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Updated – Reader’s Rides: Liberty Bikes Builds an Amazing Sub 4kg, 8.8 LB Di2 Road Bike – with Pedals!

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There’s light, and then there’s are you kidding me? That thing is actually rideable? Liberty Bike’s newest creation certainly falls into that latter category with a complete road bike with pedals that tips the scales just South of 9 pounds! Not quite as light as the 6lb road bike we featured a few years ago, but taking the wow factor up a notch is that this bike is built with an 11 speed Dura Ace Di2 drivetrain. Well, at least part of a Di2 drivetrain, meaning the shifters (modified) and the derailleurs. Mael from Liberty Bikes says that he worked with a friend and customer to build what they think is the first Sub-4 Di2 bike in the world (sub 4 kg). While they wanted it to be sub 4, they also wanted it to be safe meaning it could be ridden like a regular bike.

Is it possible to build a bike under 9 pounds that can be ridden like normal? Check out the details after the break! Updated with full specs and details on those shifters!

Liberty Bikes crazy  8 9 pound road bike super light di2 (1)

At the heart of this anti gravity machine is an AX Lightness Alpha frame, which from the looks of it is not a small frame either. The fork is a THM Scapula F with a built in front brake, while an AX Lightness Fibula brake is on the rear.

Liberty Bikes crazy  8 9 pound road bike super light di2 (4) Liberty Bikes crazy  8 9 pound road bike super light di2 (3)

Liberty Bikes crazy  8 9 pound road bike super light di2 (5)

Using Extralite Ultra Hubs laced to AX Lightness rims, the wheelset for this beautiful machine weighs a staggering 698g for the pair. Carbon chainrings on an AX Lightness crank mate with an extremely light 11-28 cassette for useable gearing for such a light bike.

Liberty Bikes crazy  8 9 pound road bike super light di2 (2)

We’ll have to get more detail from Mael as to what’s going on with the lever, but it looks like the stock rubber hoods have been ditched in favor of a carbon wrap. The Schmolke Carbon bar is wrapped very sparingly with bar tape, extending just past the hoods in either direction.

Update – Just heard from Maël on the shifters, and there’s a lot more going on than we thought. First, the mounting screw on the collar was changed to aluminum. Maël says he didn’t want to go with a carbon collar for safety reasons. The stock hoods are gone and have been replaced with vinyl that has been glued on though it is still able to be removed. Total weight saved? 3g between the two levers. Finally, what Maël rightly calls the hardest job was he somehow managed to remove the stock electronics from the shifters and replaced them with the guts from the TT shifters! He says the system is bigger, but lighter. Wow.

Liberty Bikes crazy  8 9 pound road bike super light di2 (6)

Finally, a very light one piece seat/seatpost provide a place to sit.

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There it is – sort of a strange way to weigh a bike, but it works. 3985g, or 8.78542 lbs impressive in metric or imperial. We’re told that it may even get lighter soon as they are working with Cola Wheat and FastDad on a new derailleur!

Specs

 

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42 Comments
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Will
Will
8 years ago

I love this. I would not ride it (that saddle!), but I absolutely love it.

I remember reading about the weight differences between Graphene and Carbon fiber, and doing some mental math came to the conclusion that a bike could be built around 5lbs in theory. Its amazing to think it is getting there, even without the graphene!

Brilliant build, kudos guys.

Alain
Alain
8 years ago

Will,
I have a AX Lightness Leaf saddle, weighs 71gr and has more comfort than a SLR.

Jimbo
Jimbo
8 years ago

Too bad they used so much of the Ax stuff which has a high failure rate. Would have been better to see them choose something a bit more reliable and less predictable for this “regular” bike. I also wouldn’t call the crazy light Tufo tires ride-worthy.

ilikeicedtea
ilikeicedtea
8 years ago

What’s that BIG BLACK uh, tube do?

Evs
Evs
8 years ago

The ‘BIG BLACK uh, tube’ looks like it joins the seat tube to the head tube…

Mike
Mike
8 years ago

Poor guy spent all that money on an obsolete bike (no disc brakes). Just kidding – I’m not into discs on road bikes either.

Ultraclyde
Ultraclyde
8 years ago

ilikeicedtea – I think that’s the bar tape that hasn’t been applied yet. At least, in the enlarged shot the bar looks bare, and the “tube” looks kind of like something wrapped around a foam cylinder. If not, then I’m ( as usual) clueless.

Michael
Michael
8 years ago

Big black tube is the top tube, sitting on a gram scale on a table with the rest of the bike suspended underneath.

pmurf
pmurf
8 years ago

He could have gone lighter with a Scapula SP and a set of AX 3000’s 😉 Seriously though, I can’t wait to see what FastDad and Cola Wheat come up with for the Di2 RD. BikeRumor, please stay on top of that story and post accordingly!

g-man
g-man
8 years ago

good for him.

mario
mario
8 years ago

1+ ultraclyde that seems like the bar tape, strange way to store that though…

MeroMasta
MeroMasta
8 years ago

I wonder how you take off those carbon wraps from the hoods.

Did they build the seat/seatpost specifically for this rider? I’m just wondering since the fore/aft of the seat changes once you lift/lower the seatpost.

Last but not least, the fork seems to be built to be aero, but it has the brake cable sticking out the side!

Other than that, wow that’s light.

Nate
Nate
8 years ago

This bike was over a pound lighter 3 years ago and was supposedly ridden for a ton of miles attributing to it’s durability. Supposedly many of those parts went into production. And that isn’t carbon wrap around the levers, that’s how the lever covers look.

http://antranik.org/worlds-lightest-road-bike-at-2-7kg

nunyab
nunyab
8 years ago

Not a bad build. Almost as light as this Di2 bike which was done 5 years ago: http://fairwheelbikes.com/geoff-mcfetridge-rue-sports-light-bike-ezp-33.html?chapter=1

Devin
8 years ago

I spy several cable stops that have become unnecessary. Quickly, to the Dremel!

The Guy
The Guy
8 years ago

Good work y’all. #pantstent

cobrahawk
cobrahawk
8 years ago

Would love to take this beast on some pave… Paris-Roubaix anyone?

JoeNomad
JoeNomad
8 years ago

Wonder what’s the rider weight limit. If the owner is a 250lb doctor, lawyer, CEO then it’s a nice piece of wall art.

DrMabuse
DrMabuse
8 years ago

What pedals are these?

Dereksmalls
Dereksmalls
8 years ago

@DrMabuse – custom built Speedplay Roubaix by the looks of things, not originals. I like the drillings in the bowties – will look into doing that to mine if possible!

Also the rear brake is not a THM Fibula, it’s another AX Lightness, looks like an Orion

Dereksmalls
Dereksmalls
8 years ago

@DrMabuse

They look like custom built Speedplay Roubaix copies. Much the same as the pair I had built but with CNC machining done instead of using readily available off the shelf parts. I like the cnc work in the bowties!

Also the rear brake is not a THM Fibula, looks like an AX Lightness Orion

olimlili
olimlili
8 years ago

I am the owner of the bike , just read your comments and for futher questions Maël from liberty bike(www.libertybike.fr) will be delighted to answer… just wanted to say two things it was a challenge and I understand that fiability is at risk in some parts of the bike …
and no cobrahawk I won t do Paris-Roubaix with this bike 🙂 and yes and no JoeNomad I am a CEO but ride about 12.000 km each year. Anyway tks for your comments and in puts.

Mike
Mike
8 years ago

The seat/post combo looks like a Berk composites.

Tomi
Tomi
8 years ago

Call me a hater if you want but there are some big issues with this bike:

tufo elite 110 are track tires —–> high risk of flat even on the best roads.
recon cassette —-> theses aluminum cassettes are so fragile they are basically disposable one time use parts.
ti spokes are not known for making great wheels, those things must be noodles.

unknown to me : do carbon chainrings works as well as alu ones ? Shifting performance can make the difference between a great bike and a shitty one.

I’m pretty sure this bike would have been already very light with standard dura-ace cassette, a set of veloflex tires, DT swiss revolution spokes without compromising anything in term of performance and reliability. That bar tape job is also ridiculous considering the small weight gain. And don’t get me started on weight-weenies brakes.

Also, weight is not necessarily bad. Last week I rode in the swiss alps and the wind was so high it was a bit scary in the descents. I was glad I had taken my old +8kg aluminum bike instead of my current 6.x kg carbon one.

Bobby Frontbutt
Bobby Frontbutt
8 years ago

Meh. Art is one thing, but can be shaped like a bicycle. A bicycle is a different thing, but can be artistic. This sadly falls on the art side of that equation for me. I ride my bike hard and expect it to work without fail or issue every time I pull it off the wall.

Dereksmalls
Dereksmalls
8 years ago

@Tomi aluminium cassettes are not one time use throw away parts. I’ve got over 2000km out of mine and it’s going fine

I’m impressed with the bike

tkeaton
tkeaton
8 years ago

5g of tubular glue, huh?

1Pro
1Pro
8 years ago

i wouldn’t trust my life to anything AX makes.

Devin
8 years ago

@olimlili- give me a call, I’d love to build you a custom version of that frame- we could drop some weight for sure.

Xris
Xris
8 years ago

Things like this make me feel happy inside.

Aaron
Aaron
8 years ago

Yawn. Until they make the entire frame into a supercapacitor to power the di2 battery using layered graphene sheets with and inlaid conducting wire instead of dura ace wire, I’m not even remotely interested.

Champs
Champs
8 years ago

It would be lighter with 650B…

EM2
EM2
8 years ago

@olimlili
I challenge you for a 7kilos bike that can really race (with pedals and computer) for no more than 3000$

eric
eric
8 years ago

Still can’t figure out what that big black tube to the left of the handlebars does.

iperov
iperov
8 years ago

No thanks. Life more expensive than 4kg paper bike.

Tomi
Tomi
8 years ago

@Dereksmalls : in my experience unless you soft pedal for 2 seconds at every gear change those alu recon cassettes get trashed in a very small number of ride. Unless you intend to start in small hillclimbs TT, they are totally useless.

Colin
Colin
8 years ago

@Tkeaton

Take your favorite tubular glue, find a solvent that will dilute but not reduce the effectiveness of the adhesive. Reduce the viscosity to about that of maple syrup. Paint on in thin layers, letting it dry thoroughly between coats. Stick on tire.

I’ve done this on a few of my weight weenie wheel sets and my glue job holds better than the zipp or challenge base tape glue.

Paniagua
Paniagua
8 years ago

Thinning tub glue? now I’m scared

Aaron
Aaron
8 years ago

Awesome build, but I’d rather have a 10lb bike with GP4000S clinchers, full bar tape, and a stronger (slightly heavier) stem.

Dereksmalls
Dereksmalls
8 years ago

@Tomi I think maybe you’ve had a bad experience with them then.

I race mine all the time, and don’t soft pedal for 2 seconds whilst shifting, if I had to do that I wouldn’t be running one. My shifting with Campag Centaur shifters, a tuned Super Record RD and Aican Bungaras cables is damn crisp with no need to soft pedal at all either on up or down shifts.

FrankieB
FrankieB
8 years ago

That has got to be a noodle. No thanks – I will just cut down on beer and pizza.

yaya
yaya
6 years ago

I think Di2 is heavier than mechanical. They will be able to lighten the bike.

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