A good reason to always use steel chainring bolts- Mtbr.com
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  1. #1
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    A good reason to always use steel chainring bolts


  2. #2
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    I don't think your failure was caused by aluminum ring bolts. More than likely they came loose and caused the problem. Looks nasty hopefully you didn't land on your head.
    Ride, Race or just polish it.... Do it till you smile!

  3. #3
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    i popped two sets of aluminum bolts, why I bought another after the first incident i don't know.
    I just ordered a set of Ti bolts that are hopefully "hammer" proof from these guys:http://www.jerseycycles.com/Product-Pages/Titanium.html
    "If women don't find handsome , they should at least find you handy."-Red Green

  4. #4
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    Yeah, not the first time I've had aluminum bolts shear. It's just that I just got this setup off eBay and the bolts were a pretty RED so I didn't swap them out. Duh... haven't I learned this lesson before?

    Just my second day on this setup. I did check the tightness just yesterday. Still, I guess they could have come loose. I've lost a steel bolt more than once, and have still been able to ride home. Never had anything catastrophic like this happen before. I don't use lock-tite on them anymore. Just a little grease seems to snug them up real well.

  5. #5
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    i only use steel bolts to avoid this very situation.

  6. #6
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    Chainring bolts, by design, have a built in stress riser, and that combined with the added stress of chain ring torque makes aluminum or titanium a poor choice over steel. When it comes to sharp edged stress riser points such as the lip around a chain ring bolt, Alu. and Ti. fail in pretty much the exact same fashion.
    PoisonDogFart

  7. #7
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    Wow, lucky you didn't break a arm off the spider. The crank looks like one of my modified 960's with a HBC ring. I use Shimano's steel bolts from the granny rings with alloy nuts but include 4 XTR alloy bolts for those who wish to save 7g and take a chance of a failure such as this. Be glad you weren't injured.

  8. #8
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    One steel chainring bolt on an aluminium chainring got me through about 50kms of a 100km race. Guess I had a good chainline.

    I use loctite now.

    I see hills.

    I want to climb them.

  9. #9
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    I've broken cheap no name alloy chainring bolts. If you buy higher end bolts they work well, at least I have never broke one.
    OB1 Kielbasa

    One is good!

  10. #10
    120
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    I went through this recently as well. Never had a problem with ti bolts...yet. Chain derailed on every climb until I sorta fixed it.





  11. #11
    master blaster
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    ^^
    nicely done

  12. #12
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    Never broken any chain ring bolt or had one break on a customer's bike that I handled for that matter. I really think that set up and installation are the cause of most broken chain ring bolts. I started using thread locker when I was 16 though and I wish cranks still came with those brass washers, but the gram or so those paper thin washer's weigh is too much for... someone, I guess.
    BBI certified, 12+ years as mechanic

  13. #13
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    the problem with the m960's and most xtr's for that matter is that there is no lip for the chainring to center on like stevob's and 120's (and 95% of other) cranks have. so when the bolts are missing, the chainring is allowed to flex until it breaks, instead of stopping when it hits the lip. It's no problem at all as long as your bolts are tight and in place, but it is a slight downside to these otherwise awesome cranks. Like crazy8 said, it's fortunate that the ears of the crank didnt break off, we've seen that before.

  14. #14
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    Quote Originally Posted by Stevob
    One steel chainring bolt on an aluminium chainring got me through about 50kms of a 100km race. Guess I had a good chainline.

    I use loctite now.

    yea, good chainline for sure!
    that happened to me on my cross bike (36t 5x110bcd). I kept hearing this noise and never stopped to think about it. When i got to a point where i was waiting for a friend, i looked down and noticed it and nursed it back to the car. I cant believe i didnt taco it, any bit of side pressure probably would have done it, especially a ring that big.
    I had just made that chainring, and i rushed to get it on the crank before the ride. I guess i didnt do such a good job tightening the bolts!

    btw, is that chain a k810-sl?

  15. #15
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    Quote Originally Posted by ISuckAtRiding
    btw, is that chain a k810-sl?
    KMC 710SL I think. Back then I'd just started using the Kickass cog which is 1/8
    I see hills.

    I want to climb them.

  16. #16
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    Quote Originally Posted by Stevob
    KMC 710SL I think. Back then I'd just started using the Kickass cog which is 1/8
    sounds about right, it just looked like a 3/32" in the pic. the 810's are a bit rare which is why i asked.

  17. #17
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    That chainring is 3/32", but the cog is 1/8". I've since ordered a custom 1/8" 33t chainring from Cycle Underground here in Oz.
    I see hills.

    I want to climb them.

  18. #18
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    sans chainring bolts.....
    Attached Thumbnails Attached Thumbnails A good reason to always use steel chainring bolts-oct-17-2010-first-rain-ride-029.jpg  


  19. #19
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    I've never found it necessary to use thread lock on ring bolts, but I always dress them with a touch of anti-seize that will lubricate the threads. I believe it helps to achieve a more accurate torque. On a SS set-up using steel bolts and alloy nuts I torque to 95 in/lb which is the high end of specs, but they won't be loosening.

    I didn't read anyone say anything about over torquing alloy bolts which I'm sure many do trying to be sure they don't want them to loosen. The added stress can over stretch and weaken the bolt and not be noticed until the head pops off. If installing a ring without the aid of a torque wrench then I'd stick to steel only..

  20. #20
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    Quote Originally Posted by crazy8
    I didn't read anyone say anything about over torquing alloy bolts which I'm sure many do trying to be sure they don't want them to loosen. The added stress can over stretch and weaken the bolt and not be noticed until the head pops off. If installing a ring without the aid of a torque wrench then I'd stick to steel only..
    very true, i cracked one the other day, and lost another on the ride, which i think was due to it cracking. I was in a hurry, as always.

    whatever you do seems to work, mine held pretty good till i changed rings and the above happened.

  21. #21
    All 26.5" all the time!
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    Chalk me up for only using steel chainring hardware.


  22. #22
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    repetitive post
    Last edited by crazy8; 11-22-2010 at 07:50 AM.

  23. #23
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    Quote Originally Posted by Zanetti
    Chalk me up for only using steel chainring hardware.

    man, what did you do to mangle that stainless steel chain ring and the aluminum spider?
    looks like it exploded or sumpthin!

  24. #24
    All 26.5" all the time!
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    Not my photo, but just an example of what can happen if just one chainring bolt lets loose.

  25. #25
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    I've lost, but never broken a chainring bolt, now I use beeswax on the threads and they have stayed secure.

  26. #26
    Dirty South Underdog
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    I've used steel ever since I broke an aluminum chainring bolt while using a torque wrench to make sure I didn't break one.
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  27. #27
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    Quote Originally Posted by stubecontinued
    I've lost, but never broken a chainring bolt, now I use beeswax on the threads and they have stayed secure.
    I'm conducting an experiment with my chainring bolt lube. My crank's got a 5-arm spider. One bolt has Chamois Butt'r, one has blackberry jam, one has KY Jelly, one has shaving cream and the final one has Herradura Anejo. We'll see which works best.

    --sParty

    P.S. Report so far... the KY was most fun to apply.
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  28. #28
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    Quote Originally Posted by crazy8
    I've never found it necessary to use thread lock on ring bolts, but I always dress them with a touch of anti-seize that will lubricate the threads. I believe it helps to achieve a more accurate torque. On a SS set-up using steel bolts and alloy nuts I torque to 95 in/lb which is the high end of specs, but they won't be loosening.

    I didn't read anyone say anything about over torquing alloy bolts which I'm sure many do trying to be sure they don't want them to loosen. The added stress can over stretch and weaken the bolt and not be noticed until the head pops off. If installing a ring without the aid of a torque wrench then I'd stick to steel only..
    What's the torque spec for alloy bolt w/ alloy nut?

  29. #29
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    In case anyone's wondering why someone would use aluminum chainring bolts in the first place, it's because they come in colors. Anyone using them to save weight is an absolute moron!
    PoisonDogFart

  30. #30
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    I have been having problems with the longer truvativ chainring bolts falling out as i ride and sometimes they are stripped and can not be tightened. Should i be using some locktight or try something else?

  31. #31
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    Quote Originally Posted by Zanetti
    Chalk me up for only using steel chainring hardware.

    previously documented problem- race face turbines with no bolt in the granny gear holes.
    nothing to do with which bolts were used on the chainring, but rather the fact that without the bolts in the granny ring mount the crank fractures through the granny boltholes.

    suggest isar make RF turbine specific single speed rings that use both sets of boltholes for max strengthening/stiffening!!
    If steel is real then aluminium is supercallafragiliniun!

  32. #32
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    Looking at that ring, it's obviously a combination of losing the chainring bolt, nothing in the granny holes and no lip on the crank (like there is in the outer ring position) to keep the chainring in place.

    You can see exactly how it happened. Chainring bolt lost, plasticine chainring bends under max torque and puts a twisting torque on the following spider arm.

    Poor engineering design IMO.
    I see hills.

    I want to climb them.

  33. #33
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    might be the case here, my point was that that happens to old turbines regardless of the missing chainring bolts.
    have to keep those granny bolts in there too!
    If steel is real then aluminium is supercallafragiliniun!

  34. #34
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    Wishing everyone a Happy Thanksgiving.
    Last edited by crazy8; 11-24-2010 at 12:41 PM.

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