gregf83 

Some manufacturers (Porsche) recommend lube so it's not a universal recommendation to leave them dry. If you use lube you won't have to deal with seized lugnuts.

AlmostTrick

I like to put a light amount of grease or anti-seize compound on almost any fastener... even auto lug nuts. Never had anything work loose, freeze up, or strip threads.

You all can, and should, look up the manufacture specs for every fastener you ever put a wrench on.

Sy Reene

However, as seems to be case usually, the specs are often either maximums or ranges for the bolt itself, and don't tell you the spec for whatever is being clamped by that component.
Here's a couple random snippets out of Shimano's dealer manual for ultegra brakes. Note that (to the point of this thread's OP) there's no indication of greased or dry. Shimano gives a tightening range. And, Shimano provides a helpful warning

AlmostTrick

Right, which is why I feel experience, skill, and mechanical knowledge trumps looking up specs for most stuff on bikes.

greatscott

And that's why I said in my post that you posted to follow the manufactures recommendation.

richart

Lots of varying opinions on this topic. Personally I use peanut butter on everything threaded on my bike and I have never had an issue (except with ants.) Believe me, I have a degree in Germanic Languages and Literature and know what I am talking about. Plus, I stayed in a Holiday Inn Express last night.

AlmostTrick

Well done.

As a side benefit, as long as you carry a mini tool you'll always have bonk recovery insurance on your rides.

Spinay70

I have seen auto mechanics frequently lube bolts that needed to be torqued to specificified numbers, it seems to be accepted that this is what you are supposed to do if you want it to be done properly. I suppose that there are applications where this is not needed. I would double check and do what the grizzled experts say...

S

mr_ko

I'd ignore what auto mechanics tell you about bicycles. If it has a thread, it gets grease or anti-seize, depending on material/material contact. That said, bolts like Ergo/STI are usually pregreased to some degree from the manufacturer. Remember (as I'm sure some have already pointed out) greasing is not for just anti-seizing, it's to allow you to get the bolt to the correct torque specs E.g. seat binder bolts, stem plate, etc. I will disagree with those that say stem bolts don't need grease.

greatscott

All one needs to do is google this: "should car wheel nuts be greased" and start reading, but more importantly read your owners manual.

73SchwinnWV

Need to go with manufacturer data. As default, all fasteners clean and dry. If manufacturer says otherwise then do that. Example: electronic fuel controller on an F16 is mounted on the P&W motor. Hugh vibration and heat. Fuel is routed through it to cool the circuit cards. All fasteners are greased and torqued in steps, sequence, even running torque before final torque. Some as low as 4 inch/oz. The manufacturer and AF tech data demand it be assembled that way.
Be careful freelancing assembly when riding your bike in traffic or high speed.
If no direction for assembly communicate with manufacturer. Otherwise, rely on engineering data for size, material, and application.
Don't forget to use a calibrated or verified torque wrench. Manufacturing data will tell you proper storage and warm up.

u235

Lol, F16 aircraft vs your bike seat clamp. Yeah, I see your logic. Next up... Are the screws on my hallway light switch cover too tight?

djb

Light switch covers, chuckle.
Come on, everyone knows you tighten those little buggers until the cover makes a slight cracking sound, then back off half a turn.

Duragrouch

Everyone's an expert. Not. I'm a mechanical engineer and even I am not the best expert, but I understand the ones who are, which are, *fastener engineers*, the ones that design (engineer, with calculations and computer modeling) threaded (and other) fasteners and connections. Here's the scoop. I wrote this after seeing on a very well-respected bike repair shop's website, advocating grease and oil on threads:

"Each bolt and nut (threaded part example: pedal) is lubricated (oil for bolts 5mm and smaller, grease for bolts 6mm and larger) to allow the proper torque to be reached and prevent corrosion. Counterintuitively, lube allows a bolt to be torqued easier and stay tight better than a dry bolt." (my note: INCORRECT)

Threaded fasteners (bolts and nuts) are designed assuming clean, dry bolts (and new surface finish on threads); regular lube (oil or grease) does reduce the coefficient of friction and increases clamping load over spec. Do not do that. But a dry thread can cause corrosion and even galling (especially with softer stainless steel fasteners). I am not advocating a dry bolt. But the wrong lube can cause over-torquing beyond spec. HOWEVER, "Anti-seize" thread lube does not. It specifically contains extremely fine malleable metal powder to counteract the effect of the greasy medium that contains it. Besides lubing, it also counteracts galling much better than grease or oil. Oh and instead of a dry press fit on square taper bottom brackets, anti-seize there will prevent corrosion and ease disassembly without affecting function or causing an excessive press. The gray anti-seize contains aluminum, copper, and graphite and is rated for the range of -80 to 1600F. The copper anti-seize uses all copper and is rated for -30 to 1800F. Since I'm not operating in the arctic, I prefer the copper as it's easier to see and also is electrically and thermally conductive, it's superb for things like antenna and spark plug threads (especially important in an aluminum engine head), and most especially bolts on the exhaust system. The good part about anti-seize is that the bottle comes with a brush applicator, very convenient. The bad part is the stuff is messy, you don't want it on your clothes (unless you want to look like an aircraft mechanic, they use it everywhere). I think copper anti-seize on a black shop apron looks especially cool, but that's just me.

Duragrouch

BAAAAAHAHAHAHAHA! Post of the day.

Duragrouch

Or, you could use anti-seize to prevent seizing. Lube is not anti-seize. WD-40 is not lube. Something is not WD-40.

Booger1

If your not confused enough yet.......Now we should talk about how different lubes affect torque readings......

greatscott

Ok another myth busting moment, WD40 IS A LUBE, read: https://www.wd40.com/cool-stuff/myths-legends-fun-facts

Duragrouch

Spit is lube, just not a very good one. WD-40 was designed as a Water Displacer. The spray (from wiki) "was originally designed to be used by Convair to protect the outer skin of the Atlas missile from rust and corrosion." It was also great for drying out wet spark plug wires. It would do both and have a lasting effect by leaving behind a varnish coating after the solvent carrier evaporated. However this varnish was why WD-40 was banned from things like lubricating spherical rods ends ("Heim joints") on aircraft control linkages; they would gum up over time. In college, people would lube the foosball table rod felts with WD-40. Over time, they needed to add more and more quantity each time, not for lube, but to dissolve the constantly increasing volume of varnish left behind. In recent years, I had to use WD-40 as a lube in an emergency, and there didn't seem as much varnish residue as in the past, they may have changed the formulation to appeal to the wider range of lubrication applications. I much preferred CRC 5-56, which I can't find any more. Not for lubricating, as it was a lube so light that it would evaporate over time. But this made it ideal for spraying on brake rotors for cars I had in garage storage over the winter to prevent rust. By spring, the lube was entirely evaporated from the rotors (but no rust), and any lube that had soaked into the pads would burn off after a few brake applications.

In a pinch, WD-40 can act as lube. I have used it as such when nothing else was available. But it is far from ideal as a lube. Now, I am not one to tout very specialized lubricants, like spending $10 for a small tube of bike chain lube. That's just slick marketing. There are so many fantastic lubes around now at much lower prices. One is automatic transmission fluid, great lube, cheap. I would chose that because I know it's designed for severe use, and is the right viscosity for chain lube in all temperatures, especially synthetic ATF. But now engine oils have gotten down to 0 (zero) weight, which is also the right viscosity, and is designed for high-pressure point contact, so also makes a good bicycle chain lube (and even when thicker, oil was always the lubricant on engine timing chains).

Duragrouch

Allow me to summarize my previous statement and unconfoose: Anti-seize (under various trade names) does not change the relationship between fastener (bolt) torque and tension/clamping force. The metal particles (soft, such as aluminum or copper) in it were added to counteract the effect of the carrier grease, and also remain if the carrier grease burns off such as when used on engine exhaust bolts.

Grease and oil CAN increase the bolt tension/clamping force for a given tightening torque spec, and thus exceed strength limitations for the bolt or what it is clamping, and thus break stuff.

yannisg

Thanks for responding.
1. Most likely seatpost
2. I used the stem spec because the handlebar was aluminium
3. I meant the derailleur and break wire tightening bolts
I make sure the threads are clean, and don't use any grease on torqued bolts.
If I remember there is a special compound used in industry where you are suppose to applied to threads before torquing.

Bikesplendor

I wanted to express my appreciation for this. Interesting stuff. It's what I was hoping to find with the original post.

Some people just seem to have more of an engineering mindset and engineering perspectives.

Would anti-seize be appropriate for all threads found on bikes? If there are exceptions, what if anything should be used instead?

Would threadlocker be better in some cases?

Duragrouch

Anti-seize is appropriate for all threads that do not use threadlocking adhesive, nor any with Nylock style nuts (read below), as it might damage the nylon. For metal-to-metal threaded interfaces, even if not needed, it does no harm. Notably, it seals out water and prevents corrosion, whereas using grease to do the same thing will change the torque/tension relationship. However, in areas adjacent to bearings, be careful that the anti-seize compound does not get on the bearings (internally), as the metal particles in it would be very bad for the bearings.

Threadlocker: Most threads on the bike are designed to be "self-locking", in other words, the static friction of the threaded joint, once torqued to specification, exceeds any operating forces wanting to cause the threaded part to unscrew. Note: A "finer" thread helps this (in English threads, higher number of threads per inch (TPI), in Metric, smaller pitch length), this represents a "shallower ramp angle" when analogizing threads with an inclined ramp. Also, some parts have a left-hand thread to also counteract unlocking forces. A "Nylock" nut with nylon insert, and also nuts that are "crimped" to be tight on the bolt threads, are both "prevailing torque nuts", those features meant to help the nut self-lock. Some car parts have a special nut that is just a tiny bit off in thread pitch in order to self-lock. In cases with a free-running (normal) threaded interface, a threadlocking adhesive will provide more resistance to coming undone. Most frequent applications are on bolts and nuts where you cannot tighten them fully as that would impede function. Example: Handle bolts on multi-tools like a Leatherman: Fully tightening would make the handles hard to open, looser torque with dry threads and the bolts constantly come loose, so they use threadlocker adhesive. To disassemble, heat bolt with soldering iron and unscrew while hot. Another example: Bike brake levers, the handle pivot bolt. Too tight and the handle won't release. Usually no thread locker there, but rather a Nylock nut. Another way to lock a loose thread is a cotter pin like on car wheel bearings, or multiple nuts tightened against each other like the wheel bearing cone and lock nut on bicycle wheel bearings (without "cartridge" bearings).

Bonus info!: Most "lock washers" use some design that "cuts" into the underside of the nut or bolt. I had an early Dahon folder with a crank bolt that wouldn't stay tight with normal lockwashers. I ended up using a Nord-Lock, I ran across them in my last job in defense applications, very cool: Two washers against each other with friction outer surfaces, and with the internal mating surface a series of wedges (at a steeper ramp angle than the bolt thread) such that, if the bolt tries to unscrew, the wedges make the washers expand away from each other, tightening the joint. With a Nord-Lock, the crank never came undone again unless I was wrenching on it.

Sy Reene

This is great info! I would like to know though where or how you know that anti-seize does not by default, change the torque/tension relationship as grease does? There are so many brands and formulations, I just don't know how you can be sure?

u235

The rate of speed a bolt is tightened reduces the resulting friction of the threads and therefore changes the resulting clamping force for a given torque applied, what is the suggested tightening speed of bolts? Temperature plays a role as well, even more so with dissimilar metals. How far does someone want to go with this.

https://books.google.com/books?id=GE...torque&f=false