64g Dura Ace Derailleur

There are self professed weight weenies out there who bolt on the lightest weight parts they can find, and then there are theses guys – dare we say light weight artists? Found over on the Light-Bikes forum, this stunning 64g (!) derailleur is the product of a duo who go by the handles of FastDad and Cola Wheat. What started life as a spare Shimano Dura Ace 7800 rear derailleur weighing a rather portly (comparitively) 180-190g, was morphed into the show stopper seen above complete with a carbon b-spring. Yes, a one-off carbon spring.

Check out the details, next.

 Original Dura Ace Derailleur

Tuned Dura Ace Derialleur

Based on the looks of things, Stefan who goes by FastDad is quite handy with a Dremel – this is part of where the art comes in. Not only was he able to get the weight down to a very impressive 69g before handing it off to Cola Wheat, but the lines of the cutouts are beautiful. By just looking at it you’d have a hard time figuring out it was done by hand. At the top is an exploded diagram with every stock piece weighed, with the modified versions and the addition of the first cage below.

Tuned Dura Ace Derialleur 2 Tuned Dura Ace Derialleur 1

The final result from Stefan is impressive enough as it is, but it gets better.

Carbon Spring

After the hand off was made to Cola Wheat, Thomas started his magic by building a carbon fiber b-spring! Thomas actually goes into pretty great depth on the creation of the spring which weighs just over 1g.

10g Cage 64g Dura Ace Derailleur 2

In addition to the beautiful anodizing, Thomas also provided the new Tron-esque derailleur cage and pulleys. Total weight for the entire cage is 10 grams.

64g Dura Ace Derailleur 3

All said and done you have a functional derailleur that weighs less than half of the original. I don’t want to know how many hours went into this thing, and I certainly don’t want to be around if it ever gets ripped off by an errant stick, but it sure is nice to look at.

Nice work.


  1. dwiz on

    another item that while gaining lots of attention from the weight weenies of the world..but i ask you these questions:
    how durable is this flimsy thing gonna be?
    how AVAILABLE is this thing gonna be?
    how much of a pain in the ass is servicing/repairing/parts/pieces gonna be.

    is this gonna be one of those items where you can ride it a dozen times then have to replace and or service the crap out it……….one word for ya’ll—-SILLY

    • Marck on

      @dwiz – everything you posted is correct – it can also be said about any part of a F1 racecar – but that is how we evolve things and push the limits… one thing leads to another and so on…. be happy!

  2. M.C. Slammer on

    It’s art… Some get it, some don’t. It’s remarkable not only for it’s appearance, but for the level of skill and craftsmanship applied. Some aspects sport go beyond the utilitarian.

  3. sardinian rider on

    Find yourself spending a gazilion of euro for a swank-a-drool rear derailleur and see it crumble apart at the very first bad@ss chain crossing.

  4. Rob M on

    dwiz, you do realize this is a one-off custom, right? Don’t worry, it won’t make it’s debut on your 2014 Cross Check… silly is right.

  5. martin on

    It wouldn’t work as the first half decent bump you get there is nothing to stop it from throwing the chain!!! ( you have to have an inner chain guide plate! )…..

  6. bbb on

    I don’t care about the weight, function and durability.
    I just can’t take my eyes off those jockey wheels.

  7. Lou on

    1. It’s a one off. It took like 6 months to complete by the parties involved.
    2. Durability is irrelevant. If it makes it 1/10 of a mile then it has succeeded in being one of the most ridiculously light “functional” derailleurs ever built.
    3. And who knows, a lot of stuff on bikes is there for a “what if” scenario. Chain catchers, chain tensioners, lawyer tabs, derailleur guide plates, etc. I bet this thing gets a lot farther than you would imagine.

  8. David on

    A Weight weenie exercise just married up with an artist.
    Gorgeous execution, yet it really too pretty to risk a ride with it.
    And what about that scale, 4 decimal place accuracy on a gram?

  9. Chris on

    Not something I would ever want but I appreciate the workmanship that went into it. The over sized pulley bearings are actually kind of interesting though not having an inner cage plate seems like a sure fire way to get a dropped chain at the first bump.

  10. Marc Gibeault on

    Incredible work.
    Imagine halving the weight of a part already so light while still being functionnal.
    And they didn’t start with a cheap overweight derailleur, it’s already top-of-the line!

  11. ds on

    Incredible. And high tech should always look like art. Question of total devotion in every domain !

    What kind of bearing are in the huge jockey wheels of the 64g ? Needles ?

    Congratulations and continue !

  12. Andrew on

    only having a one sided cage is not a big deal at all, Sunrace did it for a long time with no problems. Believe it or not Sunrace drivetrains actually worked pretty well, their spirit line had some cool design features like top normal front derailleurs (that one was weird), the no outer plate RD, and the cable pinch bolt on the RD was sometimes located ‘inside’ the derailleur, it was very elegant and worked well too.

  13. Dex on

    By far the best component tooling I have ever seen. To know this was done by hand with a Dremel makes it that much more impressive. The carbon spring and anodization shows just how far the creators were willing to take the weight and style issue to the max. Serious kudos very well done!

  14. ACE on

    Will this last through an entire race?Who cares if it snaps before you take a left turn. Its pretty and light and and Ive got too much money.

  15. WV Cycling on

    I’m betting Shimano follows little weight-weenie projects like this behind the scenes to see whether they can improve and copy anything these guys do.

    Never said that they would copy or even use the work, but I’m sure they like watching what others are doing for inspiration.

  16. greg on

    Beyond the functionality aspect, it is also a great design and style exercise. Like a show car that is kinda drivable- it could be a sign of things to come. Wouldn’t you want a derailleur that looked like that but was still bulletproof on your bike? I certainly would.

  17. CtoF on

    Love it!!! I would love to see it mounted on a bike with a black and red KMC chain running through it. THAT’S HOT!

  18. jim on

    a thing of beauty!
    just enlarge the outer diameter of the pulley guide to match the chain.. you’ll have an instant chain guide/cage.
    nice work!

  19. JCL on

    Just to be complete and to show their dedication and savvy, they also designed a special tool for the “special” jockeys !!!

  20. NASH on

    @epo pusher. Metal on metal is fine if there is lubrication between the surfaces, jockey wheels are not a high load part such a wheel bearing.

    The general name for this type of design is a bushing and is not commonly associated with (deleted).

  21. CXisfun on

    @epo pusher: isn’t your chain/cassette/chainring combo metal on metal? Did that only last 10 minutes then epically fail?

  22. ABW on

    Amazing. Makes me so happy that “tuning” a bike now has a definition more like that of the automotive/hot rod world, where you take what you have and make it work better/lighter/more attractive/etc. rather than taking what you have, throwing it in the recycling bin, and buying the next expensive part. Tuning should never be confused with upgrading.

  23. Kark on

    @ epo pusher. you’re a fool. Metal on metal is commonplace in moving and rotational parts. e.g. bearings, sintered bronze or alum bushings, gears, sprockets etc.

    perhaps think before you post nonsense and hypothetical gibberish.

  24. ride on

    So many haters.if you have love for the design and plain awesomeness of bikes then you understand why they took so much time to make this.it dosnt matter if it literally never shifts a gear.for all of you haters keep taking your whip in to someone else for service and shut your mouth.meanwhile people like us will push the envelope of of standard issue gear just to finish and say.damn.that’s sick.also I doubt that this is much if any less durable then a normal DA derailleur.I guess everyone should stop making concept bikes because they are not practical….Lets tell Reynolds to stop using carbon “spokes” on the rzrs because they are not practical.lets tell thomson to stop machining from billet because its time consuming.lets tell k edge to stop retrofitting di2 to work with xtr to have a electronic mtb drivetrain.lets stop the use of tapered head tubes and 30 mm spindles and thru axles because the old stuff worked fine.lets tell the guys who built the lightest road bike in the worls that they wasted their time.

  25. Slow Joe Crow on

    It looks amazing and Fairwheel should put one on display, but only Germans could be that obsessive about this.

  26. DaleC on

    EPO pusher – the crankshaft and camshaft bearings in my Checvy V8 are “metal on metal” and they had made it a pitiful 203,000 miles.


  27. Colaweizen on

    i’ am one of the constructors for this fantastic RD. Firstable i’ll said many thanks for your great comments. About durable, i’ll mean that it is each of the original RD when not better. All parts are selfmade! It was the first one lightweigt part……

  28. Wijask on

    Even though I’m a Campy rider and not to much of a weight weenie, this derailleur I would would put on almost any road bike. Just for the swag alone. Then I’d boast the weight and wish for one made for or by campagnolo and bragging rights.

  29. Steve M on

    Damn that is a bunch of work and quite beautiful. As for the jockey wheels. The bushing /bearing is relatively large due to the big through hole. The friction should be relatively high due to the reduced lever arm. With the large bushing diameter the ‘race’ will have to rotated much faster than if it was the traditional size. There is a reason bike wheels have smallish hubs/bearings/axles.

  30. Iso on

    Well done!
    Rolhoff makes really heavy (sturdy as well) internal geared rear hubs,
    they should dispatch one asap to these guys.

  31. Kevin on

    What a lovely piece of work, and probably not fragile at all, despite what many might think.
    I bought a book many years ago called “Fahrradtuning” in German, with loads of examples like this where components were reduced to 30 or 40% of their original weight using a file or dremel. The only material removed is the low stress material. Look how much metal is being used just to support the word “Dura Ace”, because even on the original the corresponding back plate has already been hollowed out. Correct application of file or dremel will improve stress flow and remove stress concentrations in the part making it lighter AND stronger. If you don’t believe me then double butted spokes are the easiest example of this lighter and stronger concept.
    The most interesting question is why components as high end as Dura Ace don’t come off the production line like this ?? Are they just saving the weight reductions piece by piece for next year and next year?

  32. JimmyZ on

    I’m getting older, so seeing someone furiously drilling, filing and grinding away on a part to lighten it, only to have the part break under machining, is more gratifying than porn to me.

  33. Bikinbobs on

    Embed it in acrylic and either place it in a time capsule here on earth or send it into deep space on the next interstellar launch as representing 21st century mankindtechnogeekery.

  34. Ashok Captain on

    FastDad and Cola Wheat,

    Greetings from India. That reworked rear mech is utterly B R I L L I A N T – S U P E R G O R G E O U S!

    There seem to be a few (few!) places that can still be drilled. And I was mentally Photoshopping the mech to see what it would look like in ‘stealth black’, green (dark and fluo-lime), gold, blue, pink (tribute to the Giro).

    And Bike rumor, thanks for passing that around : )



  35. Glenn on

    I’d like to see what you could do with a steel lugs. Watch out Hetchins! Very impressive. You are an artist and superb craftsperson. Grand ingenuity. – Glenn

  36. Dave on

    Just stumbled on this. Very pretty. For those of you commenting why Shimano doesn’t do this its because they know it will not be as stable or consistent as their production version. Back in the 90s when CNC boutique was all the rage Shimano answered exactly this question on a sign in a display case full of their CNC prototypes.

    Simply put Shimano said we have CNC machines too. We use them for prototyping to determine the best final design before making their forging tooling for production. Forged parts are far stiffer and stronger than machined billet.

    Machining a part post forging removes the hardest material at the surface removing significant strength and stiffness. This one off might work for one guy but at the volume Shimano produces it would be a warranty nightmare. Trust me I was a warranty tech during that CNC craze in the 90’s. A lot of CNC parts makers didn’t survive past a few years because they made pretty stuff but Shimano made robust stuff that worked.

  37. Jimmy Stevens on

    I see a real genius would make one more part to make it not blow up when you bale, fall over. Then it becomes trash. And smart people would not spend that much money on a derailleur$3199. Are you kidding. And a real genius would no how to make a derailleur for under $200.00.its built for a art show. Not for biking.

  38. Odlaw on

    Exactly. Enjoy the genius in effort and innovation. There are scientists in Switzerland working tirelessly; crashing atoms into each other to produce microscopic black holes which last fractions of a second. They can’t point to the results of their hard work.


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