There seem to be a lot of opinions about anti-seize and bottom brackets. I'm replacing a steel BSA BB in what I assume is a steel BB shell (in a 90s steel frame). Anti-seize or grease?

It's not a disease, it's anti-seize Bleepin Jeep Anti-Seize

I use grease. #2 lithium grease. It is nearly black in color because it has additives that differentiate it from the white lithium grease. While anti-seize is good stuff, I feel like Matt from Bleepin Jeep when I use it.

I've always used grease. Steel cups in a steel shell have little chance of seizing.

I use grease, but if you decide to use anti-seize wear gloves. If you get it on your fingers you will have to wait until you grow new skin to get rid of the stain. It will NOT wash off.
Don’t ask me how I know.

Grease and a torque wrench. Torque wrenches help you maintain consistency and attain reliability.

"I've always used grease. Steel cups in a steel shell have little chance of seizing."

except the ones in some old italian bikes, any Raleigh from before 1978 or so, most of the waterpipe era bikes, that beat up 720 Trek MTB i just torn down as scrap, my nephew's unibagel desert bike, etc.

any lube is better than no lube.

anti-seize can turn to a clay-like putty that can ruin some threads, after too many years.
i think frequency of removal/reinstall is a bigger factor than what is used.

The only grease I have or use is Marine Grease. When working with dissimilar metals I use Anti-Seize compound. Also note that there are so many variations of steel, aluminum, and mixed alloys who is to say what is dissimilar or not. In that, I use anti-seize compound on just about everything now days. On Bottom Brackets I use Anti-seize compound, but I have been known to use a touch of Permatex blue threadlocker on non-cooperative bottom bracket cups.

Also take note that I have not worked on Carbon bikes. They may call for an entirely different compound...

As already mentioned, anti-seize is a dirty mess from hell to clean up from bike, skin and clothing. When you remove your BB to service or replace you need to do a fairly thorough job of cleaning off the threads and is a PITA with anti-seize. Grease of almost any kind that has some moisture resistance lasts a long time and is easier to clean up. I just buy a tub of marine grease which can be used on almost the entire bike; bearings, corrosion protection on seatposts/clamps, metal steerer tubes, metal handlebar stem and bars, fastener threads, etc. Only freehub/freewheel inner bearings need something less viscous in most cases.

Use grease, anti-seize is reasonable for titanium frames to prevent galling or corrosion or other times when you have dissimilar metals, metals in a nasty corrosive environments or unusually high temperatures.

"frequency of removal/reinstall is a bigger factor than what is used." maddog

This!! Just like bathing with soap it's the bathing, not the soap, that counts. Andy

Did I need to state "little chance of seizing when greased"? When the previous sentence said to apply grease? Most assemblies of steel bike parts that have been abused and neglected will transmogrify into a single rusty lump before crumbling to dust, all the quicker when used in a maritime environment or an area that salts roads. There are some arid environments that corrosion proceeds at a much reduced rate, but generally the low population density of those areas means there's not much stuff there apart from antique mining equipment.

If you're like me, the bottom bracket is going to go in and stay there until it needs to be replaced, probably years after the install. Teflon plumbers tape will still be in place after years, keeping the BB and the shell from rusting together. After my first experiences with the problems rust and bottom brackets can lead to (on two bikes, about three months apart), teflon tape has been my go-to.

Anti-seize is intended for use on surfaces that typically do not move against each other when in use. So using it on BB threads will be okay. In general, anti-seize is just grease with other stuff in it. Powdered nickel, aluminum or copper typically and some other stuff.

Grease however, can serve both roles. It is good for use on surfaces that move against each other or for surfaces that don't move against each other when in use.

Except for some few dissimilar metals in certain environments, bicycles don't typically experience the extremely high temperatures. Nor are their components made from materials that are prone to galling when being threaded together as are some other things.

So grease is fine.

Grease works just fine. But anti-seize will probably last longer. I question the maintenance practices of those that need the longer life of anti-seize. This applies to Ti frames as well.

When threading a metal part into another metal part, I use whatever grease I have within arm's reach. Sometimes it's my tub of red high temp bearing grease, sometimes it's moly, sometimes it's Phil Wood waterproof grease, whatever. I've found that the parts generally don't care what the flavor is. By and large, the purpose is to prevent corrosion and galling and any generic.grease will do that.
Things get a little more interesting when you're dealing with high heat (something you won't encounter on a bicycle, think vehicle exhaust) or carbon fiber but most metals, to my knowledge, will roll with anything you slather on it.

It's all about how the bike is stored and the conditions it's ridden in.

I have a 40 year old bike that was stored indoors and ridden sparingly. When I overhauled it a few years ago, nothing was seized.

I've seen bikes in a saline environment (sea spray or smart trainer) with outrageously corroded bolts after a year or two.

Like the guy above me said, a dab of whatever you have handy. It's probably not a terrible idea to basically disassemble and reassemble your bike every few years. Back in my heyday, I'd often replace cables after a single rainy ride.

I have a tub of Marine grease I use by default and have for years. Moving parts, threads, whatever. When I assembled our titanium bikes the companies specified copper anti sieze for something. I can't remember what though. So it sometimes helps to get advice on specific applications.

When I bought my fist Ti bike, I reached out to Litespeed for recommendations and they said grease was fine. Remember that Litespeed sprung from a company with decades of Ti fabrication experience in the aerospace industry. A few years after that "everybody" was recommending anti-seize but I continued to use grease with zero issues. It's been 27 years since that original recommendation and I've never had a problem with over 250K miles on two Ti bikes.

When I got my Airborne 25 years ago, it came with a small packet of copper anti-seize. I had ordered an optional titanium seatpost, and the anti-seize was recommended for use to prevent "cold welding" of the seatpost to the frame. I've refreshed this 2 or 3 times over the years, and there's been no evidence of bonding. This is the only application for copper-based anti-seize that I've ever heard of, though I will readily admit my experience in this area is limited.

Another fan of grease. For stuff I want a race feel, Phi Wood's traditional green grease. Mariine grease for just about everything else. I love teflon on BB threads but usually only remember if I put it on that BB last time. (Teflon tape lives in my plumbing box. Doesn't announce it's presence when I'm doing bike stuff.)

My ti bikes just get grease. I use ti seatposts on those bikes so no issues there. BB cups in grease see3m t work just fine. I don't change out the BBs very often but I also haven't had any issues, so , if it works, is easy, cheap and right there on my bike bench, why not? (Bikes have 22k/14 years and18k/17. )

The reason to not use anti-seize is that it will contaminate loose bearings, and it is generally messy and stains.

The problem with Ti and aluminum is galvanic corrosion, not galling. Copper is good for anti galling, but something like magnesium anti-seize would be better protection for corrosion.

Kontact makes an important point, antiseize is not generic but formulated for different metal combinations and
attention should be paid to this aspect.
My experience with a Teledyne Titan frame built up ~1976, riden for several years and hung up when life got
complex, only to be taken apart ~2000 and the AL seat post slid right out. Probably because the frame was
anodized. OTOH the Phil BB grease had turned to wax.

Exhaust manifold studs and nuts. 😀 I use it on chainring bolts when I remember.

I really only use anti-seize for my titanium bikes everything else I use grease (usually Phil Wood). However if you leave something sitting forever and ever and ever and never touch it whatever you had put in there might not even matter unless it is some really super long life grease that can handle anything. If you install and remove stuff on occasion and clean and regrease things and torque them properly it should come out fine every time. However as others have said if you remove it and re-install with some regularity you could use whatever thread lubrication you wanted. I know Phil Wood recommends their blue colored thread locking compound.

I also use grease and teflon tape(for AL cups in steel frames) and a torque wrench. Anti-seize is a mess but works so well for threaded freewheels and certain seatposts in certain frames. Use sparingly if you do. Do wear gloves, wipe any excess with something you can dispose of pronto.