Originally Posted by
JanMM
How are the inner surfaces of your rims?
How are your rim strips?
Is the hole in the tube always in the same place?
How is your installation technique?
Haven't found anything sticking through on the inside of the tire?
Marathons are not known to be delicate tires.
If these questions don't lead to an answer you might take some time to view this installation video. When ever I think Schwalbe Marathon I wince at the thought of mounting them without ruining the tube. The video helped me, perhaps you'll find it not only entertaining but also helpful.
http://thelazyrando.wordpress.com/20...-to-fit-tires/