I've got a Specialized Pave carbon seatpost that I'm thinking of putting on a mountain bike – because I'm getting a new frame and don't want to fork out for a new one and this one will fit
whilst I don't move the seat up and down that much, I might do it every now and then
will this cause any problems, apart from some cosmetic scratching?
can I put any special grease on that will reduce this?

carbon grease, but then constantly moving it wil cause it to score after time

You'll need to use carbon paste, but it's really not a good idea to be moving it too much as you'll soon wear off the surface layer.

Scratches is going to be the big problem really, but it's mostly just cosmetic. Received wisdom says carbon for not moving metal for moving, but I've never had it properly or adequately explained

druidh, the surface layer of what? the lacquer? surely that'll take a while.
post might be moved once or twice a ride so not that much really.

Friend has a race face carbon seat post. Moving it up and down. It's ok so far.

bakes – Member
druidh, the surface layer of what? the lacquer? surely that'll take a while.

Much will depend on how well the seat tube has been reamed.

I've been using a Raceface Next carbon post for ages, constantly moving up and down often while plastered in mud. It looks a bit rough- and it picked up some scratches from a tiny burr in a seattube- but other than the cosmetics it's still absolutely fine. It IS wearing down, just not at a rate that concerns me at all, bike stuff is for using after all.

yeah, main concern is that it will be shared with my road bike
so whilst I don't want it to look perfect, I don't want it to look too tatty
.
I'll see if there are any Thomsons going on the classifieds