carbon “not safe” grease

So ive just seen a post on facebook from the lads at mbr mag. It seems that some greases can completly scrap your carbon frame if they come close. Im just wondering what these are?

In theory you’re supposed to use carbon assembly paste. However before that I’ve just used standard lithium grease and it’s been fine. I think the theory is that some greases can attack the epoxy, but don’t know how accurate this is.

Had a quick Goole and avoided going down that rabbit hole but I struggled to find anything definitive. Most articles seem to be about bikes, so unclear how much of it BS.

I’m not saying MBR are bullshit merchants, but they are a bit clickbaity on FB.

I have to be fastidious about it at work (mechanic). Grease/anti-seize on unprotected carbon (seat tubes, headset recesses bottom bracket seats) is a serious no no and has to be cleaned off immediately. Afraid I don’t know the exact science behind it as per the already mentioned internet rabbit hole, some grease is really bad- some seems ok.

I can tell you that for at least one manufacturer it is a big deal; use carbon paste/fibre grip etc.

Trek recommend rock n roll super coat grease for bb and headset on carbon in the manual

Specialized specify lithium grease for headset bearings etc

Some of the additives in grease can in theory cause delamination between the epoxy and the carbon. Ive never heard of any issues using bike grease, maybe if you use some of the nasty petroleum based greases from the automotive trade there might be an issue.

I think a lot of it comes from carbon seat posts saying do not grease, you need to use assembly paste because you cant wrench the post up like a metal one. Assembly paste is just grease with gritty bits in. But if you grease a carbon post you’ll need far too much torque to stop it slipping which is far more dangerous.

Trek specify grease on carbon and they’re probably the most experienced carbon bicycle manufacturer so id have no concerns.

Yea just thought it was a strange thing to say.