Boxcar Stem – Paul Component Engineering Skip to content

Covid-19 Update:

We’re still receiving and shipping orders, and really appreciate your support! Please be patient, as it may take a few weeks for orders to be shipped under the current manufacturing circumstances. Rest assured, we will get your parts to you as fast as we are able to, while still observing Covid-19 safety protocols - even if you don't hear from us.

International Customers: We have been seeing parcels sit in customs all over the world for up to 2 weeks with no update to the tracking information. These orders are eventually delivered, you will just have to be extra patient.

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Shop | Components | Cockpit | Boxcar Stem

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Boxcar Stem

The Boxcar Stem is the perfect combination of stiffness, strength and light weight.  Available in +/- 0^ in 35, 50, 70 and 90mm. Also +/- 15^ in 70 and 90mm, and +/- 7^ in 100 and 110mm. All screws are high strength stainless steel with the popular T25 head. Made in Chico, California with US sourced 2024 aerospace alloy.

$141.00 – $159.50

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Technical Information

  • Weight
    35mm +/-0: 118 g
    50mm +/-0: 137 g
    70mm +/-0: 153 g
    90mm +/-0: 155 g
    70mm +/-15: 169 g
    90mm +/-15: 172 g
    100mm +/-7: 181g
    110mm +/-7: 203 g
  • Material
    American 2024 Aluminum
  • Finish
    Anodized or Polished
  • Anodized Color
    Black, Purple or Silver
  • Bar Clamp Diameter
    31.8 mm or 35.0
  • Lengths
    35mm
    50mm
    70mm
    90mm
    100mm
    110mm
  • Stem Angle (deg)
    35, 50, 70, 90mm: +/- 0
    100, 110mm: +/-7
    70, 90mm: +/- 15
  • S.H.I.S. Stem Clamp Diameter
    28.6 mm
  • Stack Height
    36 mm
  • Instructions
    Download
  • Torque Settings
    Steerer Tube: 5nm
    Faceplate: 4nm
  • Rise & Reach
    Download

Product Story

This stem was designed from the ground up to be stiff, strong and very light. We went through several design iterations and believe we’ve reached the best combination of these three principles. Extensive real world and machine testing have 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. How’d we get it so light, while still being so strong? We started with obsessive computer design time, then took the strongest and highest quality alloy made (American 2024), and precision machined it to .002” tolerance (that’s really tight for a stem). We use over 20 different end mills, drills, saws and taps to make 1 stem.

The stems come in a zero rise and a +/- 15 degree rise, and in 100mm and 110mm length they are available in +/- 7 degree rise. Lengths are 35, 50, 70, 90, 100, and 110mm. All screws are the same pan head T25 Torx type screws in stainless steel. Why Torx? To encourage torque wrench usage and avoid strippage (People tend to overtighten faceplate bolts). Also the Torx head is wider, distributing stress better, 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 as awesome as possible.

 

 

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When we saw the Sierra Buttes Trail Stewardship an When we saw the Sierra Buttes Trail Stewardship announcement that all events for 2021 were cancelled due to Covid, we were crushed. Anybody who’s been to the Downieville Classic, Mountains to Meadows, or Lost and Found knows we 
LOVE supporting these events with our aid stations, and partying with some of the best bike weirdos in the world, in one of the most beautiful areas in the world.
 SBTS rely heavily on these events to help raise funds and awareness for all the amazing trails they build in the Lost Sierra, involving, employing, and assisting the local small communities in the process. It’s truly inspiring to behold the hard and meaningful work they put in, and a cause we will trumpet until we’re out of breath. 
 What can we do to help? Well, we’ve decided to offer up one of our few remaining Limited Edition 30th Anniversary Box Sets as a prize to one lucky person, chosen at random, who donates to SBTS by March 14th. Consider donating the amount you would normally spend for entry fees and this will help keep the trails and community in good shape for 2022 when we’re all back out there shredding and partying together!
How to enter:
1. Head over to the Sierra Buttes Trail Stewardship website and donate any amount you can afford. 
2. Forward the confirmation email you receive from SBTS to travis@paulcomp.com
That’s it! Paul will choose a winner at random after March 14th in some bizarre way, so stay tuned!
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#Repost @l__ermitage
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(Could be a fun t-shirt 🤔 🤷‍♂️)
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