They are all single wall tyres, i actually had less pinches on the tyre that i got with the bike, than the one i bought from a lbs! Try getting a old inner tune, and cutting the valve off, and then sliting along the seam right around the tube, so the whole tube is open (hard to explain) then wrap it around the tube thats good, and whack it in the tyre, makes it double the thickness tube, maybe a tinybit heavier though, but hey, give some, you lose some!