cracked jockey wheels - Ultegra R8000

I recently noticed my jockey wheels have small cracks radiating out from the centre. Both pulleys, similar size cracks. They are on a Ultegra R8000 mech with about 8000km on them. I haven't seen anything like this before. I suspect they weren't about to fail anytime soon and it did not stop me from riding the next day. But I did manage to find replacements (the same). It'll be interesting to see how the new ones hold up.
I can't find any examples of this online (at least in the last few years). Anyone seen this? Otherwise they have lots of life left. I don't think I had ever removed them from the RD for cleaning. I do have a habit of staying in my big chainring unless it is big/big - perhaps that loads them up a bit more than typical. By comparison, my XT M8000 drivetrain is well worn, the T pulley is well on its way to being a disc, and they are otherwise fine. Interestingly, the Shimano website lists R8000 jockey wheels as being compatible with mtb rear mechs, but not the other way around - perhaps an oversight on the spec sheet.

Any thoughts on the cracks?


Comments

  • dj58
    dj58 Posts: 2,224
    Could be a material defect affecting a batch or just a one off. I suppose only time will tell if this happens to other owners and reports are made indicating te scale of the problem, if any?
  • MattFalle
    MattFalle Posts: 11,644
    Ultegra, eh....
    .
    The camera down the willy isn't anything like as bad as it sounds.
  • ibr17xvii
    ibr17xvii Posts: 1,065
    MattFalle said:

    Ultegra, eh....


    Are the DA any better though?
  • MattFalle
    MattFalle Posts: 11,644
    edited May 2021
    Yup. Loads. You should try them.
    .
    The camera down the willy isn't anything like as bad as it sounds.
  • ibr17xvii
    ibr17xvii Posts: 1,065
    MattFalle said:

    Yup. Loads. You should try them.


    I'm on the verge of needing some new jockey wheels for my winter bike that currently have 105 & was gonna get some Ultegra which I know will horrify you but the 105 never seem to last that long, for me anyway.

    DA seems a bit overkill for a winter bike though.

    What makes them better?
  • andyrr
    andyrr Posts: 1,823
    ibr17xvii said:

    MattFalle said:

    Ultegra, eh....


    Are the DA any better though?
    'Cos Ultegra's what them #clubbees use and them is muppets. Obvs.
  • far_from_home
    far_from_home Posts: 7
    edited May 2021
    dj58 said:

    Could be a material defect affecting a batch or just a one off. I suppose only time will tell if this happens to other owners and reports are made indicating te scale of the problem, if any?

    I did wonder about it being a material defect. Though that presumably requires that both came from the same batch of material/ manufacturing run. I suppose that is possible.
  • veronese68
    veronese68 Posts: 27,866
    Why have you started a new thread about this?
  • Why have you started a new thread about this?

    Yes, sorry... by mistake. The original still sits in drafts and I thought I had never successfully posted it. Once I found my live thread there didn’t seem to be much I could do to prevent the other one going live. Newbie mistake using this forum.
  • veronese68
    veronese68 Posts: 27,866

    Why have you started a new thread about this?

    Yes, sorry... by mistake. The original still sits in drafts and I thought I had never successfully posted it. Once I found my live thread there didn’t seem to be much I could do to prevent the other one going live. Newbie mistake using this forum.
    Ah, thought it odd. Something weird with the forum software i think. If you save a draft it stays there even if you post it.