Creaking in the crank area, can't fix!

Discussion in 'Cycling Equipment' started by farangbish, Oct 23, 2016.

  1. farangbish

    farangbish New Member

    Joined:
    Oct 23, 2016
    Messages:
    4
    Likes Received:
    0
    I've been dealing with a creak for the past few weeks and I'm at the end of my troubleshooting knowledge. Bike is a 2009 Cervelo S3, cranks are 2012 Sram Red Exogram with GXP bottom bracket. Here's the gist of it so far. It's a creaking/clicking type sound at each crank rotation, more so just cruising along and not really when out of the saddle. It isn't bad when pedaling with one foot, either side. It is definitely coming from the crank area, but even so, I've dealt with alot of noises over the years, so I've gone through all the usual suspects and greased/tightened accordingly( cleats, pedals, derailleurs, cassette, seatpost/saddle, headset, chainring bolts) So originally, I took off the crank, and put alot of grease on it and cleaned the bb bearings and regreased, and they felt smooth. Next ride, everything sounds good for the first 30 min, then the noise comes back. Even though it didn't feel loose and I torqued it, I figured I didn't tighten down enough or overloaded with grease, so took the cranks off, removed some of the excess grease and tightened to the high end of the torque spec, which is pretty high with these cranks(478in/lbs). Same thing, about 30 min into next ride, noise comes back. Next i figured the bb was worn out because they did have about 5000miles on them, and the GXP bb's aren't known for being great. Even though it felt good without the cranks on, I figured maybe when everything is tight, that's when any defects in the bearings will show. So got a new bb, and splurged and bought the Sram ceramic GXP bb this time. Put everything together, and it's whisper quiet on my next ride. This time, it was quiet for about 3 hours of riding... then the same thing.. creaking came back. Maybe not as loud, but still there at each rotation. So that's where I'm at.. any thoughts?? Thanks.
     


  2. CAMPYBOB

    CAMPYBOB Well-Known Member

    Joined:
    Sep 12, 2005
    Messages:
    11,936
    Likes Received:
    1,032
    The disclaimer: I am not familiar with GXP BB's at all, but they do have some similarities to Campagnolo's UltraTorque cranksets / bottom brackets..

    Remove the chainrings after marking spider and rings for any index positions. Clean and grease up all contact surfaces between the spider and rings. Reassemble and wipe off excess grease.

    Are SRAM bearings press fitted into the cups or are they a just a 'fit' and removable with no tools being necessary? If just a fit or slip fit you can try to bond the bearings into the cup with something like Loctite 641 Bearing Retaining compound. I'll be honest with you here...from my experience even with bearings and cups cleaned with acetone and then allowed to cure for 72 hours after using the Loctite I could easily break the Retaining Compound loose with pedal pressure in just a few hours of use.

    As a guess you may need just a little more axial preload on the bearings. Is there any endplay in your current setup that you can feel or even suspect being present? You don't want to overload those new ceramic bearings, but a lot of the Campy UltraTorque BB ticking and creaking is attributable to too much endplay movement in the crank spindle and bearings inside the external cups. Add another plastic shim to the left side stack?

    Campy and SRAM both use wave washers in their BB's. The Campy wave washer has about a 20-pound spring rate and almost any rider can exert more side-to-side pressure on the spindle assembly, thus compressing the wave washer and causing the spindle to move axially in the bearings and/or the cups...causing ticking, knocking, creaking noises.

    Go after the chainring interface first. Then tackle the BB endplay.
     
  3. farangbish

    farangbish New Member

    Joined:
    Oct 23, 2016
    Messages:
    4
    Likes Received:
    0
    thanks for the response. yeah, I made sure the chainring bolts were tight, but I should try taking of the rings, cleaning and greasing bolts and contact points. The GXP BB I have is a thread fit. Doing some more reading, I probly could have greased these threads a bit more, as I didn't put to much on them. I also read that even when the cups are snug in the frame, some people having luck with teflon tape to take care of noises, so maybe I'll try that. I'm not super savvy on BB's, but I believe these BB's are not "pre-loaded", it is just the bolt on the non-drive side that gets tightened onto the axel. And as I mentioned, I torqued this down to the high end of spec, and it spins nice and doesn't come loose, no play in it even when it starts to creak. Regarding shims/spacers, my old sram red crank(replaced it with the new one last month) seemed to be a bit wider at the area that contacts the BB, with what looks almost like a 'built in spacer', compared to the new crank that seems narrower. I've searched alot on forums though, and the consensus seems to be for road bikes you don't need spacers with GXP BB's though.
     
  4. CAMPYBOB

    CAMPYBOB Well-Known Member

    Joined:
    Sep 12, 2005
    Messages:
    11,936
    Likes Received:
    1,032
    Can you put up a link to your model GXP crankset and BB. I probably pulled up the tech docs on an older version. It listed the same torque spec that you referenced though, so I figured it might be yours.

    That doc showed the wave washer, shim washers and the left side fixing bolt (with built in puller?).

    I've heard of all kinds of cures for cup/frame creaking, but I still think just a little grease on the threads and getting the cups tight is going to eliminate any shot at generating a creak there. I'm still more apt to believe creaking can originate between the cups and the bearings unless the bearings are a good press fit.
     
    steve likes this.
  5. farangbish

    farangbish New Member

    Joined:
    Oct 23, 2016
    Messages:
    4
    Likes Received:
    0
    https://www.sram.com/sram/road/products/sram-red-crankset-10-speed
    Here's the link for the crankset, at the bottom, the first document in the 'service' section, shows my GXP BB on page 16. No washers for this bb.
    Haven't been out on a ride yet, hopefully tomorrow, after I put either more grease and/or teflon tape on the bb threads. By the way, I've got a torque wrench for the crank, so I know that is good, but for the BB, don't have a torque wrench, just tightening nice and firm.
     
  6. CAMPYBOB

    CAMPYBOB Well-Known Member

    Joined:
    Sep 12, 2005
    Messages:
    11,936
    Likes Received:
    1,032
    Yeah...carbon spider same as my Campagnolo. Smear heavy bearing grease all over the surfaces that contact the chainrings and the counterbored holes in the rings that seat the bolts.

    My rings had a film of black carbon on them from the spider flexing and rubbing slightly against the spider surfaces.

    The service manual references the shim washers I talked about in my reply above. You may need an additional shim or two to remove axial play in the spindle/bearing assembly. This is a known source of noise (specifically creaking/knocking/ticking) with Campagnolo wave washer preloaded designs. I would assume SRAM's design to be similarly plagued by noises.

    If there is play in the crankset, remove the crank arms and apply additional grease to the spindle. Repeat the installation procedure until play is eliminated.

    For the integrated spider version:

    If there is play in the crankset, remove the crank arms and apply additional grease to the spindle. Repeat the installation procedure until play is eliminated. Adjustments to the number of shims used may be required.

    I would think the preload collar or additional shims would silence the creaking, depending on which features your GXP crankset has. I can NOT see adding additional grease doing much of anything permanent as far as not or too much axial play is concerned.

    Again, in case you have not yet done so, please do grease your chainring/spider interface surfaces first of all. Then go after the spindle clearance issue if there is one. Eliminate the easy sources of noise first. I found out even tight spider bolts will still creak. The grease silenced mine.

    Good luck and do report back what you find. Noises are maddening and other rider may benefit from your research and wrenching.
     
Loading...
Loading...