161 Dura-Ace rear der- Mtbr.com
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  1. #1
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    161 Dura-Ace rear der

    Okay here are my initial dabblings with weight weenism. Despite my usual mechanical ignorance I was able to install the Speedware cage and pullies as well as the SRP bolts pretty easily. The pivot bolt has a clip that flew off, which required some time searching for it. Sorry about blurring the pic. Waiting on a alloy adjuster barrel that might take a little more off.
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  2. #2
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    Very nice. Just wondered what model that is. I have a similarly tuned 7700 model but only managed to get it to 180g.

  3. #3
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    Quote Originally Posted by top_ring
    Very nice. Just wondered what model that is. I have a similarly tuned 7700 model but only managed to get it to 180g.
    This is the RD-7800.

    I don't know how durable this will be. Some people have broken the carbon cage. I will just have to find out. The SRP pulley bolts are arguably better then the speedware cage bolts which are not hollow and silver.

  4. #4
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    I'm down to 157 grams now by replacing the barrel adjustor and this is the final weight.
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  5. #5
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    Very nice! That's almost 100 grams lighter than my XT 737.

    Can I ask what the main pivot bolt was worth alone (if you know)? Or maybe weight the original (is it steel?)?

    Carbon =
    I ..... need ..... DIRT!!!!!

    ... and cookies.

  6. #6
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    Quote Originally Posted by AndrewTO
    Very nice! That's almost 100 grams lighter than my XT 737.

    Can I ask what the main pivot bolt was worth alone (if you know)? Or maybe weight the original (is it steel?)?

    Carbon =
    I don't know what the savings were for the main bolt alone but I suspect it was a large amount because it is originally steel or maybe stainless steel. Everything is off the shelf parts-there is no personal tooling/dremeling to get this weight. It was not cheap mainly due to the Speedware parts which are around $100usd from Fairwheelbikes.com. The SRP stuff I got via ebay through Toronto cycle and they were pretty cheap, less then $20 I believe. In the end I feel good that it is lighter and cheaper than a Tiso rear der. It is just a matter of durability however (just need to finish the build and get good weather).
    Last edited by Slobberdoggy; 01-19-2006 at 06:44 AM.

  7. #7
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    Quote Originally Posted by Slobberdoggy
    I don't know what the savings were for the main bolt alone but I suspect it was a large amount because it is originally steel or maybe stainless steel. Everything is off the shelf parts-there is no personal tooling/dremeling to get this weight. It was not cheap mainly due to the Speedware parts which are around $100usd from Fairwheelbikes.com. The SRP stuff I got via ebay through Toronto cycle and they were pretty cheap, less then $20 I believe. In the end I feel good that it is lighter and cheaper than a Tiso rear der. It is just a matter of durability however (just need to finish the build and get good weather).
    For me is ridicolous to pay 100 $ for a very simple piece of carbon cage and 2 pulleys. I bought a X.0 carbon cage and 2 Vuelta derlin pulleys for around 30 euro...
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    Last edited by scapin; 01-19-2006 at 07:12 AM.

  8. #8
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    Quote Originally Posted by Slobberdoggy
    This is the RD-7800.

    I don't know how durable this will be. Some people have broken the carbon cage. I will just have to find out. The SRP pulley bolts are arguably better then the speedware cage bolts which are not hollow and silver.
    Speaking from experience with my DA it's really not durable at all. Watch out for picking up sticks on the trail: a small stick in the cage destroyed mine. It's not designed for offroad stuff but that's a tradeoff I'm willing to accept for the gram savings. I got mine down to 175 with similar tuning. BTW: I have found that the DA 12/27 cassette wears out pretty quick too. Not the steel cogs but the TI ones. Wish I could locate a source for the TI portion of this cassette. The whole cassette is really pricey.

  9. #9
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    Quote Originally Posted by scapin
    For me is ridicolous to pay 100 $ for a very simple piece of carbon cage and 2 pulleys. I bought a X.0 carbon cage and 2 Vuelta derlin pulleys for around 30 euro...
    So, the XO cage will fit on the DA? How much weight do you save over the original cage with the XOs?

  10. #10
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    Quote Originally Posted by Axis II
    So, the XO cage will fit on the DA? How much weight do you save over the original cage with the XOs?
    No, don't fit on the DA. I say that only to explain why is crazy to spend so much money for a stupid simple carbon sheet...

  11. #11
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    Quote Originally Posted by scapin
    No, don't fit on the DA. I say that only to explain why is crazy to spend so much money for a stupid simple carbon sheet...
    Huh? I thought we were talking about tuning a DA der. here? Don't confuse me like that anymore. If there are cheaper alternatives for the DA let us know.

  12. #12
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    Quote Originally Posted by Slobberdoggy
    I don't know what the savings were for the main bolt alone but I suspect it was a large amount because it is originally steel or maybe stainless steel. Everything is off the shelf parts-there is no personal tooling/dremeling to get this weight. It was not cheap mainly due to the Speedware parts which are around $100usd from Fairwheelbikes.com. The SRP stuff I got via ebay through Toronto cycle and they were pretty cheap, less then $20 I believe. In the end I feel good that it is lighter and cheaper than a Tiso rear der. It is just a matter of durability however (just need to finish the build and get good weather).
    Yeah, I have one already, too. Tom at TC is great, eh?!?!

    I just haven't had the time to put it on yet. (trying to finish too many projects!!!)

    Thanks Slobberdoggy!
    I ..... need ..... DIRT!!!!!

    ... and cookies.

  13. #13
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    Quote Originally Posted by scapin
    For me is ridicolous to pay 100 $ for a very simple piece of carbon cage and 2 pulleys. I bought a X.0 carbon cage and 2 Vuelta derlin pulleys for around 30 euro...

    Why buy a 13g carbon cage when you can make your own 11g aluminum cage ! This is a picture of mine that I made last year for my XTR to replace the 34g steel one.




    But the Vuelta Delrin pulleys ARE interesting...lots lighter than the stock 22g XTR ones...



    Where did you get those Vuelta pulleys ? online source ? 30 Euro is sure cheap for what you got.

    Thanks in adavance,
    Jean-Sebastien
    2004 Giant XTC Custom
    2001 Giant Boulder HD
    2000 Devinci Chili Pepper (frame only)
    1993 Proflex 853 (frame only)
    1988 Kuwahara ProStar
    1982 Peugeot Record Du Monde (fixed gear)
    1980 Raleigh Sprite (restoration)

  14. #14
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    Quote Originally Posted by jean-seb
    Why buy a 13g carbon cage when you can make your own 11g aluminum cage ! This is a picture of mine that I made last year for my XTR to replace the 34g steel one.

    But the Vuelta Delrin pulleys ARE interesting...lots lighter than the stock 22g XTR ones...

    Where did you get those Vuelta pulleys ? online source ? 30 Euro is sure cheap for what you got.

    Thanks in adavance,
    Jean-Sebastien
    I'm not interested to extreme lightness. I'm able to lighten my carbon cage under 10 gr. too, but I prefer reliability. I ride my bike, I don't want only to watch it or drive me crazy for breakage.
    Sorry, I bought Vuelta pulleys from my friend. I don't know where he bought them...

  15. #15
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    Quote Originally Posted by scapin
    I'm not interested to extreme lightness. I'm able to lighten my carbon cage under 10 gr. too, but I prefer reliability. I ride my bike, I don't want only to watch it or drive me crazy for breakage.
    Sorry, I bought Vuelta pulleys from my friend. I don't know where he bought them...
    I was afraid myself when I built the cage that it would break because it was way lighter than the steel one, but it seems to hold up pretty well. My bike is around 19,5 lbs right now (hardtail with discs) so there is nothing crazy light about it, just like you.

    Thanks anyway for the info on the pulleys, I'll just ask at my local bike shop to see if they can get them.

    Have a good day !
    Jean-Sebastien
    2004 Giant XTC Custom
    2001 Giant Boulder HD
    2000 Devinci Chili Pepper (frame only)
    1993 Proflex 853 (frame only)
    1988 Kuwahara ProStar
    1982 Peugeot Record Du Monde (fixed gear)
    1980 Raleigh Sprite (restoration)

  16. #16
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    Look at mine (152 g) :

    http://www.forumfree.net/?t=3754181&st=0
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  17. #17
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    Quote Originally Posted by Dream Bikes
    Look at mine (152 g) :
    Lupus in fabula...

  18. #18
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    Those Vuelta Delrin pulleys look good. Too bad they aren't 11t though

  19. #19
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    alloy adjuster barrel?

    Slobberdogy et all, where are you guys finding these alloy adjuster barrels?
    Thanks.

  20. #20
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    Quote Originally Posted by mtbbiker1
    Slobberdogy et all, where are you guys finding these alloy adjuster barrels?
    Thanks.

    Contact fairwheelbikes.com . They know their light weight bike part stuff. Apparently this adjuster is a regular bolt drilled out by fair wheel bikes. (520) 884-9018 They are super easy to deal with. You might try doing it yourself by getting the appropriately sized bolt from one of the big bolt companies listed on the FAQ and elsewhere and do it yourself.

  21. #21
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    i just got mine down to 161g as well using those Vuelta Pulleys (grazie Mauro!) and
    i also put a drilled out M5 alloy bolt instead of the standard steel adjuster bolt.

    another 13g saved
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    Last edited by nino; 01-27-2006 at 09:56 AM.

  22. #22
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    Quote Originally Posted by nino
    i just got mine down to 161g as well using those Vuelta Pulleys (grazie Marco!)
    Mauro...

  23. #23
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    Quote Originally Posted by scapin
    Mauro...
    si giusto! ero troppo in fretta a scrivere...

  24. #24
    Woz
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    Well, I might as well join in.

    http://weightweenies.starbike.com/ph...ighlight=extra

    That was the first prototype of a tuned DA I did. Final version is looking much cleaner, and the weight is now down to 139.6grams.

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