Viewing 9 posts - 1 through 9 (of 9 total)
  • Firex 3.3
  • neilmon
    Free Member

    Hello,

    I recently bought a truvative firex 3.3 crankset for my dmr side kick and i am having real grief getting the bb fitted.

    Basically my frames threads are spot on and in top condition, as are the threads on the bb cups.

    My problem is that the drive side cup will only thread into the non drive side of my frame and vice versa, meaning the ring will be on the left? Now this is not possible for the obvious facts that my disc is on that side and the rear cog is going to be on the right? (Normal)

    Yet when i try and thread the drive side cup in the drive side of the frame it just wont happen nor will the non drive side fit, no mater what way i turn it just starts to cross thread so i stop???

    Am i missing something really silly out? please help me.

    Forgot to add it’s the gxp bb

    jimmyjames
    Free Member

    Hang on, the BB cups?! They should only screw in to the side they are meant for because the threads are reversed. Unless your BB shell is threaded the wrong way then I have no idea what’s going on here. The left hand cup should screw on clockwise and anti-clockwise for the right hand cup. Is this what you’re doing?

    jimmyjames
    Free Member

    Okay, it looks like the markings are wrong. This seems bonkers but the same thing happened to someone here:

    http://www.bikeforums.net/showthread.php/705194-SRAM-Omnium-GXP-BB-Installation

    I would assume if they go on then they are right, as you have discovered they will only go on one side by design.

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    julianwilson
    Free Member

    If the markings are the wrong way round, be aware that the innards also differ slighly left and right on GXP bb’s: the non-drive side bearing needs to be the one with the slightly smaller hole in it, on my old firex cranks it was basically a small collar that pushed into the same size bearing on the drive side.

    neilmon
    Free Member

    Right this is so hard to explain so bare with me, basically if i thread the cups in the only way the will go, it means the chain ring is on the left hand side and because each cup is tailored to fit the axle one way only, due do different internal diameter sizes of the cups bearings i cant just switch it if that makes any sense?

    jimmyjames
    Free Member

    Yes, that makes sense. In that case something is seriously wrong. Where did you get it? Can you call the shop or get a replacement? Or at least send them a photo so they can compare the threading on yours to to a “good” one (might be a useful sanity check).

    neilmon
    Free Member

    It does seem that the bearings are in the wrong cup’s?

    Unfortunately i bought them second hand off pink bike and the seller clearly stated they had been used, this now seem’s like he has mugged me off as there is no way these could possibly be run on any bike. On the bearing’s in the cup’s they have a sort of retaining clip that slots into a rim and i assume they secure the bearings in place so a swap may be possible?

    Here’s the add…
    sale

    jimmyjames
    Free Member

    Yeah, that seems odd. These BBs are common on tandems apparently, and one set of cranks has the drive on the left on a tandem:

    That may go some way to explain what’s going on here…

    neilmon
    Free Member

    Hmmm in a pm to me he stated that the bb will fit most 68-73mm bikes so i think he’s pulled a fast one on me 😡

Viewing 9 posts - 1 through 9 (of 9 total)

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