Tech Tuesday - Thread locker Basics

Aug 23, 2011 at 0:02
Aug 23, 2011
by Mike Levy  
 
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The 411 on thread locker: Thread locking compounds, sometimes referred to as 'Loctite' despite it being a brand name, is an adhesive that can be applied to the threads of a fastener to keep it from loosening over time from vibration or shifting parts. This is especially useful on smaller bolts that require a relatively low torque such as rotor bolts, but can be put to use anywhere that a bolt can repeatedly loosen even though it has been properly torqued. Lubricating a fastener with grease, the swear-by for cycling mechanics, is done to allow a bolt or nut to be precisely torqued, and to ease removal down the road. Grease and thread locking compounds should never be mixed. While there are other ways to keep bolts from coming loose - cotter pins, lock washers and even safety wire - none of those methods are suitable for use on our expensive and lightweight mountain bikes. Thread locking compound is a thixotropic fluid, which means that its properties change under certain circumstances. For most types of thread locker, especially the blue colored version that is used on bicycle parts, this refers to a lack of oxygen that allows the fluid to set once the fastener has been tightened down to the correct torque. It is best to allow the locking compound a full 24 hours to fully set, although it will dry sooner than that.


n a
Thread locking compound is available in both a stick (left) and liquid (right) compound, and is used to keep bolts from backing off. It can be used in a number of places, including brake caliper and rotor bolts, or can come in especially handy on places like stem bolts if you spend your days doing hot laps in the bike park and want to keep your rig running safe.


Blue is your friend: Medium strength Loctite is most often blue in color and can be used on many places on a mountain bike to keep bolts from coming loose. It is thought of as being 'removable' in that it shouldn't require excessive leverage or heat to break free, and requires roughly 115 in/lb of torque to loosen a typical bike-part fastener. It is available in a squeeze bottle with a needle tip that allows you to apply it only where needed, but it can also be bought in a tube, similar to a glue stick, that is great for applying to places where you don't want it to run onto other surfaces (lever reach adjustment screws being a perfect example). Blue thread lock is ideally used on any steel fastener that has repeatedly loosened despite having having been tightened to the recommended torque. Safety is a primary reason for thread locking compounds, and international standards specify that brake rotor and caliper mounting hardware are treated with it so there is little if any chance of an improperly torqued fitting rattling loose. Same goes for shock mountain hardware or any threaded fitting on a rotating part. Thread locking compound is also the go-to for press-in or threaded parts that tend to develop creaks over time (a touch of blue thread locker on some clean BB threads, for example).


What not to use: Thread locker is available in different compounds and strengths that are usually color coded, although most are not suitable for use on a bike: red thread locker requires 230 in/lb to loosen and should be thought of as permanent, meaning that it will likely require a large leverage tool to remove the bolt. There is really no reason to be using the red colored compound anywhere on your bike. Green thread locker is best at penetrating into nooks and crannies, and can be used to hold sealed bearings in place (being careful to not get anywhere near the rubber seal) if the bearing bore is oversized. The green compound needs roughly 90 in/lb to crack lose, and should be used very sparingly.


n a
Start by removing the trouble making bolt and giving it a thorough cleaning with an alcohol based spray, being sure to remove any old grease or grime. Do the same to the threads that accept the bolt, using a Q-tip if needed to clean it properly. Let it air dry and take a minute to inspect the bolt's threads for damage or stretching that may have been caused by over tightening.
n a
Apply a small amount, usually just one drop, to the threads on the bolt. There is no need to go overboard, too much will only make a mess.
n a
Thread the bolt back in, tightening it to the specified torque. Wipe away any excess thread locker that may be present. It is recommended to let the bike sit for 24 hours before riding to allow the compound to fully set.


Where to not use thread locker: Although blue thread locker can be put to use on many places, there are some where it shouldn't be applied. It should be avoided when working with titanium bolts, especially when they are being threaded into a dissimilar metal, such as steel or aluminum. Anti-seize is your best bet here because it will prevent galvanization, allowing you to easily remove the fastener down the road. We would also recommend that you skip using Loctite on aluminum bolts as well for the same reason, but it can also make removing fragile aluminum hardware difficult, leading to rounded or broken off heads. Here are some other places that shouldn't see thread locker:

• Chain ring bolts, especially aluminum versions (use grease to allow you to loosen them later on)
• Most crank set bolts (grease used here allows it to attain the proper torque)
• Pedal threads (pedals won't loosen due to their reverse threading, but using grease will eliminate creaks and make them easier to remove)
• Axle threads on either front or rear thru-axles (grease here prevents the two aluminum surfaces from galling)
• Any small hardware that hasn't repeatedly loosened (M3 sized bolts or smaller, such as those used to attach the adjustment dials of a fork. Using thick grease here will prevent loosening and make them easier to remove)



Are you an arm chair thread lock expert? Want to add to what Mike has to say? Do it below!



Past Tech Tuesdays:

Technical Tuesday #1 - How to change a tube.
Technical Tuesday #2 - How to set up your SRAM rear derailleur
Technical Tuesday #3 - How to remove and install pedals
Technical Tuesday #4 - How To Bleed Your Avid Elixir Brakes
Technical Tuesday #5 - How To Check And Adjust Your Headset
Technical Tuesday #6 - How To Fix A Broken Chain
Technical Tuesday #7 - Tubeless Conversion
Technical Tuesday #8 - Chain Wear
Technical Tuesday #9 - SRAM Shift Cable Replacement
Technical Tuesday #10 - Removing And Installing a Headset
Technical Tuesday #11 - Chain Lube Explained
Technical Tuesday #12 - RockShox Totem and Lyric Mission Control Damper Mod
Technical Tuesday #13 - Shimano XT Crank and Bottom Bracket Installation
Technical Tuesday #14 - Straightening Your Derailleur Hanger
Technical Tuesday #15 - Setting Up Your Front Derailleur
Technical Tuesday #16 - Setting Up Your Cockpit
Technical Tuesday #17 - Suspension Basics
Technical Tuesday #18 - Adjusting The Fox DHX 5.0
Technical Tuesday #19 - Adjusting The RockShox BoXXer World Cup
Technical Tuesday #20 - Servicing Your Fox Float Shock
Technical Tuesday #21 - Wheel Truing Basics
Technical Tuesday #22 - Shimano Brake Pad Replacement
Technical Tuesday #23 - Shimano brake bleed
Technical Tuesday #24 - Fox Lower Leg Removal And Service
Technical Tuesday #25 - RockShox Motion Control Service
Technical Tuesday #26 - Avid BB7 Cable Disk Brake Setup
Technical Tuesday #27 - Manitou Dorado Fork Rebuild
Technical Tuesday #28 - Manitou Circus Fork Rebuild
Technical Tuesday #29 - MRP G2 SL Chain Guide Install
Technical Tuesday #30 - Cane Creek Angleset Installation
Technical Tuesday #31 - RockShox Maxle Lite DH
Technical Tuesday #32 - Find Your Tire Pressure Sweet Spot
Technical Tuesday #33 - Three Minute Bike Preflight Check
Technical Tuesday #34 - MRP XCG Install
Technical Tuesday #35 - Stem Choice and Cockpit Setup
Technical Tuesday #36 - Handlebars - How Wide Affects Your Ride
Technical Tuesday #37 - Repairing A Torn Tire
Technical Tuesday #38 - Coil spring swap
Technical Tuesday #39 - Trailside help: Broken Shift Cable
Technical Tuesday #40 - Installing a Fox Float Air-Volume Spacer
Technical Tuesday #41 - Replace the Seals on Your 2011 RockShox Boxxer World Cup Fork
Technical Tuesday #42 - Clean and Lubricate Your Fox F32 Dust Wiper Seals


Visit Parktool.com to see their entire lineup of tools and lubes
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88 Comments

  • + 35
 A good tip: Use thread lock on all of your pins on your pedals, giving them a little love can be a good investment.
  • + 2
 I do that too and it's definitely worth the effort.
  • + 4
 i like red on pedal pins myself.
  • + 1
 No doubt, but why not lock washers? Not ny-loc washers, just regular lock washers. Don't know why they aren't recommended... durable, removable, cheap.
  • + 1
 especially straighltine pedals as the pins on those just fall off straight away. USE THREAD LOCK!
  • + 17
 an excellent article, very useful and informative. keep up the great work!
  • + 3
 My crank interface on my stylo was warped and the arm wiggled until it would fall off (a mile in usually). I considered loctiting the the entire interface. Then I decided to use epoxy. If I every have to get off I might need a hack saw, but at least my bike is rideable.
  • + 1
 My Stylo cranks did the same, used loctight but would still have to tighten every ride, my friend has the same problem with his stylos to.
  • + 5
 truvativ crank-spindle interface sucks. I'm going to get shimano slx when the money comes in.
  • + 2
 if i could give taletotell 100 props I would.
  • + 2
 thanks
  • + 2
 i once had a left side FSA gravity crank arm become stripped and start to wobble, i took out the bolt and dumped in some red loctite, then put the bolt back in with a bar on the allen wrench. worked great till i nearly needed a grinder to get the thing off.
  • + 1
 Got those slx I mentioned, then sold that bike. Now I'm on a spesh bighit 2 that came with truvativ cranks again. Thankfully it will be cheaper to upgrade the cranks this time around.
  • + 2
 1. Threadlock IS a lubricant, so you can acheive a correct torque setting.
2. Threadlock can be used on threads where oil and grease is present.
3. Loctite 243 is yer man for most, if not all bicycle fastener applications.
4. You're welcome.

Lot of SRAM/Park references & obvious, blatant product placement in there, other brands of bicycle components are available.
  • + 1
 One thing I have been doing recently is applying low-strength Locktite to the limit screws on front and rear derailleurs. It seems to me that over time these screws tend to back out and of course this is not something you want to have happen, especially on the front derailleur. I suppose that teflon tape would also work.
  • + 2
 Low strength is also what I usually build my wheels up with. It's nice stuff, more tolerant of adjustments than the medium, provides a nice lubricant for an easy build and helps stop the threads getting filled with crap for the inevitable time a few months down the line when the rim needs stripped out and replaced.

Also, it's worth noting that the colour of these compounds, whilst fairly set, is not hard and fast. The stuff that I use is Tru-Loc and the light is red, the medium blue and the strong (stud lock) is dark green. Medium strength nut/screw/threadlock is what you're after guys.
  • + 0
 or you dont have mess around with strengths and just use proper spoke prep ...
  • + 3
 I just use linseed oil.
  • + 0
 and thats what OGC uses and it hasnt proven to stand the test of time very well (spokes unwind fairly quickly when linseed oil is used)
  • + 2
 I've used linseed oil for years on my own and customers' bikes. and that's what I was taught to use at United Bicycle Institute. It works great.
  • + 1
 personal experience has taught me other wise but thats not my issue as i use wheelsmith spoke prep and that shit works like nothing else.
  • + 1
 Well it appears that our personal experiences differ.
  • + 0
 you are correct, but if u ask any one of the guys at UBI they will tell u they use wheelsmith lol so whatever.
  • + 2
 There are different teachers there now. In 2000, they told me to use linseed oil. So far it's worked out great.
  • + 1
 Just serviced the bearings on my demo ( you should check them, just 4months and 1 race in the wet and were dry and dirty) .. just tighten the pivots by hand, and i want to apply some loctite and use a torquemeter to get them done right. The pivot bolts are Aluminium, is ok to use loctite ? Cheers
  • + 1
 Does anyone know what the plastic-like blue stuff is that is on, for example, rotor bolts before installation. I know it is not Loctite because Loctite is anaerobic and if you put it on a bolt and leave it out for a week it still does not harden like the blue stuff on rotor bolts. Also, Loctite is quite brittle.
  • + 1
 My experience is that loctite does harden. It is anaerobic so it doesn't need the air to harden so it can once it is threaded in.
  • + 3
 it is indeed Loctite. some people believe you should let it harden/dry before installing the bolt. this is wrong
  • + 6
 It's pre-applied threadlocker, specced by the manufacturer and required by ISO (iirc). It's a formulation designed to be pre-applied to bolts. It will hold just fine, but it won't give you as accurate a torque reading while installing as fresh, wet thread locker.
  • + 1
 @jmblur - Great info, jmblur! It's common to see people reapplying thread lock but it seems that they don't have to.
  • + 1
 jmblur, thank you.

I would prefer it over Loctite as Loctite's bond needs to be 'broken', whereas that threadlocker does not. I've had a pivot bolt or two come loose after re-installation, despite the threadlocker on the bolts (which gets crushed over time). So now I apply Loctite every time I strip my linkages down. This means I have to 'break' the Loctite which sometimes means putting a decent amount of pressure on a relatively soft aluminum CNCed bolt head.

I understand your point about torque settings.

Where can I buy it, or is there a good substitute?
  • + 2
 For all bolts I use a small amount of beeswax on the threads. It works as well as removable thread locker, but is cheaper and not a nasty chemical product. For wheel building, I use linseed oil on the spokes.
  • + 1
 One place not to use thread locker is on plastic, it makes it brittle. It might have been mentioned but I didn't have time to read the whole thread. I did see someone mention there's two different green ones, one is OK for plastic and is formulated for use on circuit boards and HPI sells it for RC cars, try some.
  • + 1
 Not great info on threadlock guys. The amount of torque required to break it loose doesn't depend 100% on the color but also the bolt it was used on. ie one dot of red on a 5mm bolt will require less force to break loose that several drops cured over time on a huge 1in diameter bolt. Also 220in/lbs needs lots of leverage? that only 36.6 lbs of force on 6 inch wrench-not much. Also you didn't really specify the difference between green-low strength lock tite and green gap filler/retaining compound lock tite-the highest strength.

Also maybe a mention of heat will allow any locktite to be more easily removed.
  • + 6
 For sure, we could have expanded on the article... and then expanded on that even more and more. But this is meant to be a basic primer as to what to do w/ thread locker, nothing more. That is where information like you just posted comes in handy.
  • + 2
 "Lubricating a fastener with grease, the swear-by for cycling mechanics, is done to allow a bolt or nut to be precisely torqued, and to ease removal down the road"

Sure, I agree with the last statement. But a lubricant will reduce the friction between the threads of the fastener and thus increases the torque applied to the bolt/nut. Unless its a wet-torque specification where you're supposed to used a lubricant. This can easily destroy or set a component up for fatigue/later damage.

Otherwise an informative article! Keep it up. Sorry for being picky, but I can't help it.
  • + 2
 Grease allows for receiving a true torque, if it had not been greased and binded before it was actually torqued, you would have a lower torque, grease would not allow the torque to exceed targeted torque but lack of can result in lower torque than intended
  • - 1
 Maybe I explained it in a weird way. A lubricant will reduce the friction in the threads and the fastener will be over tightened.
  • + 4
 For torque you do not want to be getting a reading of resistance on the threads but rather a reading of the torsional and stretching force exerted on the bolt and what it is threading into. Grease will not allow you to over torque, rather the less friction on the bolt the more accurate of a torque reading you will get
  • + 2
 I agree with jagarcia89. I think grease will reduce friction preventing the threads from potentially binding, therefore allowing a more accurate/proper torque to be achieved.
  • + 1
 and that would be correct
  • + 1
 Thats not how it was taught to me in either of my automotive programs. So what your claiming is for example. I put a dabb of grease on the studs for my lug nut, and torque to 100 in/lbs, after I drive the car in some rain for a couple hundred miles and all the grease is gone and the car dries out. My lugnut will have increased torque say 115 in/lbs??? I think not
  • + 1
 From that article above: "lubricating a fastener designed to be torqued dry could over-tighten it, which may damage threading or stretch the fastener beyond its elastic limit, thereby reducings its ability to clamp a joint". This is what I'm trying to say - you shouldn't smear grease on fasteners that are supposed to be torqued dry.

And no. The torque won't increase after the grease has been washed away, but the torque during the installation will be incorrect, compared to what your torque wrench reads.
  • + 3
 I second dannythekiwi from years working on motorbike engines. Most torque figures, unless otherwise stated, are 'dry' figures, which means that the friction between the bolt and the threaded piece is taken into account. That means that when you tighten the bolt the torque (force on the spanner) is the friction between the threaded piece and the bolt + the force of the bolt stretching. If you grease or oil the thread you remove that friction between the bolt threads and the threaded piece and for the same torque reading the bolt will have been tightened more, risking stripping the thread, breaking the bolt or deforming the piece you're tightening.
  • + 2
 Wow, this thread is old but I can't help but notice the comment by dannythekiwi being shut down. He is dead on here. Jagarcia89, you are confusing torque with tension. Torque is nothing more than the rotational force placed on a nut or bolt. The tension exists lengthwise in the bolt and is a combination of the thread pitch, thread friction, and torque applied.

This is why when you change the friction you effectively change the tension the bolt applies on the materials it holds together, even though the torque is the same. If you replace "torque" with "tension" then your statement of applying a lubricant allowing the bolt to receive the tension becomes absolutely correct. The problem as dannythekiwi has stated it is that torque specification only apply to a specific thread friction (lube vs no lube). In situations where lube is part of the torque spec, going dry would mean you aren't applying appropriate tension, the torque is whatever your torque wrench reads when you stop cranking.

If we reverse the above situation where the torque rating was specified for a dry bolt, and you lube it, the same torque will put excess tension that could make components fail.
  • + 4
 do you really need a video to show you how to apply loctite to threads?
  • + 32
 It appears they didn't.
  • + 3
 This could prevent someone from messing up their expensive bikes with too strong threadlocker.
  • - 4
flag luigi (Aug 23, 2011 at 7:21) (Below Threshold)
 do people really not know how to do this....
  • + 11
 If they didn't know, they do now. Hence the point of 'how to' articles. Apologies for assuming everyone knows as much as you do, sir.
  • + 18
 @CrashAB - Do we really need to tell you that there isn't a video? Next time we'll check with you to see if you already know enough about the Tech Tuesday topic before proceeding!
  • + 8
 apologies, this was meant as a reply to octalex's no more videos comment, not as a standalone post. I personally found the info helpful and spot-on, like all of these tech posts. I was commenting that applying thread locker is not something that required a video demonstration.
  • + 2
 sorry waughwillam...ment to positive prop...damm homer Simpson fingers and small iPhone screen...
  • + 1
 Sorry dude, just found this now.
  • + 2
 i never used thread lockers or how and when to use it but its worth knowing just the same. thanks PB!
  • + 3
 im pretty sure titanium and titanium aren't dissimilar metals.
  • + 1
 well observed! I don't think people would have worked that one out alone.
  • + 2
 Tomato ketchup is also thixotropic
  • + 1
 PTFE Tape, best stuff in the world, cheaper and just as effective as loctight, and prevents bolt seizing
  • + 1
 Yes, and it doesn't smell up the place or go where you don't want it. I know this much, whatever the torque spec could be "loose" isn't one of them...
  • + 1
 "Pedal threads (pedals won't loosen due to their reverse threading...)" - o really ?
  • + 3
 @ Gnarbar - To clarify, only one side is required to have reverse thread to keep it from loosening during riding. The drive side BB cup uses reverse thread for the same reason.

@ Carlos - Pedals seizing so bad that the axle turns out of the crank arm is no doubt a very rare thing. Grease the threads, don't apply thread locker.
  • + 1
 @mike... np I was kinda chuckling at the comment....ANYTHING AND EVERYTHING can come loose if you ride hard enough, aggro enough, or are a full on ogre/goliath rider, no matter how often or how thoroughly you check things over pre-ride
  • + 1
 I would rather my buggered peddles (which you would notice before you left your driveway) loosened off than tightened into the crank arm and wrote off a far more expensive pair of cranks with them! Its the same with BB's. the reverse thread on one side means it shouldn't waste a frame by getting stuck in there.
  • + 2
 I just wrap some teflon tape around the bolts. It's a good alternative.
  • + 1
 It's all i use as it acts as a lube and anti vibration at the same time plus it also makes bb shells water tight at the threads.
  • + 1
 problem with teflon is that it is a non-stick surface so it might still make it slick, but if ti works it works. Cool.
  • + 1
 more often than not components end up seize than coming lose through vibration... no?
  • + 1
 This and people don't check their bolts on a weekly basis.
  • + 1
 caliper adapters and rotors bolts can sometimes work themselves free because of the vibration caused when braking.
  • + 3
 It depends on the part. Vibration can easily cause parts to shake loose over time, especially on rotating parts (where the rotation can encourage precession). Thread Locker will also prevent seizing, since it coats the threads similarly to grease - it just dries to form a weak cement, rather than grease which stays liquid (albeit high viscosity).

Rule of thumb: Every bolt, every thread on your bike should have either grease, loctite, or anti-seize on it.
  • + 1
 finally someone who knows what they are talking about ^^
  • + 3
 thanks PB very helpful
  • + 3
 I miss the videos too...
  • + 1
 No vid needed for this particular TT, but you'll see more of them in the future.
  • + 1
 Anyone using loctite on the rear derailleur bolt?
  • + 4
 In my experience, loctiting the rear derailleur just causes issues down the road....if the hanger breaks and the derailleur bolt is threaded into the broken piece of the hanger, its an absolute pain to get out. derailleur bolts dont back out very easily at all either, and usually when they begin too, its noticable as your shifting will go to hell very quickly.
  • + 1
 ^^^ no, grease is what you should use on d/r bolts
  • + 1
 haha
  • + 1
 no more videos?
  • + 7
 We skipped the video showing you how to put a dribble of thread locker on a bolt, but you'll see more of them in future TT's =)
  • + 1
 k cool im just a visual learner
  • + 13
 ...and pictures aren’t visual? lol
  • + 1
 Most threadlocking compounds are not meant to be mixed with grease/oils/lubricants as it reduces their effectiveness, especially during the curing process. There are of course compounds which are designed specifically for use in these conditions but are usually significantly more expensive than their standard counterparts.
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