Originally Posted by Nessism
None if the steerer is carbon. If the steerer is steel or aluminum, you can use any type of common grease where the headset contacts the steerer but keep grease away from the clamp area where a threadless stem will grab.
Good luck.
Ed
In fact - and I don't mean to start an argument Nessim
, on a metal steerer, there is no problem with grease on the clamp area. I usually give everything in this area a smear and never had any problems. Also at the stem-bar clamp to prevent creaks. These are both potential moisture/salt traps so a little grease should help to prevent corrosion.
Raiyn is also spot on with the grease recommendation. I even "smuggled" a can of Marine grease from the USA to use on my bikes here in England. Brilliant stuff, though hard to find here in the UK, expecially in landlocked Oxfordshire...
Cheers,
Ed