I've got a stock GF Marlin and I'm looking to drastically reduce the flats I'm getting. I ride on very rocky mostly flat trails and the tires go flat AFTER each ride. There are thorns and cactus along the trail which I'm sure contribute to the problem. I weigh 190 and ride at 40psi. I'm not a serious rider, but I demand my equiipment to work. Is there a tube out there that is less prone to puncturing?--I assume that is the main problem since I've seen the ends of a few thorns on the inside of the tires when I'm changing tubes. The stock tires are Bontrager and I'm wondering if it might also be an advantage to get different tires as well. I do occasionally ride on the street so I would need to strike a balance if I get new tires. Thanks for the help!