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Discussion Starter · #1 ·
On my ride this afternoon, I believe I bent my middle chain ring. I noticed a skipping and looked down, and saw that it looked like it was bent in one place. I moved to the 1st and 3rd chain rings, and they moved with no issue. When I moved back to the middle ring, the warped look and clicking came back. I'm new, so I hope I don't have to replace the entire front crankset. I assume they just sell the chain rings separately. Can anyone tell me how hard this will be to fix, time involved, and how much I can expect to spend? Also, is this something I should tackle on my own, or should I let a bike shop do the work? I'm supposed to ride with a guy from work tomorrow afternoon, so I need it fixed pretty quick, if possible. If it matters, I have straight SRAM x7 components, and my bike specs are listed below. Thanks for your help.

http://jamisbikes.com/usa/thebikes/pdfs/11_dragon29sport.pdf
 

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Mmm... Tasty
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That is a really nice looking bike!

As for the chainring - that sound could be a bent chainring or it could be a mis-adjusted front derailleur. While possible, the bent middle chainring is quite unlikely. Usually, chainrings only bend if they've been hit pretty hard (like smacking into a log with all your weight), and 95% of the time it is the outer chainring that gets bent. Now don't confuse the complex forming and shift ramps for a bent ring. This is a common misconception. Many of the bendy looking features are there to help the front chainrings shift better.

To check if it is indeed the chainring that is bent, shift to the granny ring and use the front derailleur as a straight edge reference to inspect the *teeth* of the middle chainring to see if they waver back and forth. Check the outer chainring while you are at it. This should take you no more than a couple minutes. If it is indeed bent, and adjustable wrench makes a fine tool to straighten out the offending bends.

To check if it is the derailleur making the sounds, prop the bike up to allow the rear wheel to spin and run through the whole rear cassette while in each of the front chainrings. The middle ring should not rub the derailleur for the whole cassette, the big rig should work with the smallest half, and the granny ring should work with the biggest half with no noise.

A bent chainring should be dealt with sooner rather than later. A mis adjust front derailleur can be nothing more than an annoyance, but should be made to work like it should at your convenience.

-Damon
 

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Discussion Starter · #3 ·
Thanks! I love the bike. It's a steel frame 29er hardtail, and it's a lot of fun to ride. I've only had it a few weeks, but I've tried to log as many miles as I can on it.

Tonight, I think I had a little more confidence and maybe got ahead of myself on my shifting. I was shifting both triggers and sped up quite a bit from my previous rides. However, after about 8 miles, I started hearing a small clicking, and then the chain started skipping on the middle ring. I looked at it again tonight, and it definitely looks like the middle chainring is bent. I didn't slam anything hard at all today, so I assume it's from my shifting. But, the bike is just a few weeks old, so it's not like it's seen a lot of abuse, and just broke. I'm kind of confused about it, but I'm running it by the LBS tomorrow to see what they say. From what I can tell, the middle chainring is $35 or so....so not too bad. I'm hoping that's all there is to it.
 

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Middle rings do bend. My son's MTB developed rear shifting problems and went through the obvious routine: adjust, lube, change chain, change cassette, change rear-derailleur. Nothing helped. The problem was a bend middle ring in the front. Once the ring was on the table, the warp was easy to see. And once a new ring was installed shifting worked great again.

So: possible.
 

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Discussion Starter · #5 ·
I attribute it to my newbie poor shifting style. When I took it into the shop, I got the same question from everyone there, including a friend of mine who met me there: "How the F did you break the one thing that's impossible to break on a hardtail?" I honestly think it was just shifting up too early, and shifting both the back and front simultaneously. I heard a "ching" sound a few times, which isn't representative of proper shifting, I'm sure. However, it was 5 or 6 miles later before I started having the problems. Good thing, though. At least I only had to granny gear it for a half mile, instead of 7 or 8 miles. That would have sucked.
 

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yes middle chainrings do bend due to improper shifting, or out of adjustment front der. since the bike is new the cable could have "stretched", actually its the housing compressing. so if you do not solve both of these problems and buy a new chainring, 35 dollars, you will most likely bend this one as well. most of the time you can bend the bent one back. you could try giving it a whack with hammer in the bent spot or put a large flat head screwdriver on the bent spot hitting the screwdriver with the hammer. if not comforable with this bring it to your lbs. another cause of bent look of a chainring could be a loose chainring bolt, probably not the case, but i would check anyway. as far as shifting goes when shifting from the inner(small ring) to middle ring try holding the lever until the chain goes completely on to the middle ring, then release, remembering not to apply to much force pedaling.if you you are having a hard time going from the middle to the inner(small ring) its usually a too much pedal force thing, try shifting before the hill, timing is everything with front shifting. hope this could be of some help
 
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