Boo Bicycles SLG carbon and bamboo race-ready gravel road bike

Boo Bicycles has been making carbon fiber-and-bamboo bicycles for years now, but they keep refining the process. The latest iteration becomes the new premium SL offering, which not only drops weight from the frames, but makes them stiffer and stronger, too.

Above is the new SLG top-level gravel road bike, and this one’s built for Boo’s Nick Frey to race at this year’s Dirty Kanza and Crusher in the Tushars.

The upgrade is a new way of forming the top and downtubes. On their normal tubes, they hollow out the bamboo. On these, they hollow it out even more, making it lighter, then an S2 fiberglass load dispersion material is placed on the inside of the bamboo tubes and is cured while under compression from the inside. The result is a tube that’s much more impact resistant. Frey told us there tends to be a lot of downtube damage on composite frames in events like the Dirty Kanza, coming from really sharp gravel flying off the front wheel. Frey says they took a normal bamboo tube and smashed it on a table corner and it cracked, but repeated blows with the new S2-enhanced tubes didn’t show any damage.

But those aren’t the only changes growing on this bike…

Boo Bicycles SLG carbon and bamboo race-ready gravel road bike

Boo Bicycles SLG carbon and bamboo race-ready gravel road bike

This one’s made with aggressive, racing geometry and 700×42 tire clearance. But all of those metrics can be whatever you want, they’re all made custom. You could even build it for belt drive, or choose between mechanical or electronic (or both) groups.

Boo Bicycles SLG carbon and bamboo race-ready gravel road bike

The other big new feature debuting on the SL models is it’s their first thru-axle design, which stiffened up the rear end enough that they could eliminate the seatstay bridge.

Boo Bicycles SLG carbon and bamboo race-ready gravel road bike

It’s built around a Santa Cruz Bicycles’ rear derailleur mount and Syntace X12 thru axle. They use a dummy axle during construction so they can mold the rear dropout structure directly around the hanger, so there’s no extra metal used in the dropouts, it’s all bamboo and carbon fiber. The only other metal on the frame are the water bottle bosses.

Boo Bicycles SLG carbon and bamboo race-ready gravel road bike

It’s also their first post mount brake design, which further cleans up the bike and drops weight.

The SL moniker will refer to all top level bikes, and they’ll only be available as full custom. This one’s the SLG, for Super Light Gravel. There’ll also be an SLX (cross) and SLR (road). Retail is $4,495, a thousand dollar premium over the standard bamboo and carbon frames. This brings with it a stiffer carbon layup, too, making the front end laterally stiffer. All told, the thru axle dropouts save about 80g, and tube saves about 100g, but you add a bit back with the actual thru axle compared to a QR skewer.

The gravel bikes will also get a smaller diameter seatstay to add more compliance. That wasn’t done on Nick’s bike because he’ll be doing a lot of road riding, too.

Boo Bicycles SLG carbon and bamboo race-ready gravel road bike

Another cool thing they figured out with this build was that you can hack XX1 rear derailleurs to work with CX1 drop bar shifters. Nick wanted the wider gear range for the Crusher in the Tushar, where there are bigger climbs, but the CX1 rear derailleur won’t clear the larger cogs on an XX1 cassette. But, the XX1 derailleur’s movement didn’t jibe with the CX1 shifters…until they found you could determine the pull ratio by putting the CX1’s derailleur cable loop and mounting it on an XX1 rear derailleur. By swapping that piece (the black plastic bit that the cable wraps around between the adjustment bezel and the derailleur’s pinch bolt), you get the XX1’s bigger pulley offsets with CX1 shifter compatibility.

The one above is shown in stock formation, but he’ll be switching things over based on the next race’s elevation profile.


They also figured out you can combine XTR Di2 shifting with an XX1 cassette and get the best of both worlds: crisp, motorized shifts with a wider range cassette.



They said it worked perfectly with no modifications to either group’s parts.


Below the SL is the RS, which uses the standard alloy dropouts, regular seatpost, no internal Di2 wiring, and is offered in stock sizing.


The beauty of custom is you can get things like this awesome monster crosser/off road touring bike.


  1. So now the tube are basically glass fibre attached to carbon.

    Why don’t they make a full carbon frame and laminate it with bamboo. They can still have the BOO name with none of the fuss.

  2. Please do an post about the CX1 levers with an XX1 rear and an XD 10-42 cassette. A 46t chainring with the 10-42t sounds like a nice set up.

  3. Cool! Just take the bamboo out, and you have some… bikes.

    Seriously though, why is anyone post mounting rear disc brake calipers to the seat stay? They seem perfectly suited to sit inside the rear triangle, on the burlier chain stay.

  4. That so boring sram decided different pull for their 11 speed der. I really wonder what’s the supposed gain in doing that. At least if they sell this plastic adapter it could ease things a bit.

    I wonder what is that big range 11speed sram cassette that is not a XX1 in the first screenshot. Is it the 11-36 featured here a few months ago ?

  5. Come ride it in Land Run 100 this weekend in Stillwater, OK! I know you guys know Bobby and crew, come back and hit our gravel.

  6. I’ve been watching Boo’s bikes over the years, and they keep removing bamboo and adding more of other materials. Perhaps bamboo simply isn’t as good of a frame material as originally claimed. Not trying to harsh on Boo, as it’s awesome to see new ideas reach the market. It’s just been interesting to watch over the long term.

  7. Does Boo, or anyone else have a method to contol the OD of the bamboo? A few years ago, I was considering building my own bamboo bike, I thought about making some clam shell sleeves that would be bolted over the bamboo of a diameter nearing the size I needed, then wait until it fill out the clamshell. Wouldn’t know if this process would work, but in theory it should.

  8. To be entered above. Clamshell tubed sleeves that would be bolted together over a length of growing bamboo, then when the bamboo grows into the sleeve, they would be cut and un bolted, then treated.

  9. I see 10% bamboo and 90% other. If BOO are a bunch of talented engineers then just go ahead and stop acting all environmental and make the bike 100% other.

  10. So they’re now saying their normal bamboo tubes crack easily? I know they’ve said before that bamboo is very impact resistant but now they’re saying it isn’t to show how much better the new stuff is?

    ***I’m excited about the SRAM stuff. Not so much about their bamboo talk. I’ve ridden a bamboo bike and love the feel of it. I know people have done well in races with it but I wouldn’t actually want to race a bamboo bike that I paid for with my own money. However, I’d be happy to buy and RIDE a bamboo bike for a training bike or farting around bike. I’m all for making anything from more sustainable materials but long term durability needs to be included in that. Maybe the flax fiber bikes still have a future?

  11. I want a Bamboo bike but hold the bamboo.
    For crying out loud. Just make a carbon bike and give them all a Bamboo bong in the box. Problem solved.

  12. Regarding the bamboo part, don’t knock it until you ride it. I was skeptical about the benefits of bamboo, but then had the opportunity to take a 30 mile test ride on a Boo that included a mix of gravel and roads. I’ve ridden on many top tier carbon bikes, but none of them have come close to the Boo in terms of ride quality. The stuff works – it is super smooth. And the bike was not a noodle – it had plenty of snap for jumping and accelerating. The only disconnect was the Enve fork which seemed less compliant compared to frame.

  13. zman- any ride quality you seek is easily available in a more dependable and repeatable fashion from a variety of materials. Purely marketing is all the bamboo is about. It gets a marginal builder lots of internet hits and curiosity from the ill informed.

  14. Guys, it’s not obvious but the carbon is a very thin wrap on top of the bamboo. The only *tube* in the bike frame that isn’t bamboo is the seat tube and that’s to allow for a consistent OD for the FD clamp.

    Bamboo is superior in many ways to a bladder-moulded carbon monocoque frame. I’m the first to love how “engineer-able” carbon is, and we obviously wrap our joints with it. But the frame is about 70% bamboo and 30% carbon fiber. The bamboo naturally dampens vibration way better, is much more durable, and has amazing bending stiffness with a little torsional give that keeps the bike from punishing its rider over a long race. It’s easy to ride fast for long periods without having to pick the “perfect” line.

    I wouldn’t have been doing this for ¼ of my life if it were a gimmick. I have a lot easier ways of making a living, but Boo’s bikes are far better than most of the crap with stickers and paint all over it that has become ubiquitous. If you haven’t put one to the test, you’re hearing it now: these are NOT a green, sustainable, novelty bike. Go to a dealer and try one, and if you still think they’re bad bikes, feel free to blast us on any comment forum you can find.

    Boo is a group of very smart and talented people, mostly engineers, pouring heart and soul into actual innovation in an industry that is full of lies and marketing BS. This is what we do:

  15. Thanks for chiming in Nick.
    One question I have is that some bamboo builders have said that the coefficient of expansion difference between carbon fiber and bamboo doesn’t work out that well in the long run so they recommend using hemp fiber instead. What are your thoughts on this?
    Thanks, I’m glad to see you guys are still around (I was a slow grad student racing back in C’s back when you were in A’s).

  16. Nick…
    I’ve ridden a Calfee and a Philippine made Bamboo bike. I loved the ride of them!!! I’d say they were MUCH smoother than my custom Ti SEVEN and any carbon bike I’ve owned. The Philippine bike wasn’t stiff(probably not the goal…had hemp wrapped lugs only $800 US), the Calfee had a huge downtube and was “stiff”. Not as stiff as my SEVEN(which I also wouldn’t want in a Cat 1/2 bunch sprint) but good enough for pretty much anything but crit racing at my 190lb bodyweight. I’ve never ridden an Boo bike and maybe your bikes are that much stiffer than a Calfee. At my weight, I’d need to try one built for extra stiffness from you to compare(the Calfee was a friend’s that’s just a hair smaller than me). I get not building them for sustainability but I actually like that aspect and hope more sustainable materials are used in bike manufacturing in the future…more important for the mass market than custom jobs since they’re the ones producing more pollution(of course this goes for nearly all manufacturing of anything).

    ***My only question is the impact properties. Saying Bamboo has spectacular impact properties in the past, but now saying that it cracks easily unless it has this “inner treatment” seems odd to me.

  17. It’s yet to be shown that you can get exactly the ride quality out of one material that you can another. That doesn’t it isn’t possible, but I don’t know that it’s been done to date. There certainly seems to be a market for bamboo bikes. At least Boo and Calfee are successful with their bamboo bikes. Cycling news hasn’t been reporting a rash of bamboo bike failures, and there’s no empirical or scientific reasons why bamboo isn’t a satisfactory material for bikes.

    That bamboo isn’t titanium, steel, aluminum, or carbon fiber isn’t relevant, except in the case where a prospective buyer values the opinions of the peanut gallery. If it works for a given cyclist, that’s all that matters.

  18. @Al: Thanks! I miss that ECCC 🙂 The CTE argument is a red herring. Yeah it’s true the CTEs are quite different, but that is true between carbon and titanium as well…it doesn’t prevent us from mixing a number of disparate materials. The devil is in the bamboo growth and treatment. James has his own plantation of bamboo outside of Saigon and harvests and treats in-house. I was just there two months ago filming and working on R&D, and the bamboo he grows is absolutely the best in the world. Others use inferior bamboo and get inferior results…and then point at carbon joints as the issue. We’ve had our share of poor dropout designs and FD mounts, but we have literally never had a single bamboo-carbon joint failure in the entire history of Boo since 2009.

    @Veganpotter: You definitely need to ride a Boo RS-R or SL-R then. They are definitely “racier” than a Calfee, quite a bit lighter and stiffer. Blindfolded, you’d probably guess it’s a full-carbon bike in terms of stiffness, but you’ll notice it dampens a lot of the harshness that is normally transmitted through brittle carbon monocoque frames (and even Ti, to a lesser extent). We don’t need to “overbuild” a frame for someone your size, to the contrary we have to work to “underbuild” a frame for someone under 150lbs. The interior S2 application is for two reasons: 1) use in an extreme-cases gravel race bike with our standard tube thickness for ultimate impact resistance from sharp-edged gravel, and 2) use in an SL-R case where we minimize tube wall thickness for minimum weight, but want to maintain or even increase the durability of the frame. Most carbon rigs are disposable…and ours simply don’t break. Read more about our thoughts on sustainability and design here: and about the SL-G here:

    @Psi Squared: I won’t lie, we have had failed dropouts due to soft aluminum and poor design. Our very first bikes had failing front derailleur mounts because they screwed in rather than clamping on. We don’t have these issues now, and have literally *never* had a single bamboo-carbon failure, even in drastic cases of car accidents and major crashes. I personally believe bamboo works better in many cases (even NRC Criteriums) because it has a little give and liveliness to it that carbon bikes just lack–they’re overly stiff and handle poorly because of it.

  19. At first i thought it was a gimmick but i got the aluboo frame off eBay(he got it off kick starter but never got a chance to build it up) and built up my own bike and the first ride i was so shocked how smooth the road became (newark,nj had horrible roads). It’s smoother than my lite speed Tuscany titanium bike. I wish i could commute daily on it but I’m too scared it would get stolen as it has a huge sentimental value as i never put a bike together before…. The fact that it’s so smooth is an added bonus. I sold my biachi nirone 7 and cannondale bad boy 1 as the aluboo bless them away. Only thing close is my titanium bike that i debadged so I’m not worried about it getting stolen as it look like a cheap bike

  20. @Ravi c: The Aluboo is a fantastic frame for that price, eh?

    @VeloRockStar: Well put yourself!

    I guess that confirms it: anyone who actually has one or has ridden one believes in it. Everyone else: I encourage you to just try one, and I’m all ears for criticism *after* that.

  21. @chasejj – If a similar ride quality can be engineered into any bike, I have not experienced it. I have ridden multiple top-tier carbon bikes (the latest Spesh S-works, BMC SLR01, Cannondale Evo) as well as top-tier Titanium bikes and classic steel bikes (Bridgestone RB1). The Boo definitely had a smoother ride and a different feel than the carbon, ti or steel race bikes. Frankly, I’ve found them all to have a different ride quality. The material matters. But the Boo stands apart. If you are skeptical about that, it is worth a ride to see for yourself.

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