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  1. #1
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    Chainring Bolts - Stainless vs Aluminum, / Locktite vs Lube

    What are the pros and cons of stainless steel and aluminum chain ring bolts?

    Which do you prefer and why?

    Do you Locktite your chainring bolts?

    Or do you lubricate your chaninring bolts?

    Or do you tighten your chainring bolts dry?

    And why or why not?


    Thanks for your opinions,

    Scott Novak

  2. #2
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    The pros of alloy is that they come in different colors and are about 20 grams lighter. The cons are that you can't torque them as tight and theoretically they may not be as strong, but I haven't seen a lot of problems with them other than people rounding them out with ill fitting wrenches. I think grease (or anti seize) is by far better than loctite or dry.

  3. #3
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    Aluminum does break there have been several posts about this on the tandem forums bikelist.org mailing list archives I recommend not using them on the smallest bolt circle. Locktite sticks to aluminum much harder than it does to stainless so use the lightest grade. Consider Wheelsmith spoke prep which has locktite with Teflon.
    "Dish is illogical." Spoke of Vulcan.

  4. #4
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    I went back to steel after striping several of the alloy single speed chainring bolts. I've found they're just too soft. I've found I don't need to locktite them, but then I take my rings off once a month to clean and make sure they are torqued properly.

  5. #5
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    Quote Originally Posted by hkenshin View Post
    I went back to steel after striping several of the alloy single speed chainring bolts. I've found they're just too soft. I've found I don't need to locktite them, but then I take my rings off once a month to clean and make sure they are torqued properly.
    Well that explains why aluminum doesn't work for you. Personally I can't see any advantage in taking a ring off for cleaning and I would never remove one except to replace it but yeah, if you're going to do that you better go steel.

  6. #6
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    Chainring Bolts - Stainless vs Aluminum, / Locktite vs Lube

    For single speed I use blue loctite with aluminum bolts. This is because I have had bolts back out, shear, and the ring fold.

    For gears I use grease because even if the bolts back out the ring is less likely to fold and even if it does you have a second or third ring to get home with.

    I always ride with extra bolts.

  7. #7
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    One of the first rules of threaded fasteners is NEVER use a bolt as a locating device! Of course this rule is violated more often than not and as a result many bolts come loose.

    When you use a bolt as a locating device, the side forces cause it to come loose. It's only a question of how soon before it comes loose. When you use a bolt as a locating device you need to make the bolt much larger and tighten it more and even use a threadlocker.

    Typically the small granny ring is just bolted on and the bolts are acting as locating devices with lots of side force as you pedal. No surprise if they comes loose.

    You could cure the problem by using a hollow pin that is press fit in to the crank body. The granny ring would slip over the hollow pins. Then drill and tap the hole deeper for the threads of a bolt that goes through the hollow pin to hold on the granny ring. You just need to make sure that the hollow pin does not protrude further than the thickness of the granny ring.

    The larger two rings on a triple crankset are held on by a fastener that isn't being used as a locating device per se. The outer barrel of the outer chainring bolt is basically a sleeve that the chainrings contact. Because the outer barrel is the locating device, you don't really need that much bolt tension to hold the chainrings in place.

    Also, most people don't know that not only does Loctite require the absence of air to cure, but it also requires the presence of certain metal ions to cure properly.

    Threadlocking User's Guide|Using Loctite Threadlockers - Henkel Using a Loctite Threadlocker

    Both stainless steel and aluminum are considered inactive metals. They require a primer to cure to full strength. Also, there are probably at least 20 different Loctite formulations for various purposes, from very mild holding power to so strong that you will break a bolt before removing it, unless you apply heat to degrade the Loctite.

    Scott Novak

  8. #8
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    Quote Originally Posted by Scott Novak View Post
    You could cure the problem by using a hollow pin that is press fit in to the crank body. The granny ring would slip over the hollow pins. Then drill and tap the hole deeper for the threads of a bolt that goes through the hollow pin to hold on the granny ring. You just need to make sure that the hollow pin does not protrude further than the thickness of the granny ring.

    Why complicate so simple a matter? Grease, (or use loctite if it eases your mind) torque, and ride. This is not a problematic area of a bicycle, I check mine now and then but they are always good to go.

  9. #9
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    J.B. Weld,

    Adroit Rider has already pointed out that he has had problems with the granny ring bolts coming loose and even carries spare bolts because of it.

    If you correct the problem you no longer have a need to check the bolt tightness of the granny ring. Not that you shouldn't check all of your bolts from time to time just be on the safe side.

    Bolt loosening is usually a sign of a design problem. Loctite should not generally be necessary. However, it is a quick and dirty fix for many design errors and design shortcuts.

    The single worst area on a bicycle where bolts are used for locating devices are the dropouts, when the manufacturer has been sloppy and the wheel doesn't bottom out in the dropout and line up centered between the chainstays. They tell you to adjust the wheel so it sits centered in the dropouts and then tighten the axle bolts. That is a copout for SLOPPY quality control!!!

    If you try to keep the wheel centered in the dropouts by the sheer clamping force, it's gonna come loose eventually! Not to mention that the quick release applies enough force on a hollow axle to actually reduce bearing clearances. Having to use extra clamping force to try to keep the wheel from coming loose makes the bearing situation even worse.

    After having my rear wheel come loose 3 times, I said enough is enough. I carefully cut and filed a metal insert to use in the dropout on one side so my rear wheel sat centered in the chainstays and then epoxied the metal insert in place. That was 3 years ago and the wheel has not come loose again and I barely need to use any clamping force to keep the wheel in place. Sometimes you can file one of the dropouts to center the wheel. But in my case filing one chainstay deeper would have set the wheel out of place for the brake pads. So an insert was required in the dropout.

    Scott Novak

  10. #10
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    I adjust my QR-hubs to have a bit of play when off the bike, and correct adjustment is achieved after tightening the QR when the wheel is installed on the bike.

    As for the topic, I haven't had trouble with aluminum chainring bolts. I grease the threads to increase clamping force for any given torque, so the bolts are not used as a locating device - the chainring is clamped against the spider hard enough to prevent any movement. Naturally the mating surfaces must be clean.

    I also use steel chainring bolts, I don't think the weight difference is significant. Grease on the threads here as well.

  11. #11
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    In one torque test that I performed, with a steel bolt screwed into aluminum threads, with the same torque applied to the bolt head, threads lubricated with copper anti-seize compound had about 19.5% more clamping force than dry threads. Using a synthetic lubricant would have resulted in an even high clamping force.

    I never bolt dry threads together. I either lubricate the threads, apply anti-sieze compound, or apply some Loctite formulation.

    I have been using medium strength Locite on the grannny ring bolts, but it's always a pain removing it.


    Saul Lumikko "I also use steel chainring bolts, I don't think the weight difference is significant."

    It's far more important for a guy to get rid of his spare tire before he worries about the heavier weight of steel chain ring bolts.

    Has anyone tried Chrome-Moly chainring bolts?

    Scott Novak

  12. #12
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    Quote Originally Posted by Scott Novak View Post
    The larger two rings on a triple crankset are held on by a fastener that isn't being used as a locating device per se. The outer barrel of the outer chainring bolt is basically a sleeve that the chainrings contact. Because the outer barrel is the locating device, you don't really need that much bolt tension to hold the chainrings in place.
    Old school M950 series XTR uses a sleeve & bolt for both the middle & small chainrings, with the big ring being part of the spider to which everything is mounted. It came with aluminum alloy bolts & sleeves, I never had a problem with them even though the fasteners were on the fragile side. Our shop mechanics broke a few bolts back in those days when were replacing chainrings on those cranks.

    On my personal bikes I use alloy fasteners on my XTR crank and grease them before putting them in. On my other bikes I went with alloy with for the big & middle ring and steel bolts for the granny so I can reef it down without rounding out the head or breaking it off. They get greased as well. With alloy bolts on the granny, it doesn't take long before I get creaking noises from the crank as the bolts either loosen themselves off or start to deform and fail.

  13. #13
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    aerius: "With alloy bolts on the granny, it doesn't take long before I get creaking noises from the crank as the bolts either loosen themselves off or start to deform and fail."

    And that is exactly my point. Because the granny ring bolts are being used to locate the granny ring you have to go to extraordinary measures to keep them from coming loose, such as using steel bolts and bolting them very tightly, and/or using Loctite.

    Bolts that loosen are usually the result of poor design.

    Scott Novak

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