Bicycle disc brake caliper piston spreader

Wedge to press disc brake caliper pistons back into the caliper body during service. Print two, use them in a pair. Insert from opposite sides of the caliper, push them together, then use the finger holes to remove them. Quick and easy, easier than using a tire lever.

Featured by Dave Rome of Escape Collective and James Huang of N-1, and used by pro bike mechanics the world over. Also reviewed (badly) by Seth of Berm Peak.

NOTE: This is the original. If you see it elsewhere, including AliExpress, they've ripped off this design without permission. I've gone so far as to look into the IP takedown options on AliExpress, but if you've seen how many other tools are shamelessly ripped off over there - including pretty much the entire Park Tool catalog, down to the colors, you'll see that there is pretty much zero recourse from AliExpress IP infringement.

Four widths - 36mm, 26mm, 18mm and 14mm. Standard 26mm fits anything from Shimano road/MTB 2 piston calipers that take K/L pads up to four piston brakes. 36mm fits many four piston brakes, although some (early SRAM Guide) partially obscure the piston pocket and so the 26mm is the call there. Narrow 18mm fits calipers that don't load pads from the top, such as the lower end Shimano calipers that take the B pads, or Magura's 4 piston calipers with split openings and individual pads for each piston. 14mm is for the lower end calipers which have barely any opening.

Print instructions

Print two! This might work on its own but it will work far, far better as a matching pair.

Print on the side (should load in the proper orientation) so both surfaces of the wedge have a consistent, smooth finish. Layer height, shells, infill, all can be pretty much whatever you want as these don't need particularly high strength. I do 0.2mm layer height with a 0.4mm nozzle, 4 shells, and 25% grid infill. Contrary to what many youtubers will have you believe, grid infill is just fine.