I don't have any experience with the wheeled carry-ons, but the material (Oxford weave nylon) for their foldable Boston Bag, Boston Tote and backpack is not water resistant nor colourfast when saturated.
I have not saturated the bag with water, but I did put some weather proofing spray on it to help water bead up.
http://www.grangers.co.uk/product.cf...12&productid=6 My bag is grey and waterproofing helps it clean off more easily.
To the OP - Are you looking for a spinner for frequent carry on travel? As much as I like the Bellows CO, I'd probably double my luggage budget if I was looking for a spinner which can survive a road warrior's life style. It is a nice case but the materials make it a "leisure use" bag. It is light and well priced, kind of like some compact cars.