Following a hawthorn puncture through my 29" EMTB Marathon Plus tyre (on the centre line!) I opted for a belt-and-braces Schwalbe SV19+AP heavy duty inner tube, 70% more butyl, from Tredz (great service by the way). Massive tube. The weight isn't really an issue and I haven't noticed any ride penalty during my pottering but the bulk was a handicap when replacing the tyre. Pic shows the AP tube with a "standard" Schwalbe. Never again.
