I’m not going to say much about changing oil in an IGH other than to say that lubricants in a bicycle application will probably last until the sun goes cold because the stresses put on them are so small. You need to change oil in internal combustion engines because the lubricant is subjected to extreme conditions. Bicycles don’t experience that.
Originally Posted by
Broctoon
I believe I've also read from Sheldon Brown that bringing an IGH inside from the cold is not such a good practice. When the hub gets cold outside and then comes in and quickly warms up, moisture can condense inside it. If there's a secure, dry place to leave it outside in the cold, that might be better for it in the long term.
This, however, chaps my hide. It’s just straight up wrong. If you want to test it, put a cup of hot tea next to a glass of iced tea and see which one causes condensation. You
might have some condensation if you are taking a warm bike into the cold but even that is a stretch. Warm air from a heated house doesn’t have much water in it during the winter...cold air can’t carry much water and heating it doesn’t add water to it. Taking a warm bike out into the cold does lower the amount of water that the air can carry but that just brings it back down to the level of the water in the cold air. No condensation should occur.
Even if it could possibly happen, the amount of moisture is tiny and the volume of air it could condense from is also tiny. At 20°C (78°F), fully saturated air has 0.0017g of water in every cubic meter. That almost 2
milligrams of water in a 1 m cube. There are a million mL in a cubic meter. There are about 100 mL in a IGH hub. If the hub shell were completely empty, that a grand total of 2 one millionth of a gram. It’s not even a “drop” of water. It’s barely a “hint” of water.*
To put it another way, to get to a gram of water, you’d have to take the bike in and out of the house 500,000 times.
*I usually give the US equivalents for this kind of discussion but we have no easily used way of measuring that small a volume. A US teaspoon has almost 5 mL in it or 2.5 million times the volume.