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  1. #1
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    Aeffect crank wiggle

    One thing that has always troubled me about the aeffect crankset on my fatback is the lack of a preload adjustement. After many miles and more than a few removals, there is noticeable freeplay when rocking the crank side to side. I have replaced the bearings in the race face B.B. to no avail. Will a better quality B.B. tighten things up or do the compression fit cranksets just get sloppy over time?
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  2. #2
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    Standard RF issue. Shimanoís pinch bolt system is worlds apart. I wonít buy another interference fit crank for this reason

  3. #3
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    Quote Originally Posted by Haggis View Post
    Standard RF issue. Shimanoís pinch bolt system is worlds apart. I wonít buy another interference fit crank for this reason
    Shimano doesn't make a crank with a spindle long enough for a fatbike (Fatback makes fatbikes), so it's not an option.

    It could be that the whole system wasn't installed right from the start. That maybe the bb wasn't pressed all the way from the beginning (if it's a pressfit bb), or maybe that the crank bolt wasn't torqued appropriately on installation. IME, failing to torque the crank bolt is the biggest reason that interference cranks get sloppy. You have to wail on that mofo to get it appropriately tight. 50Nm (typical torque spec) is actually kinda difficult to get on a crank bolt, since the cranks want to rotate on you while you tighten it. I use a torque wrench on my bike for two things: crank bolts and clamping sensitive parts (carbon or dropper posts). A $25 beam style torque wrench does the job just fine.

    The other possibility I could see is that everything is installed correctly and that the play is developing as the bearings wear, which seems to be your concern. If that's the case, you probably ought to make sure it's the case, but RF is not known for selling the best quality bearings, so it's possible. I bought a RF bb for my fatbike once and trashed it in too short of a time, and then bought something else. My application is different than yours (I have a Turbine CINCH crank), so the bb I settled on won't really make a difference for you. I bought an Enduro/RWC bb. No fancy ceramics or anything. Just a good steel bb. Has lasted 3x as long as the RF bb.

    If the problem is the crank arm/spindle interface loosening up (insufficiently tightened crank bolt), then the interface is probably buggered to the point that it'll never be completely tight again.

  4. #4
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    Quote Originally Posted by Harold View Post
    50Nm (typical torque spec) is actually kinda difficult to get on a crank bolt, since the cranks want to rotate on you while you tighten it. I use a torque wrench on my bike for two things: crank bolts and clamping sensitive parts (carbon or dropper posts). A $25 beam style torque wrench does the job just fine.
    RF recommends 61 Nm for the Aeffect. That's a decent amount of torque. A torque wrench is definitely recommended.

  5. #5
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    Quote Originally Posted by Brad Pitted View Post
    One thing that has always troubled me about the aeffect crankset on my fatback is the lack of a preload adjustement. After many miles and more than a few removals, there is noticeable freeplay when rocking the crank side to side. I have replaced the bearings in the race face B.B. to no avail. Will a better quality B.B. tighten things up or do the compression fit cranksets just get sloppy over time?
    Hi, your symptoms don't sound like this, but you may want to check if the left crank arm has come lose from the spindle. This happened to me on 2 new Aeffect cranks recently (got new cranks, returned for refund, got 2nd new cranks, returned for refund). Symptom for this one was bad crunchy/creaky noise with pedaling pressure. I don't think I did anything in the install that would cause the problem twice in a row, but it seemed to be a manufacturing defect and perhaps RF built a bad batch. I upgraded to Turbine cranks for what it's worth.

  6. #6
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    Iíve had it happen with the crank bolt bottomed out, so itís not a loose bolt issue IME. Seen it do the same with other RF cranks on friends bikes too.
    Itís a pity that Shimano donít do a wide axle because that solves it every time


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  7. #7
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    Quote Originally Posted by Haggis View Post
    Iíve had it happen with the crank bolt bottomed out, so itís not a loose bolt issue IME. Seen it do the same with other RF cranks on friends bikes too.
    Itís a pity that Shimano donít do a wide axle because that solves it every time


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    Bottomed out means nothing. What was the TORQUE on that bolt?

  8. #8
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    Quote Originally Posted by Harold View Post
    Bottomed out means nothing. What was the TORQUE on that bolt?
    Actually it kinda does... bottomed out is the state just before stripped or sheared (your $25 bendy rod may not have markings to indicate this).

  9. #9
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    Quote Originally Posted by Haggis View Post
    Actually it kinda does... bottomed out is the state just before stripped or sheared (your $25 bendy rod may not have markings to indicate this).
    Not really. You could be bottomed at 1Nm or 100Nm. Big difference. Either way, if you are bottomed at all on a crank like the Aeffect, your spacer arrangement needs work.

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  10. #10
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    Spacers have NOTHING to do with crank interface tightness. You take out play after tightening the crank bolt with the pre-load ring (or before assembly with pre-load spacers in older RF cranks).

  11. #11
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    Quote Originally Posted by Haggis View Post
    Spacers have NOTHING to do with crank interface tightness. You take out play after tightening the crank bolt with the pre-load ring (or before assembly with pre-load spacers in older RF cranks).
    There is no preload ring on Aeffect cranks. BB shell width, spacers, and bb thickness are critical for the Aeffect crank. Instructions for installation are the same as for the older EXI interface cranks.

    Note this little tidbit in the install instructions about the tolerances for bb shells (I would venture that the appropriate tolerances for a 100mm fatbike bb shell would be 99.25mm - 100.25mm, following the convention below, but this should probably be cleared with RF first):

    Critical!!! BB shell width tolerance after face milling must be:
    - 68mm shell = 67.25mm - 68.25mm*
    - 73mm shell = 72.25mm - 73.25mm*
    How many people do you suppose put calipers on their bb shell to ensure that it's within spec and that the bb will have the appropriate preload, and that the crank will be appropriately held together?

    https://www.raceface.com/products/de...ct-cinch-crank
    https://www.raceface.com/media/B1006...I_Crankset.pdf

    Sounds to me like you're only guesstimating if the crank bolt is tightened to spec, anyway. And yeah, you're right that interference fit cranks are pretty notorious for loosening up if not installed correctly. But unfortunately, if you ride a fatbike, that's the only choice you've got. So you better install them right the first time.

    What answer resolves the problem in OP's case will depend on exactly which parts are permitting play. Is it the crank bolt/spindle interface? Are the bearings wearing out? Was the crank installed with insufficient spacers at the start?

  12. #12
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    And you think a $25 bendy rod is providing an accurate torque measurement? Even RF use an educated guesstimate - see 1:32 and 3:50 https://youtu.be/NpSebuWLRi4?t=230

  13. #13
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    Quote Originally Posted by Haggis View Post
    And you think a $25 bendy rod is providing an accurate torque measurement? Even RF use an educated guesstimate - see 1:32 and 3:50 https://youtu.be/NpSebuWLRi4?t=230
    So you're saying you can ID 61Nm with your arm just as well as or better than a beam torque wrench?

    My Race Face cranks haven't loosened up on me at all when using my cheap torque wrench. They HAVE loosened up on me when I haven't used it, which tells me that my arms certainly are not calibrated very well at all.

  14. #14
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    I'm putting my money down on a person underestimating 61 Nm every time. The only time I had my Aeffect cranks get any kind of noise was when I didn't torque the bolt enough. Not that this has anything to do with the OP's issue, but it's also worth checking the torque on the Cinch ring. Before I had a torque wrench I under torqued that too. And yes, it's a beam style torque wrench.

    Torque on the crank bolt may or may not be contributing to the OP's problem, but it's at least worth considering and eliminating as a possible cause.

  15. #15
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    Could also be wallowed out splines on the crankarm. My affect crank did that to me. The arm now wobbles on the spindle regardless of installation torque. It can happen quickly if the arm comes loose and you don't catch it quickly (minutes tops). Arm is basically trashed at this point.

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