingiverse

Some Giant Mountain bikes use the OD2 steerer-tube stem diameter, which is 1.25", or 31.8mm. Giant sells stems, but they only go down to 60mm. I had one on order, but I got impatient waiting for it and decided to design this to see what 50mm feels like. A bike stem is a high-stressed part that can break easily if not printed correctly. This part was made extra thick to be strong, but depending on how you print it, it may still break, which could lead to injury or death. You have to decide for yourself whether you are willing to use this or not. I recommend buying the real Giant 60mm part for $40. I rode my bike with no problem, and here's a link to the ride: https://www.strava.com/activities/595607124 The strength of the stem depends on printing parameters and orientation. I printed it in eSUN PET-G with 100% infill. To get the best results, orient the front plate part sideways so that it has good layer strength and an accurate profile for the bars. Print the stem itself in the orientation where it sits on the bike. This gives a good surface finish to the visible parts and a reasonable layer strength orientation. You will need six 30mm M5 socket-cap screws, six M5 washers, and six M5 nuts to assemble this part. You may also want to glue some sandpaper to a 1.25 inch wood or 3D printed dowel and clean up the surfaces.