Dura Ace BB wear ??

Discussion in 'Cycling Equipment' started by Galil, May 3, 2005.

  1. Galil

    Galil New Member

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    Both my brother and I have Dura - ace (7700 series) gruppos on our road bikes. We have had to replace the bottom brackets at about the same time after 16,000 km (10k miles) over a 14 month period. I'd estimate the kilometrage in the rain to be no more than 1-2%. Personally I am surprised that the BBs already required replacement since this almost Shimanos' top of the line.

    My question is what kind of kilometrage/ mileage are other riders getting out of their Dura - ace bottom brackets before they had to replace them?

    Regards,

    Galil
     
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  2. daveornee

    daveornee New Member

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    27,000 miles in 2+ years.
    After each rain ride I serviced it. BB-7700 are not well sealed. If you want to give up a little performance and have longer BB life without servicing, try the Ultegra Octalink BB. Ultegra has seals.
     
  3. Galil

    Galil New Member

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    Thanks for the info. By servicing it do you mean to just open up the BB, remove the cartridge and clean it and the frame BB housing, threads etc., regrease and assemble?

    Regards,

    Galil
     
  4. daveornee

    daveornee New Member

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    Yes, I took it out, cleaned it (Flushed it with solvent), pack in fresh grease, and put it back in. If you get rain and leave it in there, the seals don't hold out water. The lubrication fails to protect the bearings and bearing surfaces. I rode 6 of 7 days in the rain and serviced the bottom bracket 6 times in one week. Since then I switched to the Ultegra Bottom Bracket. 23,000 miles without service and still running smooth.
    Check out some details at Park Tool Repair Section:
    http://www.parktool.com/repair_help/FAQadjbb.shtml
    DURA ACE Bottom Bracket needle bearings and ball bearings provide superior stiffness and support, but the weather seals are a "joke".
     
  5. boudreaux

    boudreaux New Member

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    The DA is not a cartridge.It's got a bunch of loose bearings,and if you don't know what you are doing, it's best left alone or just replaced.
     
  6. daveornee

    daveornee New Member

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    The bearings are retained in left and right side cups. I would call them cartridges, but they certainly are far from sealed.
    I took out the cups with the proper tools and flushed them with solvent after each rain ride.
    The picture shown at the Park Tool Repair site shows what one cup and it's associated ball & needle bearings looks like. You must exercise great caution in removing and re-installing the cups. I use anti-sieze on the threads and a torque wrench to tighten to specifications. The spline tool needs to be clean and undamaged. The splines of the cups should also be clean and kept from damage. I wouldn't suggest this procedure unless you understand the risks.
    We still use XTR bottom brackets of similar design on our road tandem. However, we have managed to avoid rain for about 12,000 miles. The XTR BBs have the same design as DURA ACE 7700. Octalink design allows for multiple removals and re-installations without the "trouble" you would have from interference fit of the square spindle type interface. Our road tandem is S & S coupled. This means it travels with us and is taken apart and put back together a couple of times each trip. It helps protect things to have the cranks removed.
    I watched a Tour de France USPS team mechanic service an entire team's worth of DURA ACE bottom brackets in less than an hour after a rainy day ride. This was when BB-7700 first came out and long before the 7800 version.
     
  7. Hypnospin

    Hypnospin New Member

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    i can vouch for this, even though serviced and adjusted mine could not survive even one winter. while the ultegra has no prob.



     
  8. Rocket69

    Rocket69 New Member

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    The 9 speed version of the DA bb is HORRIBLE... I suggest you just replace it with an Ultegra 9 BB... better quality, LESS money... You get a bargain on them through e-bay!

    Rocket 69
     
  9. DiabloScott

    DiabloScott New Member

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    If I had known then, I would have gone Ultegra BB also when I was building my bike up. But I have a different rain bike and my DA bike doesn't see too much foul weather so the DA BB is holding up fine. Maybe I'll be able to leave it there until it's time for a new crank and then I'll go with the 10-speed crank/BB combo.

    So I don't know about "horrible" ... 10k miles isn't too bad for a $50 part, but the Ultegra one probably would have lasted longer.
     
  10. Gonzo Bob

    Gonzo Bob New Member

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    ~60,000 miles in 19 years on my DA-7400 cup-and-cone BB so far :)
     
  11. Galil

    Galil New Member

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    The version of Dura Ace I have is indeed a cartridge with the full serial number being BB-7703 for a triple. (Can be found on most web cycling stores.) My local bike shop already opened it up and regreased the cup threads holding the cartridge but to no avail. The bearing is rough and creaks under mild leg force. Anyway they ordered me a new one. It seems the replies mostly were in regard to the older DA which was loose bearings.

    Anybody know if the DA cartridge is less durable in the rain vs the Ultegra?

    The weight difference is only a couple of grams. I doubt if a masters cyclist like myself could really tell the difference in smoothness between an Ultegra BB and a DA BB.

    Regards,
     
  12. boudreaux

    boudreaux New Member

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    And it is a different unit than the 7700 double.
     
  13. daveornee

    daveornee New Member

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    The tiple & double Bottom Brackets are cartridge units.
    See URL:
    http://www.1upvelo.com/velo/ftp/shimano/duraace/bb7700.pdf#search='bb7700'
    The seals on both BB-7700 and BB-7703 are not good compared to the Ultegra BB-6500 or BB-6503.
    The interior structures are vastly different, with the stiffness advantage going to DURA ACE. However, the seals used on both double and triple DURA ACE Bottom Bracket cartride units are not good in wet riding environments. I have not used the BB-7703 or even had one in my hand. From the documentation I can find on the BB-7703 it doesn't come apart for service like the BB-7700 units.
    The ball bearings and needle bearings in the BB-7700 are retained. There are no loose bearings in BB-7700,
     
  14. GuyStevens

    GuyStevens New Member

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    Well I must be blessed then. I've had mine 5 years, I ride in very wet conditions and I've never had to service it.
     
  15. boudreaux

    boudreaux New Member

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    The fact that the bearings in the 7700 are in retainers,does not make it a cartridge BB in the sense that the ultegra is.The 7703 doesn't come apart because as I said, it's a true cartridge type like the ultegra.
     
  16. daveornee

    daveornee New Member

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    Interesting to say the least!
    Where did you say the DURA ACE BB-7703 is a cartridge before the above posting?
    I do remember your saying "It's got a bunch of loose bearings,and if you don't know what you are doing, it's best left alone or just replaced."
     
  17. Galil

    Galil New Member

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    Dave,

    Thanks for the in depth reply. I have also read on the RBR (RoadBikeRider) news letter about DA complaints and recommendations to move to Ultegra.
     
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