IIRC regular 3 in 1 also contains citronella oil which is vegetable based and all vegetable oils will oxidize and cause varnish buildup eventually. As noted 3 in 1 Motor Oil is straight mineral oil.
I have the original documentation from SA for a NOS S5-2 Alloy hub I got recently and it specifies SA oil OR SAE 30 weight oil. Compared to a car SA hub service is easy on oil as speeds parts move at are moderate and the oil is not subjected to combustion heat or blowby contamination as it is in a car engine. Too thick an oil can cause sticky pawls in the hub supposedly, particularly in cold weather. I would expect that based on climate conditions any 10 to 30 weight automotive oil would be suitable.
__________________
Gear Hubs Owned: Rohloff disc brake, SRAM iM9 disc brake, SRAM P5 freewheel, Sachs Torpedo 3 speed freewheel, NuVinci CVT, Shimano Alfine SG S-501, Sturmey Archer S5-2 Alloy. Other: 83 Colnago Super Record, Univega Via De Oro
Visit and join the Yahoo Geared Hub Bikes group for support and links.
http://groups.yahoo.com/group/Geared_hub_bikes/
Last edited by tatfiend; 12-07-09 at 02:23 PM.
Reason: correct typo