For stiff leather (like bags) I'm wary of some conditioners. I don't want the leather to soften and sag on my bags. I rubbed some snow seal on my bags after warming them in front of the wood stove (not hot, just warm). Snow Seal is a soft sticky wax but it isn't sticky once it soaks in and dries. It doesn't soften the leather too much and ought to keep my bags from getting soaked by the rear tire spray.
Chilly
Chilly
