Forum menu
I've just popped a new BB and crankset in my carbon road frame, and used copperslip on the threads like I do on every BB installation.
Now I've realised that the copperslip's job - stopping different metals binding - isn't really an issue on a carbon frame. But is copperslip going to do 'bad things' to my carbon frame? Should I pull the BB and re-install using grease instead?
Yours worriedly 😕
Get some carbon assembly paste.
Carbon can cause metallic corrosion in alu, as I can testify, because it can conduct. Or at least, it appears to.
So I imagine copper grease could cause trouble..
Surely your carbon frame still has a metal (normally alu) BB shell?
Does the frame have carbon threads or does it have an alloy insert?
The BB will be metal surely unless its a weird BB type? - So just use sommink - grease, copperslip etc I use grease on my CC frame BB if that helps.
Ah - I hadn't thought of that. Presumably the BB threads aren't made of carbon fibre (!!!). I will double check this evening, but looks like copperslip is the right call. Thanks everyone 🙂
Presumably the BB threads aren't made of carbon fibre
D'oh! Of course they won't be! Silly me 🙂
I too have just installed an XTR bottom bracket on my Merida carbon frame, the threads were certainly not carbon fibre! I have used copper grease and it is fine.
I wouldnt use copper slip purely on the worry that some could be squeezed out and come into contact with the epoxy resin.
Copper slip can damage polymers and rubbers so unless you know it is one safe for the epoxy then I wouldnt use it and just put some grease or other anti-seize on. I bought some of the expensive Shimano anti seize but I got the big pot as I want to use it on other stuff not just my bike. It has no metallic particles and is safe for any material and up to 1200degC (what I wanted it for).
Shimano BBs nomally come with a blob of their excellent green grease on the threads so grease is fine. Carbon assembly past would also be a no for me unless the BB was coming undone but that would be either due to a failing bearing or damaged threads so you have other problems if that is happening.
Andy - do you have a link for the degradation of polymers by copperslip as I was not aware of this till now?
But if you put a tiny bit of grease or copperslip on the start of the threads then it would not be a issue for me - I have never found any excess material in the BB if you use is on the threads sparingly?
Not for epoxy but I have 1st hand experience with rubber parts 'swelling'. I googled it and found a lot of discussion about it. Normally from motorbike riders who I find are a little bit more careful with their maintenance as their life is a little bit more at risk and they are more likely to do DIY and check regularly.
This is why you get a little tube of special grease with rear drum brake kits - the wheel cylinder seals tend to go a bit gooey with the copper grease I have.
Maybe some are okay? Simply depends on the grease component used and whether it damages epoxy which is after all different to rubber. Personally I just avoided the problem completely when building my carbon bike by using some normal bike grease known to be polymer safe.
epoxy != rubber