Oops, I think I stripped my chain ring bolts.
08-18-12, 12:27 AM
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Oops, I think I stripped my chain ring bolts.
At least one of them.
I was told, "tighten them up as tight as you can".
With my little pocket tool I managed to strip one of them
.
So, how much torque should I actually use on these things so I do not strip them?
I was told, "tighten them up as tight as you can".
With my little pocket tool I managed to strip one of them
.So, how much torque should I actually use on these things so I do not strip them?
08-18-12, 05:27 AM
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One of the polycarbonate bash guards I have specifies a max torque of -- I believe it is -- 40 inch pounds, which is about 5nm. Park Tool has a chart here showing a similar value for aluminum bolts and a somewhat higher max torque for steel:
https://www.parktool.com/blog/repair-...s-and-concepts
Are you certain you stripped the bolt? Sometimes they spin around in place if you don't have a second wrench to hold the backside while you unscrew the front side.
https://www.parktool.com/blog/repair-...s-and-concepts
Are you certain you stripped the bolt? Sometimes they spin around in place if you don't have a second wrench to hold the backside while you unscrew the front side.
08-18-12, 05:32 AM
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IMO Probably the back is turning, you really need to be a gorilla to strip one. Check out the back of the bolt and turn the front too, sure is turning all together. Bike manufacturers put 5nm for everything 
5 nm is a lot of torque anyways.
5 nm is a lot of torque anyways.
08-18-12, 07:55 AM
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It is possible to strip aluminum chainring bolts but it's fairly difficult. Steel chainring bolts are just about impossible to strip.
Odds are the bolt is OK, but the back is turning. This is very common which is why there are slots in the back to hold the nut side. If the screw is short enough you can hold the nut with an oversize screwdriver, and sometimes even with a dime held in pliers. But often the screw comes up high in the slot and you need a chainring nut tool.
Odds are the bolt is OK, but the back is turning. This is very common which is why there are slots in the back to hold the nut side. If the screw is short enough you can hold the nut with an oversize screwdriver, and sometimes even with a dime held in pliers. But often the screw comes up high in the slot and you need a chainring nut tool.
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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.
08-18-12, 09:34 AM
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I witnessed my friend, not a mechanic, snap one from over tightening, when he was trying to "help" me build his bike, I figured meh' chainring bolts he can handle that, WRONG.
*they were alloy*
*they were alloy*
08-18-12, 09:43 AM
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In any case, as I've said thousands of times, and you're friend has proven,
Nothing is foolproof, because fools are too ingenious.
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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.
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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.
08-18-12, 01:01 PM
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Yep, 100% sure I stripped one of them.
Going to the lbs today and get some steel bolts.
Going to the lbs today and get some steel bolts.
08-18-12, 01:59 PM
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See if you can pick up Shimano's TL-FC21 "Dust Cover and Ring Bolt Tool" to hold the back nuts still while removing and replacing the bolts. It's cheap and is the only tool I've found that really fits the nuts properly. Don't forget to grease the threads so they don't seize due to corrosion.
08-18-12, 02:51 PM
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Okay, looks like at least three were stripped.
Crappy aluminum bolts!
Replaced them with some origin8 steel bolts, so for so good.
Crappy aluminum bolts!
Replaced them with some origin8 steel bolts, so for so good.
08-19-12, 09:45 AM
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08-19-12, 11:05 AM
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Assuming you stripped the 3 CR bolts, how did you not immediately know that the two others were stripped? Was it the CR threads or the hex head that striped out?
08-19-12, 12:54 PM
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It was the threads, I was pretty sure three were stripped, but I refused to admit/believe it. Even to my self, nothing could be that weak.
08-19-12, 02:29 PM
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1. Those who have never used aluminum chain ring bolts/nuts
2. Those who have used them and had them fail.
3. Those who use them and will have them fail.
08-19-12, 02:41 PM
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Campagnolo and other OEMs have been using aluminum chainring bolts for years with no issues.
One of the keys is how the crank is built. On cranks where the chainrings are securely located and on shoulders in the crank arms alloy bolts work fine. However on cranks without such precise locating on shoulders, the bolts are the only thing resisting the tangential load of the chain. This makes the rings want to walk as the crank is rotated (you can often hear the creak) and the bolts have to be that much tighter to counter this. On these, aluminum bolts just won't cut it.
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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.
FB
Chain-L site
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.
08-19-12, 03:58 PM
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A harsh and unwarranted indictment.
Campagnolo and other OEMs have been using aluminum chainring bolts for years with no issues.
One of the keys is how the crank is built. On cranks where the chainrings are securely located and on shoulders in the crank arms alloy bolts work fine. However on cranks without such precise locating on shoulders, the bolts are the only thing resisting the tangential load of the chain. This makes the rings want to walk as the crank is rotated (you can often hear the creak) and the bolts have to be that much tighter to counter this. On these, aluminum bolts just won't cut it.
Campagnolo and other OEMs have been using aluminum chainring bolts for years with no issues.
One of the keys is how the crank is built. On cranks where the chainrings are securely located and on shoulders in the crank arms alloy bolts work fine. However on cranks without such precise locating on shoulders, the bolts are the only thing resisting the tangential load of the chain. This makes the rings want to walk as the crank is rotated (you can often hear the creak) and the bolts have to be that much tighter to counter this. On these, aluminum bolts just won't cut it.
I agree.
08-19-12, 08:11 PM
#19
mechanically sound
My set of steel truvativ chainring bolts with hex interface on bolt and nut are one of the best purchases I've made recently. Highly recommended.
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08-19-12, 10:08 PM
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08-20-12, 09:38 AM
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Came across those the other day, and I was like, OMFG WTF aren't they all like this, dammit!
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Sheldon Brown's bike info ~~~ Park Tools repair help
Half-step triple, using double gear ~~~ 6400 STI rebuild walkthrough ~~~ Want 8/9/10s @126mm OLD? OCR. ~~~ Shimano cassette body overhaul ~~~ Ergopower Escape wear repair ~~~ PSA: drivetrain wear
List of US/Canada bike co-ops ~~~ Global list
