Yo Sludge Packer.
I roll with Schwalbe Marathon Plus.
They're wide and I use a 25c which is more like a 28.
If they fit yo frame 28's are sweet.
Try spacycles
http://www.spacycles.co.uk/products....Marathon_Plus_
or they do a 2 x tyre x tubes offer here:
http://www.discountcyclesdirect.co.u...9dd4ce56f05fcd
x