# Torque: dry vs lubed



## dundundata (May 15, 2009)

I have been goggling this issue and cannot come up with a solid answer. Alot of the debates I have read go into hypotheticals and start talking about automobiles or even the space shuttle. So I am hoping some of our esteemed wrenches can shed some light on the subject in a practical, real world application of torquing bicycles.

(I did do some searching but if I missed a topic about this please let me know)

Are most torque values listed for dry threads? (For example Shimano techdocs and ParkTools values)

What is the effect on torque values when applying grease, anti-seize, or loctite to threads?

What is your method to this madness?


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## reptilezs (Aug 20, 2007)

some products they say grease this and that and than then torque to xyz. then i will asume wet torque. until the bike industry specifies wet and dry torque it all up in the air. i only use a torque wrench cranks and carbon components. new bikes come with grease on the seat collar bolt, stem etc. we tend to grease everything for corrosion resistance


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## NYrr496 (Sep 10, 2008)

I've been a mechanic for a lot of years. I've almost never seen any threads that get torqued dry. If you do a comparison of tightness of a bolt at a given torque wet or dry, you'll notice the corners of the bolt will be "more tight" on the lubed threads, which tells you you have more clamping power at the same torque value.


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## curtboroff (Sep 21, 2010)

Zinc coated fasteners shouldn't need lube, unless they're old or hacked up, in that case you should replace them. But any non coated fasteners need lubed. 

Proper torque is a HUGE debate, you're likely going to get all kinds of answers to this one.


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## dundundata (May 15, 2009)

curtboroff said:


> Proper torque is a HUGE debate, you're likely going to get all kinds of answers to this one.


That's fine, I'm looking for what people actually do. I always grease or anti-seize threads, except for something like rotor bolts that come with loctite or whatever.

My understanding is a lubed bolt would have less friction and so you would end up tightening it more given the same torque setting.


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## RockyMt (Jan 29, 2011)

The tension achieve in a bolt can vary significantly for a given applied torque to the bolt.
Variable factors include:

- Fine thread vs course thread (fine thread has a more shallow inclined plane and produces more tension in the bolt for a given torque)

- Thread finish is important because some of the torque force is absorbed by friction and therefore less applied torque is available to increase tension in the bolt.

- Thread lube, including thread locker, reduces friction and allows a given torque value to apply more tension to a bolt. Chances for galling is also reduced by using a thread lubricant or thread locker.

Without going too deep into this subject, my suggestion is to use a removable type thread locker on the appropriate bolts. e.g. bolts that hold the stem to the steering tube. Use bolt lubricant on all less critical bolts. Then use the recommended torque on ALL bolts.

This practice will protect serve you well and the life of the threaded joints will be maximized.


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## mechBgon (Jan 28, 2007)

In practice, the torque you exert on bolts with dry threads (and dry shoulders on the bolt head) could be going mostly to overcome friction, with not much left over to generate clamping force. It depends entirely on the specific situation. Lubricating the threads and the contact area of the bolt head helps ensure that the torque you apply is actually going into the clamping of the parts.

One specific example is front-derailleur clamping bolts. They tend to end up dry and gritty due to their location. If that bolt's dry and gritty, then X amount of torque might keep the FD from rotating on the tube, but if that bolt's fully greased and happy, that same X amount of torque might generate enough clamping force to delaminate a carbon seattube or break the FD clamp.

So the moral of the story is, "it depends." I default to lubricating almost all fasteners so they're not Mission Impossible down the road, then using a torque that gets the job done well without breaking stuff.


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## curtboroff (Sep 21, 2010)

Also when you hear or feel the fastener catching as you tighten, at the point just before said catch releases, their is a tremondus amount of torque at the thread contact only. This will lead to a false torque reading and thread damage. And the aluminum threads will give before the fastener threads, no good. Lube or blue threadlocker will stop this friction and allow for a more uniform torque.

Unless otherwise specified, I threadlock fasteners that I want to stay put, and I lube fasteners that I remove frequently.


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## NYrr496 (Sep 10, 2008)

An added note about threadlocker... it protects the threads by blocking air and moisture from getting in. Threads with purple or blue Loctite will come apart perfectly after a long time.


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## dundundata (May 15, 2009)

So as far as torque values are concerned, just go with the manufacturer's specs, and if there is a range shoot for the middle? I realize certain parts have more specific instructions that should be followed.


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## customfab (Jun 8, 2008)

Given the small torque values for most bicycle parts I think the difference between dry and lubed is within the margin of error for the tool you are using. In other words it's not worth worrying about. I always put something on the bolt. Most of the time it's anti-seize, sometimes a thread locker. I have always just gone with it. I have known of A&P's that have been anal enough to measure the drag of the fastener and then added that amount of torque on top of the torque spec. Makes lots of sense when you think about. 

Everybody has brought up some interesting points though. 

Heres another torque related question, why does the cycling industry seem to be the only one that gives a torque range? Everything else I've worked on or ben around has had a simple torque value. No wiggle room or gray area.


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## NYrr496 (Sep 10, 2008)

customfab said:


> Given the small torque values for most bicycle parts I think the difference between dry and lubed is within the margin of error for the tool you are using. In other words it's not worth worrying about. I always put something on the bolt. Most of the time it's anti-seize, sometimes a thread locker. I have always just gone with it. I have known of A&P's that have been anal enough to measure the drag of the fastener and then added that amount of torque on top of the torque spec. Makes lots of sense when you think about.
> 
> Everybody has brought up some interesting points though.
> 
> Heres another torque related question, why does the cycling industry seem to be the only one that gives a torque range? Everything else I've worked on or ben around has had a simple torque value. No wiggle room or gray area.


Want exact? Older Cat diesels I used to work on first had a torque spec you would turn a bolt to with a torque wrench. Then, you would mark the corners of the nut or bolt with a paint pen and turn the bolt 120 degrees or two corners. This was called Torque Turning. I believe some late model cars use this method as well. There's a tool for it, but a paint pen on the hex head works perfectly.


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## paetersen (Jul 28, 2007)

As a long time auto, bike and industrial mechanic I can add that all torque specs are given *assuming* properly lubed threads with no burrs in good condition. The torque value directly correlates to the amount of force the manufacturer wants the head of the fastener exhibiting on the parts being held together, not the amount of force the threads are soaking up.

Also- the smaller the torque value the smaller the margin of error. The difference between 6nm and 8nm is much greater than the difference between 78nm and 80nm.

Proper technique is as important as proper tools when it comes to torquing fasteners. You want to bottom the fastener and then make sure you have the range of motion for the tool to torque-to-spec in one continuous motion of at least half-a-turn while applying smooth consistent force on the tool. Starting a stopped fastener that is tightened but not quite at the torque spec will often require more force than the torque spec. Your tool will click, but you will have a false torque reading.

Any time you have more than one fastener attaching a part you will need to walk each fastener up to the proper torque spec while following some kind of alternating pattern. Bottom each fastener, then torque to half-spec, then torque to spec.

But the bottom line is that all this is way more critical in automotive, aerospace and industrial applications. The bike industry is getting a little silly about torque specs and carbon fiber. Most likely you are putting too much thought into it.


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## mechBgon (Jan 28, 2007)

paetersen said:


> But the bottom line is that all this is way more critical in automotive, aerospace and industrial applications. The bike industry is getting a little silly about torque specs and carbon fiber. Most likely you are putting too much thought into it.


I tend to agree. People get very focused on torquing stuff just so, when the parts are from entirely different companies who certainly haven't done any broad testing or validation of their ...stem, for example, on twelve different carbon bars and ten different carbon steer tubes. If it were parts of an aircraft engine, or even an automotive engine, then sure, we'd have reason to believe the specs are the result of actual engineering. Take it all with a grain of salt and don't abandon common sense, folks.


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## alkemyst (Sep 30, 2009)

Much of the debate above is why dry vs wet values are given. IMHO it is assumed you will be torquing bolts dry in most industries unless specified otherwise.

However on something like a bike that sees the elements putting something on the threads prevents more problems down the line than any torquing advantage it gives.


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## RockyMt (Jan 29, 2011)

NYrr496 said:


> Want exact? Older Cat diesels I used to work on first had a torque spec you would turn a bolt to with a torque wrench. Then, you would mark the corners of the nut or bolt with a paint pen and turn the bolt 120 degrees or two corners. This was called Torque Turning. I believe some late model cars use this method as well. There's a tool for it, but a paint pen on the hex head works perfectly.


I believe the recent Ford diesels are designed where the head bolt strain (stretch) goes into the yield range and the bolts cannot be reused. Most engineers consider it good practice to only design to a maximum of about 90% of yield stress or less. In other words staying within the elastic range of the bolt material with some safety factor remaining. The maximum yield stress before ultimate failure can be approximately 10% or more above the maximum elastic range of the material.

To be honest I have been turning bolts for 50+ years and I seldom use a torque wrench. I do tend to use removable thread locker on some bolts and anti seize on everything else. This tends to ensure joints are tight and threads are not galled and can be reused over and over again. Use a torque wrench especially if you are just starting to do your own mechanic work.


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## nov0798 (Nov 27, 2005)

I always use a torque wrench, more for the fact that this way I have a repeatable uniform force on everything. Like another poster stated, for the minimal torque ranges on the bikes, I wouldnt worry about using lube. Might try reading information on ARP's site, they are pretty good with fastners.


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## What&son (Jan 13, 2004)

Very interesting subject. I'm enjoying this thread, keep posting :thumbsup:


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## artizin (Jul 4, 2011)

I say lube it a little, like someone said earlier in the thread it helps fight corrosion.


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## mtb143 (Aug 26, 2007)

I've found one situation where dry vs lube definitely makes a difference: aluminum chainring bolts. If I lube them then torque to spec the nut on back will crack in half about half of the time. This is with a few different, reputable brands of fasteners. Torque wrench has a current calibration too.


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## NYrr496 (Sep 10, 2008)

mtb143 said:


> I've found one situation where dry vs lube definitely makes a difference: aluminum chainring bolts. If I lube them then torque to spec the nut on back will crack in half about half of the time. This is with a few different, reputable brands of fasteners. Torque wrench has a current calibration too.


Just put some blue Loctite on those and make em snug.


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## retro74 (Jul 30, 2016)

*Wet Vs Dry Matters*

Some of the posts have it right. Unless it reads as "Wet" or "Lubed," the torque is stated as dry and clean. Once you apply grease, assembly grease, wet Loctite, etc. then the numbers are not dry. In general, wet can be 25%-40% less. We are not torquing big V8 motor connecting rod bolts here, but it does matter with carbon and alloy and of course small bore bolts like 4mm, 6mm, etc. I always use assembly lube or Loctite Blue (wet). So I use the lower end of the range and sometimes less. I have rotated handlebars from hard landings, but that is rare.

Bottom line is that the specs are "dry" unless otherwise stated.

J



dundundata said:


> I have been goggling this issue and cannot come up with a solid answer. Alot of the debates I have read go into hypotheticals and start talking about automobiles or even the space shuttle. So I am hoping some of our esteemed wrenches can shed some light on the subject in a practical, real world application of torquing bicycles.
> 
> (I did do some searching but if I missed a topic about this please let me know)
> 
> ...


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