Paul Component Engineering Boxcar Stem

This stem was designed from the ground up to be stiff, strong and pretty darn light too. We went through several design iterations and believe we’ve reached the best combination of these three principles. Extensive real world and machine testing and proven this to be one strong stem.

With respect to torsion, the rounded box shape is some 25% stiffer than the competition. As for strength, we ran it through 1,000,000 cycles of above normal use stress without a single problem.

The stems come in a zero rise and a +/- 15 degree rise. Lengths are 50, 70 and 90mm. All screws are the same pan head T25 Torx type screws in stainless steel. Why Torx? Because they work so well, and are the same wrench size as the ubiquitous rotor screws all makers use. Also SRAM has made a switch to T25 screw heads in almost all their products, which is a good sign.

As usual, by letting the function and material properties dictate the shape of the product, we have come up with another one of our often complimented and purposeful designs. Yes, it looks a little different, but with us there is always one good reason for this: to make it work it as awesome as possible.


  • Weight
    50 mm +/- 0: 137 g
    70 mm +/- 0: 153 g
    90 mm +/- 0: 155 g
    70 mm +/- 15: 169 g
    90 mm +/- 15: 172 g
  • Material
    2024 Aluminum
  • Finish
    Anodized or Polished
  • Anodized Color
    Black or Silver
  • Bar Clamp Diameter
    31.8 mm
  • Lengths
    50 mm
    70 mm
    90 mm
  • Stem Angle (deg)
    +/- 0
    +/- 15
  • S.H.I.S. Stem Clamp Diameter
    28.6 mm
  • Stack Height
    36 mm
  • Additional Information

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