Hi all. I'm a heavy rider - 275 lbs - starting up again. I have a Jamis Exile, maybe an 05. I'm relatively new to this, and I have a small problem. I've got standard, mountain bike tires, and I've been thinking about replacing them with a more general purpose tire, as I'm doing much more street riding.
My problem is that when I sit on the bike, the rear tire flattens out. Now, I'm not sure if this is because of the pressure in the tire (could be down), or my weight (more likely). And when it gets this flat, I just don't feel safe on it.
Any ideas on what I should do? Thanks!