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I purchased a 50t Force 1 x-sync chainring. The SRAM install instructions say to place the hidden nut (thin item that has "teeth" on the outside that becomes "permanent" in the chainring once installed) on the hole marked "Crank here for hidden bolt". Unfortunately the chainring I have did not have this label on it so I put it in the wrong hole and only noticed later. I managed to knock it out again but it isn't really a part that is intended to be re-installed, so I want a new one.

I can't find anywhere that sells this part. I can't even find the part number in SRAM's parts catalog. Also, annoyingly, most chainrings seem to come with this nut already embedded in the chainring so this problem is not widespread (mine came in a bag along with the bolts and washers needed for the chainring). Its a super small thing - like 2 mm deep. Threaded on the inside, teeth on the outside that grip the hole edges. Seems like a terrible design because if those teeth fail the part will just spin along with the bolt and you'd never get the bolt off. There's no slot on it (like used on other chainrings) so using the special chainring bolt slot tool doesn't help.

Can anyone tell me what this part is formally called (ideally a part number), and possibly any place that will sell it? Even better - is there a superior alternative (preferable steel)?

42t chain ring with hidden bolt in correct spot.

42t and 50t side by side in same orientation.

50t chainring. Correct spot has slight rounded edges like the 42t ring. I accidentally put it one to the left.

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  • just for my own curiousity, would you mind posting some photos of this (both were you placed the nut originally and where it should be)? – Paul H Mar 24 '16 at 17:13
  • Will do - hopefully have them up here for you tonight. – WillyC Mar 24 '16 at 20:49
  • Ok - images added. Let me know if it is t clear. The correct location has slightly rounded edges at the bottom on the place with the bolt hole. Says "50t x-sync" on the 50t but says "Crank here for hidden bolt" on 42t - which is what Sram's documentation claims they should both say. – WillyC Mar 25 '16 at 16:53
  • ...oh and the spot I put the hidden bolt in was one hole counterclockwise to the correct hole. (One left of where it says "50t x-sync". ) – WillyC Mar 25 '16 at 17:30
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The official Sram part number is 11.6918.000.001 , those are said to work on the RED and FORCE models. That is the number for the hidden bolt set anyway. I also read that someone spoke to Quarq and they advised him to pop it out of the old ring and use it for his new ring which he also stated worked just fine, so you may save yourself $20.

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  • SRAM actually got back to me via Twitter and said it was part number 11.6218.017.000. Maybe the difference is for different years? Interesting that Quarq said it could be reused - maybe I'll give it a shot, it's just that the teeth on it look a little compressed and I can only imagine the nightmare if they fail and that part just starts spinning. – WillyC Feb 23 '16 at 17:55
  • Right on, I would go with what sram said in that case. Hopefully it works out for you. I thought it was interesting as well. it was in a review on amazon that I read it. Might be worth trying though and if it doesn't seem snug or safe order the new one. – Nate W Feb 23 '16 at 18:05
  • The fear isn't that I won't be able to get it snug - it's that if I want to swap out the chainring in the future I won't be able to remove the bolt. I'll probably just try it though and let future me deal with the consequences. – WillyC Feb 23 '16 at 18:08
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Don't use that hidden nut piece of garbage. Remove the spider (3 - T25 bolts) and you have access to all of the holes. Install the chainring and then re-install the spider. A couple extra steps but much better in the long run.

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