I'm going to replace the old steel and chrome quill stem on my steel framed MTB with a new aluminum one. What grease or other coating can I put on the stem to stop it reacting with the steel headset tube and seizing in place?
Many thanks for any help and advice.
Why would aluminium suffer galvanic corrosion with a non stainless steel grade frame?
It's only when metals differ alot in nobility (so higher voltage).
And how could it lead to seizing in place?
It's the opposite, the aluminium gets dissolved - things come lose. Byebye screwthread etc. You can see white powder in place.
An example of galvanic corrosion is between an inner tube valve and an aluminium rim.
You see a little bit white powder around the valve basis, that means the hole in the rim got abit wider.
But it's not worse / acceptable, because once the hole got wider, contact is less or nothing, and without contact, no electrical current, and no corrosion. Also, the amount aluminium is way bigger than the amount stainless, so the current has more "conducting material " to pass through / no concentration. The opposite, an aluminium screw in a stainless plate, wouldn't last long.