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Hack! 112g Carbon Fiber X0 Rear Derailleur!

Written by Tyler Benedict
German Alex modded carbon fiber SRAM X0 rear derailleur and shifter clamps
33 Comments
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German Alex modded carbon fiber SRAM X0 rear derailleur and shifter clampsA German modder working with carbon fiber created these amazing ultra-light XO trigger clamps and derailleur. Compared to this custom carbon fiber X0 rear derailleur, the standard 10-speed SRAM model looks downright porky at 203g. Even XX pales in comparison at 181g.

The derailleur weighs 112 grams currently, but creator Alex claims sub 110 grams would not be problematic. He shaves grams by swapping the original spring with titanium, using a custom made carbon fiber upper arm, and a “prototype” lower jockey wheel created out of one-piece laminated/wound fiber. The lower jockey wheel will (obviously) wear faster than a normal milled one, but he claims that because the fibers weren’t severed, this will take a long time.

UPDATE: Here’s the link, hope you Sprechen Sie Deutsch.

A future sale is planned in a limited release with more details to follow once the jockey wheel designs are finalized. Sign us up.

Make the jump for lots of photos…

German Alex modded carbon fiber SRAM X0 rear derailleur and shifter clamps

112.81g on the scale.

German Alex modded carbon fiber SRAM X0 rear derailleur and shifter clamps

Upper linkage: Original 13.79g versus 5.47g for the carbon version.

German Alex modded carbon fiber SRAM X0 rear derailleur and shifter clamps

Return spring: Original 12.54g versus 6.42g for ti upgrade.

German Alex modded carbon fiber SRAM X0 rear derailleur and shifter clamps

The shifter mounts come in at just 2g each in full carbon.

German Alex modded carbon fiber SRAM X0 rear derailleur and shifter clamps

German Alex modded carbon fiber SRAM X0 rear derailleur and shifter clamps

German Alex modded carbon fiber SRAM X0 rear derailleur and shifter clamps

We’re working on getting a little more info and links and will update. Thanks to Saris for the pics and summary!
Tyler Benedict
11,282 articles

Tyler Benedict is the Founder of Bikerumor.com, where he’s been writing about the latest bikes, components, and cycling technology for almost two decades. Prior to that, Tyler launched and built multiple sports nutrition brands and consumer goods companies, mostly as an excuse to travel and ride in new places.

Based in North Carolina, Tyler also loves the Vanlife & family adventure travel and is always on the lookout for the next shiny new part and off-grid adventure.

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33 Comments
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O'Neill Ryan
O'Neill Ryan
12 years ago

Not sure about those pulleys though.

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Brandon
Brandon
12 years ago

Awesome to look at, but I’d never ever ride it.

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Mr. P
Mr. P
12 years ago

Those last pics look Alien.

Like it will unwrap, jump on your face and lay an egg.

P

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cw
cw
12 years ago

think those i-links are on backwards. . .

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Ron
Ron
12 years ago

Howdy–

The upper pulley is the jockey pulley, as it jockeys the chain across the cassette. The lower pulley, which helps take the slack out of the chain, is the tension pulley.

Happy Trails.

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MTB
MTB
12 years ago

shimano xtr shadow rear derailleur = 175 grams

I think that’s the lightest mass-produced MTB rear derailleur.

Have it on my bike for two years now…..never had a problem.

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Topmounter
Topmounter
12 years ago

I’m too old and wise now to bother with any such sketch for a mere 70 grams.

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Bailey
Bailey
12 years ago

That’s like the grown up version of the “speed holes” I used to drill in my bmx bike.

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Joshua Murdock
Joshua Murdock
12 years ago

112g rear derailleur… on an aluminum bike. I think there are more practical ways to drop weight here.

That being said… this is really, really cool. I love the look of the carbon upper linkage and especially the mount/cable stop. That is awesome.

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Chris
Chris
12 years ago

Damn…that lower pulley looks like it was made from a paperclip.

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Steve M
Steve M
12 years ago

Reminds of one of the great movies of all time- Dumb and Dumber.

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cw
cw
12 years ago

and is that a cn-7901 installed inside out? agh

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salad toss
salad toss
12 years ago

dont forget the $450msrp. i am sure every weight weenie will love that….

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Sir Eddy
Sir Eddy
12 years ago

Enough of the hating people!! Every time something like this is published, its followed by a deluge of negative comments. Yeah we know it’s not as durable as a standard derailleur, and we know some of you think it’s silly to try and save 70g, but how about admiring the craftsmanship that went into this and thank people like this for continuing to push the envelope so we can all eventually enjoy lighter, stronger parts in the future.

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Kurt the Mechanic
Kurt the Mechanic
12 years ago

Very cool. However, it would really suck to go down on your drive side with a derailleur like this. I would suggest a der. hanger designed to break away at a much lighter load.

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craigsj
craigsj
12 years ago

This will contribute nothing to “lighter, stronger parts in the future”. If for scale riding, not trail riding.

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Joshua Murdock
Joshua Murdock
12 years ago

This will definitely contribute to lighter, stronger parts in the future. A first iteration of any product isn’t perfect. The super light parts aren’t usually super durable. People doing stuff like this and always trying to improve is the source of advancement on cycling technology.

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Topmounter
Topmounter
12 years ago

Strange, drilling holes in my Giant Sedona’s steel fork did not contribute to lighter, stronger parts in the future.

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Evan
Evan
12 years ago

“This will contribute nothing to “lighter, stronger parts in the future”. If for scale riding, not trail riding.”

I hope you realize that things like this are integral to the progression of components. The first carbon fiber mountain bike frame was just as ‘far out there’ as this derailleur. Now carbon fiber is at home on the mountain, more affordable, and lighter…

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dontpanic
dontpanic
12 years ago

I expect to see all the “pretty stupid for 70g” naysayers hit the trails this weekend on your un-modified Schwinn Collegiates, wearing Levis 501’s and Red Wing workboots. Do us all a favor and go old school in the helmet department too. That’s your philosophy right? Innovation is a waste of time and money?

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notapro
notapro
12 years ago

whoever said “admire craftsmanship”- you first thru a rocknroot garden with it and then I’ll admire your surgeon’s “craftsmanship”.

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Bee money
Bee money
12 years ago

To anyone who hates on this part- get over your self. All equipment you ride now was a wild prototype at some point. This thing is absolutely bangin! This is the heart of ingenuity fleshed out. There would be no hot rods, race cars, or even mountain bikes, without this type of” because I can” type of experiment. I can’t afford it, nor am I aspiring to. From my keyboard just like the rest of us posters, this gets full respect.

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What?!
What?!
12 years ago

To the guy drilling his giant Sedona; really? You ride a Sedona. Come on buddy. A Sedona. Your like the guy driving a whipped 1988 Hyundai sonata bitching about the gas mileage in a Ferrari. Your out of your league skippy!

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Rich
Rich
12 years ago

The real concern here is that this is a 9 speed derailleur. I guess this IS revolutionary…if you’re homeless.

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Jose E
Jose E
12 years ago

I wanna see that piece ruin a race like Ruta de los Conquistadores 1st stage in the infamous Carara park muddy hell fest! jajaja

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Justin
Justin
12 years ago

Fun

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Philip
Philip
12 years ago

Stop hating just because you wouldn’t ride with it.

It’s a show of what’s technically possible and also of some sweet carbon skills. Not all bikes or parts are meant to be practical or durable. We’d all be riding a Surly if that was the case.

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Steve
Steve
12 years ago

“Strange, drilling holes in my Giant Sedona’s steel fork did not contribute to lighter, stronger parts in the future.”

Maybe because that required little to no innovation or thought.

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guyonnabike
guyonnabike
12 years ago

See? This is what I love about bikerumor. Not only are the comments great, but the writing is even better.

Look at the typos in the first sentence:
A german modder working with carbon fiber created these amazing ultra-light XO trigger clamps and derailed.
German is capitalized. Note the last word. Classic.
Then you look at the cassette. Its 9 speed.
Note the chain installed inside out.
And after all that, lower jockey wheel?

Keep the excellent reviews coming!

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Tyler Benedict
Author
Tyler Benedict
12 years ago

Typo’s corrected, thanks.

To clarify, this derailleur may be 9 speed, we’re just comparing it to weights of modern 10-speed derailleurs. For the record, SRAM’s X0 9-speed derailleur has the same 203g claimed weight for the long-cage model. The pics are from the builder, we haven’t had a chance to review this.

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Adam
Adam
12 years ago

Um… you guys do realize that bikes, and all that goes along with them, are supposed to be fun. Right?

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Philipp
Philipp
12 years ago

There is a XTR M972 with < 90g already.
It is from one of the owners of the light-bikes.de forum:

Take a look at: http://www.forum.light-bikes.de/showpost.php?p=191741&postcount=207
If you speak german, you get the full story in the thread, otherwise just enjoy the lots of pictures.

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Bob Fairlane
Bob Fairlane
12 years ago

I converted to single speed. Holy cow I saved a lot of weight. But I gained it back in muscle. 😉 Cool bike. I would be afraid the pulleys would shred, but maybe they don’t really take a lot of strain. Good luck.

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