I was going to reuse the original black rubber breather, but it looked a bit perished, so went with Jules clear tubing. I also thought this would allow me to see any oil coming out as I was worried about possibly clogging the valve. Joolz said his hasn't clogged in 5 years. I might replace mine with thicker-walled tubing to prevent the current kinking. As to where it vents, because it doesn't suck, you can take your pick. I kept mine venting over the front cog and no oil has been evident, fingers crossed. Anyway, Joolz is the man to ask, so I'd wait for him.