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  1. #1
    horseman
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    bottom bracket drainhole anyone?

    Hey there! I have an '06 RX100 and have been "working with" the Shimano external /Hollowtech bearings program. I would have thought that advances might have been made in external bearing technology from the first ones I had in the mid eighties, but I digress. When I got inside and pulled things apart to repack there was moisture/water in the bottom bracket area. Some folks recommend drilling a small drainhole in the bottom bracket. Has anyone done this? What size hole/drill did you use? What does Titus think of drilling drainholes? Will the frame warranty be voided? I have an aluminum frame so I am not really concerned about the moisture from an steel frame perspective, but I think that the external bearing program might fair better with a drainhole. After all, not all of live in the desert (I live in southeastern Vermont).

  2. #2
    Not an O2 thief.
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    I live in the desert and still drilled drain holes in mine (5 ti frames). I got tired of frying bearings due to water in the bb. Not sure about warranty, but if you only put a hole about 1/16", it shouldn't cause any problems. If a frame is going to break, it's not going to be the shell.....maybe the weld around the tube/shell junction, but not the shell itself.
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  3. #3
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    I put a 1/8" hole in mine a few years ago. I called Titus before I drilled it and they said "no problem". Dunno if that's still true today - it was a different regime back then.

  4. #4
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    Even though it's a somewhat common practice, I prefer not to do something like that. Instead, I just pack the BB shell and the BB itself with tons of grease. Never had a water intrusion problem or an ISIS BB failure.

    The water can even get in through the headset area, but is more likely due to condensation inside the tubing and the gas relief holes made for welding.

  5. #5
    horseman
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    1/16th, 1/8th ?

    I figured that some of the moisture issues were from condensation build-up. The bike is used for winter riding, to & from the barn, in & out of extreme warmth and cold conditions. We certainly do ride here in wet conditions but I haven't submerged the BB yet.
    In any event... What are thoughts regarding the size drill bit/hole?

    (interesting notes... My old Scott Windriver '82-3 had an older version Shimano BB program that incorporated a drill hole/grease fitting that allowed for grease to be injected until it seeped/oozed past rubber washers. I still use it for gravel road workouts)

  6. #6
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    A few weeks ago I replaced the original cranks/BB on my wifes year-old Specialized FSR XC. It had lots of water and rust in it. Remember that the water can get in to the seat tube and down tube and run down and collect in the bottom bracket. I drilled a 1/8" hole in it before I cleaned it out and installed the new cranks. This is the same size hole I drilled in my Switchblade a few years ago with no problem. I think it's a good idea.
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  7. #7
    CAO
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    It wont hurt anything to drill a small 1/16-1/8th" hole into the bb shell. Your external bb has a a tube that has a seal on either side to prevent moisture from getting to the bearings and their seals. Make sure that the tube is in good shape (doesn't leak) and there is a good amount of lube on the seals. If you drill a drain hole on the you will still need to use lube the bb and service it as contaminants will not evaporate out. Nothing works better than some routine maintenance. The only time that I suggest drilling is if you take out the bb and there is standing water in there. All other issues can be handled with lube and maintenance.
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  8. #8
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    Those seals only slow or reduce intrusion of water, not completely eliminate it. There are ways to augment their performance, but it has to be noted that they can't be completely sealed, as opposed to "well sealed".

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