I am starting a tour on Monday on this Brompton folding bike with the Brompton bag on the front and standard hiking backpack rigged to the rear with bungee cords. This setup works except that I don't have a rain cover for the backpack. I was going to use trash bags but that will get expensive and seems wasteful, and I can't justify spending $30 on a simple rain cover.
Any suggestions for waterproofing my bag?
[And since someone will ask ... I almost bought a used set of Ortlieb front panniers which would have fit on my rear rack, but the backpack works better because I can wear it when my bike is folded.]
Pretty sure REI sells covers....give them a holler.
You could possibly make a simple cover from a rain slicker/poncho from your local thrift store.
Garbage bags are expensive? BROMPTONS are expensive! garbage bags are cheap. Try the dollar store for kitchen trash size, they look like would fit, or go all out and get 20 heavy duty GLAD bags for $5. How long is your tour for?
Try a spray on. It's called NIKWAX. My friends have used it and said it works great and very well priced. nikwax.com. My friends swear by it. Hope this helps.
I use tall kitchen tash bags. Hardly expensive.