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Old 08-18-12, 12:27 AM   #1
ben4345
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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?
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Old 08-18-12, 05:27 AM   #2
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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:

http://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.
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Old 08-18-12, 05:32 AM   #3
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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.
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Old 08-18-12, 07:55 AM   #4
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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.
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Old 08-18-12, 09:34 AM   #5
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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*
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Old 08-18-12, 09:43 AM   #6
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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*
Yes the alloy ones are more prone to cracking than the steel ones, but for both stripping is difficult because either the flange breaks off, or the hex rounds out first.

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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Old 08-18-12, 01:01 PM   #7
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Yep, 100% sure I stripped one of them.
Going to the lbs today and get some steel bolts.
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Old 08-18-12, 01:08 PM   #8
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+100000000000000000000000000000x10^99999999999999999999999999999999999999999999999999999999999999999 99999999999999999999

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Nothing is foolproof, because fools are too ingenious.
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Old 08-18-12, 01:27 PM   #9
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Without a chainguard, 60 Inch-pounds, which is not much. bk
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Old 08-18-12, 01:59 PM   #10
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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.
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Old 08-18-12, 02:51 PM   #11
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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.
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Old 08-18-12, 02:57 PM   #12
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Remember you are working with a bike not a darn tank next time you want to crank bolts in your bike

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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.
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Old 08-19-12, 09:45 AM   #13
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Originally Posted by ben4345 View Post
Okay, looks like at least three were stripped.

Crappy aluminum bolts!

Replaced them with some origin8 steel bolts, so for so good.
The problem wasn't the bolts. It was you.
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Old 08-19-12, 11:05 AM   #14
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Originally Posted by ben4345 View Post
Okay, looks like at least three were stripped.

Crappy aluminum bolts!

Replaced them with some origin8 steel bolts, so for so good.
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?
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Old 08-19-12, 12:54 PM   #15
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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?
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.
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Old 08-19-12, 02:29 PM   #16
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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.
Much like sunblock, aluminum bolts are for fools and cowards. Seriously, there are three types of cyclists.
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.
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Old 08-19-12, 02:41 PM   #17
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Much like sunblock, aluminum bolts are for fools and cowards. Seriously, there are three types of cyclists.
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.
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.
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Old 08-19-12, 03:58 PM   #18
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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.
^^

I agree.
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Old 08-19-12, 08:11 PM   #19
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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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Old 08-19-12, 10:08 PM   #20
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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.
Oh now you tell me!
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Old 08-20-12, 09:38 AM   #21
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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.
Came across those the other day, and I was like, OMFG WTF aren't they all like this, dammit!
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