Why You Should Check Your Chainring Bolts

Check chainring bolts for tightness to avoid disaster on the trail

…So this doesn’t happen to you mid-ride.

While bike shops and warranty departments hate to hear it, this truly did happen while Just Riding Along (aka JRA). Coming around a corner, I put a mild amount of acceleration into my ride and instantly heard and felt a crunch. The bike came to an immediate stop. Looking down, I assumed the chain had simply fallen off or gotten jammed. It took a second to see what had really happened, and another few seconds to determine why.

Quite simply, one of the chainring bolts had apparently been missing for a while. Normally, having one bolt missing would lead to cyclical chain rub when at the extremes of the cassette with each pedal stroke. Whether it’s a testament to the stiffness of high end rings from SRAM (and, likely, other brands, too) or just weak legs, I don’t know, but I didn’t experience any early warnings until *POW* things went south quickly.

Upon inspection, I did find the second chainring bolt that had popped out and actually caused the small ring to fold under a (honestly) fairly light pedal stroke. When I finally pulled them off, both of the other two bolts were in various states of looseness, too…

Check chainring bolts for tightness to avoid disaster on the trail

The other two bolts weren’t quite as loose as the one shown here, but it was visibly loose to the point where I could rotate it with my fingers.

Check chainring bolts for tightness to avoid disaster on the trail

With cranksets like SRAM XX that uses two sets of bolts, one each for the big and little ring, tightening the bolts is easily done with a single allen wrench. If you don’t have a torque wrench, just do them until they’re snug. Otherwise check the manufacturer’s recommended settings and get them torqued properly.

Check chainring bolts for tightness to avoid disaster on the trail

If your crankset uses a single set of bolts for both rings, you’ll likely need a specialty tool like Park Tool’s Chain Nut Wrench. Thankfully, it’s one specialty tool that’s cheap, about $4 to $7. This tool holds the nut on the inside of the chainring still while you loosen/tighten the bolt with an allen wrench.

If this does happen, usually you can just put it onto the other chainring and get out of the trail. And who knows, you may just find out you’re perfectly fine with a single ring up front. Hooray, weight savings!


tom - 12/29/11 - 4:26pm

If I had a dollar for every time that happend to me I’d have no dollars!

uglyyeti - 12/29/11 - 4:51pm

Done that a few times after aluminum chainring bolts snapped – switched to ti bolts and no more problems.

bart - 12/29/11 - 5:34pm

And that is why it is important to check your bolts often. It only takes a minute to check them all before a ride and will save you money and keep you riding instead of walking.

dimples - 12/29/11 - 6:04pm

Or you could, you know…install them w/ blue loctite or beeswax and not have to check another component all that frequently.

Adam - 12/29/11 - 6:34pm

There should have been an annoying rattle before this ever occurred. Loose chainring bolts have a very distinct sound. Take warning….listen to our bicycles.

James - 12/29/11 - 6:44pm

“If you don’t have a torque wrench, just do them until they’re snug. Otherwise check the manufacturer’s recommended settings and get them torqued properly.”

What the hell does that even mean? Either do it up a little or torque it properly?? How many Nm to a snug?

Greg - 12/29/11 - 6:55pm

With all the buzz about the Amazon App, you might consider changing the link to the park tool website. Or how about your LBS. You know, anything else.

Robin - 12/29/11 - 7:49pm

You know it’s not JRA if a part fails because you were riding it while a bolt was missing or because you didn’t check.

chuck - 12/29/11 - 8:02pm

James, a snug is 3.2 Nm, or 28 in/lbs if you can’t find a metric torque wrench.

shop mechanic - 12/29/11 - 8:51pm

Yet another example of why I believe that Shimano parts are superior to Sram. Its nice to see that Shimano has some competition, but I won’t be spending my hard earned cash on Sram parts any time soon.

Matt - 12/29/11 - 10:19pm

Love my spiderless chainring setup every time I see this.

fabricio - 12/29/11 - 10:24pm

Same happen to me riding uphill, my alloy bolts exploited literally and the small chainring turnet to a eight figure. I had to break the chainring and keep running with the middle. Never will use again alloy bolts in the crankset. And this came with my 10v Race Face Chainrings when I swap in my SIXC 9v Cranks/Chainrings. Lesson learned, harder materials are better for high torque viewing parts.

Greg - 12/29/11 - 10:25pm

I have to chime in that I had a similar incident, but with my rear rotor bolts. (and of course, the day before a 24 hour race!) When my incident happened, it sheared the rotor bolt arms on my rear hub, effectively destroying it.

Locktite and torque-wrench, very important.

alloycowboy - 12/29/11 - 10:25pm

This is why a good winter tear down of your bicycle is invaluable for having a smooth riding bicycle for spring riding season. By the looks of Tyler’s bike it is due for a lot of TLC.

Scott - 12/30/11 - 1:43am

Congratulations, you’ve been SRAM’d.

MissedThePoint - 12/30/11 - 1:53am

I twisted a few chains from a granny ring coming loose, but I never mangled a chainring like that. I regularly check my XX crankset bolts, since they have a tendency to come out. The rings are stiff enough to hold up. The replacements have been behaving ever since I used blue Loc-Tite on them.

James - 12/30/11 - 4:37am

Chuck, you’re the man!!

dgaddis - 12/30/11 - 7:30am

I’ve done this to a steel Surly SS ring. After I got home I flattened out the taco hoping it would still be good to use, but no-go. It wasn’t round anymore, I couldn’t get more than two bolts in it. Lesson learned.

That Guy - 12/30/11 - 8:18am

Do you do any proofreading at all? This makes me want to kick puppies.

Tyler (Editor) - 12/30/11 - 9:12am

AlloyCowboy…um, I like to think of my dirty bike as “real world testing”.

FrenchPress - 12/30/11 - 10:19am

I did the same with my XX crank on a small rise. Took the other bolts out, big ringed it home and replaced the ring & bolts. Maybe I check those more often…

Sam - 12/30/11 - 8:29pm

I had a bolt fall out during a race once and had to pedal very delicately to the finish. It cost me at least two places. Ever since then, I’ve made it a habit to check those bolts regularly.

SteveB - 12/31/11 - 12:03pm

Had my small ring on my XX crankset do the same thing (though I stopped pedaling before I mangled the ring). My little ring sees very little use here in MI, and it happened the first time I had used it for more than a few min in a ride. not sure what the cause for that is.

Paul - 01/02/12 - 11:44pm

I did the same thing. I believe its a known issue with some early edition XX cranks. Sram sent me a completely new crank and chainrings for free.

Scott Hicks - 01/08/12 - 12:21pm

Personal responsibility people. If you don’t check for loose bolts and something goes wrong, how is that the manufacturer’s fault? “Known issue”?! Pffft! I’ve seen this happen with Shimano, SRAM, Ritchey, Bontrager and Sugino; probably other “JRA” incidents as well, but they have (blissfully) slipped from memory.

rhyspekt - 01/09/12 - 6:19am

yea failure to maintain ur bike properly doesn’t qualify as JRA unfortunately.

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