Yes.

I have been greasing every thread on every bike I own for 30 years with Phil Wood Green grease and I have never found any bolt that loosened prematurely or did not come loose when I wanted it to.

^^^^This.

Use Phil Wood (or any polyurea-based grease...they are usually green, blue, or red and semi-translucent vs. lithium-based which is a creamy white). Apply a small dab to the threads and rub it with your finger to cover all the threads with a light coat. The purpose is to both prevent binding, and to protect the metal from moisture.

Note: Some bolts come with blue threadlock on the last few threads; do not grease these.

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ECMGN Therapy Silicon Valley:
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Its a real double edged sword.
There are lots of dissimilar materials + dampness and sometimes road salt etc too.
So it's easy for bolts that rarely get touched to seize. And unlike a car, not easy just to heat up or burn/cut off and put new ones in. So the grease defo helps.

BUT... if you apply the required / stated torque you'll provably get the wrong end load in the bolt (and what you're really wanting when torquing a bolt is not torque per se but the right end load that the joint is designed for. (Too much load = crush carbon fibre bars or seat posts etc. Too little... they come loose !).

What the bike industry is shiiite about doing is actually stating whether the torque specified is for a dry bolt or 'as supplied' (= often a very light bit of oil on them) or to be greased. Each gets a rather different end load for the same torque.

Me ? I do grease (and some I use Copperslip on, where I do think it will seize otherwise) but am VERY wary that the torque marked will not necessarily be the right thing, and use some 'feel' when doing up a bolt.


But for the Alu bolts on the suspension pivots on my full susser ( Alu into Alu) i use threadlock (as specced) then use a torque wrench to the design values. As those fine threaded 'special' (40+ quid a set) Alu bolts will strip REALLY easily and be a total PITA to subsequently remove from a tapped hole in the frame or fix.

From an engineering perspective...

(https://www.velonews.com/...eads-and-warm-shoes/)

“ I hope I can contribute to the “greased fastener threads” conversation from your last column.
For a little background, I’ve been a mechanical engineer for the past 15 years, prior to that I was a bike mechanic for a couple of bike shops while I was a student. I don’t pin on a number much anymore, but I’ve raced road, MTB and ‘cross throughout the years.
I’ve designed quite a few fasteners and bolted joints throughout my career, which spans everything from really big bolts when I worked at Caterpillar, to really, really small ones when I worked at Microsoft. Currently, I’m the lead mechanical engineer for the bike and scooter division of Lyft, where we design the bikes and scooters available in many cities as part of publicly available bike-share fleets — we are the largest bike-share operator in the US. But enough about me, let’s talk about screws!

As you pointed out in your column, most bolted joints in automotive and motorsport applications don’t get greased, but it’s standard practice for most bike bolts.
The head mechanic at a shop I worked many years ago always said “grease every bolt when you assemble a new bike, so when that bike comes in for service in 3…4…5 years, we can get it back out”. Anecdotally, he was right, but let me explain a few of the technical reasons why applying grease to bicycle fasteners makes sense, and why it is rarely done in some other settings.
1) Greasing a fastener reduces thread friction (in bolted-joint engineering terms, this is usually referred to as reducing the “K” value), which results in a higher clamp-load for a given installation torque. An ungreased fastener would have a thread friction coefficient, or K value, of 0.18-0.2, whereas a greased fastener would have a K value closer to 0.12-0.14. For example, an ungreased M5 stem mounting bolt, torqued to 4Nm, would result in a clamp load around 6,000N. The same screw, with grease applied, would achieve a clamp load of 9,600N when installed at the same 4Nm of torque.
2) Greasing a fastener helps prohibit galvanic corrosion, which can be an issue even for stainless steel fasteners in painted or anodized aluminum threads. Just like you would always grease an aluminum seat post when installing it into a steel bike frame, the same best practice applies to steel and stainless steel fasteners in aluminum threads. The table below shows the relative risk of galvanic corrosion for various dissimilar metals. These two reasons are as true for a bolted joint on a car or motorcycle as they are on a bicycle, so why grease bicycle threads in particular?

Relative risk of galvanic corrosion.
Most fasteners used in automotive and motorsports applications are “grade 8.8” or “grade 10.9” alloy steel bolts. A grade 8.8 bolt has an ultimate breaking strength of 800MPa, and a yield strength around 640MPa, and a grade 10.9 bolt has an ultimate breaking strength of 1,000Mpa and a yield strength around 900MPa. These are the minimum strength values defined in ISO 898. These high-strength steel screws, typically combined with a large, high-torque drive interface, can be installed to relatively high torque values without stripping the drive interface or yielding the bolt shaft. You can really torque ’em down, and if corrosion effects over time cause the bolts to “freeze” (a dramatic increase in thread friction due to corrosion of the threaded interface), you can again apply a relatively large torque to remove them.

Most bicycle fasteners conversely are made from grade A2-70 (or similar) 300 series stainless steels, with an internal hex (“Allen”) drive. An A2-70 stainless steel fastener has an ultimate breaking strength of 700MPa, and a yield strength of 450MPa. These are the minimum strength values defined in ISO 3506. As you can see, most bicycle bolts are only 70 percent the strength of an automotive-grade 8.8 bolt and only half the strength of an automotive-grade 10.9 bolt. Conversely, these bike bolt fastener drives and bolt shafts are capable of considerably less torque than their automotive brethren before stripping occurs. This can be exacerbated if the driving tool (I’m looking at you 10+year old Park Tool 5mm Allen wrench lying on the shop bench) is worn down. The lower friction of a greased thread allows higher clamping forces within the torque range available from the weaker bolt shaft and bolt drive feature. A greased thread also helps ensure that the torque required to remove the fastener after time in the field is not significantly higher than the force required to install it.
So should we all be greasing up our bicycle bolts prior to installation? As I pointed out in the example above, a greased fastener can have significantly higher clamp loads for a given installation torque than an ungreased fastener. For carbon fiber structures that are highly sensitive to clamp loads, it is safest to assume the torque recommendation (e.g. 5Nm) provided by the frame/component manufacturer assumes an ungreased “dry” fastener. Greasing this fastener and then applying the 5Nm installation torque could significantly exceed the clamp load recommended by the manufacturer.”

I'm the same, though not particular on the brand of grease.

I do not grease bolts that have threadlock on them, though I also don't usually replace the threadlock.

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http://www.jt10000.com/

In part this seems to be tolerable due to the relatively wide torque ranges specified on many bolts. 4-6nm is fairly wide open, so I lightly grease and torque at the lowest spec and only increase of that proves to not be enough over time (which is once ever on a seatpost that was terribly designed and still slipped after fully degreasing and even over torquing. It was just replaced with a better product)