weird crankset problem

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  • Hello again people! I am after your help one more time. I am currently using a Sram Force 22 crankset, with a power2max types S powermeter, sram red chainrings, praxis works bb conversion (2 months old) from PF30 to GXP and a complete Sram Force groupset. When i try to sprint on 53/11 my chain wil drop outwards, every time at the same spot, the downstroke of left pedal. At first thought chainrings were too used so i changed everything with new (it was their time so no problem, chainrings,cassete,chain everything is new). A professional mechanic tuned everything to perfection so definitely not a set up problem, although problem still exists. I even removed and reinstalled the powermeter to ensure its not wrongly installed at first. Before the removal there was a movement of the chainring about 5mm from side to side (i used derailleur cage to determine the amount of play) When reinstalled this movement almost was cut to half, maybe even less. Any thoughts why this may happen? Its annoying and dangerous

  • definitely not a set up problem

    Sounds like a set up problem

  • It was adjusted several times. my mechanic is also a teammate so we ride together a lot. He is also on the job for over 15 years so i trust him. We even moved the derailleur so close that it rubs the chain on 53/11. Problem still there though

  • Well there's nothing inherently wrong with sram force groups and you said your self you even changed all the running parts and problem persists.
    Is there any play in the crank arms or bb?

  • No, not at all. I know that Force group is top tier and thats why i am so confused. Can the powermeter be bent where chainrings are screwed and drop the chain as a consequence? Cant think of anything else.

  • Are the rings still out of true? I've never seen anything but dead straight chainrings on my sram cranksets

  • Just a tiny bit, about 1 or 2 mm...

  • Pass

  • Are you sure the power2max is properly tightened? Has it been used when not adequately installed and is now not fitting properly?

  • It looks like when originally installed it wasnt tighten or screwed correctly (another mechanic installed it originally with not so great credentials). After the removal, reinstallation was done correctly and was tightened to spec using a torque wrench.

  • The splines could now be fucked.

    :-(

  • English is not my mother language so i dont understand which part is this.

  • The ridges on the crank and the power meter. They may no longer be the right shape.

  • Before the removal there was a movement of the chainring about 5mm from side to side

    Yeah something is fucked. Do you mean the PM and chainring were moving together, from side to side, by 5mm? Is it the entire crankset moving laterally, or the PM moving independently of the cranks?

    There should be no play anywhere, at all.

  • Entire crankset is moving lateral, there is no play anywhere. I wish it was play somewhere, it would be an easy fix.

  • Entire crankset is moving lateral, there is no play anywhere.

    Huh?

    It’s one or the other. It’s moving laterally or there’s no play?

  • Sounds like the bottom bracket isn’t spaced out correctly, perhaps? Time to call in to your local trusted bike shop. Whereabouts are you?

  • n+1

  • Guys thanks for all the help! I am located in Greece, english is not my mother language so i have difficulty explain th situation. Let me clarify some things. There is no play, anywhere, crankset,bb, chainrings everything is tightened correctly. BUT if i observe the movement of the big chainring inside the derailleur cage i can see it move 1 or 2 mm outwards, so chain is rubbing the outter plate of the derailleur, when my left pedal is between 2 and 3 o'clock. Thats why i suspect that either splines are damaged as said before, or powermeter bolt holes are bent in some way. I dont know if i explained it correctly.

    Ps1: I appreciate the time you put on this!

  • Big chainring is buckled?
    edit-(As well as what DJ said)

    Clamping with two adjustable wrenches you may be able to straighten the area (or just make it worse/damage it).

  • How does the SRAM mount differ from Rotor? If it also has a lockring then fucked splines won't let it move side2side just creak forward/back.

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weird crankset problem

Posted by Avatar for Apostolis14 @Apostolis14

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