|Bottom Bracket Selection||dobby|
Sep 24, 2003 12:28 PM
|Can I use either a Dura-Ace or Ultegra bottom bracket with a Ultegra Crankset?|
Sep 24, 2003 12:33 PM
|Yes but get the Ultegra BB||sidley|
Sep 24, 2003 12:43 PM
|My LBS told me DA BBs are for people who will use it for a race season and be willing to throw it away. I guess they are more delicate than Ultegra|
|Yes but get the Ultegra BB||Galibier|
Sep 24, 2003 12:57 PM
|Dura Ace BBs require more careful installation and maintenance. Basically, if you ride through heavy rain, you will evenutally need to remove and regrease the BB. Otherwise, properly installed and maintained, the Dura Ace BB will provide years of smooth service. They are not designed to be disposable.|
|did Shimano fix the DA BB problems with 10v?||ColnagoFE|
Sep 24, 2003 12:58 PM
|I always wondered why they hadn't addressed the problems with the current DA BB before now.|
|Dura-Ace bottom bracket||Ironbutt|
Sep 24, 2003 1:09 PM
|The current Dura-Ace bottom bracket is probably the smoothest rotating on the market. It is not an install and forget unit, and absolutely must have the bottom bracket shell properly prepared before installation. If correctly installed and maintained, it will last for years. It's kind of like owning a Ferrari or a Volkswagen. One is use and abuse, the other is not. But lots more rewarding in the right hands.|
|It may be an Ace, but it ain't very Dura (nm)||mapei boy|
Sep 24, 2003 3:21 PM
|did Shimano fix the DA BB problems with 10v?||russw19|
Sep 24, 2003 2:28 PM
|Shimano,(like myself) were not convinced there were problems with the DA BB. If properly set up and maintained, it was a perfect bottom bracket. It was everything that pro level racers wanted out of a BB. It was light as all heck (when it hit the market in 1998 there weren't any lighter BB's except a Phil Wood Ti that was 3x the cost) and it's smooth as smooth can be. It rivals the mid 80's Campy C-Record BB for smoothness. And it's super duper stiff spindle launched the whole ISIS craze to match that spindle stiffness in a non-proprietary spline pattern.
The catch was not really any concern to Shimano because it was designed as a pro-level bottom bracket. The catch was that it was not an install and forget BB like the UN series were. The pros wanted a better BB and wanted it to be adjustable and rebuildable... Shimano came thru. Now, just because it says Dura-Ace on it, every weekend warrior rider who wants the latest greatest same as the pro's equippment on their bikes too has a problem. The weekend warriors don't have a full time mechanic at their disposal to rebuild the BB on regular service intervals, which it was designed for. So really the Ultegra may be a better BB for them, but it is NOT a better BB than the Dura-Ace.
It's kinda like this... a Honda F1 engine is a better engine than the one in my Accord, but not a better engine for me.
And after that little rant... to answer your question, yes, Shimano did change the bearings for the 10v group. The bearings are now again in a sealed cartridge unit outboard of the bottom bracket shell. That way they can make an even stiffer BB-Crank unit. But to have the bearings outside of the frame pretty much forces them to use a sealed cartridge unit.
|did Shimano fix the DA BB problems with 10v?||divve|
Sep 24, 2003 10:46 PM
|There have been some problems with XTR 03 outboard BB bearings. Apparently they're quite susceptible to water and dirt intrusion. Some blame it on lousy seals and others suspect Shimano is using sub standard bearing quality (I have some doubts regarding the latter). I'm sure a road bike won't see anywhere near that kind of exposure, but due to the wide bearing spacing I think proper facing of the BB shell is important as well. Also, left crank clamping bolts should be checked regularly...some people have been loosing their XTR crank on the trail:)|
|Makes sense... it's an outboard bearing...||russw19|
Sep 25, 2003 12:09 AM
|It's not like it's sheltered from dirt and water by being inside the frame.... it's outside and so only the seals are going to protect it... not the frame. And that is one of the dirtiest areas of a bike.
I think the idea is cool, but I do see the need for way better seals in that area if it is going to hold up.
|Quite the opposite||russw19|
Sep 24, 2003 2:15 PM
|Dura-Ace bottom brackets are user servicable. They were NOT designed to be an install and forget BB. The opposite is true of the Ultegra. It WAS designed to be tossed once it goes bad. You can not service the bearings on the inside. I wish shops would stop spouting out this line of crap. The truth is more likely that your shop doesn't have any mechanics who remember how to service a bottom bracket as it seems a lost art. It's like wheelbuilding. Now that everyone is buying pre-fab boutique wheels, in another 5 years mechanics won't remember how to build them.
But you MUST chase and face your frame if you plan on using a Dura-Ace BB. Otherwise the 2 sets of needle bearings won't line up right and you BB will die prematurely. And if you ride thru the rain a lot, you will want to overhaul it periodically. On the other hand, if you ride in the rain a lot with the Ultegra, you will want to replace it periodically. I have a Dura-Ace BB with over 40,000 miles on it. It's a first generation Octalink spindled BB from about 1998. I am willing to bet nobody here has an Ultegra BB with that kind of mileage on it.
The thing about shops and the Dura-Ace BB is that I would charge you $15 to overhaul your Dura-Ace BB. But I would only charge you $10 to put an Ultegra BB in, and I would still make the profit off the bottom bracket itself. It takes about 30 to 40 minutes to properly overhaul the D-A BB because of the needle and ball bearings, but it would only take me 5 minutes to swap it to an Ultegra. That is the real reason your shop is telling you to swap it out. More money for the amount of time spent working on it, plus the profit from the new BB as well.
|Great posts, Russ! nm||Uncle Tim|
Sep 24, 2003 6:28 PM
|Just for clarification...||JonnyHu|
Sep 25, 2003 4:57 AM
|Does the design of the NEW Dura Ace BB mean that they will now also be essentially unserviceable (like the ultegra) because of the sealed bearings?|
|Based on seeing the XTR design, I would say Yes.||russw19|
Sep 25, 2003 12:16 PM
|But I haven't had my hands on the new Dura-Ace stuff yet. It will be a swap fix, not a rebuild fix. But the BB's are pretty cheap, as there is really not much to them anymore. The spindle is now part of the crankset, so the BB is just bearings pressed into the cup and a sleeve.
But whenever someone gets one in hand they may tell you otherwise.
|Just for clarification...||JonnyHu|
Sep 26, 2003 5:49 AM
|Does the design of the NEW Dura Ace BB mean that they will now also be essentially unserviceable (like the ultegra) because of the sealed bearings?|| |