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  1. #1
    luddite
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    Oct 2005
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    FSA Platinum Pro Ti ISIS lacks sufficient preload?

    I have been having trouble with my FSA platinum pro Ti ISIS BB (68x113) from the day I bought it.

    When I put any of the cranks I own on the drive side spindle (Bonty Race, Bonty Sport, RaceFace Turbine LP), and espeically with a RF there is little or no preload, meaning it just slides right on and hits the hard stop. There is not any noticeable play, but definitely no preload. When I crank down the retainer bolt and start riding the crankarm develops wobble within a mile.

    As a further test, I can crank down the bolt, then remove the bolt and try to pull the crankarm off. It comes right off, no need for the crankarm puller tool.

    I went to isisdrive.com to educate myself about the finer points of the ISIS specifications and design elements, and especially to find the machanical drawings... So I made some digital caliper measurements to see if the spindle dimensions are out of spec. The spindle appears to be in spec, but just barely, all dimensions were less than 0.2 mm of the low side of the ISIS tolerances. Curiously, the hardstop and the end of the spindle are not parallel. Using a caliper, I measured the distance from the end of the spindle and the hardstop (axially along the spindle) and there is 0.4 mm of difference between the distances from one side of the spindle and the other. I noticed this non-parallel effect first when pedaling the crank, because I had a serious chainring waver. You know, scrape-scrape-scrape on the front derailleur when your driveside crankarm sweeps through one position. The caliper measurements confirm the source of the wobble.

    The same preload symptoms occur with this BB spindle and the other two Bonty cranks but to a lesser degree, there *is* some preload just not very much. Both cranks still wobble and can be removed by hand. My RF crank fits the other two ISIS spindles in my garage with ample preload and no wobble.

    This seems to be a bum BB so I took it to my LBS to send back to FSA for warranty.

    Anyone else notice this with any of their bottom brackets?
    Last edited by MadCowRider; 01-26-2006 at 12:28 PM.

  2. #2
    mtbr member
    Reputation: lebikerboy's Avatar
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    Jan 2005
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    I've been using FSA Platinum and Platinum Pro (Chromoly spindles) for years and have never had the problems you've experienced. All my cranks are Raceface in various versions.
    Quote Originally Posted by MadCowRider
    I have been having trouble with my FSA platinum pro Ti ISIS BB (68x113) from the day I bought it.

    When I put any of the cranks I own on the drive side spindle (Bonty Race, Bonty Sport, RaceFace Turbine LP), and espeically with a RF there is little or no preload, meaning it just slides right on and hits the hard stop. There is not any noticeable play, but definitely no preload. When I crank down the retainer bolt and start riding the crankarm develops wobble within a mile.

    As a further test, I can crank down the bolt, then remove the bolt and try to pull the crankarm off. It comes right off, no need for the crankarm puller tool.

    I went to isisdrive.com to educate myself about the finer points of the ISIS specifications and design elements, and especially to find the machanical drawings... So I made some digital caliper measurements to see if the spindle dimensions are out of spec. The spindle appears to be in spec, but just barely, all dimensions were less than 0.2 mm of the low side of the ISIS tolerances. Curiously, the hardstop and the end of the spindle are not parallel. Using a caliper, I measured the distance from the end of the spindle and the hardstop (axially along the spindle) and there is 0.4 mm of difference between the distances from one side of the spindle and the other. I noticed this non-parallel effect first when pedaling the crank, because I had a serious chainring waver. You know, scrape-scrape-scrape on the front derailleur when your driveside crankarm sweeps through one position. The caliper measurements confirm the source of the wobble.

    The same preload symptoms occur with this BB spindle and the other two Bonty cranks but to a lesser degree, there *is* some preload just not very much. Both cranks still wobble and can be removed by hand. My RF crank fits the other two ISIS spindles in my garage with ample preload and no wobble.

    This seems to be a bum BB so I took it to my LBS to send back to FSA for warranty.

    Anyone else notice this with any of their bottom brackets?

  3. #3
    luddite
    Reputation: MadCowRider's Avatar
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    Oct 2005
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    It's been my first FSA problem, in fact

    I agree, it's strange. In fact, the other BBs in my garage of which I spoke are of the $35 FSA Ultimax variety. Never been let down too badly by FSA, they usually make reliable parts.

    My original post was a "I wonder if this problem is just an abberation?" question, not really a rant, though it sounds that way!

    Cheers.

  4. #4
    luddite
    Reputation: MadCowRider's Avatar
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    FSA is the model of customer service

    This is a delayed post, but I had to ride it a bit to make sure it worked OK.

    FSA sent me a brand new BB. It only took three days. They replaced my PlatinumPro Ti with a MegaQuad Ti. Nice.

    Mounted up with no issues and plenty of preload. After 2 months and 500 miles it still spins smoothly.

    I have nothing but good things to say about FSA customer service. Thanks, FSA!

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