PRESS RELEASE: Paul Component EngineeringWhen we first set out to make a handlebar stem, our engineers got a bit carried away, we’ll admit it. With so many other brands on the market, we didn’t want to invest the time and tooling unless we felt we could really out-engineer the competition with a stem that would be lighter, stiffer, and stronger than the rest.
We started with American 2024 alloy due to its extremely high strength and fatigue resistance, allowing us to machine the stem walls extra thin from the outside and inside without sacrificing durability. 2024 is widely used in aerospace, especially wing and fuselage structures under tension. It’s more expensive and difficult for us to source than 6061 or 7075, but we refused to compromise on this project. We ran our prototypes through 1,000,000 cycles of above normal use stress without a single problem. Our rounded-box shape tested 25% stiffer than the competition, inspiring the name, and giving it a very unique, purpose driven aesthetic. We designed the faceplate to have massive handlebar gripping surface area from edge to edge, eliminating slippage and handlebar stress points, but again using 2024 alloy, which allowed us to keep it thin, light, and failure free.
We use over 20 different end mills, drills, saws and taps to make 1 stem, machining to .002” tolerance (that’s really tight for a stem). So yeah, it’s not a rush job, it’s more of an obsession project by bike nerds that just so happen to be engineers and machinists who take a lot of pride in their work.
The Boxcar stem has been around for a couple years now, so what’s with this press release? Well, every time we’ve posted the Boxcar on our Instagram account (like the proud parents that we are), somebody would pop into the comments with “How come you don’t offer it in a 35mm handlebar clamp diameter?” When you’ve put this much detail-oriented work into the design of a stem, you can’t just push a “35mm” button on the machine, you have to delve into the programming and make new fixtures from scratch. But the comments wouldn’t stop coming, and we soon realized this new standard might actually stick.
So here it is, our first 35mm handlebar clamp diameter stem! The first length we’re offering is also 35mm long, so we’re referring to it as the 35x35 around here, with a 50mm length coming very soon.
Technical Information:•The only stem on the market machined from 2024 American Aluminum.
• Finish: High Polish or Anodized in Black, Silver or Purple.
• Machined in Chico, California by total bike nerds.
• Lengths: 35mm Clamp: 35mm (50mm very soon) / 31.8mm Clamp: 35, 50, 70, 90, 110.
• Weight: 118-203 grams depending on length.
• MSRP: $123-$149 depending on length.
• Availability Date: Now
Link to product page:
paulcomp.com/shop/components/boxcar-stem/
Then this one comes out, it's just as expensive (or more so, depending on the size) and it doesn't look near as good, and everyone is singing its praises as though it was the second coming embodied in a stem. All comments criticizing said stem have been relegated to "Below Threshold."
So what's the difference? Two days ago, a stem was a stem, and anything over $33 was for dentists. Today, everyone's all about it. How did Paul get all the Bro credit?
I don’t think that’s what you’re driving at, though. And I don’t think the guy above is talking about what you’re talking about, either.
Nukeproof Horizon stem with how the faceplate is installed - nukeproof.com/wp-content/uploads/DSC_9929.jpg - This takes higher precision to produce than the standard 4-cross-install stem too...
Anyway, having used both, I can’t say I’ve had a problem with either holding the bars in place,or breaking the stem. Using a torque wrench would probably help if people are having problems, I guess. I’m inclined to agree with most people here — a stem is a stem. They all kind of sit there without much thought. I guess pick one based on weight, or color, or bolt pattern or whatever combination will float your boat.
Mine made it less than 24 hours before I bent it. Which was a bummer, because that thing was gorgeous.
Not sure about their statement about the competition working with Al6xxx series. It is typically being used for frame tubes and rims because it can be extruded, but a stem is typically being forged or (CNC) machined (or cast for the lower end ones). Or maybe they use Al6xxx for forging too? I'll have to check.
Now for us riding with 35 length stems, I'm not sure how much increased stiffness actually matters. Actually, especially as the edges (where the handlebar exits) appear a bit sharp, I'd rather see it give a bit more to protect my handlebars. I'm currently running the Spank Spike stem because I like that it has a more gradual release of the bar near the edges which allow the bar to deform more. And the Spank may not be made out of Al2xxx, but it is forged instead of machined. So yeah, I'd like to see a comparison between the two. Not a lab test of the stem clamped in a fixture, but a lab test where the stem clamps a steerer and a handlebar so that we can also see how these fare when clamped by the stem.
Please don't take this as me being skeptical or claiming my own stuff is better. Just because Paul Components put in the effort to explain what makes their product so great, I'm curious to see how it works out in real life against products that are great as well.
That said, comments like mine above sometimes trigger a very insightful discussion with the manufacturer that schools me too. Back a good while ago I had a discussion with Cesar from Unno cycles. I was wondering why he didn't armor his frame with an aramid weave instead of just a carbon weave. Seems like the ballistic carbon they're using is on par with aramid. And I think they do use a thermoplast resin instead of thermoset, which often also has better impact resistance.
Then a couple of months ago I had a similar discussion with a rim manufacturer. It started with an H but it wasn't Halo, have to look it up. They were using Al6069T6 which apparently is a whole different beast than the Al6061T6, so I learned from that too.
So yeah, with the article here. They don't just throw a bunch of technical terms over the fence to look interesting. This is a company that actually designs and produces their own stuff. So I'm curious again how this turns out. I'm talking about series (Al2xxx etc) but just like with the Al6061T6 vs Al6069T6 discussion earlier, there could again be a difference between the Al2025 I'm familiar with and the Al2024 they're using. Makes me curious. Back in the days I was riding a lot with a guy who went through several frames but there was one he kept and that was a frame from Miyata made out of Al2xxx aluminium. Because it was more fatigue resistant the manufacturer could uses thinner material hence make the frame more flexible/comfortable. I don't expect anyone to make them like that anymore. Because steels became better and more accepted. And because this aluminium gets the T3 heat treatment it can't be welded so you're getting a lugged frame (tubes soldered in lugs). And lugged frames probably aren't that accepted anymore .
So yeah, an article about materials would be great but it is very hard to give a clear picture without taking things out of context. Now of course we're already seeing that. Perceptions of "carbon frames are light", "aluminium is a lightweight material", "steel is comfortable" have been developed over the years but very often we see the polar opposite. However if someone could write a comprehensive article about this, it would be great. But it would become long and you'd see more than a few "TL;DR" in the comment section, just like you typically find under my posts .
More nerd info to geek out on .
Stuff is stronger than 6000 or 7000 series.
Still a cold forged stem of 7000 series is probably stronger than 2024 that is just machined.
A good example of a strong forging is a Saint crank.
How often do you see those break?
Who runs 35 mill diameter bars?
31.8 gets the job done just fine.
As for 35mm clamp diameter, no I feel no need to upsize from 31.8mm with my 780mm bars and pretty mellow riding style. Not sure where the demand comes from really. I don't recall any broken handlebars anywhere recently nor would I expect people to want to have their handlebars even stiffer. But yeah if the demand is there then it is great that it is on offer. If it is another one of those "what diameter are we going to increase this year" driven choices it is not getting any love from me.
As a CNC machinist/designer by trade, that was music to my ears! Now someone go explain that to my boss...
www.paulcomp.com/shop/components/limited-edition-purple