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  1. #1
    On Two Wheels sam83's Avatar
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    Bottom Bracket Smooth, but...

    I've got a Truvativ Giga Pipe Ti bottom braket that turns very smoothly, but with a noticable resistance when compared to my old Ultegra 9-spd bottom brackets. It's been that way for over 2000 miles and turns the same installed or not.

    So, I bought a Truvativ Giga Pipe team SL and it feels similar; smooth, but with resistance. Like it's in thick grease.

    Did a crank conversion on a friend's bike and have a left over FSA Platinum bottom bracket. It has noticably less resistance, but maybe not as easily as the Ultegra.

    Are these Truvativ bottom brackets steeling what little power I have?!

    What's a good choice for an ISIS BB for road use?

  2. #2
    Senior Member MudPie's Avatar
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    Dang good question. I too would like some suggestions. I installed a Truvativ Gigapipe about nine months back and as I spin the spindle with my fingers, it's smooth, but stiff. I've learned to live with it and consider it a "training feature". When it's off the bike it spins easier, but once mounted, it stiffens. The original bottom bracket was always easy to spin. I've installed it the recommended installtion torque, too. I'm hoping my bottom bracket shell is not distorting it.

    I looked up bottom brackets on http://www.mtbr.com/reviews/bottom_bracket/ and it seems most of the more common ISIS BBs (Race Face, Truvativ, FSA) had extremely poor ratings and common talk of bearing failure measured in months. As a corollary to the original post:

    1. Why do ISIS BBs have such poor quality (or is it just a few disgruntled riders complaining the loudest?)
    2, BBs are relatively simple - spindle, cartrdige bearings, seals, and cups - what can go wrong?

  3. #3
    Senior Member Nessism's Avatar
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    No worry about a little seal drag in the bottom bracket. As I recall, Velonews quantified the power loss to be all of 1 Watt from this. My farts generate more power than that so I don't waste time thinking it.
    Becareful buying/selling bike parts on-line. I learned the hard way. :(

    Good/Bad Trader Listing

  4. #4
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    Quote Originally Posted by MudPie
    Dang good question. I too would like some suggestions. I installed a Truvativ Gigapipe about nine months back and as I spin the spindle with my fingers, it's smooth, but stiff. I've learned to live with it and consider it a "training feature". When it's off the bike it spins easier, but once mounted, it stiffens. The original bottom bracket was always easy to spin. I've installed it the recommended installtion torque, too. I'm hoping my bottom bracket shell is not distorting it.

    I looked up bottom brackets on http://www.mtbr.com/reviews/bottom_bracket/ and it seems most of the more common ISIS BBs (Race Face, Truvativ, FSA) had extremely poor ratings and common talk of bearing failure measured in months. As a corollary to the original post:

    1. Why do ISIS BBs have such poor quality (or is it just a few disgruntled riders complaining the loudest?)
    2, BBs are relatively simple - spindle, cartrdige bearings, seals, and cups - what can go wrong?
    There's a few factors working against an ISIS BB; the primary of these is the size of the Euro/English BB Shell compared to the size of the spindle; especially compared to that of a square taper. The Larger ISIS Spindle size means you have to use smaller balls in the bearings, and that typically leads to shorter lifespan (Oddly enough Shimano's Octalink stuff holds up quite nicely even though in theory it has the same drawback... I wonder why.)

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