Paul Components Release 35mm Boxcar Stem

Oct 25, 2018 at 13:59
by Paul Component  

PRESS RELEASE: Paul Component Engineering

When 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:

35mm Boxcar Stems


  • + 30
 I wouldn't call it ugly but it does have that distinctive Paul Components look. Wouldn't expect anything less from them. Buy a King headset and move it from bike to bike (until "standards" change), buy something from Paul and expect the same.
  • + 18
 I still have their derailleur on one of my bikes
  • - 4
flag BlackspireAaron (Oct 26, 2018 at 8:18) (Below Threshold)
 I call it ugly!
  • + 25
 Trying to understand here... Two days ago, Industry Nine releases a BEAUTIFUL stem with unparalleled finish and craftsmanship -- lots of colors to choose from -- that underwent whatever testing there was, and all anyone could talk about was how expensive it was, and they could buy a Race Face for $33, and why would anyone spend that much for a stem, and dentist this, dentist that, blah, blah, blah.

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?
  • + 30
 Ok, so where you're going wrong with this one, is that you are trying to apply logic to a Pinkbike comments section. It doesn't work like that... Valid point tho
  • + 5
 One word : hipsters
  • + 8
 Everyone is stoked with Rampage today. By tomorrow everyone will be ready to poo poo it again. I agree that the I9 stem is the one that deserves more praise, its the one I would buy out of the two.
  • - 3
 @Curtis-Gillen: They're both pretty mediocre stems, still clinging onto an outdated method of installation, in my opinion.
  • + 6
 Because in between that time we got presented a $2700 fork so the outrage fatigue for the week has worn people out. Perfect time to release a product.
  • + 4
 @muyguapa: Outdated Mode of installation? Tightening bolts? Is there another way to do it? Is there a burning need out there for another way to do it?
  • + 7
 @TheR: Obviously there is a better designing something, it's a secret for now, but it'll change the industry. I can say it involves inserting the stem into the top of the steerer, then tightening a screw which pulls on an angled piece of metal with grooves...its gonna be the new standard for certain, you'll wanna be sure to get in on the ground level.
  • + 1
 @Davschall: Yeah, if someone could come up with an easier way to align the stem straight with the steer tube, I think that would be a nice stem — maybe a notch on the stem that aligns with a bump on the steerer. Not sure why this doesn’t exist — probably because there is no universal steer tube height. I don’t know.

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.
  • + 1
 Profile did a Hidden Internal Piston almost 20 years ago, where the stem tightened onto the bars and steerer at the same time. Looked cool, but was kinda tricky to install and didn’t hold very well as I recall.
  • + 2
 What I'm driving at is the next mtb calling it....the frindle stem...
  • + 1
 @Davschall - this sounds very fascinating, make sure you patent it. What are you going to call it? Might I suggest Kwill?
  • + 1
 @Davschall: My bad dude. I read through your first post too quickly. Now I get it. Zzzziinnngggg!
  • + 1
 @Davschall: my kuwahara had a stem like this... Almost lost my teeth when it broke loose....
  • + 1
 @TheR: It's not just tightening bolts, but the way you tighten them. The Nukeproof Horizon stem, as an example, has you tighten the top 2 bolts until the faceplate bottoms out against the body of the stem and then you tighten the bottom 2 bolts to torque. There's less chance of unequal torque and spacing issues with this method than the standard 4-cross method of installing the faceplate, used on the majority of stems available, this Paul Components one included. There's a reason why so many Thomson stems crack in the faceplate.
Nukeproof Horizon stem with how the faceplate is installed - - This takes higher precision to produce than the standard 4-cross-install stem too...
  • + 1
 @muyguapa: Ok, I see what you’re saying. My Straitline stem does what you’re saying, though it recommends an ungodly torque of 100 inch-pounds. (Not such a great idea with carbon bars). Looks better than this, 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.
  • + 2
 I have seen both stems. The i9 is very nice but similar to other stems out there. The paul is much smaller and much lighter.
  • + 1
 @TheR: A stem is a stem is true, but not all stems are created equal. That Straitline stem being one of the few that's actually worth the price you'd pay for them. If the rumour's correct, Straitline's stopped focusing on their bike components and that's a huge shame.
  • + 23
 Every time you buy a Paul component you know it'll still be rocking in 10 years, and the money is going to good people who put so much back in to mountain biking it's hard to believe (asides from being there way back and helping shape it too).
  • + 0
 Some of the best components anywhere. If you don’t like Paul you’re a f*cking dipshit.
  • + 1
 *except for their derailleur.

Mine made it less than 24 hours before I bent it. Which was a bummer, because that thing was gorgeous.
  • + 3
 Owner of the 31.8 boxcar in a 35mm on my HD4 and a 50mm on my hardtail, as well as canti levers / mini-motos on my cx rig. Love them all. Stoked on the 35mm diameter option.
  • + 11
 I heard Paul tested other premium stems on the market and theirs lasted over 50,001 cycles, beating the nearest competitor.
  • + 6
 Is it $123? Yes. Am I still drooling for some dumb reason despite the fact that I could literally buy 2 new tires or a dropper post? Yes.
  • + 7
 I made a stem, it is 26% stiffer than some...
  • + 7
 Made from 2024 aluminium - the alloy from the future
  • + 12
 Yeah, glad someone finally uses the Al2xxx series aluminium again. Al7xxx series is great in terms of absolute strength (and in aerospace is being used for members under compression) but for some reason they kept on ignoring the Al2xxx series (which is being used for members under tension for the better fatigue resistance). Glad someone is doing it again.

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.
  • + 1
 @vinay: I didn't know about the inherent properties of the different AL series, I always thought it was 'higher number' = higher strength. Thanks for the pointer, I'll have to read up on that! (@Pinkbike: Article about metallurgy for the geek bikers? :-)
  • + 5
 @Lankycrank: Well yeah, but never view the material in isolation. I'd say there is always this triangle of product - material - production process. You shouldn't change one and not change the other. Obviously this mistake has been made more than once. Back when metals were considered superior to wood so they simply replaced the material but didn't change the designs. And more recently when there was this shift from metals to (carbon) fibre reinforced plastics.

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 Wink .

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 Wink .
  • + 4
 @vinay: I just googled 2024 al. The Alcoa web site came up.
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.
  • + 2
 @Sshredder: Lots of folks run 35 bars. Why? because their bike (mine included) came with one. Would I switch back to 31.8? I dunno. The 35 is working just fine for now.
  • + 7
 @Sshredder: Yeah, the grain structure of a forged product is superior for fatigue life. Fatigue always occurs in aluminium (unlike steel, for instance). It is just that a forged product has a flatter grain structure near the surface (kind of parallel to the surface) so a crack that starts there will be directed parallel and merely chips a part off instead of going straight through. CNC machining typically starts with a chunk of metal with a parallel grain from rolling (or extrusion, typically for many pedals) so often they're going to have to go perpendicular to that. Now of course it is not that black white. Most (if not all) forged products need some post machining where surfaces need to be very accurate (at the mating faces and of course the drills and threads). And good CNC machinists/designers do take the grain structure of the billet into account. So yeah, it is not 100% black/white. But I personally prefer forged products. And as only the big brands who sell large quantities can afford to invest in the molds for drop forging, I often find myself gravitate towards those.

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.
  • + 6
 It’s been a good week for STEM(s) Wink
  • + 1
 "you can’t just push a “35mm” button on the machine, you have to delve into the programming and make new fixtures from scratch."
As a CNC machinist/designer by trade, that was music to my ears! Now someone go explain that to my boss...
  • + 4
 cant find the purple color in the options for this stem...
  • + 3
 It's in the special edition colors at the bottom of the list.
  • + 1
 @six8nate: thanks! Would go sweet with my bike.
  • + 4
 If only my name was Paul this would be sick
  • + 3
 An entire article, and no mention of stack height....
  • + 3
 Almost as nice as the Profile Helm
  • + 3
 Almost... but not. I like me some Profile parts.
  • + 2
 Are you crazy? This looks like something Fred Flintstone chiseled out of rock.
  • + 1
 @TheR: I was being nice. Love my Helm. And I agree
  • + 1
 @TheR: er. It's just polished AL. A bit bling for my preference, but, being AL, is easy to scuff to a brushed look, or you could always paint it black.
  • + 3
 The plain aluminum colored one is sweet...
  • + 1
 My buddy Randy says Paul components kick ass and polished stems are faster! Now that's some serious endorsement.
  • + 2
 Chico Whiskey Round Up!
  • + 2
 Performance stems...
  • + 1
 by the look of the inside this stem should be called paul - notch effect
  • + 0
 I love Paul stuff, but don't really think this can hold a candle to a Thomson with regards to looks...
  • + 1
 stem !
  • + 3
 New designer stem idea: add internal spray foam for "damping quality".
  • + 0
 @PinkyScar: i wonder if some dense version of moto foam or rubber foam,cut an inserted would have the same effect?
  • + 0
 @PinkyScar: oohhhh you were being sarcastiiiiiiiiic
  • + 1
 Nice stems!
  • - 1
 Who is Paul? Is he related to Randy?
  • - 2
 $149 for a stem...... yeah no thanks
  • + 3
 Yeah, you can get something that works for nothing compared to that. Totally not what its about man.
  • + 3
 I dunno what you do for a living but I imagine whatever it is depends on folks from your own country investing in you.
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