Grease vs. Anti-seize
 

I installed a Praxis PF30 BB onto a frame a few weeks ago and the instructions were very particular about where to use grease vs. where to use anti-seize. I followed the instructions and all is good, at least until that BB needs to be removed in some undetermined future (or never).

But when should one generally use anti-seize instead of grease? Can anti-seize be applied to all threads or only when specified? I would think for bearings it should always be grease. On the BB, the press-fit shell was to be greased but the cups were thread together types and the threads used anti-seize.

I only ask because now I have a tube of anti-seize and my old tube of Phil grease is dwindling. Both may still be enough to last me a lifetime. I bought that tube of Phil grease in 1980 or so when I took my first bike mechanics class at the local coop and learned how to service hubs which were all loose bearing back then.

At the risk of raising the ire of people who get paid to fix bikes and are experts…I use anti-seize on basically anything that is threaded where the threads are not exposed. Anti-seize is grease with suspended solids, so it shouldn’t be used in applications that move (e.g., bearings or suspension pieces). But, for threads it is ideal, as it lubricates while torquing to ensure getting the right torque, and it prevents galvanic corrosion if dissimilar metals are in contact. For whatever reason, regular grease is claimed to not do that second piece, and I’m not willing to experiment to see if it is true. I just accept the science.

Specifically to that BB, which I have used on two difference bikes, the only place you need anti-seize is on the threads where the two sides mate. I also used it on threads for the crank where it mates. I used grease where the BB cups press into the frame on both the cup and frame, and also where the crank spindle pressed through the bearings. Having switched both of those bikes over DUB BBs and cranks, I still do it the same way. And I’ve never had any issues with disassembly. I also use anti-seize on pedal threads and on the threads of screws that fasten my derailleurs. Again, never had an issue.

Generally, if the materials in contact are likely to cause dissimilar metal corrosion, &/or be problematic with galling I'll consider using antiseize. If the hardware requires a critical high torque & doesn't specify not to use lube, I may apply some lube. Should the parts be moving, be exposed to the elements, & would benefit from reducing as much friction as possible, then grease is likely to be used.

Generally my $00.02

My long-winded detailed drivel on anti-seize (including the carbon mounting paste).

At least that's what's worked for me so far.

TL/DR: grease is for bearings (sliding parts in general), anti-seize (mounting paste) is for mounting stuff (threads, assemblys etc).
Many (most?) people use grease instead of anti-seize, but I sleep better when I use anti-seize - I'd say it offers a lot longer anti-seize protection than grease.

Generally anti-seize is only used when the mating surfaces are not going to be in motion with each other when in normal use. Such as for the treads of a fastener.

Generally grease is used where two mating surfaces will be moving against each other when in use.

It's more acceptable to just use grease to substitute for anti-seize than it is to use anti-seize as a substitute for grease.

Though there are some exceptions.

OK, thanks all. What you are saying makes sense.

For the BB, I used the anti-seize only on the threads where the two side go together. I used grease everywhere else. The instructions were different between using the PF30 shell vs. not using it and anti-seize was used for something else. It didn't apply to my assembly though. I just looked at the instructions and it says to use anti seize on the contact surface as well as the threads if you are NOT using the PF30 sleeve.

So in sum, every bolt on a bike is a candidate for Anti-seize, and it's likely a better/safer option than choosing just grease?
Grease for anything that moves, though of course not on chains, or pivots, etc?

Antiseize for places where dissimilar metals pose a risk for galling or galvanic corrosion, e.g. aluminum on steel. Otherwise, grease is sufficient, and less messy.

From a chemistry standpoint, anti seize is good for dissimilar metals. Say, a steel bolt in an aluminum hole. Or a location that needs some lube but has issues with corrosion/water. Like a bottom bracket. That is why some folks choose marine grease for bottom brackets, less water intrusion.
My friend works on a vintage schooner in Seattle. They used marine grease on some turnbuckles and other parts, but surprisingly it didn't hold up well. Regular grease did better. Which may be to say that marine grease does better when sealed into some threads, less so when exposed. I noted the same on some headsets where I used marine grease. It started to dry out much sooner than I thought it would. I now use SuperLube, which I think has teflon in it. Good stuff. And of course in the end, just service your bearings every so often when the grease gets old.

Good points.

I'd also argue that high-quality greases (lithium complex, especially with a synthetic base oil) are very resistant to water washout, often more than a low-end "marine grease."
Not that it really makes much difference for bikes in my experience - it boils down to regular maintenance, more than the grease quality (auto-store lithium complex is more than good enough IMO).

Anti-seize, on the other hand, seems to help in preventing even the neglected stuff from geting seized so much that it can't be removed without some permanent damage.

Seconding on the neglected stuff. In my experience virtually nobody ( present company excepted, of course :)) ever touches the BB. For the most part the BB is the very definition of a neglected area. So a good swabbing of anti-seize is a good idea when the chance arises.

Grease works just fine in this application UNLESS you plan to never clean and lube your bike. While not really true, in bicycling applications anti seize is just grease that lasts a long time in threaded applications. I've been using grease on all mating surfaces on bikes for the past nearly 60 years and have NEVER had anything freeze up. But then I actively maintain my bikes.

In my city, bikes are used for transport quite often (it's a lot like Amsterdam... only better :) ).
Based on my experience, most people don't regularly overhaul their bikes. I'd say it's a vast majority of users.
Stuff like seaptosts, bottom brackets and even pedals often cause problems when removal/change/overhaul is needed.

Riding conditions (moisture, temperature, amount of rain etc) also play a part.
Some areas get more rain, higher air moisture etc. That also affects the probability of stuff getting seized.

Bikes used for sport ("avid cyclists" and similar) are usually regularly overhauled (either DIY or by mechanics).
But even with those, I find it hard to justify not bothering with anti-seize when it's appropriate.
Of course, different people have different experiences and opinions - but that's mine.