I commute every day no matter what the weather's like. My bike has full mudguards at the front and rear and I would say the bb area never gets minging. I suspect the reason the vent holes remain rust free (if they even do) is because they are not at the lowest points and therefore not where water collects.
I commute every day no matter what the weather's like. My bike has full mudguards at the front and rear and I would say the bb area never gets minging. I suspect the reason the vent holes remain rust free (if they even do) is because they are not at the lowest points and therefore not where water collects.
The idea of a drain hole seems sound to me.