Surly Chainring - Bent in Half???- Mtbr.com
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  1. #1
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    Surly Chainring - Bent in Half???

    I was riding my new niner sir9 for the fist ride today. 10 miles in I was going up a large hill and the whole crank lurched forward. I thought the bb had slipped or I threw the chain. I looked down to see that the whole chain ring had bent in half and dug into the frame unfortunately causing a large gouge. I also noticed the chain ring was missing one of the chainring bolts which I am assuming caused the failure - But still that chainring is stainless steel! Have you ever heard of this happening before?

  2. #2
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    Quote Originally Posted by shomes
    Have you ever heard of this happening before?
    Yep. Especially the 4-bolt versions of the Surly ring are prone to bending.
    Ride more!

  3. #3
    Out spokin'
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    Chainring bolts need to be greased, torqued and regularly checked. On two different rides I was on this week, riders suffered loose &/or missing ring bolts which caused them trouble. Each CR bolt carries a very heavy load. It only takes one missing bolt to cause a folded ring.

    Tangential mention: the bike industry did us all a disservice when it went from 5-arm to 4-arm crank spiders.

    --Sparty
    disciplesofdirt.org

    We don't quit riding because we get old.
    We get old because we quit riding.

  4. #4
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    Surly rings are SOOOOO SOFT! They bend so easily, i can see how missing only one bolt would cause this to happen.

    I ride with a bash guard because of how soft my Suly ring is.

  5. #5
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    I bent my surly ring for the 3rd time (in a few months) today. All 3 were enough of a bend between 2 bolts (on my 4 bolt crank) to throw the chain. Luckily all were trail repairable by bashing with a rock. At least steel is nice in that way.

    However I'll be buying a new ring and bash guard to replace my surly ring after today's incident.

    In a related note, I rode about 15 miles home with 2 crank bolts on my crosscheck the other day. By some stroke of luck the aluminum ring held up, even though my gearing required out of the saddle climbing. Take that for whatever it's worth.
    Stache 7 --- Rigid Surly 1x1 B+ --- Dirt Drop CrossCheck

  6. #6
    No, that's not phonetic
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    Quote Originally Posted by Slurry
    Surly rings are SOOOOO SOFT!
    Werd.

    I have used Surly SS rings a few times on dual ring setups and simple shifting can cause the chain to gouge a burr in a tooth that then causes chain suck or chain binding on the ring until I stop and file the offending spot down. It's freaking nuts that a solid steel ring would get deformed so easily. I have never had an alu ring do that. Even cheap Shimano steel rings never get whacked like that.
    My video techniques can be found in this thread.

  7. #7
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    Quote Originally Posted by tscheezy
    Werd.

    I have used Surly SS rings a few times on dual ring setups and simple shifting can cause the chain to gouge a burr in a tooth that then causes chain suck or chain binding on the ring until I stop and file the offending spot down. It's freaking nuts that a solid steel ring would get deformed so easily. I have never had an alu ring do that. Even cheap Shimano steel rings never get whacked like that.
    I could be wrong, but I believe Shimano, Truvativ, and others use CroMo for their steel rings, and CroMo is a much stronger steel. Not all steel is equal.

  8. #8
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    dont use aluminium chainring bolts. they FAIL early and OFTEN. recap, DONT USE ALUMINIUM. and uh, steel is real.

  9. #9
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    Seen it happen? I've done it! Now I always carry extra chainring bolts. I had broke a steel one. It happens. I also don't use that ring anymore.

  10. #10
    I'm gonna have to kill ya
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    Quote Originally Posted by thefuzzbl
    dont use aluminium chainring bolts. they FAIL early and OFTEN. recap, DONT USE ALUMINIUM. and uh, steel is real.
    Never used anything but and have never had a problem, With the amount of Ali bolts sold you would thick there would be thousands of failures all over the place My Chainset came with ali bots as standard!

    A correctly sizes Ali chainring bolt is extremely thick, in fact thicker than the surrounding Ali of the chain ring itself.

    If you have a loose one that is a whole different ball game, the twisting side shear forces and the lack of engaged threads will be more prone to failure than a steel one in the same situation but this is not the Bolts fault but lack of maintenance

    The only worry you should have about them is striping the peg spanner slots on the back

    just my opinion / experience

  11. #11
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    Quote Originally Posted by thefuzzbl
    dont use aluminium chainring bolts. they FAIL early and OFTEN. recap, DONT USE ALUMINIUM. and uh, steel is real.
    +1. I`m a 220lb rider and folded one using Aluminum Bolts. Luckily I didn't gouge the frame, just my leg. I only roll Salsa Rings with steel BMX type chainring bolts. Not saying those won't break either but so far, they`ve been pretty solid.

  12. #12
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    Quote Originally Posted by Sparticus
    ...Tangential mention: the bike industry did us all a disservice when it went from 5-arm to 4-arm crank spiders.

    --Sparty

    Word. This is exactly why I still rock 5 arm cranks on my SS.

  13. #13
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    Thanks for the replies. I know that the first cut is the deepest and all but too bad I could not make it through the first ride before the chainring ripped into the frame! Live and learn -

    I was using aluminum chainbolts which I know now is a big no no and will be riding steel from now on. I also noticed that one of the chainring bolts was missing - either by breaking or simply fell out. I am pretty sure they were all tight when I left so not sure which one was the cause. What I do know is that I will never take the chance of that happening again - Too bad because I always thought Surly stuff was bomb proof. In their defense if one of the bolts was missing I am sure that there was a tremendous amount of torque being applied without the proper support. I push 250 and was going up a pretty decent hill.

    From what I have read aluminum has more torsional strength than steel. Aluminum from now on with Steel bolts and small dab of locktite - At least it did not happen at iceman - That would have really sucked!

  14. #14
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    Last week on my 2nd night ride ever I had the exact same thing happen. Heard a creaking sound. Thought my EBB had started creaking. Started up hill. Seemed like my chain broke. Looked down & one bolt was missing. Surly ring was folded over leaving nice scratch in my frame. Now I am using stock ring & steel bolts with bashgaurd . With the ring I hide the scratches and use regular size steel bolts

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