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nearly avoided a disaster(18 posts)

nearly avoided a disasterRideLots
Apr 2, 2002 3:36 PM
I'm an idiot sometimes, and thought I'd share this to maybe save someone else a disaster.

A buddy and I did a long ride. The last 50 miles, my rear derailleur was shifting like crap (Record 10). It was shifting by itself, making noise, and not shifting when I told it to. I pressed on, griping about it, and attributing it to some muck we went through earlier.

My buddy stops to pee about 5 miles from home. I shift down to stop, and the rear makes an awful noise. I look down, and something just doesn't seem right. Closer inspection reveals a pulley bolt hanging halfway out, and the chain at this point had worked itself around the upper pulley. Another 10 feet and I may have trashed the derailleur and lost the bolt.

Lady luck was smiling on me that day. The lesson is, if something doesn't seem right, by all means stop and look at it. Don't assume.

Lesson 2: Loctite.
Good advice, butKerry
Apr 2, 2002 4:26 PM
Loctite is a crutch. Despite 30 years of annual total teardowns (everything that can be taken apart is taken apart), bolts don't loosen and things don't fall off my bike. Proper bolt tightening and routine checks of the bike prevent such disintegrations. There is no spontaneous process that loosens properly tightened bolts on a bicycle.
Good advice, butRideLots
Apr 2, 2002 4:34 PM
Any reason not to do it, though? I'm talking about the medium strength stuff.
You makes your choicesKerry
Apr 2, 2002 5:50 PM
I think that Loctite makes truing wheels a pain, as it tends to significantly increase spoke windup after the wheels are a couple of years old. Also, since it is not as good a lubricant as grease, it makes it harder to get the proper tightness. With age, it can get pretty stiff and then confuse you about how much torque is required to take things apart. You're right though, it is a better choice than having things come apart. I simply find that it's not needed.
I call BS!grzy
Apr 2, 2002 6:57 PM
Stuff loosens if you actually use it. A few solid examples:

1. Mavic Ksyrium spoke nipples need loctite or they will unthread due to the spoke pitch.
2. Just about every self respecting disc brake mfr. supplies pre-loctited bolts to attach the rotor to the hub.
3. Shimano makes ample use of thread locking compounds to hold the tiny screws in place on many mechanisms
4. Phil Wood used to supply little tubes of loctite with their BB's (circa 1980).
5. Many wheel builders use linseed oil as a form of loctite to keep the nipples from backing off.

You obviously haven't spent much time around machinery subject to stress, vibration and hard use - airplanes, cars, motorcycles, trucks, boats, and, yes, bicycles often rely on loctite, castle nuts, lock nuts, lock washers, and siezing wire to keep nuts and bolts in place least they come loose and cause a disaster. Your STI shifters wouldn't function very long without loctite. In fact, Shimano leaving loctit off the Ultegra STi shifters results in a small screw backing out and the levers failing.

It all comes down to vibration, frequency response, and the insight of the designer of the component. You can fawn over your bike every night and tighten the bits that routinely come loose and never ride 11 miles on a dirt road. Or you can use a dab of loctite where needed and keep riding.
I call BS!gtx
Apr 2, 2002 9:25 PM
I've never used loctite for anything bike related except crown races that didn't seat perfectly or bolts for fenders. In general I think that anything that is designed and torqued properly on a bike shouldn't require loctite. Of course if a manufacturer uses loctite somewhere to begin with that's fine--anything brake related is an obvious example. I just don't see much of a need to go adding it where it isn't already.
I call BS!grzy
Apr 3, 2002 10:35 AM
So you do use loctite. Problem is that not everything ever made for bikes has been properly designed and tested.

Ever hear about the guy that wore a belt and suspenders?
Apr 3, 2002 2:09 PM
"I just don't see much of a need to go adding it where it isn't already."

One word: insurance. If the use of something as simple and cheap as Loctite can help to avoid a malfunction, why the heck not use it? Other than getting sloppy with it and fowling something up, I can't think of any downside. I don't think that a philosophical objection to using it is good enough, but that's just me; the next time you have a bolt loosen up and spoil a ride, at least your conscience will be clear, though. :-)
Call BS if you like.Kerry
Apr 3, 2002 5:25 PM
My experience is about 200K miles on bikes, spread over 305 years, which have never used Loctite on any thread. Things have not loosened up for me, including spokes on the wheels I've built. I understand that intense vibration from engines can wiggle things loose. I'm talking about my bikes.
It's a fact Jack.grzy
Apr 3, 2002 5:59 PM
You started by saying that loctite had no business on any bike ever. Since then you've basicly back pedaled down to just your bike, and made allowances for designers and certain things. You called it a crutch - does that mean that lock nuts and lock washers are canes?

You can obsessively check every bolt all the time and be totally sure, but given enough time things loosen up from the road vibration. There is a whole vast segment of the biking population that doesn't work on their own bike and only take them into the shop when something falls off. Given that they may be using crappy components for things they weren't really designed for are you going to just replace the bolt with the same thing and have it fall off again? You can't replace a spoke on a Ksyrium without it. You can't totally rebuild an STI shifter either. Same is true for an XT/XTR Vee brake or the rotor bolts on a disc brake. I can assure you you'll be buying some or making use of the supplied stuff.

I too have been working on bikes for 30+ years and haven't really used loctite until recently - when some of the super light and often ill-conceived mechanisms start to come apart under long and demanding rides. The problem gets a whole lot more critical on MTB's deep in the woods.
loctite good...losing bolt in woods bad!merckx56
Apr 3, 2002 6:30 PM
you are absolutely right. on the new superlight stuff, the bolts come with a sort of loctite on them already! if it's small, relatively important and fragile, and will strand you if lost, loctite the bitch!
Why linseed oil?Stampertje
Apr 5, 2002 4:25 AM
What different characteristics does linseed oil have compared to other vegetable oils (corn, sunflower, rapeseed...)?
Why linseed oil?grzy
Apr 5, 2002 9:29 AM
Not sure exactly, but the stuff tends to quickly dry out a bit and become semi-sticky. Maybe the difference is that the linseed oil isn't as likely to spoil and attact bacteria and the like. Linseed oil is often used as a preservative and a finish for wood products. It's advised in several refernces like the UBI/DT wheel building manual and, if memory serves me right, Brandt's book. I can't remember what The Art of Wheel Building advises and it's not handy. DT also makes nipples that have a nylon locking washer inside them if you want an alternative.
Why linseed oil?curlybike
Apr 5, 2002 1:55 PM
Linseed oil dries to a real draggy goo that helps keep stuff from loosening. Art of Wheel buildig suggests the DT loctite special formula .Alpina has the nipples with the plastic, Dt has a loctite pill.
Why linseed oil?grzy
Apr 5, 2002 3:35 PM
I've seen the DT nipples at the DT booth at the Sea Otter Classic last year - aren't these made by them? They certainly had glossy marketing literature.
Why linseed oil?curlybike
Apr 6, 2002 7:19 AM
The stuff in the DT nipples are a Loctite product as is their Spoke Freeze. They are called Pro-Lock. Alpina has a plastic insert, that said, loctite does change to a plastic solid after curing. So, that may be a confusing factor.
Why linseed oil?grzy
Apr 8, 2002 2:19 PM
Naw, the rep-guy was showing me their spoke with a nylock type of insert incorporated (just like an aircraft nut) - it may never have made it to market. I wasn't simply a pre-loctited nipple that utilized the heat from fiction to set it off.
Apr 2, 2002 8:13 PM
I put a pully on a Chorus Der and used too much Locktite. The stuff wicked into the shaft part and froze up the pully. Very bad juju

It's great stuff when used properly. ;)