Left crank arm fell off after 3 years
07-25-12, 07:27 AM
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Left crank arm fell off after 3 years
Good morning,
After 3 years of riding my left sided Rival crank arm fell off yesterday. I was able to re-install the crank arm and it seems to be ok, visually. I have not had a chance to ride since last night.
Is this a maintenance issue, or a sign of something being wrong with the crank? I emailed SRAM and I am waiting for a response. I don't wanna cause anymore damage, or get stuck while on a long ride.
After 3 years of riding my left sided Rival crank arm fell off yesterday. I was able to re-install the crank arm and it seems to be ok, visually. I have not had a chance to ride since last night.
Is this a maintenance issue, or a sign of something being wrong with the crank? I emailed SRAM and I am waiting for a response. I don't wanna cause anymore damage, or get stuck while on a long ride.
07-25-12, 08:51 AM
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Bolted on parts are not permanenty tight or adjusted. They all will flex, wear or vibrate loose, so need regular maintenance. If your bike had yearly tune-ups the crank arms should be tightened as part of that, but even that may not be enough. Loose crank arms often announce their state by creaking or clicking - any unusual noise from your bike should be investigated before it causes damage.
If you have not had tune-ups or yourself gone over every nut and bolt on the bike on a regular basis you need to do so now. The crank arm may come loose or off again. If it does then you need a new crank arm, and is not any kind of defect.
If you have not had tune-ups or yourself gone over every nut and bolt on the bike on a regular basis you need to do so now. The crank arm may come loose or off again. If it does then you need a new crank arm, and is not any kind of defect.
07-25-12, 09:38 AM
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Every good LBS should check every bolt on every tune-up. If you do your own work, check every bolt at least once a month if you ride 3 or more times a week. Most creaks can be silenced by tighten bolts. (see avatar)
07-25-12, 10:05 AM
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Once tightened properly and sometimes retightened once crank arms usually stay tight forever. But usually isn't always, and the owner has to have some responsibility for attending to regular maintenance.
I don't think crank arms need to be checked on a regular basis, but they don't magically fall off without plenty of warning. The retaining bolt would first have to loosen and eventually fall out. That means that the bike would be ridden with the bolt hanging out a fair distance nd that should be obvious unless you only ride at night. Also the cranks generally loosen before the bolt falls out, so you'll hear and maybe feel a vary telltale click with every revolution.
So, I'm sorry to har the crank fell off, but suspect you ignored warning signs for a long time, and therefore can't really blame anybody but yourself.
I don't think crank arms need to be checked on a regular basis, but they don't magically fall off without plenty of warning. The retaining bolt would first have to loosen and eventually fall out. That means that the bike would be ridden with the bolt hanging out a fair distance nd that should be obvious unless you only ride at night. Also the cranks generally loosen before the bolt falls out, so you'll hear and maybe feel a vary telltale click with every revolution.
So, I'm sorry to har the crank fell off, but suspect you ignored warning signs for a long time, and therefore can't really blame anybody but yourself.
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An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
07-25-12, 11:19 AM
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No warning at all, and the bike has had regular tune ups. I contacted SRAM and they are sending a replacement part.
Thanks for the advice.
Thanks for the advice.
